Boeing MD600N accident near Mesa, Arizona, February 3, 1998
On February 3, 1998 at about 4:35 pm local time, a Boeing MD600N (helicopter), registered N9204D, was substantially damaged in an accident near Mesa, Arizona (Falcon Field). It was a flight of an unrecorded kind under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the attempt by flight test engineers to verify a height/velocity data point that was subsequently shown to be outside the aircraft's performance capabilities.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 3, 1998 · about 4:35 pm local time
- Place
- Mesa, Arizona · Falcon Field · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing MD600N
- Registration
- N9204D · no longer on the register · serial RN004
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While in the process of verifying a height/velocity performance data point, the pilot entered an autorotation at takeoff power and maximum gross weight. The onboard telemetry revealed that the pilot reduced the throttle to flight idle at the entry point but that the remaining momentum caused the aircraft to accelerate and climb. During the descent, the main rotor rpm decayed and an excessive vertical sink rate developed. The aircraft landed hard at the intended touchdown point. The aircraft was hover-taxied from the landing area and a normal shutdown was completed. The test pilot reported that the height/velocity data point was outside the aircraft's performance capabilities.
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, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: glider; rotorcraft: helicopter
- Flight time: 10,361 hours in all; 308 in this make and model; 54 in the last 90 days; 18 in the last 30 days; 6,526 as pilot in command; 2,972 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 191 hours
- Last inspection: 100-hour inspection, May 5, 1997; 164 hours since
- Maximum gross weight: 4,100 lb
- Seats: 2
- Landing gear: fixed
- Engine: Allison 250-C47M (turboshaft); 0 hours total
The flight
- Departed from: FFZ at 2:36 pm
- Flight plan: none
- Runway 4L, 3,800 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 040° at 1 knots
- Visibility: 7 statute miles
- Sky: scat at 20,000 ft
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
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.
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.