Engine Issues

The following information is derived from the FAA's Service Difficulty Reports and Aviation Maintenance Alerts


Lycoming IO-540-AE1A5 – Failed Intake Valve
Inspection of the cylinder removed from a Robinson R44 Raven II showed catastrophic damage to the piston and combustion area from multiple (piston/valve/head) contacts. Fractured valve parts became wedged in the induction tube and in the common manifold area. The top portion of the valve stem above the ‘keepers’ was the area of separation/failure. In the submitter’s opinion, the failure may have been caused from a stress riser created during manufacturing.

Part Total Time: 381.0 hours

Lycoming TIO-540 – Broken Fuel Injector Line
On departure, the Piper PA-31-350 Chieftain pilot reported all engine indications were normal prior to rotation. Climbing out of 4000 feet, the right engine lost power. The pilot returned and landed without incident.


Inspection revealed the number one cylinder injection line (p/n LW120980100) had broken. AD 2011-26-04 was last complied with in May 2012. The aircraft was last inspected 67.7 hours prior. No defects had been found during the inspection.

Part Total Time: 20,555.3 hours

Champion Spark Plug REM38S – Mis-manufactured
New REM38S fine-wire plugs were installed in the Lycoming IO-540 powering this Maule. A problem with the plugs’ resistors was noticed—engine starting was difficult when hot. At the next annual inspection, seven of the 12 plugs had failed: The resistors were completely open, registering “1” on an Ohm meter. The other five plugs were high—one at 36,000 Ohms. All plugs were removed and replaced.

Part Total Time: 205.0 hours

Slick 6310 Magneto – Failed Contact Point
The engine in this A36 Bonanza was running rough—when the magneto switch was moved to the right position, the engine would stall. The magneto was removed from the engine and disassembled. The contact assembly (p/n M3081) arm was missing the contact point. Further inspection found the missing point—it was removed from the magneto. The magneto was reassembled with a new contact assembly. Engine run-up was then performed with no defects noted. An improper crimp of the contact point to the arm at the time of manufacture is suspected as the cause of this failure.

Part Total Time: 10.0 hours


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