加拿大航空服务难度报告 Canadian Aviation Service Difficulty Reports(5)

PIPER PA44-180 SDR # 20040517002
Stabilator Servo-Trim Cable Frayed
While removing an electric trim servo used in the stabilator system, the forward stabilator trim cable, P/N 62701160, was discovered frayed. It also had wound itself around the electric trim servo pulley. The cable was replaced with a new one.
The submitter added that this it is a difficult area to inspect. In order to locate any defects on the cable, the electric trim servo may have to be functionally operating in both directions.
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AEROSPATIALE AS332L SDR # 20040504001
Tail Rotor Pedal Adjuster Cracked

This SDR may be worth keeping in mind while inspecting this area.
BELL 407 SDR # 20040413006
Water in Tail Rotor Blade
A tail rotor blade, P/N 406-016-100-119, was discovered to have absorbed water. This anomaly caused an imbalance of the tail rotor creating excessive vibrations.
Time Since New (TSN):
The manufacturer added that the water ingress might have been caused by a void in the sealant.

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AVCO LYCOMING O-320-E2D (Cessna 172M) SDR # 20040216005
Excessive Wear Due to Improper Lubrication
The engine oil on a Cessna 172 was found contaminated after only 33 hours since overhaul (TSO). Following engine disassembly, the source of the oil contamination was obviously due to the abnormal and excessive wear found on all four connecting rods. A deep scar was also noted on the crankshaft.
The operator completed a thorough inspection of the engine and concluded that all of the manufacturer's inspection requirements were carried out satisfactorily at overhaul.
Following a discussion with the pilots, it was learned that the engine had recently been subjected to cold weather starts without being pre-heated. It was also revealed that the aircraft was in operation with 100-grade mineral oil (summer oil) because 80-grade mineral oil (winter oil) was not available. The operator stated that they use 100-grade oil for the "break-in" period following engine overhaul.
The operator concluded that the use of 100-grade oil in very cold starting conditions caused a lack of lubrication in the engine power section (crankshaft, connecting rods).
The viscosity of engine oil is imperative to ensure proper lubrication under all operating and temperature conditions. In addition to reducing friction, the viscous oil film acts as a cushion between moving parts thereby reducing friction. The engine manufacturer’s recommended oils should be used at all times.
AVCO LYCOMING TIO-540-J2BD (Piper PA31 350) SDR # 20040312002
In-flight Engine Fire
During cruise flight, noises were heard coming from the #2 engine. Shortly thereafter, there was a loud bang and vibration followed by oil and smoke coming from the engine cowl. The crew immediately feathered the propeller and shut down the #2 engine and carried out an uneventful landing.
　
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