Maintenance Alerts
| Title | Summary | Applicable Makes |
| Piper: PA28-235; Cracked Rudder Bar Support; ATA 2720 (June 2011) | An Aviation Inspector says, "(This support assembly...) should have AN960 washers under the four AN3-4L bolts to spread the load on the (support) assembly (P/N 63451-00). There are no washers shown in the parts list." |
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| Cessna: 551: Cracked Seat Base Assembly; ATA 2510 (June 2011) | A repair station provides this brief defect report concerning a seat frame. "The upper seat base assembly is cracked at the chair back attach points. (I speculate) stress on the chair back and metal fatigue as the probable cause. A previous, inappropriate repair (has been observed on this frame). This chair was repaired in accordance with AvFab STC STO1043WI, P/N 42-0312K, and drawing D-10394, Revision 'A'." (Seat assembly P/N: 5519015-16; Seat base P/N: 5519009-22. The Alerts profiled these seats four separate times in 2005: reference July, September, November, and December—all with attached photos. The SDRS database reflects eleven of the -22 part numbers.) |
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| Cessna: 340; Chafed Oil Pressure Tube; ATA 7931 (June 2011) | "I ran the (TSIO 520) engine to check the magneto drop," says this A&P mechanic. "(Subsequently), engine oil was observed dripping out of the port side wing root. I removed the inspection plates and found the ¼ inch aluminum tubing (P/N 5600107-11) routed over the top of the three inch SCAT (flexible air tubing). The wire in the SCAT tubing chafed a hole in this ¼ inch aluminum oil pressure line that runs from the engine to the cockpit. The starboard line was also routed the same way—(it too) was rerouted to prevent chafing." |
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| Beechcraft: 58; Cracked Flap Nose Rib; ATA 5753 (June 2011) | The previous report's repair station technician again describes a cracked nose rib for a different airplane. "During an inspection (prior to purchase) the left flap nose rib was found cracked through the leading edge relief cut out in the upper flange bend radius. (It continued) through the actuator attach bracket nut plate rivet holes. This is a very difficult area to access and inspect. The addition of a small opening in the bottom flap skin would be advisable for inspecting this area. (I) suspect this (rib crack) is caused by flaps being extended at higher than designed airspeeds, or incorrect up-stop bumper rigging. My research (found) no Beech service information addressing this common failure item." (L/H Flap P/N: 35-165050-78; Nose Rib P/N: 35-165050-84: the same P/N as previous entry.) |
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Beechcraft/ Hawker Beechcraft
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| Beechcraft: A36; Cracked Flap Nose Rib; ATA 5753 (June 2011) | "During an Annual Inspection," says this repair station technician, "one nose rib was found cracked in the right flap. It is the rib located directly beneath the attach bracket mounted on the skin." (R/H flap P/N: 35-165050-79; nose rib P/N: 35-165050-84. The SDRS database reflects 17 of these ribs.) |
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Beechcraft/ Hawker Beechcraft
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| Piper: PA28-140; Wing Spar Corrosion; ATA 5711 (May 2011) | "Corrosion (has been found) on the right wing spar aft side," says an unidentified technician, "at wing station 59-61 (and) the fuel tank flexible access." (Wing spar P/N: 6207001.) |
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| Piper: PA24-260; Cracked Rudder Hinge Castings; ATA 5540 (May 2011) | A mechanic writes, "The top rudder hinge casting is cracked at the roller bearing location." (Displayed drawing and P/N for the 24-260: 20707-02. P/N for the 24-400: 20707-06; drawing is similar. A parts list might have resolved the mystery why the photo shows P/N 20707-8! However, the location and problem is quite clear; thanks—Ed.) |
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| Diamond: DA40; Cracked Heat Exchanger Exhaust; ATA 2140 (May 2011) | An unidentified writer says, "In accordance with Power Flow System's 'Continued Airworthiness Instructions' (dated 7/22/2008), paragraph 7.0 states, 'The exhaust system must be thoroughly inspected, especially within the heat exchanger section...'. During a 100 hour inspection of this airplane a crack was found in the chain weld at the exhaust exit ball and the heat exchanger cover. The cracks start at the finish point of the weld and continue through the center of the weld—to the start point of the weld segment. Paragraph 5.4.1 'Maximizing Service Life' states, 'Dynamically balance your propeller to below 0.2 ips (inch per second) every two years or 1000 hours (whichever occurs first).' This aircraft was manufactured in 2009 and has 398.6 hours since new." (Heat exchanger P/N: 41303; Exhaust assembly component number: PFS15102.) |
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| Cessna: P206E; Cracked Bulkhead; ATA 5312 (May 2011) | A technician states, "During inspection per AD72-07-09 (10/17/1974) and Service Letter SE72-3, the aft bulkhead (P/N 1212858-2) was found cracked in both rudder cable cut outs. Upon removal of the aft bulkhead, the left and right stabilizer attach brackets (P/N's 0712629-3 and -4) were also found cracked." |
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| Cessna: 177RG; Failed Nose Landing Gear; ATA 3230 (May 2011) | This submitter says, "The nose landing gear failed to extend when the gear was lowered for landing—a nose gear 'up' landing (followed). Examination revealed the up lock bell crank forward arm (that activates and disengages the up lock roller from the up lock hook) was found bent—and 90 per cent cracked (through). It would not allow the up lock to disengage. (The engine/nose gear mount was also found warped out of alignment—this was removed and repaired by a repair station. The probable cause: severe side loading during landing at an unknown time.) |
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| Piper: PA28-161; Carburetor Heat Valve Shaft Damage; ATA 7160 (April 2011) | "Both grommets (failed) and damaged the carburetor heat valve shaft," states this mechanic. These Teflon bushings (became) worn out in approximately 2,000 hours of operation and (subsequently) damaged the pivot shaft. This aircraft was manufactured in 2008." |
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| Fairchild: SA227AC; Cracked Hydraulic Accumulator; ATA 2911 (April 2011) | An A&P mechanic says, "During a Lima-Huánuco flight this aircraft (developed) a hydraulic leak from a cracked accumulator (P/N 22300-2). The aircraft returned to Lima and performed emergency (landing) procedures without any problem.
"This hydraulic accumulator is an 'on-condition' component; (the cause of the crack) unknown. We are investigating this problem."
"For preventative maintenance, (we have) accomplished inspections of all the hydraulic accumulators and hydraulic lines in the fleet for hidden damage." |
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Fairchild Dornier/Fairchild (Swearingen)
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| Diamond: DA42; Unsecured Nose Landing Gear Pin; ATA 3233 (April 2011) | "During a routine annual inspection," says this writer, "the technician noticed the aft nose landing gear actuator attach pin (P/N D60-3223-00-33) had migrated to the right. Approximately one-half inch of the retaining pin had come loose (P/N DIN471-10-ZP) and fallen from the assembly, leaving the pin unsecured. This clip (retaining ring) is item number 030 for figure 32-30 'hydraulic actuator'." |
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| Beechcraft: 58P; Failed Nose Gear Drag Leg; ATA 3230 (April 2011) | An FAA inspector says, "(This aircraft) landed with the nose landing gear in the unlocked position. The pilot reported on take off the aircraft had a severe vibration at (approximately) 85 knots. He continued the flight, (allowing) a second aircraft to verify the nose landing gear was 'flopping around'. The pilot burned off fuel, and then landed with crash response at the airport. The aircraft nose settled upon landing, remaining on runway center. Damage was minor. The nose landing gear drag leg assembly had failed at the top end of the casting (P/N 002-820017-1). The metal broke apart—with indications it had been cracked for some time. This (area) cannot be inspected with the part on the aircraft." |
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Beechcraft/ Hawker Beechcraft
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| Velocity SRG; Nose Gear Failure; ATA 3231 (April 2011) | An unknown submitter states, "The left nose gear door would not open to let the nose gear come down. After landing with the nose gear up, (I) found that the linkage had come off in flight and jammed the door closed. After removing an inspection cover, I was able to free the linkage and drop the nose gear while a fireman held the (aircraft) nose up. An online (search) found a recommendation to modify the doors so they spring open if the linkage failed. Minimum damage (occurred to this experimental aircraft) , and was limited to the nose gear door area." |
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| Piper: PA28-180; Failed Landing Gear Strut; 3213 (March 2011) | A general aviation report states, "The right main landing gear lower strut fell off when the aircraft lifted off the runway at (the airport). The student pilot flew to (his destination) and landed, resulting in damage to the upper landing gear strut (P/N: 6531904). When the lower strut departed (from the) upper housing, it struck and damaged the flap skin.
"The right main landing gear upper torque link mounting ears broke off the cylinder, allowing the lower gear leg to fall out of the upper cylinder and depart the aircraft. This cast aluminum cylinder is original since 1972. The inboard ear appears to have been partially broken for some time. Once it broke all the way, the outboard ear could not support the twisting forces applied during normal turns, taxi, and torque during takeoff. I feel this led to the outboard ear breaking off, and on takeoff, the gear left the aircraft. This upper torque link attach point is covered with a fairing, preventing the pilot from seeing any defects during preflight." (The SDRS database reflects this part number 22 times.) |
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| Gulfstream: G200; Burned Lavatory Electrical Connector; ATA 3897 (March 2011) | An electrical technician states, "While troubleshooting the flight phone (I) found the lavatory plug (number) 548 P2 showing signs of discoloration and overheat. I capped and stowed the wires for plug 548 P2 IAW WDM 20-00-00. I collared (blocked) the circuit breakers for the lavatory water heater, the ribbon heater, the water system control, and the toilet—and verified no power at plugs 548 P2 and J2." |
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| Cessna: 172S; Loosened Seat Lock Attach Screws; ATA 2510 (March 2011) | A writer says, "During a training flight the student pilot reported his seat would not lock into position. The aircraft returned to base without incident. Upon troubleshooting the problem a maintenance technician found the attachment screws of the left and right seat stop pins had backed out, allowing them to be detached and ineffective. A check of the other aircraft in the fleet found six (additional) aircraft (having) loose attachment screws (P/N MS35207256). All loose screws were removed, inspected, and reinstalled with Loctite 242 as per the manufacturer's suggestion." (Component name, P/N, and manufacturer: Seat Latch Assembly; SPL19251; Birk Aerosystem.) |
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| Beech: 58; Burned Landing Light Circuit Breaker Switch; ATA 3340 (March 2011) | "The pilot reported a burning smell in the cabin," says this submitter. "An inspection revealed the taxi light circuit breaker switch to have an unusual feel. Following replacement of the switch, the failed switch was disassembled and found to have burned internal components. This switch (P/N 35-380132-105) is the improved model that was required by AD2008-13-07 which was modified to prevent the burning situation in the failure mode. This was accomplished by installing two insulator pads at the actuator spring to prevent current from flowing through the spring when the wire braid fails. Unfortunately, when these switches overheat, it is difficult to impossible to determine if the insulators had been installed improperly, or installed at all. This is the second post AD switch in our fleet that has failed and overheated." |
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Beechcraft/ Hawker Beechcraft
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| Piper: PA23-250; Corroded Elevator Trim Arm; ATA 2731 (February 2011) | A repair station technician states, "The elevator trim arm assembly (P/N 15618-05) is corroded to the point of having a 3/16 inch hole through both sides of the aft end of the tube." |
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| Embraer: 145; Sheared Landing Gear Axle; ATA 3213 (February 2011) | "This event occurred late in the evening," says a quality manager, "during disassembly of the landing gear at overhaul. While accomplishing the un-torque check IAW SP145-32-0097, the nut fell off the subject axle as torque was applied to the upper attach axle (P/N 23092029001). The axle had sheared at the point where the threads entered the nut. The operator was informed of the defect by phone and e-mail, (and provided this defective) axle." |
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| Diamond: DA42; Broken Pedal Pivot Tubes; ATA 2720 (February 2011) | A flight school submission states, "During preflight, the flight crew noticed the rudder pedals were no longer symmetrical, compared to each other. A maintenance technician inspected the co-pilot's L/H pedal (P/N DA4-2723-35-00) and noticed the vertical web connecting the pedal to the brake master cylinder rod had torn at the welded intersection of the tube. The tear/crack in the horizontal pedal pivot tube indicates a torsion failure of that tube." |
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| Cessna: 208; Cracked Horizontal Stabilizer Spar; ATA 5511 (February 2011) | "During a phase 10 inspection of a Cessna 208 (on floats), maintenance personnel discovered multiple cracks in the center section spar of the horizontal stabilizer (P/N 26300038). Several ribs were also found wrinkled and distorted, and a straight-edge confirmed deformation of the stabilizer's top surface.
Removal of this stabilizer revealed extensive damage to the center spar web, rendering it unairworthy. Subsequent investigation determined the damage was caused by cleaning personnel using this critical flight surface as a work platform during cleaning of the tail area.
Inspection of this operator's remaining fleet of aircraft found no other problems. The stabilizer was repaired and reinstalled. No Step placards were fixed on all subject aircraft in the effected areas. The total cost of this repair exceeded $17,000.00—not including down-time of the aircraft. Operators should be vigilant for those ground operations that can cause aircraft damage—cleaning activity is but one example. Proper training and adequate support equipment (proper stands) are critical elements for elimination of this kind of safety hazard and economic waste." |
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| Cessna: 177RG; Power Cable Short; ATA 2497 (February 2011) | A technician writes, "(I) found an improperly sized (too long) interior trim replacement screw installed in the pilot side lower door sill opening, shorting into the Main Power Cable (P/N W-PA4). The pilot (had) complained of intermittent panel lighting/flickering, and recent regulator replacement (twice) and alternator/charging issues." |
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| Beechcraft: 58; Cracked Spar Web; ATA 5711 (February 2011) | "A Beechcraft Barron 58...was in for a routine maintenance inspection at the operator's home facility," says this technician. "During the Annual Inspection a crack in the right forward spar web bend radius (forward side) was noticed during a visual inspection of the area. A dye penetrant inspection was performed and the crack was verified. The inspection was performed following the Hawker Beechcraft Corporation Barron 55 and 58 Maintenance Manual: P/N 55-590000-13G, Rev. G2, dated October 1, 2010; Section 53-00-00, page 202; B(1) 'Wing Forward Spar Carry-through Structure Inspection—Without Repair Kit'. The aircraft was then flown to our facility for verification of the crack and the installation of Hawker Beechcraft Corp. Kit P/N 58-4008-9 (which is applicable to this aircraft serial number TH-1990). It should be noted AD90-08-14 'Wing Spar Structure'—and Beechcraft MSB2269 Rev. 1 'Fuselage: Wing Forward Spar Carry-Through Structure Inspection and/or Reinforcement' are not applicable to this aircraft by serial number. The crack was found in the area referenced in both the AD and MSB, but 'stop' applicability for this aircraft model 58 was at serial number TH-1475. The Hawker Beechcraft Corp. Kit P/N 58-4008-9 was installed on both the right and left forward spar, forward web structure in accordance with Beech Aircraft Corporation Kit Information—Reinforcement Installation Instructions, Drawing number 58-4009 and Kit Information Drawing number 58-4008, Revision C."
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Beechcraft/ Hawker Beechcraft
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| Beechcraft: M35; Cracked Flap (Leading Edge); ATA 5753 (February 2011) | "(I) performed an inspection," says this repair station submitter, "according to Hawker Beechcraft Safety Communiqué number 313/FAA SAIB CE-11-21. The R/H flap leading edge was found cracked (approx. 1.50 inches) in the vicinity of the 'flap actuator bracket'. The nose rib was also cracked. This flap (P/N: 35165050606) was removed for repairs." |
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Beechcraft/ Hawker Beechcraft
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| Beechcraft: E18S; Broken Elevator Cable; ATA 2730 (February 2011) |
Inspector Anderson states, “This report concerns an operational check flight after an Annual inspection. After takeoff, the pilot heard a “snap” and the aircraft pitched up. The pilot realized he had lost down elevator. Control of the aircraft was regained by the use of power reduction, help from the passenger in the right hand seat, and elevator trim. The aircraft returned for a successful high speed wheel landing.
"The cable appears to be galvanized steel and was completely covered with Paralketone. The break was at the pulley above the tail wheel, at bulkhead number 14. The pulley was free to rotate, however, it did show signs of wear—possibly from over tensioning of the cable. After removal of the cable from the aircraft, further inspection revealed broken strands in the area of its attachment to the elevator control bull wheel (reference the attached figure). Note the total time on the elevator cable (P/N 414-187097-1) is unknown." |
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Beechcraft/ Hawker Beechcraft
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| Piper: PA46-350P; Fractured L/H Side Pilot's Window; ATA 5610 (January 2011) | "The pilot leveled off around 15,000 feet," says this technician. "The left side, cockpit window fractured and the center part departed the aircraft, removing the pilot's headset in (the same process). Piper SB1175A pertains to cracking at the lower aft rear corner of the storm window. That area of the window remained in tact. A new window (P/N 82282-022) without the storm window was installed." |
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| Piper: PA31-350; Failed Fuel Cell; ATA 2810 (January 2011) | A mechanic states, "A fuel cell seam failed while the aircraft was parked on the ramp. (It) suddenly emptied its contents. There were no prior indications of improper installation or other damage. The bulk of the fuel followed the main spar into the belly of the aircraft, then out through drain holes, vents, and seams in the skin." (Floats and Fuel Cells P/N: 5712.) |
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| Piper: PA28R-201; Cracked Rudder Horn Weld Assembly; ATA 5541 (January 2011) | (The following combines two identical reports on the same type but different N-numbered aircraft.)
"The inner portion of rudder horn tube (P/N 63547-000) cracked at weld assembly (P/N 63546-000) on the underside of the weld bead," reports this submitter. "The area in question exhibited signs of excessive weld penetration along with projecting globules. The probable cause of the crack occurrence is weakening of metal from improper welding techniques. To prevent reoccurrence the manufacturer should re-examine the heat range requirement in order to gain proper depth of weld penetration, insuring fission of base metal and filler rod." |
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| Hawker: 850XP; Malfunctioning Hyd. Non-Return Valve; ATA 2910 (January 2011) | A repair station technician writes, "The aircraft departed after routine maintenance. Upon opening the main air valves (MAV's) the pilots noticed smoke in the cabin. They declared an emergency and returned to the airport. An investigation found hydraulic fluid in the bleed air ducting. During servicing, hydraulic fluid bypassed the non-return valve in the R/H pipe connecting the hydraulic reservoir to the bleed air supply that provides head pressure to the hydraulic system. During subsequent ground runs no smoke was noted. The aircraft was returned to service. (While) sitting overnight, the hydraulic fluid migrated into the bleed air system. When the MAV's were opened after departure, hot air was allowed to contact the hydraulic fluid and produce smoke—(which then) transferred to the cabin. "All contaminated components were cleaned and reinstalled. The malfunctioning valve was replaced. (Additionally), a servicing non-return valve on the reservoir was (also) replaced. The aircraft was returned to service, departing without further incident." (No P/N's accompanied this report.) |
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Hawker Beechcraft/ Hawker
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| Bombardier; CL600-2412; Cracked Fuselage Frame; ATA 5311 (January 2011) | A repair station submitter says, "The forward fuselage frame at station 235 above the pilot's and copilot's floor was found cracked during a 240-month inspection. Refer to the attached picture." |
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Bombardier Learjet/Canadair
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| Boeing: 777; Improper Service of Evacuation Slide; ATA 2565 (January 2011) | An unidentified submitter states, "During a preliminary inspection of the evacuation ramp/slide the following discrepancies were noted:
1) The main pack cover was installed backwards.
2) The proper pack contour (dimensions) were not achieved.
3) The slide pack release cables were incorrectly routed.
4) Roughly 80 % of the corrosion resistant coatings were missing from the aluminum Release Rod Assembly.
5) A length of round black cord was discovered wrapped around the inflatable inside the slide pack. This black cord was drawn tight around the inflatable folds and securely tied off. It is believed the black cord was used as a folding aid during slide packing.
"With these conditions present, it is not likely this Evacuation Ramp/Slide would have been able to function as designed in the event of an emergency." (Goodrich Component P/N: 5A31092.) |
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| Fairchild: SA227-DC; Cracked Spar Web; ATA 5711 (December 2010) | "During an NDT (non-destructive testing) inspection," says this air carrier submitter, "a crack was visually identified at stringer number 14 on the wing spar shear web. Photos of the defect have been provided. (We) are currently in contact (with the manufacturer) for a repair disposition." |
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Fairchild Dornier/Fairchild (Swearingen)
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| Cessna: 510; Loose Aileron Trim Actuator; ATA 2711 (December 2010) | A quality manager for a repair station says, "During maintenance on (this aircraft) and while carrying out Mustang SB510-27-01 (service bulletin), a loud rattle was noticed from inside the LH aileron prior to refit. The noise sounded like multiple loose items toward the inboard end of the aileron. On removal of the aileron trim actuator access panel (532EB), it was discovered that the noise was being caused by two AN3-3A bolts and matching washers (P/N NAS1149F0363P) inside the compartment where the trim actuator is located. Further investigation revealed the two bolts had fallen out of the aileron trim actuator mounting points and had dropped inside the aileron. The two remaining bolts which secure the actuator in position were very loose—(these) also in process of falling out." |
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| Cessna: 182T; Cracked Firewall Doubler; ATA 5412 (December 2010) | "A crack was discovered in a firewall doubler (forward side)," says this submitter. "The crack is located behind the right hand 'cowl exit ramp' (P/N 0752732-2; see manufacturer's IPC 53-10-00, revision 19; item 241). The longest section of the crack is six inches. There is also a secondary crack (3/4 inch long) radiating out from the rivet hole at the center of the six inch crack. Another small crack (3/4 inch) was found just outboard of the 6 inch crack during rivet removal (in preparation for repair). This area is very difficult to inspect with the lower cowling removed on a P2 (100 hour inspection) or P3 (Annual inspection)—but it is accessible. There was (also) substantial dirt and oil build-up in the area behind the cowl exit ramp, making the area harder to inspect."
(Doubler P/N: 075360024. The SDRS database provides four examples of this crack. See also the next report.)
A few days pass when the above submitter again writes, "A 1.5 inch long crack was discovered in a doubler on the forward side of the firewall. The crack location can be found by locating the 'bracket-parking brake control' aft of the firewall (see Cessna 182T IPC Revision 19, Chapter 32-32-02, figure 01, item 38; P/N 0713070-20). Translate this location to the forward side of the firewall. The crack was centered around the top rivet attaching the 'bracket-parking brake control' to the firewall and firewall doubler. "When the parking brake handle is pulled, this area of the firewall and firewall doubler flex a little. It is very probable this flexing action has caused the crack in the firewall doubler. Two small dents can be seen in the firewall from the 'bracket-parking brake control'." (Doubler P/N: 075360024. See last month's Alerts for another of these cracked doublers.) |
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| Cessna: 182R; Failed Fuel Injection Intake Tube; ATA 3710 (December 2010) | "A significant problem occurred in the fuel induction system," says this aircraft owner, "where a rubber intake tube connects the intake manifold to the fuel induction rail. Shortly after a flight where an entirely normal operation was experienced, engine restart could not be accomplished. The rubber tube was found to be fully separated from the intake manifold, causing a large vacuum leak (downstream of the carburetor) and rendering the engine inoperable.
"The probable cause is incorrect installation of the rubber tube at engine overhaul, 262 hours previously. The failed connection was between the Y-shaped intake manifold and the fuel rail on the right side. This could result from 1) failing to force the rubber tube far enough onto the manifold tube, or 2) failing to seat the hose clamp far enough (in) from the end of the manifold tube. (Another) possible cause is the clamp or hose worked loose in normal operation.
"To prevent recurrence, I suggest the following:
a) The rubber connecting tube on the intake manifold must be installed to achieve maximum depth on both the intake manifold and fuel rail.
b) The clamp position is critical to maintain the position of the rubber tube on the manifold, since there is no enlargement bead at the end of the manifold tube.
c) Use correct torque on clamps and consider safety wire to prevent loosening.
d) Consider preparation of the surface; (for example), removing paint and lubricants at assembly time.
"The consequences of this failure would have been much more serious if the separation had occurred in flight—causing a complete power loss." |
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| Boeing: 747-409; Arcing Lamp Holders; ATA 3320 (December 2010) | A foreign repair station submitter writes, "The cabin log records the first class galley, number one work light as 'inoperative'. (We) removed this light and found the light assembly lamp holders had arced. The galley ceiling was checked (for water leakage)—none was found. This light assembly was replaced." |
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| Beech: 95B-55; Corroded Fuel Pressure Line; ATA 2820 (December 2010) | A general aviation submission states, "I was (motivated) to access and closely inspect the right fuel-flow, pressure gauge line where it crosses the CEET type defrost duct because it looked like they may be contacting each other. I was concerned about chafing or corrosion. The upper right side area behind the instrument panel is very difficult to inspect. It is not accessible from above, or at arm's length from below. The line crosses above the duct. (I) almost gave up inspecting (this area) closely, but ultimately I found extensive corrosion at the point of contact. After the line was removed, slight bending pressure cracked the area wide open and it was seen that the corrosion had actually penetrated to the inside of the line, yet the line was not leaking up to this point (in time). If a leak started, the only way to stop it would be to shut down the right engine. I strongly recommend careful, intense inspection of the lines in the vicinity of any CAT or CEET type duct—(these) are notorious for causing corrosion or chafing. This particular instance is, of course, model specific (and is sufficiently serious) to demand attention. This (particular) aircraft has very little corrosion overall, (but this fuel line defect) was definitely caused by the ducting." |
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Beechcraft/ Hawker Beechcraft
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| Cessna: 441; Failed Hydraulic Tube Line; ATA 2910 (November 2010) | "Three (events) of hydraulic fluid depletion have occurred on three of the Cessna 400 series aircraft that this company operates," says a mechanic. "Two were flap failures (as in failure to extend)—and on one the landing gear had to be extended using the emergency system. These failures were caused by a crack (and leak) forming in a 3/8 aluminum alloy hydraulic line at (various) bend radii.
"I would like to note: 1) the cracks formed at bends (just barely meeting) industry minimum recommended radii for 3/8 inch tubing, 2) these cracks formed at what looks to me as minor tool die marks or stressed areas in the bend radii.
"I do recommend all operators of a 400 series Cessna aircraft have all the hydraulic lines inspected, (including) removing the paint at any bend radii on 3/8 inch hydraulic lines—(inspecting) for tooling die and stress marks. Any line that appears to be under the minimum bend radius (standard) should be replaced." (No specific part numbers were provided. Three airplanes, three cracks—check. But this airplane has a cracked line...where? Ed.) |
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| Cessna: 208; Broken Nose Landing Gear Spring; ATA 3222 (November 2010) | (The Wichita Aircraft Certification Office provides the following safety admonition. Aerospace Engineer Gary Park narrates the discussion; contact information follows the article.)
The FAA Wichita ACO received a Cessna 208 broken nose landing gear spring (P/N 2643062-3) shown in Photo 1. Installed on the airplane in December 2004, this NLG spring fractured during a landing in Puerto Rico in May 2010. It had nearly 3,000 flight hours. The fracture was analyzed and the following conclusions were identified: (1) Significant corrosion in the area of the fracture origin was present at the outside diameter of the NLG spring with pit depths slightly exceeding 0.02 inches; (2) stress-corrosion cracking was observed to a depth of nearly 0.02 inches, followed by ductile overload.
The schematic in Figure 1 shows the location of the fracture relative to the Support Assembly (P/N 2643099-4). Photo 2 is a magnified view showing the chevron pattern indicating the origin of the fracture at the lower outside diameter of the NLG spring. Photo 3 presents a tilted magnified view showing pitting corrosion along the outside diameter that coincides with the origin of the facture. Photo 4 depicts a longitudinal metallographic cross-section through the origin of the fracture showing the corrosion pitting.
November 2010 AC 43-16A
Page 7
The Corrosion Prevention and Control Inspections found in the Cessna Maintenance Manual (5-30-01 &-02) require reoccurring visual inspections of the NLG for evidence of corrosion. The inspection information from the manual for mild or moderate corrosion (airplanes without TKS anti-ice system) is shown in the Table 1. For severe corrosion (airplanes with TKS anti-ice system), divide the inspection intervals in this table by two. |
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| Cessna: 182S; Cracked Firewall Doubler; ATA 5412 (November 2010) | "A 1.25 inch long crack was discovered in the firewall forward doubler (P/N 0753600-24)," says this technician. "The crack location can be found by locating the 'Bracket-Parking Brake Control' aft of the firewall. (See Cessna 182S IPC Revision 19, Chapter 32-32-02; figure 01, item #38; P/N 0713070-20.) Translate this location to the forward side of the firewall. The crack was centered around the top rivet attaching the 'Bracket-Parking Brake Control' to the firewall and firewall doubler.
"When the parking brake handle is pulled, this area of the firewall and firewall doubler flex a little. It is very probable this flexing action has caused this crack in the firewall doubler. Two small dents can be seen in the firewall from the 'Bracket-Parking Brake Control." |
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| Cessna: 172S; Failed Ignition Switch; ATA 7430 (November 2010) | A submitter states, "The ACS/Gerdes ignition switch (on this aircraft) has never been inspected in accordance with Cessna SEB91-5R1 (bulletin) to comply with Airworthiness Directive 93-05-06. Upon disassembly of the switch, the circuit board plate was found to be severely worn, and one contact point was burned. (This) contact cup was burned completely through, creating a hole in the contact point. The screw heads holding the body of the switch to the terminal board assembly were painted red—as required by SEB91-5R1 and as described by identification of a factory new switch. However, there was no visible grease on the cups or the circuit board. Discussions with other mechanics and inspectors (causes) me to believe this AD is overlooked due in part to mechanics assuming no AD exists for switches manufactured after 1993. The text of the Airworthiness Directive as well as the text in SEB91-5R1 and ACS Service Bulletin SB92-01 do not support this assumption. I have three other aircraft of the same vintage (Cessna 172S) due for inspections in this shop with no documentation of Compliance with this recurring AD." |
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| 14 CFR Part 39 | Airworthiness Directives; Cessna Aircraft Company (Type Certificate Previously Held by Columbia Aircraft Manufacturing (Previously the Lancair Company)) Models LC40-550FG, LC41-550FG, and LC42-550FG Airplanes: We are superseding an existing airworthiness directive (AD) for the products listed above. AD 2009-09-09 currently requires repetitive inspections of the rudder hinges and the rudder hinge brackets for damage, i.e., cracking, deformation, and discoloration. If damage is found during any inspection, AD 2009-09-09 also requires replacing the damaged rudder hinge and/or rudder hinge bracket. This new AD retains the inspection requirements of AD 2009-09-09, adds airplanes to the Applicability section, and adds a terminating action for the repetitive inspection requirements. This AD resulted from the manufacturer developing a modification that terminates the repetitive inspections and from the manufacture adding airplane serial numbers into the Applicability section. We are issuing this AD to detect and correct damage in the rudder hinges and the rudder hinge brackets, which could result in failure of the rudder. This failure could lead to loss of control. |
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| Continental: 470-C; Failed Cylinder Studs; ATA 8520 (Oct. 2010) | "Two hours into cruise flight," says this operator, "the engine lost power on the number two cylinder as indicated on the Ultimate Bar Graph-16 (engine analyzer). Shortly after, the number two cylinder jug blew through the engine cowl, spraying oil over the windscreen. The aircraft (Beechcraft 35J) landed safely on a two land state highway. The cylinder remained hanging on the outside of the aircraft by the UBG-16 wiring—and the plug wires.
"(Subsequent) investigation suspects improperly torqued cylinder bolts during overhaul." (P/N not provided.) Part Total Time: (N/A) |
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Beechcraft/ Hawker Beechcraft
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| Continental: IO360G2B; Stretched Cylinder Studs; ATA 8520 (Oct. 2010) | "During the torque sequence for the engine overhaul final assembly, says a repair station submitter, "fasteners on the engine case were brought to half their final torque values (with no problems) as per the current TCM IO360 overhaul manual and pertinent service bulletins. Then, while attempting to reach final torque values we noted many of the studs seemed to be pulling from the case, rather than reaching torque. We then removed a cylinder to investigate (and found) the studs were stretching. We removed two studs to examine the threads in the case—no damage was found. These studs center portions were obviously elongated and narrowed. Requests to the manufacturer and other technical advisors for probable cause (provided) speculation the studs may have been over torqued at some point—moving them from an 'elastic' state to 'plastic.' (Note: the suds were stretch between 220-350 inch pounds of torque, well under final torque value.)" (Stud P/N: 643651-1—this number found three times in the SDRS database.) Part Total Time: (unknown) |
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| Bell: 430; Cracked Tail Rotor Blade; ATA 6410 (Oct. 2010) | A chief inspector for a repair station states, "This aircraft was flown to our facility and the operator reported '...debonding of the tail rotor blade leading edge—at the tip of the blade.' Upon further investigation of the blade, it was discovered that the root end of the blade had cracked and the skin was separated from the blade end. Photographs are included with this report. Information has also been submitted to Bell Helicopter Textron, product support engineering. Probable cause is unknown at this time. This aircraft is operated under Part 135 compliance." (Tail rotor blade P/N: 222-016-001-131. Tail rotor hub and blade P/N: 222-012-701-125. Photos list as tip views 1-3, then root view 1. Quite dramatic; thanks for the photo effort—Ed.) Part Total Time: 1,404.6 hours |
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| Piper: PA31-350; Electrical Power Failure; ATA 2432 (Oct. 2010) | Another FAA inspector writes, "Loose battery cables led to a complete loss of electrical power while in flight—IFR flight level 13,000 feet. Loose cables (P/N 80009-04) caused the loss of the aircraft battery (power). When the alternators were unable to carry the load, it resulted in a total electrical loss." Part Total Time: (unknown) |
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| Cessna: 310; Failed Rod-end on Main Gear Lock Assembly; ATA 3230 (Oct. 2010) | An FAA inspector says, "A rod-end broke (when the pilot) attempted to extend the landing gear in flight...resulting in a gear up landing. Upon inspection of the rod-end, (I) found it had been cracked prior to the incident. A probable cause is fatigue failure due to the age of the component. I recommend this to be a time change requirement." (Rod-end P/N: HM-4; Lock Assembly P/N: 0841000-58. There are five such failures noted in the SDRS database for the HM-4 P/N.)
Part Total Time: 3,688.7 hours |
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| Cessna: 172M; Stuck Starter Contactor; ATA 8011 (Oct 2010) | "The start contactor stuck in the closed position," says this A&P mechanic. "(I) would turn the master switch on and the starter motor would (immediately) engage. The master switch had to be turned off to stop the starter. This contactor was changed eight months ago for the same problem. Other makes of (our) aircraft have also had this problem in the past. This (defect) seems to coincide with the use of high torque starters, and it is very dangerous." (Start Contactor P/N: 111-138D. Very dangerous, indeed! This can kill someone not wary of the possibility. The SDRS database reflects at least four of these contactor part numbers. Thanks for the admonition; good reminder for all—Ed.).
Part Total Time: 144.0 hours |
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| Continental: GTISO520H; Cracked Propeller Shaft; ATA 8510 (Sept 2010) | "The (Cessna 421) pilot had a rough running engine," states a technician, "and difficulty controlling the engine RPM's. (He) shut down and feathered the right engine, landing safely at (the airport). Maintenance performed repair (work) on the propeller control cable, and proceeded to perform an engine run. However, the engine would not develop enough RPM to un-feather the propeller. The mechanic boarded the aircraft to observe the gauges—at which time the propeller separated from the engine. It has been determined by metallurgical (analysis) that the propeller shaft failed by fatigue cracks from an initiating crack, followed by fracture. The fatigue cracks grew over some period of time." (Propeller shaft P/N: 633908). Part Total Time: 1,349.0 hours (time since overhaul) |
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| Piper: PA46-350P; Loose Landing Light Power Supply; ATA 3340 (Sept 2010) | "During landing," states a mechanic, "the operator could not reduce power of the aircraft—it landed without incident. An investigation revealed the aircraft had been modified IAW STC SA02279AT with an aftermarket, high intensity landing light. The power supply for (this) light was mounted on the forward engine firewall above and behind the FCU (fuel control unit). (It) was secured to the firewall with adhesive IAW the STC. The adhesive mounting failed; the power supply fell from the firewall and became lodged in the FCU linkage, preventing power reduction and full engine control. This high intensity power supply (P/N LSM500200128) was relocated to the engine mount and secured to an aluminum plate." Part Total Time: (unknown) |
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| Learjet: 60; Chart-holder Binding Aileron Controls; ATA 2510 (Sept 2010) | "During completion of the takeoff climb," says the submitter, "the PIC (pilot in command) reported there was trouble moving the aileron to the starboard position. The aircraft made an uneventful landing. (After inspection) it was found that the extension arms on the chart holder attached to the co-pilot's yoke were extended forward, and (these) became caught in the yoke cover, increasing the turning resistance of the aileron. The extensions were retracted and subsequent tests of the aileron movement revealed no further discrepancies.." Part Total Time: 1,728.0 hours |
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Bombardier Learjet/Canadair
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| Continental: IO550N; Chafed Fuel Injector Line; ATA 7310 (August 2010) | (The following report pertains to a Cirrus SR22 airplane.)
"An aircraft owner requested we clean his fuel injectors—which we did," says an aircraft mechanic. "I was nearly completed with the task—tightening the nut for the number one cylinder fuel injection line. I noticed the line was very loose. Upon further inspection I found the retaining clip (designed) to secure the line to an engine bracket was falling out (apart?) and not doing its job. I also noticed black staining on an adjacent engine structure. When I removed the line, I found approximately one inch of the tubing had been worn away to half its thickness and was leaking fuel over the top of the engine. I inspected the other fuel lines and found the number two cylinder fuel injection line on the opposite side of the engine also had damage, but this was caused by ignition leads rubbing against (it). This (damaged line) was less severe (and not leaking), but it was not serviceable. New lines were ordered and installed. The number one line was secured with a heavier type Adel clamp, and all ignition leads were secured to prevent further chafing. This customer is new to our operation; it is unknown how long this condition has existed." (The fuel line P/N is 646421. Nice catch! I hope the owner bought you lunch. See also the chafed Schweizer fuel tank hole under helicopters—Ed.)
Part Total Time: (unknown) |
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| Schweizer: 269C; Chafed Fuel Tank; ATA 2810 | A technician states, "During a 200 hour inspection, wear marks were found on the bottom of the fuel tank. (These chafe areas were...) caused by the attach pin (P/N MS20392-2C47) used on the strap assembly (P/N 269A8329-23). A detailed inspection found the wear (occurred) because of insufficient pad material installed on the strap, allowing contact between the pin and the fuel tank skin. Wear depth at one point was enough to require replacement of the tank. Inspection of a (second aircraft) found the beginning of similar wear marks."(Note the total part time: 194.0 hours!) |
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| Cessna: 560XL; Broken Aileron Control Lock Arm; ATA 2770 (August 2010) | A writer says, "I found the control lock system partially inoperative on post-flight inspection. Further investigation determined the left aileron lock arm was broken at the lock feature contact area. The cause of the part failure is unknown (P/N 666102127). The part appears to have suffered overloading at the contact point, resulting in a crack and (leading) to the failure of the lock arm." Part Total Time: 658 hours |
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| Cessna: 525B; Main Landing Gear Corrosion; ATA 3213 (August 2010) | "Corrosion was found at the left side, aft main landing gear Trunnion pin's bore and face while performing the Cessna 48 month/2,400 inspection. A mixture of ferrous and non-ferrous parts are used in the effected areas," says this submitter. "Lubrication of this area is performed at 12-month intervals. The lubrication process is to apply WC-393 to the forward and aft pivot points with a squeeze bottle." Part Total Time: 1,333 hours |
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| Bellanca: 1730A; Failed Nose Landing Gear; ATA 3230 (August 2010) | "During touchdown on runway 36L," says the submitter, "the nose landing gear failed and partially collapsed upon contact with the runway. It appears (from our investigation) the nose gear linkage bearing rod-end (P/N 198001-2) to the gear extension assembly experienced a fatigue failure. Based on the fracture signature, the failure appears to be a mild to high stress concentration (from a...) one-way bending load. The rod-end failed at a point where (its) threads and nut meet, shearing even with the nut face (AN316-4R). (These) threads were stretched and bent at a fifteen degree angle with about one-half inch of thread showing. The rod-end bearing movement was satisfactory. Part Total Time: 2,751 hours |
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Bellanca/Alexandria/Aeronca/American Champion
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| Beechcraft: 58; Failed Landing Light Switch; ATA 3340 (August 2010) | "The aircraft landing light was observed to be hot and emitting smoke," says an unknown writer. "This switch is post AD (Airworthiness Directive) 2008-13-17. Basically these switches are the same as the original switch with the addition of an insulator. (This) prevents a failed 'open' switch from conducting current through the point's 'hold-open' spring that (otherwise) begins to overheat and burn. Apparently, this failed switch (P/N 35380132103) had a manufacturing defect which allowed current to flow through this spring. An internal inspection of this switch was inconclusive as to the installation or placement of the insulator pads due to the damage sustained during the overheat event. Part Total Time: 1,486 hours |
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Beechcraft/ Hawker Beechcraft
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| Beechcraft: 58; Instrument Air Water Contamination; ATA 3710 (August 2010) | An unidentified submitter states, "Water is entering the instrument air system and causing corrosion of the system components. A higher than acceptable gyroscope failure rate has prompted our maintenance staff to probe into the causes of this issue. Upon opening the instrument air, pressure regulator and manifold check valve assembly for inspection, heavy corrosion of the ferrous components were noted. Large particles of rust are breaking loose from the fittings and other steel pieces in the system, contaminating instruments. We recommend Beechcraft develop a Service Bulletin or kit to allow for an inline filter to be installed after the instrument air regulator, but before the air enters the instruments." Part(s) Total Time: 5,243 hours |
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Beechcraft/ Hawker Beechcraft
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| Continental: IO470N; Failed Oil Cooler Gasket; ATA 7921 (July 2010) | (The following short report references a Beech V35 aircraft. The photograph is excellent. Unfortunately, how or why the gasket failed is not included.)
A technician for an aviation company says, "The oil cooler gasket failed." Part Total Time: 160.0 hours |
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| Continental: IO550C; Leaking Dipstick Housing; ATA 8550 (July 2010) | A technician states, "During a routine oil change a puddle of oil was observed in the bottom of the cowling. No oil was spilled while filling the crankcase. Having seen this problem several times in the past, the mechanic immediately knew to look at the dipstick tube (P/N 6494061) in the chafed area. As in all the previous situations, the hole is located at the first inside bend below the filler opening. Even though the OEM says they are not aware of the problem, most of our in-service engines show some sign of chafing which can be observed by looking down the oil fill opening on the crank case side of the tube. Fortunately, once the dipstick is in place, it tends to fill the chafed opening and very little oil can escape through the hole. The attached photos show the dipstick through the chafed hole—it actually creates a decent seal." Part Total Time: 1,209.0 hours |
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| Diamond: DA42; Chafed Rudder Cable; ATA 2720 (July 2010) | An unidentified submitter states, "During a routine inspection, the rudder cable (P/N CA13190) was found worn with broken strands where it exits the (guide) tube (P/N 157727) about two inches forward of the rudder bell crank. This is approximately on the rudder hinge line. Once the cable was removed, additional wear was found 33 inches inside the tube. Since both ends of the cable are swaged, this cable would never be removed to inspect for that wear (occurring) midway in the protective tube." Part Total Time: 1,313.0 hours |
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| Diamond: DA42; Cracked Fuel Tanks; ATA 2810 (July 2010) | A flight school reports, "During a routine inspection a fuel stain was noted in the left auxiliary tank area. The tank was removed and inspected. There were cracks found at several of the weld points where an internal baffle is welded to the bottom panel of the tank. A new tank (P/N D6028141100) was installed." Part Total Time: 625.0 hours |
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| Cessna: 680; Cracked Diffuser Ducts; ATA 3010 (July 2010) | A repair station technician describes a heat duct defect. "We have found these wing bleed air heated leading edge diffusers cracked or deformed on numerous aircraft. This (particular) discrepancy was found while performing A301001 Wing/Horizontal Stabilizer Bleed Air Anti-Ice System Detailed Inspection. Task 30-10-00-220 is part of Inspection Document nine—a 48 month inspection. This discrepancy was likely caused by thermal expansion and flight vibrations of the wing leading edge, anti-ice piccolo tube. The piccolo tube is hard mounted to the diffuser with no vibration dampeners or means to compensate for thermal expansion. The material for the diffusers is thin and bends easily. We have also found the piccolo tubes chafing on the diffusers. We recommend the diffusers be built with a heavier material and the piccolo tube mounting to be redesigned. This occurrence was corrected by replacement of the effected parts." (Diffuser P/N's 6922520-53, -54, -55, and -56.) Part Total Time: 3,042.3 hours |
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| Cessna: 172S; Frayed Aileron Cable; ATA 2710 (July 2010) | "During a routine inspection," says a flight school submission, " the aileron cable (P/N 0510105-364) was found shiny (worn) where it passes through the ceiling pulley cluster. When it was viewed through a strong magnifying glass many broken strands could be seen." Part Total Time: 2,311.0 hours |
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| Bombardier: CL600; Engine Cowl Support Rod; ATA (N/A) (July 2010) | The purpose of this advisory is to inform the aviation community of the importance of the correct stowage of engine core cowl stay support strut/rods for all Bambardier Regional Jet Series (CL-600-2B19) and Challenger 600 (CL-600-2412/2B16) aircraft with CF34-1 & CF34-3 engines. |
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Bombardier Learjet/Canadair
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| Bombardier: BD100-1A10; Sheared Generator Spline Shaft; ATA 2421 (July 2010) | About this aircraft an unidentified technician states, "The APU (auxiliary power unit) goes off line as soon as it is loaded. The APU generator spline shaft (was found) sheared off." Part Total Time: 1,492.0 hours |
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Bombardier Learjet/Canadair
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| Diamond: DA20-C1; Cracked Nose Gear Fork; ATA 3222 (Sept 2010) | A repair station submitter says, "The nose landing gear fork cracked on both left and right sides." (Nose Landing Gear Fork P/N: 20-3220-08-00. The SDRS database records at least five such discrepancy reports.) Part Total Time: 1,926.7 hours |
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| Continental: IO470K; Improper fuel fittings; ATA 7324 (Sept 2010) | A technician states, "(We performed...) the fuel injection setup per TCM SID 97-3E, but the electronic fuel flow computer showed flow below specifications. We were unable to increase flow sufficiently by increasing pressure. (Subsequent inspection revealed the...) inlet elbow fittings (P/N's 631658 and 628437) had been previously reversed, probably twelve years prior during installation of an electronic fuel flow transducer. Part 631658 has a restrictor orifice, while 628437 does not. The parts look identical externally. It takes a very careful (observation) to see the internal difference. The TCM engine overhaul manual does not mention this. The TCM parts manual shows the different part numbers, but does not describe the differences. This would be a very easy mistake to make, and very difficult to diagnose later. (Again), this problem probably started twelve years ago, and was not detected or corrected until now. This airplane had five cylinders changes during this time—(most likely) caused by lean operation at full power. The aircraft (may not have...) generated full power on takeoff due to a very lean, full rich mixture. It is critical to communicate this to mechanics and owners to prevent a dangerous condition." Part Total Time: (unknown) |
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| Cessna: 560XL; Shorted Light Strip (June 2010) | "On approach to the (airport)," says this submitting writer, "the crew noticed smoke and a burning smell coming from the pedestal area near the auto-pilot controller. They donned oxygen masks, then advised the passengers— and manually (caused) their masks (to deploy). The pilots declared an emergency and landed at the airport without incident. They turned off at the first taxiway and stopped in front of a (waiting) fire truck. The crew and passengers evacuated the aircraft through the main cabin entry door.
"Fire rescue personnel entered the aircraft and inspected—unable to find any cause for the smoke or smell. The crew secured the aircraft, removing battery power with the emergency disconnect switch—and physically disconnecting the battery. On-site maintenance personnel investigated (the discrepancy). The center console was accessed and inspected; all wiring was inspected; all grounds tested and checked for security. The cockpit headliner, side walls, and flooring were removed—the entire area inspected for any cause of smoke or smell. (Only) one wire connector for roll trim was found to be loose. A pin in (this) connector was replaced. The aircraft (electrical system?) was powered up and operated in the hanger for over three hours with no defects noted. It was then returned to its original configuration and flown on an operational check flight for one hour, (incurring) no defects. The aircraft was returned to service. It has since flown 7.2 hours and eight cycles with no recurring condition.
"During subsequent maintenance activity, personnel found a melted drop-isle lighting strip (P/N 9919040-26) which may be the root cause of the previously reported cockpit smoke."
Part Total Time: 4,988.0 hours
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| Quicksilver; Sport 2S; Failed Lift Strut Eyebolt (June 2010) | The following failure description is an example of what can result when the experimental aircraft builder does not closely follow assembly instructions. The aircraft is a Quicksilver model Sport 2S Experimental Light Sport (ELSA), and the owner—a very lucky pilot!
This aircraft was involved in a near disastrous event when the left hand, aft wing strut attachment eyebolt pulled out of the threaded lift strut fitting, resulting in loss of vertical control. Fortunately for the pilot/owner, he landed in a tree—breaking his fall to the ground. He walked away from this accident, but the 2S sustained substantial damage.
Post-accident investigation revealed the eyebolt was improperly installed in the lift strut fitting. The Sport 2S Assembly, Maintenance and Parts manual clearly provides detailed information on the proper assembly of this critical wing attach component. The manual specifies a minimum of 5/8 inch engagement of the threaded portion of the eyebolt into the fitting with 3 ½ threads exposed. The accident eyebolt/fitting had 3/32 inch engagement with 16 threads exposed.
The manual clearly states the importance of these assembly specifications in a note and in a warning. It is clear and concise as to the details of this important assembly. Without proper thread engagement, the eyebolt—with only a couple of threads engaged—eventually pulled out of the lift strut fitting under normal wing loads.
Any builder of an experimental aircraft is responsible for following all assembly instructions, including important notes and warnings. And any person inspecting or maintaining an experimental aircraft should be equally aware of these assembly specifications, checking for proper installation.
The following picture shows the failed eyebolt to lift strut fitting. It is positioned near the opposite wing's correctly assembled parts for comparison.
(For further information contact Aerospace Engineer Barry Ballenger, 901 Locust St., Kansas City, MO 64106; phone 816-329-4152.)
Part Total Time: (N/A)
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| Glasair II SGR; Broken Hyd. Actuator Fitting (June 2010) | An unidentified submitter says, "The owner/pilot of this aircraft was performing 'touch and go' (landings). When preparing for the second landing he noticed he did not have a green landing gear down light for the left main gear." "The pilot elected to land with the landing gear (positioned) down.... A safe landing was made, (sustaining) minor damage to the aircraft and no injuries to the pilot. Upon examination of the aircraft after recovery, it was determined one of the left main landing gear actuator hydraulic fittings had broken off the actuator. This allowed the hydraulic system to lose a substantial amount of fluid, such that the left main landing gear leg would not completely retract or extend. Physical examination of the broken fitting shows it failed at a point flush with the actuator housing. The 90 degree elbow portion remained attached to the flexible hose assembly. Examination of the gear well and the general layout of the gear components show the flex hose may have been stress loaded while the gear was in the (retracted position). This may have...focused high loads on the hose elbow at the actuator housing. The gear actuator may also be rubbing against the top of the wheel well at the outboard edge. All of these (observations) were noted by both the owner and the airport's (attending) mechanic." (Hydraulic fitting P/N: MS20822). Part Total Time: 1,916.0 hours |
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Glasair (Stoddard-Hamilton, Wag Aero)
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| CE-10-25 | This Special Airworthiness Information Bulletin (SAIB) alerts type certificate, amended type certificate, and supplemental type certificate applicants of an airworthiness concern regarding the issue of fluid flammability for TKS fluid.
At this time, this airworthiness concern is not considered an unsafe condition that would warrant an airworthiness directive action under Title 14 of the Code of Federal Regulations (14 CFR part 39). |
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| Schweizer: 269C; Cracked Support Strut (May 2010) | "During unscheduled maintenance," states an unidentified general aviation technician, "the lower drive support strut (P/N 269A5423009) was found to be cracked 90 per cent through the tube—where the upper attach lug is welded. Upon removal, the lug completely separated from the tube. If this tube had separated during flight, loss of main rotor torque would have occurred." (Okay.... That is scary!—Ed.) Part Total Time: 6,527 hours |
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| Univar: 415-C; Sheared Brake Clevis (May 2010) | "On landing," says this general aviation technician, "(this aircraft) lost braking action. An investigation found the brake piston clevis rod—between the brake pedal arm and the master cylinder—had sheared below the lock nut."
(Piston clevis rod P/N: 4008. Component name and P/N: Brake Arm; 41533458. See photo below.) Part Total Time: 617.0 hours
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Alon/ERCO Ercoup/Forney/Univair
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| Learjet: 60; Undersized Spoileron Bearings (May 2010) | A general aviation submitter writes, "New spoileron bearings (P/N AA401-12) that were ordered (for this aircraft) were received with their outside diameter below the tolerance listed in the SRM (structural repair manual)—causing a loose fit when installed. The SRM (calls for) 0.4400 inch outside diameter, with no tolerance allowed. All bearings received have measured 0.438 inches." "Reference Learjet 60 SRM: 51-71-03, page 1 and 2, item 12." Part Total Time: 7,291 hours (aircraft) |
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| Embraer: 145EP; Broken Bolts in Rudder PCU (May 2010) | Another unidentified submitter says, "The pilot reported a number two Low Quantity on the EICAS (engine indicating crew alert system) while on the ground. Maintenance inspected and found the rudder power control unit (PCU) to be leaking. (This unit) was removed and replaced in accordance with EMB 145 Maintenance Manual 27-22-03. It operationally and leak checked good. (We) serviced the number two hydraulic system IAW EMB 145 AMM 12-13-01. The aircraft was returned to service. The (defective) rudder PCU was missing (several) bolt (heads)—causing the leakage." (The SDRS database includes ten of these PC units, none but this one having a reported bolt problem!) (The PCU is from Parker-Hannifin. Great photos; but very scary scenario! I wish you would have speculated as to why this might have occurred. For example: if those steel bolts thread into an aluminum casting, we could probably rule out over-torque as an issue--right? Or, are there nut plates on the other side? Might the bolts, then, be defective? Have you seen this before? Would 24,000 hours indicate an extreme bolt life for this application? Have the bolts and/or the PCU been flagged for any kind of failure analysis? Please keep me informed of any similar PCU events via e-mail on the Alerts address page. Thank-you—Ed.)Part Total Time: 23,982.0 hours |
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| Cessna: 680CE; Vertical Stabilizer Spar Corrosion (May 2010) | An unidentified general aviation technician states, "During replacement of the rudder hinge brackets on the vertical stabilizer's rear spar (P/N 693101222), exfoliation corrosion was found on the 1) lower bracket (P/N 6931050-10) of the upper rudder hinge point; and 2) on the lower bracket (P/N 693105012) and upper bracket (P/N 6931050-11) of the middle rudder hinge point. Exfoliation corrosion was also noted on the vertical stabilizer aft spar stiffener (P/N 65931012-22) at approximate water line WL 190.763. (This stiffener) required replacement." Part Total Time: 3,856.0 hours |
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| Cessna: 402C, 414A, 421C; Cracked Main Gear Trunnion (May 2010) | (The Wichita Aircraft Certification Office provides the following safety admonition. Contact information follows the discussion.)
The FAA has received a Safety Recommendation (09.385) suggesting an Airworthiness Directive be issued for non-destructive inspections on Cessna landing gear (P/N 5141103), effecting models 402C, 414A, and 421C. This recommendation stems from a Cessna 402C gear failure in August 2009 (photos attached).
Cessna is working to develop Supplemental Inspection Documents (SID; number 32-10-05) for these specific aircraft. They have developed a surface eddy current process to inspect for cracks on the main gear (upper barrel), targeting both the actuator and upper torque link attachment fittings (photo 3). The crack initiating this failure can just be seen in the last picture—an internal view of the gear cylinder where this kind of defect may first be detected. The Cessna inspection requirement is expected to be available by August, 2011. It is scheduled to be accomplished at 5,000 landings, and thereafter at each 2,000 landings.
The gear failure depicted below occurred on an airplane estimated to have 30,000 landing cycles during 12,000 hours of flight time. Search of the FAA's Service Difficulty Reporting System (SDRS) database generated 28 failed gear reports (for these models) in a production fleet of 2,290 airplanes. Model 402C alone produced 21 of these reports—681 of these aircraft were built between 1979 and 1985. (For further information contact Aerospace Engineer Gary Park: Wichita Aircraft Certification Office, 1801 Airport Road, Room 100; Wichita, Kansas; 67209; phone 316-946-4123)
Part Total Time: (N/A)
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| Boeing: 747-281F; Cracked Horz. Stabilizer Hinge Fitting (May 2010) | The previous submitter provides another discrepancy report stating, "The L/H and R/H horizontal stabilizer hinge fitting had two cracks each: 0.8 and 0.9inches, and 0.85 and 1.1 inches, (respectively)." (No part numbers were provide with this report.) Part Total Time: 101,362 hours |
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| Boeing: 747-281F; Cracked Door Doubler (May 2010) | A very short submission from an unknown source writes, "The main entry door's number one upper outer skin doubler (has a) crack 0.35 inches at the upper hinge door (mount)." (No part numbers were provide with this report.) Part Total Time: 101,362 hours |
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| Airtractor: AT301; Cracked Isolator Mounts (May2010) | An unidentified submitter writes, "The engine isolator mounts (P/N 22387) were replaced when the aircraft was restored. At the first Annual Inspection (with approximately 60 hours total time) these mounts showed excessive cracking and deterioration—requiring replacement. The lower mounts showed the most amount of wear, with the area around the metal engine mount cracked two-thirds way around, (and there were) pieces missing. (I) was told by the aircraft owner that he had heard the (rubber) mount composition had recently been changed. I have no recommendations at this time, other than to closely monitor (these mounts)." Part Total Time: 60.0 hours |
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| Rockwell: S2R; Cracked Vertical Stabilizer Spar (April 2010) | A mechanic says, "The top rudder attach bracket cracked out of the rear spar on the vertical fin. (I) noticed this crack at Annual Inspection. (One might...) possibly install a heavier rear spar or other (support/doublers) in that area. (An included example is the Ayres Corporation Service Bulletin, number SB –AG-38. Aft spar P/N: 40261T023.) Part Total Time: (unknown) |
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CPAC ( formerly held by Commander, Gulfstream & Rockwell International)
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| Rockwell: NA265-65; Wing Panel Corrosion (April 2010) | An unidentified submitter writes, "While the aircraft was stripped for a paint job, a visual inspection of the L/H over-wing fairing (revealed) delamination. After panel removal, corrosion was found extending under the over-wing panel...(and) through the L/H wing plank at wing station 102.5—107, approximately 10.0 inches from the front spar...." (The exfoliation corrosion covered approximately 15.0 inches.) "This area is only inspected by visual means during a 150 hours inspection, and the wing planks are covered up by the over-wing fairings (fiberglass overlays)." (Skin panel P/N: 3701301213.) Part Total Time: 15,572.0 hours |
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CPAC ( formerly held by Commander, Gulfstream & Rockwell International)
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| Piper: PA46-350P; Sheared Elevator Actuator-Arm Rivets (April 2010) | "An 'inoperative elevator trim' discrepancy was found to be caused by a frayed cable jamming the trim drum," writes a repair station technician. "(I) also found the elevator actuator arm (P/N 83515-02) to be loose—(free) to move in all directions. All actuator arm-to-elevator rivets (except one) were sheared or loose. Since both up and down stops are on this (actuator) arm, we believe a jet blast or severe wind caused the elevator to hit the stops (with damaging force)." Part Total Time: 2,995.0 hours |
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| Cessna: 510; Brake Pedal Pushrod Interference (April 2010) | An English operator submitted this defect report, stating, "During a maintenance inspection in the area of the pilot's rudder pedals, it was noticed that the right brake pedal pushrod had (at some point) made contact with an adjacent, floor support angle, causing minor distortion to the angle's vertical flange. This condition could have resulted in the brake pedal remaining in a partially depressed state.
"Clearance from structure in this location is very limited. This condition was compounded by the fact that the bolt has lateral play due to insufficient washers being installed under the nut. The installation, however, was in accordance with the IPC (illustrated parts catalog; 27-20-01, figure 1, item 30)." (The "component" P/N is provided: 7060310-3. Note also the first number in the above picture—angle part number?) Part Total Time: 479.05 hours
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| Cessna: 208B; Leaking Oil/Fuel Heater Tube (April 2010) | A repair station technician says, "The ridged steel tube that feeds into the oil/fuel heater has developed little pin holes underneath mthe attached fire loop bracket. When this line is removed (the little pin holes) look like little dots of corrosion, but when pressurized with air it leaks at an extreme rate. The possible cause could be Adel clamp chafing or corrosion." (Heater tube P/N: 3013446. A Pratt & Whitney PT6A-114 is attached to the nose of this aircraft.) Part Total Time: (unknown) |
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| Cessna: 172S; Frayed Aileron Control Cables (April 2010) | "The cabin overhead center panel was removed for progressive inspection," says a flight school chief inspector. "During the flap and aileron cable inspection, flat spots were noticed on three aileron control cables. (We) rolled the cables for a better view of the contact point with the pulleys and (subsequently) were able to catch frayed wires with a rag. A substantial groove could be seen in the carry-through cable. Cable tensions were within the proper specifications, and the area was clean and free of any dirt or debris. The plastic pulleys were also inspected—they too were clean and free to roll.
"This problem seems to be happening during normal flight training (school) use. This problem has been noticed with our other 172 aircraft having about the same (airframe) time. "We feel the cause (of this cable wear) is from the pulleys themselves. They are made from a hard white plastic material. The braided steel cables are rubbing against the pulleys instead of rolling on them. This is causing them (to develop) a flat spot at first—and then a groove when worn deeper into the cable. (Additionally), there (exists) no noticeable cable deflection where the cables contact the pulleys—(as if) the pulley diameter is too small. Our recommendations: replace the pulleys with the normal, brown phenolic type pulley used in all other areas of the aircraft, or enlarge the pulley (groove) diameter to increase the cable-to-pulley contact." (Aileron control cable part numbers: 0510105-365, -364, -360. The SDRS database reflects 17, 13, and 11 reports each on these cables, respectively.) Part Total Time: 2,096.7 hours
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| Beechcraft: A36; Jammed Aileron Control Cable (April 2010) | A repair station submitter writes, "During a pre-purchase inspection, (I) found the control yoke binding when turned to the left approximately 45 degrees. I inspected the aileron control system and found a screw lodged in a pulley groove—and the cable damaged. This aircraft had flown 2.0 hours since the last annual inspection. The screw appeared to be a floor panel screw." (Aileron cable P/N: 106-524044-19.) Part Total Time: 2,266.3 hours |
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Beechcraft/ Hawker Beechcraft
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| Varieze; Engine Failure (September 2000) | Immediately after takeoff, the engine lost power. The pilot made a safe off-airport landing with minor aircraft damage. The submitter determined an excessively rich fuel/air mixture caused the engine failure. The Marvel-Schebler carburetor (Model MA-3SPA) float (P/N 30-766) was cracked and partially filled with fuel. This allowed excessive fuel into the carburetor bowl which produced the excessively rich mixture. He speculated this failure was caused by the position of the carburetor, for this particular application, in relation to other engine compartment components.
Since there was no prior indication of an impending failure, the submitter cautioned all operators of like equipment to inspect the carburetor float at frequent and regular intervals. Part total time-1,450 hours.
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| Sea Rey; Landing Gear Failure (September 2000) | While taxiing the aircraft, the left main landing gear collapsed.
An inspection revealed the two bulkhead upright support tubes (P/N 5310-006) were broken where they attach to the landing gear. (Refer to the following illustration.) The submitter suspects preload stress imposed during assembly and/or a hard landing caused the tube failures. Proper installation procedures and landing technique may alleviate recurrence of this defect. Part total time-165 hours.
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| Grumman; Model G-164A; Ag Cat; Rudder Structural Corrosion (September 2000) | During a scheduled inspection, the technician discovered severe structural corrosion on the rudder.
The corrosion was located on the main tubular spar (P/N A1203-11). Grumman Service Bulletin (SB) 61, dated June 6, 1977, deals with this subject. Airworthiness Directive (AD) 78-08-09 requires compliance with SB 61. In accordance with these documents, a recurring inspection is required at 300-hour intervals after initial compliance. The submitter of this report urged all operators of like aircraft to conduct the recurring inspection requirements during each annual inspection regardless of the accumulated operating time. Part total time-7,555 hours.
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Grumman (American Aviation/General)/Gulfstream/Galaxy
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| Bell; 412HP; Structural Defect (September 2000) | During a crew change following a 4-hour fire-fighting mission, a technician conducted a daily inspection. He discovered a crack in the skin just below the tail-boom attachment fitting on the upper left side of the airframe. After investigating further, the technician found a broken main beam cap (P/N 212-030-191-001). (Refer to the following illustration.) He removed the helicopter from service and took it to a hangar to disassemble the affected area. He found chips and burrs adjacent to all but two fastener holes on the left tail-boom attachment fitting and the beam cap. An inspection of the right tail-boom fitting and the fittings on another like aircraft revealed similar findings in all cases. The submitter stated most of the fastener holes were not properly deburred during assembly. Part total time-3,111 hours. |
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| Bell; 407; Errant Oil Pressure (September 2000) | The pilot observed a high transmission oil pressure indication (110 PSI) during flight. After landing, a technician discovered contamination and corrosion inside an electrical connector caused the errant indication. The defective connector (P/N MS3116FB-4s) is used on the indicating system transducer. He cleaned the connector, conducted an operational test, and found it serviceable.
The submitter recommended that maintenance personnel disconnect the connector periodically for inspection. Part total time-635 hours.
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| Bell; 222U; Main Rotor Grip Security (September 2000) | During a daily inspection, the technician discovered evidence of fretting between the main rotor grips and the pitch horns. The technician conducted a torque check of the retaining bolts. All four retaining bolts displayed less torque than the required torque value. He disassembled the main rotor grips and discovered the buffer pads loose and distorted. He also found positive evidence of movement between the grips and the pitch horns.
The submitter speculated the cause of this defect may be either improper installation of the buffer pads and/or the paint not being set on the grips prior to assembly and installation of the buffer pads. Also, the pitch horn dimensions were below the manufacturer’s required specifications. Part total time-73 hours.
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| Bell; 206L-4; Long Ranger; Transmission Gear Failure (September 2000) | During flight, the pilot observed the chip light illuminate; therefore, he landed the aircraft immediately.
The technician discovered a large piece of ferrous metal on the chip plug. The metal chip resembled a piece of a gear tooth. He disassembled the transmission and found the input spiral bevel gear as the source of the broken gear tooth. Also, a crack traveled 360 degrees through the gear ring, and the path took it through a bolt hole.
The submitter did not determine the cause of this failure; however, he sent the parts to the manufacturer for an engineering evaluation and analysis. Part total time-3,185 hours.
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| Stinson; 108-2; Voyager; Engine Failure (September 2000) | In July 2000, this aircraft experienced an accident due to engine fuel starvation. FAA inspector Calvin Clark from the Wichita, Kansas, Flight Standards District Office investigated this accident and determined the fuel hose running from the fuel strainer to the carburetor did not supply sufficient fuel to sustain engine operation.
Inspector Clark identified the .5-inch hose as “MIL-H6000,” and stated it was manufactured in the third quarter of 1985 (3Q85). From the available information, he could not identify the hose manufacturer. The hose had a “fire sleeve” installed over the outside for protection.
After removing the hose, the inspector found a small piece of the interior hose liner “curled up” near one end which obstructed the flow of fuel from the strainer to the carburetor. After 15 years of operation, the hose was in a deteriorated state. The aircraft was being operated under the authority of a Supplemental Type Certificate (STC) allowing the use of “auto fuel.”
The inspector speculated exposure to “auto fuel” over an extended period of time might have contributed to the hose deterioration. He recommended that all aircraft owners/operators be aware of, and comply with, the aviation hose time-change requirements. Part total time unknown.
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| SAAB; 2000; Elevator Trim Defect (September 2000) | During a scheduled inspection, the inspector found the right elevator trim actuator bracket dislodged from the spar.
Four of the six fasteners used to secure the bracket to the spar were broken and the spar was cracked in numerous places adjacent to the bracket attachment point. The submitter suggested close attention to this area during scheduled inspections and elevator trim system maintenance. Part total time-1,991 hours.
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| Piper; PA 60-601P; Aerostar; Structural Corrosion (September 2000) | During a scheduled inspection, the technician discovered several areas throughout the airframe displayed the early stages of surface corrosion. One area displayed advanced stages of severe intergranular corrosion on the right main landing gear aft side brace support fitting.
The technician removed the trunnion fitting (P/N 200021-02). Prior to installing a new trunnion fitting, he treated the damaged areas and the new part with a corrosion-preventive compound.
This aircraft operates approximately 4 months of each year in a “salt air” environment. With the “proper atmospheric conditions,” aircraft operating in such an environment, for even a short period of time, may develop severe corrosion of their structural components. The term “proper atmospheric conditions” alludes to temperature, humidity, and the salt concentration in the air. In some cases, liquid, in the form of ocean spray, may carry concentrated salt into critical areas where it can cause serious compromise of the aircraft structure.
Since it is not always possible to avoid salt air environments, it should be a standard practice to wash these aircraft using fresh water as quickly after exposure as possible. Part total time-2,065 hours.
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