Cessna 150L N19427

Summary

On 29 September 1998 at about 21:54 local time, a Cessna 150L registered N19427, operated by Jacobson, Sandra, L., was involved in an accident near Bonners Ferry, Idaho, 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

29 September 1998 at 21:54

Classification

Accident

Location

Bonners Ferry, Idaho, United States

Coordinates

48.7496, -116.5092

Aircraft

Cessna 150L

Registration

N19427

Category

Airplane

Engines

1

Operator

Jacobson, Sandra, L.

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA98LA190

Nobody was injured.

Improper maintenance by an outsourcing facility which resulted in a lack of identification of scoring of the interior of the #3 cylinder rocker shaft bosses. The scoring resulted in a fatigue fracture and subsequent permanent closure of both intake and exhaust valves. Contributing factors were the lack of a suitable landing site and trees.

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

Read the full NTSB narrative

During the initial climb following a touch-and-go landing, the engine sputtered twice and the pilot-in-command initiated an emergency landing. The field of choice was obstructed with construction equipment and she chose an alternate field. She retarded the throttle to idle, lowered full flaps, and slipped the aircraft to land as expeditiously as possible; and then steered the aircraft into small trees and brush to avoid going over an embankment. Post-crash examination revealed all 3 bosses of the #3 cylinder broken, thus rendering the intake/exhaust valves permanently closed. Metallurgical examination revealed that the separation of the rocker arm shaft bosses was initiated by fatigue cracking in the boss located adjacent to the exhaust valve. Further examination revealed the presence of heavy tool marks on the bore surface of all three bosses. The heavy manual cutting of the bore surface is not authorized by the engine manufacturer and the surface created by this procedure did not meet the engine manufacturer requirements for surface finish in the bore of the bosses. A review of the aircraft's engine log revealed an overhaul 645.4 hours previous to the accident. The overhaul facility reported that all 4 cylinders were outsourced during the overhaul procedure.

Quoted verbatim from the NTSB record.