Mcdonnell Douglas MD-600 accident near Flagstaff, Arizona, November 4, 1996
On November 4, 1996 at about 3:23 pm local time, a Mcdonnell Douglas MD-600 (helicopter), registered N630N, was substantially damaged in an accident near Flagstaff, Arizona (Flagstaff Pullium airport). 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
An uncommanded main rotor blade to tail boom contact due to a 'blowback' phenomena after a successful preplanned autorotation by the pilot to a high density altitude airport with a test aircraft designed at a maximum gross weight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 4, 1996 · about 3:23 pm local time
- Place
- Flagstaff, Arizona · Flagstaff Pullium · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas MD-600
- Registration
- N630N · registry record · serial 0004F
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The test pilot made a successful preplanned autorotation to a runway in the test helicopter for certification purposes. The aircraft was operated at a designed maximum gross weight to establish a height velocity curve for future operations in high density altitudes. During the ground slide, the main rotor blades contacted and severed the tail boom. Various combinations of engineering design and the 'blowback' phenomena allowed the retreating main rotor blades to tilt downward and contact the tail boom.
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, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: glider; rotorcraft: helicopter
- Flight time: 10,317 hours in all; 1,169 in this make and model; 88 in the last 90 days; 31 in the last 30 days; 8,120 as pilot in command; 5,001 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 1,961 hours
- Last inspection: annual inspection, April 26, 1996; 63 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: FLG at 2:40 pm
- Flight plan: none
- Runway 21, 7,999 ft by 150 ft
Weather at the time
- Light: dawn
- Wind: from 210° at 2 knots
- Visibility: 25 statute miles
- Sky: clear
- Temperature: 32°F (0°C), dew point 28°F (-2°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.
Other NTSB records under N630N the same tail number, which may have belonged to a different aircraft at the time
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.