65 MI.ENE OF MC, AK, USA
N891A
PIPER PA-22
DURING FLIGHT, THE PILOT NOTICED A PROGRESSIVE LOSS OF POWER. HE ELECTED TO MAKE AN EMERGENCY LANDING ON A GRAVEL BAR. DURING THE LANDING, THE AIRCRAFT ROLLED THROUGH A SHALLOW SLOUGH WHERE THE LEFT MAIN GEAR HIT A LOG. THE NOSE GEAR THEN HIT A BANK AT THE EDGE OF THE SLOUGH AND THE PLANE WENT OVER ON ITS BACK. THE ENGINE DIED WHEN THE AIRCRAFT TURNED OVER. AN EXAMINATION OF THE ENGINE REVEALED THAT THE NO 3 ROCKER ARM EXHAUST VALVE ADJUSTMENT BOLT HAD FAILED AND WAS LOOSE IN THE VALVE COVER.THERE WAS EVIDENCE THAT THE BOLT MAY HAVE BEEN OVERTORQUED. THE BOLT SHOULD HAVE BEEN TORQUED TO 450 INCH POUNDS. A CHECK OF THE OTHER BOLTS REVEALED TAHT THEIR TORQUE VALUES RANGED FROM 150 TO 450 INCH POUNDS. THE ENGINE HAD A TOTAL OF 3.7 HOURS OF OPERATION SINCE IT HAD A TOP OVERHAUL.
Source: NTSB Aviation Accident Database
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