Buxbaum Mark Edward LONG EZ N444MR

Summary

On 5 September 2022 at about 16:30 local time, a Buxbaum Mark Edward LONG EZ registered N444MR was involved in an accident near Medicine Bow, Wyoming, United States. 2 people were on board and 2 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

5 September 2022 at 16:30

Classification

Accident

Location

Medicine Bow, Wyoming, United States

Coordinates

41.8984, -106.4389

Aircraft

Buxbaum Mark Edward LONG EZ

Registration

N444MR

Category

Airplane

Year built

1995

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Kanab → Hot Springs

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR22LA334

2 people were seriously injured.

A partial loss of engine power due to the fatigue fracture of the No. 4 exhaust valve head.

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

Read the full NTSB narrative

According to the pilot, he and a passenger were on a cross-country flight when, at approximately 7,500 feet above mean sea level (msl), the aircraft began aggressively shaking. The pilot initially flew toward a nearby airport but decided to land on a highway. The airplane landed hard, veered off the road, and impacted terrain. Subsequently, the airplane nosed over onto a fence and sustained substantial damage to the fuselage and wings. During the postaccident examination of the engine, excessive oil and carbon were discovered on the No. 4 cylinder valve springs, guide, stem, and retainers, which is consistent with exhaust blow-by. In addition, approximately 0.8 inches of the No. 4 exhaust valve stem and valve head were not recovered from the cylinder and engine. The remaining valve stem had excessive play within the valve guide. The fracture of the stem portion of the exhaust valve was the result of a fatigue crack that emanated from severe corrosion pits at the outer surface of the stem, which resulted in a loss of engine power. The engine's logbook entries revealed that it was last overhauled 41 years before the accident, exceeding Lycoming's recommendation of 12 years. It is likely that the No. 4 exhaust valve deteriorated from age and likely fractured from a fatigue crack.

Quoted verbatim from the NTSB record.