What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) The preliminary investigation centered around the pilot's statement that he heard a loud knocking sound eliminating from the engine compartment. Shortly after, the engine began to experience severe vibration and loss of power. RPM dropped to 1100, oil and fuel pressure remained normal. But, the aircraft continued to lose power and altitude, forcing the pilot to select an emergency landing site. The inspection of the engine disclosed number three exhaust stack mounting flange and several of the cylinder studs broken. The carburator air filter box was blown open at the seams, it appears to be from engine backfire. All of the cylinder had normal compression and the engine oil showed obvious signs of metallic particles. Rub marks were noticed on the right lower engine rubber mount (lord mount) from hitting the glange of the engine's steel mounts. In addition, the magneto's ignition timing were noted at 25 degrees b.t.d.c and the fuel tanks were 3/4 full. The preliminary investigation points to a stuck cylinder exhaust valve.
As the FAA filed it
(-23) THE PRELIMINARY INVESTIGATION CENTERED AROUND THE PILOT'S STATEMENT THAT HE HEARD A LOUD KNOCKING SOUND ELIMINATING FROM THE ENGINE COMPARTMENT. SHORTLY AFTER, THE ENGINE BEGAN TO EXPERIENCE SEVERE VIBRATION AND LOSS OF POWER. RPM DROPPED TO 1100, OIL AND FUEL PRESSURE REMAINED NORMAL. BUT, THE AIRCRAFT CONTINUED TO LOSE POWER AND ALTITUDE, FORCING THE PILOT TO SELECT AN EMERGENCY LANDING SITE. THE INSPECTION OF THE ENGINE DISCLOSED NUMBER THREE EXHAUST STACK MOUNTING FLANGE AND SEVERAL OF THE CYLINDER STUDS BROKEN. THE CARBURATOR AIR FILTER BOX WAS BLOWN OPEN AT THE SEAMS, IT APPEARS TO BE FROM ENGINE BACKFIRE. ALL OF THE CYLINDER HAD NORMAL COMPRESSION AND THE ENGINE OIL SHOWED OBVIOUS SIGNS OF METALLIC PARTICLES. RUB MARKS WERE NOTICED ON THE RIGHT LOWER ENGINE RUBBER MOUNT (LORD MOUNT) FROM HITTING THE GLANGE OF THE ENGINE'S STEEL MOUNTS. IN ADDITION, THE MAGNETO'S IGNITION TIMING WERE NOTED AT 25 DEGREES B.T.D.C AND THE FUEL TANKS WERE 3/4 FULL. THE PRELIMINARY INVESTIGATION POINTS TO A STUCK CYLINDER EXHAUST VALVE.
Other reports on N32506 · 1
Matched to the same aircraft by N-number and date.