alerta - motor - informativo de manutenção

8/4/2019 Alerta - Motor - Informativo de Manuteno

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Continental: GTISO520H; Cracked Propeller Shaft; ATA 8510

"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) onthe 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 gaugesat which time the propellerseparated 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 shaftP/N: 633908).


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Pratt & Whitney: PW306A; Failed Turbine Blade; ATA 7250A technician says, "About 45 minutes into the flight and climbing through flight level 360, the crew heard a loud 'bang'

and felt vibration. The ITT (internal turbine temperature) began an immediate climb, followed by the 'FIRE' light and

smoke in the cabin. The crew brought the throttle to idle, shut down the engine via the fuel cutoff switch, declared anemergency, and was vectored by ATC to the nearest suitable airport."


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ACCESSORIES Bendix Magneto: S6RN1225; Failed Bearing; ATA 7414

(The following report not only includes careful photo compositions, but also contactinformation for interested readers having similar concerns. The magneto in questionbolts to a Continental IO550Cit connected to a Beechcraft 58. A hearty "thank-you"

goes to Ray for his frequent and detailed submissions!) Chief Inspector Raymond Benischeck from Quest Diagnostics Flight Operationsstates, "During a preflight run-up, the left engine was observed to only produce about2000 RPM. Inspection of the left magneto revealed the bronze bearing had become

loose in the distributor block, allowing the distributor gear electrode to strike anddamage several of the distributor block electrodes. This is the third instance of aBendix 1200 series magneto to fail in this conditionaround 1300 hours. These

magnetos have been inspected in accordance with the 500 hour requirements of theTCM 1200 series maintenance manual at the required intervals. All these failures

have occurred within a six week time frame. TCM has been contacted and they areaware of two other, similar failures. They are performing analytical inspections on the

returned units." (Component number: BL3493504; the Part Number 10391586reflects eight times in the SDRS databaseall for loose bearings!)


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Continental: IO550N; Chafed Fuel Injector Line; ATA 7310 (The following report pertains to a Cirrus SR22 airplane.) "An aircraft owner requested we clean his fuel injectorswhich we did," says an

aircraft mechanic. "I was nearly completed with the tasktightening the nut for thenumber one cylinder fuel injection line. I noticed the line was very loose. Upon furtherinspection I found the retaining clip (designed) to secure the line to an engine bracketwas falling out (apart?) and not doing its job. I also noticed black staining on anadjacent engine structure. When I removed the line, I found approximately one inchof 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 cylinderfuel injection line on the opposite side of the engine also had damage, but this wascaused 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 ignitionleads 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 tankhole under helicoptersEd.)


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Lycoming: TIO540J2BD; Cam-follower Pitting; ATA 8520

(The following report combines and references two different, same model engines on

two different Piper PA31350 aircraft from the same submitter..) A submitter states, "Excessive cam lobe wear is causing power loss and early

removal of several of our Chieftain Lycoming engines. This engine was removed at1,650.2 hours TTSO (total time since overhaul), with 549.8 hours remaining on our

2,200 hour overhaul interval. I have been in contact with Lycoming Technical Support

for an extended period of time, now, and have yet to find a solution. It seems forsome reason one cam follower will (usually) become pitted and begin to acceleratewear on the lobe that it rides on. (I have) no idea what is causing the pitting or how toprevent it. We use only Lycoming factory remanufactured engines in our entire fleet."


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(This second engine had 1,455 hours total, with 745 hours time remaining.)


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Bombardier: BD100-1A10; Sheared Generator Spline Shaft; ATA 2421About 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."


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Cessna: 172S; Frayed Aileron Cable"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 througha strong magnifying glass many broken strands could be seen."


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Continental: IO550C; Leaking Dipstick Housing; ATA 8550 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 fillingthe crankcase. Having seen this problem several times in the past,the mechanic immediately knew to look at the dipstick tube (P/N6494061) in the chafed area. As in all the previous situations, the

hole is located at the first inside bend below the filler opening. Eventhough the OEM says they are not aware of the problem, most ofour in-service engines show some sign of chafing which can be

observed by looking down the oil fill opening on the crank case sideof the tube. Fortunately, once the dipstick is in place, it tends to fillthe chafed opening and very little oil can escape through the hole.The attached photos show the dipstick through the chafed holeit

actually creates a decent seal."


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Continental: IO470N; Failed Oil Cooler Gasket; ATA 7921(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."

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