Bell 47G-3B-1 accident near Colorado Spring, Colorado, July 4, 1991
On July 4, 1991 at about 4:40 pm local time, a Bell 47G-3B-1 (helicopter), registered N40DP, was substantially damaged in an accident near Colorado Spring, Colorado. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 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 PILOT ATTEMPTING TO OPERATE THE HELICOPTER OUTSIDE THE DESIGN OPERATING ENVELOPE. FACTORS WERE: HIGH ALTITUDE, HIGH TEMPERATURE, AND HIGH DENSITY ALTITUDE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 4, 1991 · about 4:40 pm local time
- Place
- Colorado Spring, Colorado · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G-3B-1 · all 47G-3B-1s on the register
- Registration
- N40DP · registry record · serial 3763
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
DURING TAKEOFF FROM A HIGH ALTITUDE, HIGH DENSITY ALTITUDE HELICOPTER PAD, INSUFFICIENT POWER WAS AVAILABLE TO MAINTAIN FLIGHT OUT OF GROUND EFFECT AND THE HELICOPTER SETTLED INTO ROUGH AND UNEVEN TERRAIN. THE MAIN ROTOR BLADES STRUCK THE TERRAIN DURING LANDING. DENSITY ALTITUDE WAS 11,700 FEET.
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: multi-engine land; single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 3,300 hours in all; 500 in this make and model; 29,023 as pilot in command
- 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: 2,950 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435V1 (piston); 0 hours total
- Operator: Helitech, INC.
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 270° at 3 knots
- Visibility: 65 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 34°F (1°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.