Pilot Debrief

PIPER PA 28R-201T near Atmore, AL — 2015-09-07

Final reportERA15LA345
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Date
2015-09-07
Location
Atmore, AL, USA
Aircraft
PIPER PA 28R-201T
Registration
N44903
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

A total loss of engine power due to oil starvation caused by insufficiently torqued cylinder through bolt nuts, which caused bearings to shift and led to the subsequent failure of the No. 3 connecting rod.

NTSB narrative

The private pilot and the passenger departed on a cross-country flight. The pilot stated that the airplane was at an altitude of 4,500 ft mean sea level when the engine lost oil pressure, followed by a total loss of engine power. The pilot landed the airplane on a two-lane country road. During the landing roll, the airplane's right wing struck mailboxes, which caused substantial damage to the right wing. Examination of the engine revealed the torque values for the No. 2 cylinder upper through bolt nuts, both No. 3 cylinder through bolt nuts, and the No. 5 cylinder through bolt nuts were below factory specifications for breakaway torque. Further examination revealed that the No. 3 connecting rod was separated from the crankshaft, the No. 2 main bearings had shifted, and there were signs of oil starvation. The likely insufficiently torqued nuts allowed the No. 2 bearings to shift and rotate, which resulted in oil starvation to the corresponding connecting rods and main bearings and ultimately led to the failure of the No. 3 connecting rod, ancillary damage to other internal components of the engine, and a total loss of engine power. Review of maintenance records revealed that the No 3. cylinder had been removed and reinstalled about 1 year before the accident. The engine's most recent annual inspection was completed about 9 months before the accident. There were no irregularities noted, and all airworthiness directives were complied with as noted by the mechanic. The investigation could not determine whether the loosening of the nut torque was due to improper installation or another unrelated issue.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have returned to Foley Municipal Airport after engine oil pressure loss.

NTSB coding

Evidence available

  • Photos
  • 9 docket documents
View NTSB final reportView NTSB docket

Docket documents9

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