Cessna 172P accident near Hesperia, California, September 11, 1991
On September 11, 1991 at about 6:00 pm local time, a Cessna 172P, registered N97564, was substantially damaged in an accident near Hesperia, California. It was a personal flight under general aviation rules (Part 91). 3 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 11, 1991 · about 6:00 pm local time
- Place
- Hesperia, California · map
- Type
- Accident
- Injuries
- 3 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172P · all 172Ps on the register
- Registration
- N97564 · no longer on the register · serial 17276210
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 6,000 hours in all; 10 in the last 30 days
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded, January 2, 2000
- Maximum gross weight: 2,400 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-320-D2J (piston); 0 hours total
- Operator: Mohave Aviation INC.
The flight
- Departed from: L26 Hesperia CA at 6:00 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 330° at 3 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Observation at 5:55 pm from VCV, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.