Low-Altitude Maneuvering · NTSB CEN19LA055
Beech 36 — Fredericksburg, TX
| Date | January 17, 2019 |
| Location | Fredericksburg, TX |
| Aircraft | Beech 36 |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Maneuvering Fire/smoke (non-impact) |
| Pilot age | 50 |
| Pilot total time | 550 hrs · Building experience |
| Time in type | 5 hrs |
| Fatalities | 1 |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Engine (reciprocating)-Recip engine power section-Failure - C
- Aircraft-Aircraft power plant-Engine (reciprocating)-Recip engine power section-Fatigue/wear/corrosion - C
What happened
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.