Mooney M20J N4201S

Summary

On 28 August 1999 at about 20:10 local time, a Mooney M20J registered N4201S was involved in an accident near Emigrant Gap, California, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

28 August 1999 at 20:10

Classification

Accident

Location

Emigrant Gap, California, United States

Nearest airport

Blue Canyon Airport (KBLU)

Coordinates

39.2499, -120.6890

Aircraft

Mooney M20J

Registration

N4201S

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Palmdale → Truckee

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX99LA287

2 people had minor injuries.

The fatigue failure and separation of the number three cylinder due to the cylinder overhaul facility's improper inspection and quality control processes.

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

Read the full NTSB narrative

The pilot was at cruise altitude of 9,500 feet when he heard a loud metallic bang. The airframe began to shake violently and the engine started running rough immediately following the noise. The pilot turned toward a nearby airport and the engine suddenly quit. The pilot was able to glide to the airport and touched down on the 3,300-foot-long runway; however, he had carried extra speed on the approach to allow a maneuvering margin to miss a large ravine off the runway's approach end. The airplane ran off the end of the runway and subsequently struck scrub bush. Postaccident examination of the engine revealed that the number three cylinder had separated in half between the Nos. 9 and 10 cooling fins. Metallurgical examination disclosed that the fracture was due to a fatigue crack, which had emanated from a notch and groove on the outer radius of one cooling fin. The notch and groove were painted the same color as the engine. The engine was overhauled 16 hours prior to the accident with 3 new cylinders installed, including the failed one.

Quoted verbatim from the NTSB record.