Pilot Debrief

CESSNA 170B near Mahwah, NJ — 2009-07-19

Final reportERA09LA409
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Date
2009-07-19
Location
Mahwah, NJ, USA
Airport
4N1
Aircraft
CESSNA 170B
Registration
N8339A
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Climb

Probable cause

A loss of engine power due to the failure of the No. 1 cylinder thru bolt hold down nuts due to corrosion.

NTSB narrative

During a cross-country flight, the airplane’s engine began to vibrate heavily, lost all power, and the pilot executed an emergency landing in a field. During the landing roll, the airplane impacted a hill, and sustained substantial damage. On a previous flight, the pilot recalled a vague vibration while en route. A mechanic was unable to identify the source of the vibration, and a "no defects noted" statement was entered into the logbook after various component checks. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the No.1 cylinder revealed that two thru bolt nuts were loose. Two of the other bolts were sheered off, and one was missing. The threads on the thru bolt, with the missing nut, were rusted.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have opted for an earlier emergency landing after engine vibration.

NTSB coding

Evidence available

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

Docket documents4

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