Robinson R-22 HP accident near Scottsdale, Arizona, January 25, 1991
On January 25, 1991 at about 3:40 pm local time, a Robinson R-22 HP (helicopter), registered N21439, was substantially damaged in an accident near Scottsdale, Arizona. It was an instructional flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
THE FAILURE OF THE DRIVE BELTS DUE TO EXCESSIVE WEAR OF THE CLUTCH ASSEMBLY UPPER SHEAVE AND THE PILOT'S INACCURATE FLARE DURING THE TERMINATION OF THE AUTOROTATION. A FACTOR IN THE ACCIDENT WAS THE INADEQUATE DESIGN OF THE CLUTCH ASSEMBLY UPPER SHEAVE.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 25, 1991 · about 3:40 pm local time
- Place
- Scottsdale, Arizona · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R-22 HP · all R-22 HPs on the register
- Registration
- N21439 · registry record · serial 0096
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT, AFTER SEEING THE HELICOPTER'S CLUTCH CAUTION LIGHT ILLUMINATE, HEARD A LOUD 'BANG'. HE LOWERED THE COLLECTIVE AND ENTERED AN AUTOROTATIVE DESCENT. HE TERMINATED LOW TO THE TERRAIN, AND THE AIRCRAFT STRUCK TAIL STINGER FIRST, CAUSING IT TO BOUNCE AND THEN ROLL OVER. A VISUAL INSPECTION OF THE HELICOPTER REVEALED TWO OF THE DRIVE BELTS HAD FAILED, CAUSING A DRIVE TRAIN SEPARATION. THE HELICOPTER MANUFACTURER DISCOVERED THE BELTS FAILED AS A RESULT OF EXCESSIVE WEAR ON THE CLUTCH ASSEMBLY UPPER SHEAVE. THE EXCESSIVE WEAR ON THE SHEAVE WAS CAUSED BY THE BELTS, GRITS, AND SAND. THIS CREATED A SHARP EDGE ON THE SHEAVE WHICH CAUSED THE FAILURE OF THE BELTS.
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: student
- Flight time: 58 hours in all; 58 in this make and model; 58 in the last 90 days; 48 in the last 30 days
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 2,350 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-B2C (piston); 0 hours total
- Operator: Arizona Wing & Rotor, INC.
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 55°F (13°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
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 LAX91LA079.