The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”
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An aircraft owner delivered a Kidde Dexaero fire extinguisher to an FAA-certificated repair station for a hydrostatic test and overhaul.
After a receiving inspection, the unit was routed to the production department so the necessary work could be performed. The unit was found to be full of extinguishing agent and was purged.
While disassembling the fire extinguisher, the technician noticed that the yellow outlet rupture disk had been fired, even though the cylinder was full when it was received. Further disassembly disclosed that a steel plug used for pressure testing had not been replaced with the rupture disk prior to final assembly. The steel plug apparently had been overlooked during a previous overhaul at another shop.
Proper overhauls are important because emergency equipment tends to sit in the installed position for long periods of time and problems often are not noticed until the equipment is needed.
American Champion 8KCAB Decathlon
Wheel Brake Defect
During winter conditions, the pilot completed an aerobatic flight and noticed leaking brake fluid.A system inspection revealed the right brake fluid line had come off the plastic T fitting on the brake fluid reservoir. The brake system on this aircraft uses plastic tubes without using clamps at either the reservoir T fitting or the brake cylinder barb fittings. The aircraft records indicate no one performed maintenance on the brake system since the aircraft was new.Part total time – 325 hours.
Aviat S-2B Pitts Special
Defective Dope Application
While conducting an inspection, the technician noticed a section of the dope covering did not adhere to the fabric.On the top wing, approximately 1 inch outboard of the center section and 10 inches aft of the leading edge, the dope covering pealed off in a sheet down to the fabric. The technician stated this situation occurs when there is no nitrate dope applied to the fabric or when there is contamination of the fabric.The manufacturer had re-covered the wings in 1994.
Beech B55 Baron
Ice Removal System Failure
The pilot reported the right wing deice system failed.An inspection revealed the right wing deice boot flexible line chafed and melted. The deice line contacted the aluminum pneumatic pump output line. These two lines are just aft of the engine firewall in the nacelle. Chafing and exposure to excessive heat caused this failure.This area has limited access and may require the technician to feel for the condition and proper clearance of the plumbing line.Part total time – 3,368 hours.
Beech E55 Baron
Structural Corrosion Damage
During a scheduled inspection, technicians discovered severe corrosion on the right wing spar cap.The corrosion progressed to the point of exfoliation and disintegration of the metal. The damage penetrated the entire thickness of the wing spar cap. The affected area started at wing station 70 and continued outboard approximately 8 inches.The corrosion compromised the spar cap to the point that it would hardly bear its own weight, and wing failure was imminent.Aircraft total time – 4,137 hours.
Cessna 172G Skyhawk
Control Yoke Corrosion
After landing, the pilot secured the aircraft and applied the gust lock. That night, wind gusts up to approximately 75 miles per hour struck the aircraft.The next morning the pilot examined the aircraft and noticed that the elevator had dropped, even though the gust lock was still in place. The operator first speculated that the control cables stretched.When he removed the gust lock and pulled the yoke to the full-aft position, he could raise the elevator an additional couple of inches. This eliminated doubts about cable problems. The problem was obviously elsewhere, even though the aircraft appeared to still have full movement of the controls. The next morning he noticed the elevator drooped even lower than the previous day, and he contacted a maintenance technician.The technician noticed the elevator drooped to its full extent and no elevator movement occurred when he moved the control yoke in the cockpit. An inspection revealed the control yoke had broken as a result of internal rust.
Cessna 172P Skyhawk
Engine Stoppage
The aircraft made four forced landings, including one off-airport landing with no apparent damage, before the cause was discovered.The pilot suspected carburetor ice at first, but after the last off-airport landing the engine would not start. The left and right wing fuel tanks were sumped and approximately 20 ounces of water was present.When the aircraft was returned to its home airport, technicians hangared it and dyed water was introduced to the top left wing through access panels. A total 14 ounces of water was placed in the tank, but only 6 ounces drained out of the sump, even after rocking the wings.The aircraft had never received any repairs or modification to the fuel area. The water stands and eventually migrates into the fuel system.Part total time – 1,060 hours.
Cessna 421C Golden Eagle
Window Cracks
The technician disassembled the airframe for refurbishment. He discovered the left pilot side window exhibited compression-type flaking, chipping damage and cracks emanating from the screw holes to the edge of the pane.The same problem was found on the windows in the cabin door, the left side most-aft portal, the right emergency exit, and the window immediately aft of that exit, as well as the most-aft windows on the right side. All windows had their backup ring in place, with the exception of the pilot side window. Some of the damaged areas had sealer present, indicating that that the damage may have occurred during installation.Part total time – 3,437 hours.
Diamond DA20-C1 Katana
Engine Starter Failure
The pilot reported the engine starter made a grinding sound and the engine would not start.The technician removed the starter and discovered a sheared drive gear. The gear wore against the crankshaft gear and caused metal contamination throughout the engine.Judging from the low number of operating hours, the starter gear may have been defective when it was installed.Part total time – 63 hours.
Hartzell HC-B3MN-3
Blade Cracks
While conducting an inspection on a Cessna 208B in compliance with Hartzell SB 169A, dated Nov. 15, 1991, the technician discovered numerous cracks.All three propeller blades had cordwise cracks that were beyond acceptable limits. All of the cracks led up to and possibly under the leading edge erosion shield.Part total time – 5,378 hours.
Navions A and B
Main Landing Gear Wear and Failure
The pilot reported that the left main landing gear would not retract. This incident brought to light a problem common to Models A and B Navion aircraft.During an operational test using the auxiliary hand pump, the technician heard a grinding sound coming from the left main gear. He discovered a broken pivot shaft. The pivot shaft failure occurred at the inboard cotter key hole. Apparently, when the pivot shaft broke, it bent the two bulkheads on which it rode. The technician inspected the right main gear and discovered severe wear on the pivot shaft, and it appeared ready to fail. He also inspected two other like aircraft. One aircraft displayed evidence of wear on both pivot shafts, and the other aircraft displayed cracking and wear on the left main gear.Part total time – 1,200 hours.
Piper PA32-300 Cherokee Six 300
Cracked Spinner Bulkhead
During a routine inspection, the technician noted a crack extending from the trailing edge of the forward spinner bulkhead to one of the nut plates. The crack continued for another inch forward. This is the second bulkhead installed on this aircraft in less than 8 hours due to the same problem.The mechanic checked the bulkhead mounting and the spinner several times for proper fit and alignment, and ensured proper torque on the spinner mounting screws. Two other aircraft in the same fleet have encountered similar failures.It appears the bulkhead is not shaped to the spinners and consequently becomes stressed after installing the mounting screws. Almost all of the cracks go through the nut plate rivet holes and continue forward.
Piper PA38-112 Tomahawk
Broken Aileron Rod-End
While in flight, the left aileron did not respond to the pilots control input. The pilot made a safe landing.The technician discovered the aft rod-end of the left aileron broken. The locknut and bearing end froze as a result of metal oxidation.The submitter speculates the method of locking the controls with the seatbelt puts the controls in a position that causes moisture to run down the rod to the rod-end. This moisture accelerated the oxidation process.
Piper PA46-310P Malibu
Incorrect Nose Gear Part
During flight, the pilot attempted to extend the gear with the emergency gear extension procedure but the nose gear would not extend and lock. The pilot landed by holding the nosewheel off the ground for as long as possible. The gear finally locked when the plane slowed to approximately 30 knots.The submitter stated the nose gear emergency extension spring was 2 inches too long. Therefore, it was unable to apply enough tension to function properly.Part total time – 2,236 hours.
Teledyne Continental TSIO360EB
Bearing Failure
During a top overhaul, the technician detected metal in the crankcase sump.An investigation disclosed the number 3 main bearing had dislodged and become loose in the crankcase. After he disassembled the engine, he discovered the number 2 main bearing was also working and becoming loose. The through-bolt torque had been checked 300 operating hours prior to this inspection and was found below limits, which may have caused the bearing failure.Part total time – 1,318 hours.
