Beechcraft B36TC N30799

Summary

On 14 December 2006 at about 14:04 local time, a Beechcraft B36TC registered N30799 was involved in an accident near Peoria, Illinois, United States. One person was on board and nobody was injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

14 December 2006 at 14:04

Classification

Accident

Location

Peoria, Illinois, United States

Coordinates

40.1642, -89.6931

Aircraft

Beechcraft B36TC

Registration

N30799

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Dubuque → Centralia

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

CHI07LA038

Nobody was injured.

The loss of engine power due to a fatigue fracture of the exhaust valve as a result of maintenance not performed by the aircraft owner, and the unsuitable terrain encountered during the forced landing.

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

Read the full NTSB narrative

The airplane experienced a loss of engine power and an in-flight fire during cruise flight, and was subsequently destroyed by fire after a forced landing in a field. The pilot reported that the airplane was in cruise flight when the engine started "missing." The pilot put the mixture to full rich, switched fuel tanks, and adjusted the propeller and throttle, but the engine continued to run rough. The pilot executed a forced landing in a field with the windshield 60 percent covered with oil and with smoke coming into the cockpit. The engine teardown inspection revealed that the #5 intake and exhaust valve heads were missing. The intake and exhaust valve stems and the exhaust valve guide were removed from the cylinder for further examination at the National Transportation Safety Board (NTSB) Materials Laboratory. The fracture surface of the exhaust valve stem (Part Number: SA643767P005 C FAA-PMA) was consistent with a brittle fracture mechanism such as fatigue. The maximum clearance of the exhaust valve guide (difference between the inner diameter of the valve guide and out diameter of the valve stem) was measured as 0.019 inch. According to the 1989 Teledyne Continental Motors (TCM) overhaul manual for the IO-520 engine, the maximum serviceable limit for exhaust valve guide clearance is 0.006 inch. Maintenance records indicated that an oil analysis taken on June 23, 2004, stated the following: "Note Extreme Nickel Concentration. High Concentration of Nickel is Caused By Valve Guide Wear. Contact Engine Manufacturer's Service Rep. Resample in 25 Hours." The aircraft owner reported that no maintenance was performed on the engine in regards to the oil analysis. The oil sample was taken at 663 hours since Time Since Overhaul (TSO). The engine failure occurred about 2.5 years later and had accumulated about an additional 300 hours of operation.

Quoted verbatim from the NTSB record.