Enstrom 280C accident near Longmont, Colorado, September 30, 1999
On September 30, 1999, a Enstrom 280C (helicopter), registered N84DH, was substantially damaged in an accident near Longmont, Colorado (Vance Brand airport). 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).
The NTSB's probable cause their words, unchanged
An inaccurate touchdown during a full autorotation, which resulted in main rotor flex which cut off the tail boom. Factors were the pilot's lack of total experience in helicopters and high density altitude.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 30, 1999 · cases in 1999
- Place
- Longmont, Colorado · Vance Brand · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom 280C · all 280Cs on the register
- Registration
- N84DH · registry record · serial 1055
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While practicing autorotations, the pilot, who was a commercial pilot in single and multiengine aircraft but a student pilot in helicopters, experienced a loss of engine power for unknown reasons. During the full autorotation, which was necessitated by the power loss, the landing was hard and resulted in main rotor flex, which cut off the tail boom. Density altitude at the time was 9,000 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: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 2,127 hours in all; 40 in this make and model; 91 in the last 90 days; 30 in the last 30 days; 2,004 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 688 hours
- Last inspection: annual inspection, April 5, 1999; 12 hours since
- Maximum gross weight: 2,200 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO-360-E1AD (piston); 0 hours total
The flight
- Departed from: 2V2 at 11:30 pm
- Flight plan: none
- Runway 29, 4,800 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 250° at 6 knots
- Visibility: 40 statute miles
- Sky: clear
- Temperature: 97°F (36°C), dew point 86°F (30°C)
- Altimeter: 30.00 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.
Connections how this case links to the rest of the register
- N84DH on the register today · the tail number may have moved to another aircraft since
- Enstrom 280 Shark 65 registered today · the model family and its accident history
- Enstrom 215 aircraft on the register
- Engine: Lycoming HIO-360-E1AD 10 aircraft carry this series today · as the NTSB recorded it
- Accidents and incidents in Colorado 2,860 since 1982 · 383 in the last ten years
- Colorado 7,484 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/DEN99LA173.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.