# NTSB LAX91LA389: Cessna 172P, N97564, Hesperia, CA, September 11, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: September 11, 1991, 11:00 local (18:00 UTC)
- Place: Hesperia, CA
- Coordinates: 34.359664, -117.319671 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=34.3597&lon=-117.3197&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 3 serious
- Status: Completed, report May 3, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27355
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA389
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27355/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA389

## Probable cause

A STUCK EXHAUST VALVE DUE TO THE OPERATOR'S NON COMPLIANCE WITH A MANUFACTURERS RECOMMENDED SERVICE BULLETIN ON THE ENGINE.  CONTRIBUTING TO THE ACCIDENT WAS THE LACK OF SUITABLE TERRAIN FOR A SAFE LANDING.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, climb
  - engine assembly,valve,exhaust - contamination (cause)
  - engine assembly,valve,exhaust - seized (cause)
  - maintenance,service bulletin/letter - not performed, company maintenance personnel (cause)
- Forced landing, descent - emergency
  - terrain condition - none suitable (contributing factor)
- In flight collision with terrain/water, descent - emergency
  - terrain condition - rough/uneven

## Analysis

DURING THE INITIAL CLIMB, THE PILOT EXPERIENCED A LOSS OF ENGINE POWER, AND WAS UNABLE TO CONTINUE TO CLIMB OR MAINTAIN ALTITUDE. THE PILOT STATED TO FAA INSPECTORS THAT HE CHANGED FUEL TANKS AND ADJUSTED THE MIXTURE TO NO AVAIL. HE LANDED STRAIGHT AHEAD INTO UNSUITABLE TERRAIN AND NOSED OVER. INVESTIGATION DETERMINED THAT NUMBER 2 CYLINDER EXHAUST VALVE HAD STUCK OPEN FROM CARBON BUILD UP. A MANUFACTURERS SERVICE BULLETIN REGARDING THIS POSSIBLE PROBLEM HAD NOT BEEN ACCOMPLISHED AT THE RECOMMENDED TIME, NOR WERE OTHER ITEMS OF IN SERVICE INSPECTION/INFORMATION REGARDING VALVE STICKING ADDRESSED ACCORDING TO THE RECORDS AVAILABLE.

## Aircraft

- Registration: [N97564](https://openairdocs.org/deregistered/N97564-1992-01-24), registration cancelled 1992-01-24, S/N 17276210 (OpenAirDocs)
- Reported make and model: CESSNA 172P
- Registry model: [Cessna 172P](https://openairdocs.org/model/cessna-172p) (registry code 2072436) (OpenAirDocs)
- Category: Airplane
- Serial number: 17276210
- Engines: LYCOMING O-320-D2J 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Mohave Aviation Inc.
- Registered owner: Mohave Aviation Inc.
- Last inspection: Unknown, January 2, 2000
- Departed: L26, HESPERIA, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 6,000 total, 10 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 3 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Observed at: VCV, 1 nm away

## 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 19910911039339A](https://openairdocs.org/incident/19910911039339A), Sep 11, 1991: Cessna 172P, Hesperia, CA, Substantial damage. Engine lost power on climbout. Crash landed. Found a sticking valve. Service bulletin on valves not complied.

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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