19940715018639A

Accident · Substantial damage

FAA accident report · Aviat PITTS S1S · Stevensville, MD · July 15, 1994

Date: July 15, 1994 · 14:45 local
Place: Stevensville, MD
Airport: Kentmorr Airpark Airport
Phase of flight: Climb
Operating rules: General operating rules (Part 91)
Damage: Substantial damage
Aircraft: N515TN
NTSB investigation: NTSBNYC94LA129
Reported as: Aviat PITTSS1S
Reported engine: Lycoming O360A4G
Fatal injuries: 0

N515TNRegistration cancelled Aug 3, 2000 · Marteney Donald L PITTS S1SS/N 7-0255 Airframe modelMarteney Donald L PITTS S1S

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry by N-number and event date, checked against the reported make and model; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

Engine failed, landed in field, clipped right wing on tree skidded 150 ft ended up on nose and main gear. (.4)the airplane's engine lost total power just after takeoff when the pilot reduced the throttle. The pilot re-applied full throttle with no result. During the forced landing in a field, the airplane's wing struck a tree, and the airplane nosed over. Examination of the engine revealed that the crankshaft gear (13S19646) became disconnected from the crankshaft due to a broken bolt. Metallurgical examination of the accessory gear retaining bolt (p/n STD-2213), and dowel pin (p/n STD-1065) revealed that they separated as a result of high cycle fatigue mechanism, most likely caused by insufficient torque of the bolt.

As the FAA filed it

ENGINE FAILED, LANDED IN FIELD, CLIPPED RIGHT WING ON TREE SKIDDED 150 FT ENDED UP ON NOSE AND MAIN GEAR. (.4)THE AIRPLANE'S ENGINE LOST TOTAL POWER JUST AFTER TAKEOFF WHEN THE PILOT REDUCED THE THROTTLE. THE PILOT RE-APPLIED FULL THROTTLE WITH NO RESULT. DURING THE FORCED LANDING IN A FIELD, THE AIRPLANE'S WING STRUCK A TREE, AND THE AIRPLANE NOSED OVER. EXAMINATION OF THE ENGINE REVEALED THAT THE CRANKSHAFT GEAR (13S19646) BECAME DISCONNECTED FROM THE CRANKSHAFT DUE TO A BROKEN BOLT. METALLURGICAL EXAMINATION OF THE ACCESSORY GEAR RETAINING BOLT (P/N STD-2213), AND DOWEL PIN (P/N STD-1065) REVEALED THAT THEY SEPARATED AS A RESULT OF HIGH CYCLE FATIGUE MECHANISM, MOST LIKELY CAUSED BY INSUFFICIENT TORQUE OF THE BOLT.

NTSB investigation

The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.

NTSB NYC94LA129Accident · Minor injuriesLimited investigationFinal reportStevensville, MDInadequate maintenance by which undertorquing of the accessory gear retaining bolt resulted in fatigue failure of the bolt and the subsequent loss of engine power.Jul 15, 1994 · Substantial damage