Pilot Debrief

PIPER PA 28R-201T near Nipton, CA — 2017-11-17

Final reportWPR18LA033
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Date
2017-11-17
Location
Nipton, CA, USA
Aircraft
PIPER PA 28R-201T
Registration
N5966V
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

A loss of engine power due to the detonation of the No. 5 cylinder due to excessive leaning at high power settings, which resulted in a forced landing and the subsequent hard touchdown.

NTSB narrative

About 40 minutes after takeoff and while the airplane was at a cruise altitude of 10,000 ft mean sea level, the pilot began leaning the engine mixture. After about 5 minutes, the pilot observed that the engine was running roughly, the No. 5 cylinder head temperature had spiked, and the airplane was unable to maintain altitude. The pilot could not restore engine power and subsequently made a forced landing on a highway. The airplane touched down hard, which resulted in substantial damage to both wings. A postaccident engine examination confirmed continuity to the accessory section. Spark was produced on all six top spark plug leads, and thumb compression was obtained on all cylinders except the No. 5 cylinder. The top spark plugs were removed, and all except the No. 5 spark plug exhibited dark-colored combustion deposits; the No. 5 spark plug exhibited a molten, metal-like substance around the electrode. Cylinder Nos. 1 and 3 exhibited minor signs of detonation. The No. 5 cylinder exhibited signs of detonation/preignition with material missing from around the circumference of the piston face, and the No. 5 cylinder exhaust and intake valves showed signs of mechanical damage. The detonation was consistent with excessive leaning at high power settings.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have diverted to alternate airport instead of attempting highway landing.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

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