Squawk Box

On attempting to start the engine for a post-maintenance ground run, the propeller turned through approximately three blades then stopped. Propeller was difficult to rotate forward or backward. Inspection of the starters Bendix drive shaft revealed cracks in the gear running parallel to the teeth, causing the gear not to properly mesh with the flywheel.

During a routine inspection, the technician noted the strobe lights would remain on after the switch was selected off. Troubleshooting revealed the switch to be defective. Removing and disassembling the switch revealed the solder joint holding the braided wire had broken and welded itself to the line post. Switch was replaced IAW AD 2008-13-17 in May 2009.

Pitot heat switch would not stay in the on position. On troubleshooting, the technician found circuit breaker/switch (p/n 35-38013263) to be at fault. AD 2008-13-17 had been completed 2427 flight hours prior. Recommend breaker manufacturer develop a more durable product or aircraft maker look for a different source for its circuit breakers.

Pilot observed smoke in the cockpit, declared emergency and landed normally. Inspection of the right engine compartment revealed the mufflers aft wall was missing and exhaust was directed onto the battery box. Hot exhaust melted the battery and battery contactor, clock fuse holder, both battery cables and boots. The gascolator push/pull control knob was melted.

Engine lost power, causing aircraft to make an emergency landing, resulting in substantial damage. Investigation revealed microbial growth in the carburetor’s fuel bowl at the drain plug area, causing blockage at the fuel channel and subsequent loss of power. This could be avoided by removing the carburetor (p/n MA3) drain plug at specified intervals and draining any moisture that may accumulate in that area.

During a scheduled wing bolt inspection, the left lower aft bathtub fitting was found to have chafe marks from contact with the clip on the wing fitting cover. One mark extended into the fitting radius. The manufacturer was consulted and provided a field repair to remove the damage.

Installed a rebuilt starter adapter and overhauled starter. On starting, the prop turned about 10 degrees and stopped. Pilot then smelled a burning odor and could not shut off the battery. The cowling was removed but the battery box was too hot to touch. Using gloves, the battery was disconnected.

Upon removal, found a two-inch-long piece of material in filter outlet, which appears to be the edge of a gasket. It could only have gotten there when the filter was manufactured. The material would have plugged small oil passages had it moved into the engine as it was on the downstream side of filter.

Alternator (p/n ASG120003RX) failed to charge during cross-country flight. Alternator cooling fan came apart in flight. Front engine charging system was intermittent, then constant alternator inoperative light was observed. The right engine locked up in flight, going into feather, and could not be restarted.

During oil and filter change, chips and large metal pieces were found. During an annual inspection, the engine oil quick drain valve was blocked with debris. About a dozen pieces of what appeared to be piston ring pieces were removed. While performing a condition inspection, a crack was found on #6 intake. After takeoff, the crew noted engine vibration and lack of power. Inspection revealed excessive oil in the engine area and on the aircraft belly. After a precautionary landing due to power loss, a compression check showed zero on cylinder A4.