Amateur-built DHC-6-100 accident near Perris Valley, California, December 9, 1990
On December 9, 1990 at about 10:00 pm local time, a amateur-built DHC-6-100, registered N121PM, was substantially damaged in an accident near Perris Valley, California (Perris Valley airport). It was a flight of an unrecorded kind under general aviation rules (Part 91). 1 person had minor injuries; 20 others were unhurt. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A LOSS OF POWER ON THE LEFT ENGINE DUE TO A FATIGUE FAILURE OF A COMPRESSOR TURBINE BLADE LEADING TO FURTHER COMPRESSOR BLADE DAMAGE; A WORN POWER TURBINE GOVERNOR THROTTLE CAM ASSEMBLY WHICH LED TO LOSS OF POWER ON THE RIGHT ENGINE; AND INADEQUATE MAINTENANCE AND INSPECTION BY THE OPERATOR.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 9, 1990 · about 10:00 pm local time
- Place
- Perris Valley, California · Perris Valley
- Type
- Accident
- Injuries
- 1 person had minor injuries; 20 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built DHC-6-100
- Registration
- N121PM · registry record · serial 14
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
AFTER LIFT-OFF, AT ABOUT 100 FT AGL AND 85 KTS, THE LEFT ENG DECELERATED AND THE AIRPLANE BEGAN TO YAW AND ROLL LEFT. THE PIC ABORTED THE TAKEOFF, TURNED LEFT AND LANDED ON A FLAT LEVEL FIELD. THE AIRPLANE STRUCK A FENCE, THEN TREES. EXAMINATION OF THE LEFT ENG REVEALED THE LOSS OF POWER WAS ATTRIBUTED TO A FATIGUE FRACTURE OF A COMPRESSOR TURBINE BLADE, WHICH LED TO SUBSEQUENT BLADE FRACTURES. THE RIGHT ENG WAS EXAMINED AND FOUND TO HAVE ADVANCE WEAR ON THE THROTTLE CAM ASSEMBLY OF THE POWER TURBINE GOVERNOR. IN A TEST CELL, ONLY APRX 28% OF TAKEOFF POWER COULD BE ACHIEVED. THE CAM LOBE WEAR HAD PROGRESSED OVER AN EXTENDED PERIOD OF TIME. THE RIGHT ENGINE PROP GOVERNOR WAS REPLACED 11/18/90, FOLLOWED BY A TEST RUN.
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, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: glider
- Flight time: 5,527 hours in all; 333 in this make and model; 55 in the last 90 days; 30 in the last 30 days; 2,576 as pilot in command; 1,119 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 45,332 hours
- Last inspection: continuous airworthiness programme, August 1, 1990; 81 hours since
- Maximum gross weight: 11,579 lb
- Seats: 2
- Landing gear: fixed
- Engine: P&W PT6-20 (turboprop); 0 hours total
- Operator: One Papa Mike CORP.
The flight
- Flight plan: none
- Runway 15, 5,100 ft by 65 ft
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 19 |
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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number LAX91FA052.