# NTSB LAX94LA066: Yakovlev YAK-55M, N7090L, Greenfield, CA, November 20, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 20, 1993, 13:00 local (21:00 UTC)
- Place: Greenfield, CA
- Coordinates: 36.259849, -121.370613 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.2598&lon=-121.3706&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 13, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 28615
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX94LA066
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28615/pdf
- Page: https://openairdocs.org/ntsb/LAX94LA066

## Probable cause

UNDETERMINED.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power, maneuvering
  - reason for occurrence undetermined (cause)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing

## Analysis

THE PILOT REPORTED THAT WHILE EXECUTING AEROBATIC MANEUVERS THE ENGINE BEGAN TO RUN ROUGH.  THE PILOT SAID THAT HE ATTEMPTED TO EXECUTE AN EMERGENCY LANDING AT THE AIRPORT, BUT THE ALTITUDE WAS INSUFFICIENT TO MAKE THE RUNWAY.  THE PILOT REPORTED THIS ACCIDENT FOUR DAYS AFTER THE ACCIDENT AND HAD REMOVED THE AIRPLANE BEFORE INVESTIGATORS COULD EXAMINE IT.

## Factual narrative

On November 20, 1993, at 1300 hours Pacific standard time, an experimental Yakovlev Yak-55M, N7090L, collided with the terrain while attempting a forced landing at Metz airport, Greenfield, California.  The pilot was conducting a local visual flight rules aerobatic flight.  The airplane, registered to John W. Heinrich, Concord, California, and operated by the pilot, sustained substantial damage.  The certificated private pilot, the sole occupant, was not injured.  Visual meteorological conditions prevailed.  The flight originated at Metz airport at an undetermined time.

The pilot contacted the Federal Aviation Administration on November 24, 1993.  At that time, he reported that he was performing aerobatic maneuvers when he experienced engine problems.  The pilot executed a forced landing to Metz airport, but the airplane's altitude was insufficient to make the runway.

The pilot removed the airplane from the accident site without informing the National Transportation Safety Board.  Neither the pilot nor the operator provided the Safety Board with the required Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2.

## Aircraft

- Registration: [N7090L](https://openairdocs.org/aircraft/N7090L), registered now, S/N 930807, built 1993 (OpenAirDocs)
- Reported make and model: YAKOVLEV YAK-55M
- Registry model: [Yakovlev YAK-55M](https://openairdocs.org/model/yakovlev-yak-55m) (registry code 9830224) (OpenAirDocs)
- Registry engine: [Vedeneyev M14P](https://openairdocs.org/engine/vedeneyev-m14p) (registry code 63601, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 930807
- Engines: Vendeneyev M-14P 360 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: James D. Lewis
- Registered owner: Heinrich, John W.
- Departed: 3CA7, METZ, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: front; flight hours: 526 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19931120044479A](https://openairdocs.org/incident/19931120044479A), Nov 20, 1993: Yaklev YAK52, Greenfield, CA, Substantial damage. During acrobatic maneuvers developed engine problems. Unable to return to airport. Collided with terrain.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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