KEOKUK, IA, USA
N7973D
BEECH B35
THE PIC RPTD A LOSS OF MANIFOLD PRESS DURING CRUISE FLT AND AN INABILITY TO MAINTAIN ALT. A FORCED LNDG WAS MADE TO THE KEOKUK ARPT, BUT THE PIC STATED HE WAS TOO HIGH AND FAST FOR A LNDG. THE PIC MADE A GO-AROUND, BUT AGAIN APPROACHED TOO FAST. ANOTHER ATTEMPT WAS MADE TO GO-AROUND, BUT AN INCREASE IN THROTTLE PRODUCED NO ADD'TL PWR. THE PIC THEN VEERED TOWARDS AN OPEN AREA TO ATTEMPT A LNDG. THE ACFT IMPACTED AN AREA OF TREES AND FELL TO THE GRND. EXAM OF THE AIRCRAFT REVEALED THAT THE THROTTLE ARM WAS SLIPPING OVER THE SERRATED EDGES OF THE THROTTLE BODY SHAFT RESTRICTING FULL MOVEMENT OF THE THROTTLE SHAFT. CLOSEUP EXAM OF THIS ARM AND SHAFT REVEALED THAT THE CASTELATED NUT HAD BACKED OFF THE BOLT ALLOWING THE ARM TO LOOSEN. A COTTER PIN IS NORMALLY INSTALLED IN THE AREA OF THE CASTELATTED NUT TO PREVENT IT FROM BACKING OFF THE BOLT. THE BOLT AND NUT WERE FOUND STILL POSITIONED ON THE THROTTLE ARM, BUT THE COTTER PIN WAS NOT FOUND.
Source: NTSB Aviation Accident Database
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