Pilot Debrief

Beech 36 near Fredericksburg, TX — 2019-01-17

Final reportCEN19LA055
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Date
2019-01-17
Location
Fredericksburg, TX, USA
Airport
T82
Aircraft
Beech 36
Registration
N2021T
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Cruise

Probable cause

The loss of engine power due to fatigue failure of the crankshaft.

NTSB narrative

The accident pilot was in cruise flight in a single-engine airplane when he declared "mayday" on the radio, stating the airplane's engine was on fire. The accident airplane impacted a field, crossed a road, and came to rest upright. A postcrash fire consumed the majority of the airframe. The airplane was equipped with a turbo-charged reciprocating engine and propeller that had been converted under a Supplemental Type Certificate (STC). The engine had accumulated 412.2 hours between the last overhaul and the last annual inspection. The last inspection was about three months before the accident. An examination of the engine revealed fire damage and limited rotation. Disassembly of the engine revealed a broken camshaft and crankshaft. Metallurgical examination of the crankshaft revealed crack arrest marks in the crankshaft, consistent with fatigue, which initiated in the fillet radius at the forward end of the number 6 connecting rod journal. Multiple crack origins and prominent crack arrest lines were consistent with a relatively high stress associated with crack initiation. However, a reason for the high stress or fatigue initiation could not be determined based on the limited airplane records and the damage to the airplane.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have conducted a precautionary landing after engine fire indication.

NTSB coding

Evidence available

  • ADS-B / radar
  • Photos
  • 9 docket documents
View NTSB final reportView NTSB docket

Docket documents9

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