Amateur-built EXEC 90 accident near Glendale, Arizona, May 22, 1992
On May 22, 1992 at about 6:30 pm local time, a amateur-built EXEC 90 (helicopter), registered N7656T, was substantially damaged in an accident near Glendale, Arizona (Glendale Muni Airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE IMPROPER CARBURETOR IDLE ADJUSTMENT BY COMPANY MAINTENANCE PERSONNEL. CONTRIBUTING TO THIS ACCIDENT WAS THE CFI'S INABILITY TO ATTAIN ADEQUATE RPM AND THE SOFT DIRT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 22, 1992 · about 6:30 pm local time
- Place
- Glendale, Arizona · Glendale Muni Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built EXEC 90
- Registration
- N7656T · no longer on the register · serial RI-5001
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE FLIGHT DEPARTED THE AIRPORT ON A LOCAL INSTRUCTIONAL FLIGHT. WHEN THE FLIGHT RETURNED TO THE AIRPORT THE CFI INSTRUCTED THE NONCERTIFICATED STUDENT PILOT TO EXECUTE A SIMULATED ENGINE OUT AUTOROTATION. THE STUDENT PILOT ENTERED THE AUTOROTATION AT A LOW MAIN ROTOR RPM, BUT DURING THE DESCENT THE RPM INCREASED TO THE LOW SIDE OF ITS NORMAL OPERATING RANGE. THE CFI ATTEMPTED TO TERMINATE THE AUTOROTATION AT 200 FEET AGL BECAUSE OF THE MARGINAL LOW ROTOR RPM, BUT WHEN HE APPLIED RAPID FULL THROTTLE THE ENGINE FALTERED AND THEN FAILED. THE CFI EXECUTED AN EMERGENCY AUTOROATIVE LANDING. ON TOUCHDOWN THE HELICOPTER BOUNCED, THE SKIDS DUG INTO THE SOFT DIRT ON THE SECOND TOUCHDOWN AND THE HELICOPTER CAME TO AN ABRUPT STOP AND ROLLED OVER. THE POST ACCIDENT ENGINE EXAMINATION DISCLOSED THAT THE ENGINE OPERATED NORMALLY THROUGHOUT ITS NORMAL OPERATIONAL PARAMETERS BUT WHEN THE THROTTLE WAS RAPIDLY APPLIED AFTER A PROLONGED IDLE THE ENGINE FALTERED. THE IDLE RPM WAS MARGINAL AND THE CARBURETOR HAD RECENTLY BEEN REPLACED.
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: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: helicopter; rotorcraft: helicopter
- Flight time: 695 hours in all; 246 in this make and model; 174 in the last 90 days; 57 in the last 30 days; 615 as pilot in command; 432 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 235 hours
- Last inspection: continuous airworthiness programme, April 24, 1992; 38 hours since
- Maximum gross weight: 1,425 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway RI-162 (piston); 0 hours total
- Operator: Cobb International, INC.
The flight
- Flight plan: none
- Runway 19, 5,350 ft by 75 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 35 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.