Lancair LC41-550FG N521RT

Summary

On 11 March 2011 at about 18:07 local time, a Lancair LC41-550FG registered N521RT, operated by Robertson Contractors, Inc., was involved in an accident near Carbondale, Illinois, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 March 2011 at 18:07

Classification

Accident

Location

Carbondale, Illinois, United States

Coordinates

37.7011, -89.2492

Aircraft

Lancair LC41-550FG

Registration

N521RT

Category

Airplane

Year built

2004

Engines

1

Operator

Robertson Contractors, Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Route

Indianapolis → Poplar Bluff

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN11FA227

Nobody was injured.

The fatigue fracture and subsequent failure of the No. 2 cylinder exhaust valve during cruise flight, which resulted in a total loss of engine power.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot reported that, during cruise flight, the airplane experienced a momentary loss of engine power. While diverting to the nearest airport and completing the emergency checklist items, the engine lost total power, and the pilot chose to make a forced landing to a nearby field. During the landing roll, the airplane's right wing struck a power utility pole before the airplane impacted a ditch and came to rest in a nose-low attitude. A postaccident engine examination revealed that the piston for the No. 2 cylinder had fractured into numerous pieces. Additionally, the exhaust valve head for the No. 2 cylinder had fractured perpendicular to the stem direction where the valve protrudes into the cylinder head during normal operation. The fracture surface of the exhaust valve stem exhibited a series of crack arrest marks consistent with a fatigue crack propagation. Oxidization of the fracture surface was consistent with prolonged exposure to a combustion environment. The fatigue fracture was likely due to extreme temperature gradients experienced along the exhaust valve in the area above the valve seat. A review of available flight data established that the engine had been operated in a manner consistent with the pilot operating handbook. However, without a complete historical flight data record, it was not possible to determine if the engine had been operated outside of its normal operating limits at some point since its original manufacture.

Quoted verbatim from the NTSB record.