Simmons Gary F STOL CH 701 N422ES

Summary

On 15 July 2017 at about 18:40 local time, a Simmons Gary F STOL CH 701 registered N422ES was involved in an accident near Kenwood, California, 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

15 July 2017 at 18:40

Classification

Accident

Location

Kenwood, California, United States

Coordinates

38.4144, -122.5453

Aircraft

Simmons Gary F STOL CH 701

Registration

N422ES

Category

Airplane

Year built

2010

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Cloverdale → Sonoma

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR17LA156

Nobody was injured.

Failure of the flywheel drive assembly, which resulted in a loss of engine power and subsequent forced landing to uneven terrain.

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, a severe vibration came from the engine, and cooling fluid leaked onto the windscreen. About 30 seconds later, the engine lost total power. The pilot made a forced landing on a narrow field, and the airplane slid off the landing area into a ditch, coming to rest nose down substantially damaging the left wing and forward fuselage. An engine examination revealed that one of the spider pins and some of the material holding the pins, which connect three rubber links that transmit power between the engine and transmission, had broken. The semi-attached broken pin resulted in extreme vibration, it swung out on the other pin by centrifugal force which hit and broke the coolant line causing a loss of coolant and subsequent loss of engine power. Two days after the accident, the engine manufacturer recalled the flywheel drive assemblies and stated they would be replaced with heavier flywheel drive assemblies.

Quoted verbatim from the NTSB record.