Pilot Debrief

BEECH 77 near Stanley, NM — 2021-08-12

Final reportWPR21LA316
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Date
2021-08-12
Location
Stanley, NM, USA
Airport
AEG
Aircraft
BEECH 77
Registration
N3873Y
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

A loss of engine performance due to lead fouling of the lower spark plugs, which resulted in an off airport forced landing.

NTSB narrative

The pilot departed an airport at an elevation about 5,800 ft mean sea level (msl), and reported that, upon reaching about 6,700 ft msl, the airplane would not continue to climb. The pilot performed a forced landing to a field, during which the right wing impacted a fence post, resulting in substantial damage. Examination of the engine revealed that all lower spark plugs were severely lead fouled. According to the manufacturer, severely lead fouled spark plugs can lead to misfiring, resulting in a degradation of engine performance. It is likely that the fouled spark plugs resulted in a loss of engine performance and the airplane’s subsequent inability to maintain altitude.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have aborted the flight after noting poor climb performance.

NTSB coding

Evidence available

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

Docket documents8

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