Bell 407 accident near Littleton, Colorado, December 15, 1997
On December 15, 1997 at about 5:00 am local time, a Bell 407 (helicopter), registered N771AL, was destroyed in an accident near Littleton, Colorado. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). 4 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's inability to maintain adequate visual lookout due to the lighting conditions and his failure to follow company procedures for departure from a landing zone. Factors were dark night conditions, bright lights in the landing zone which prevented vision beyond the zone, and the power line existence was not available on charts to either the pilot or ground personnel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 15, 1997 · about 5:00 am local time
- Place
- Littleton, Colorado · map
- Type
- Accident
- Injuries
- 4 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 407 · all 407s on the register
- Registration
- N771AL · no longer on the register · serial 53068
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
On takeoff from an automobile accident site, with the patient on board, the air ambulance flight made a climbing right turn and flew into power lines. Witness marks on the helicopter provided evidence the helicopter struck the transmission line from below and impacted the ground in an inverted attitude below and to the west of the lines. Light conditions were a dark night with emergency response, construction, and emergency response vehicle lights illuminating the landing site area. The existence of the power lines was unknown to the fire rescue on-scene commander and the light conditions prevented the pilot from seeing anything outside the lighted area. The unmarked power lines were 622 feet apart and oriented northeast/southwest. The southern tower was 106 feet high and the northern tower 83.5 feet high. The towers and lines did not meet obstruction-marking criteria and were not marked. In addition, they were not depicted on sectional or topographic maps. Company policy, promulgated through documents and training, provided landing zone departure procedures which instructed the pilot to climb straight ahead in a near vertical climb to a minimum of 300 feet agl before turning. The horizontal distance from the helicopter's takeoff position to the power line was approximately 630 feet based on global positioning system (GPS) measurement.
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: instrument: helicopter; rotorcraft: helicopter
- Flight time: 4,118 hours in all; 122 in this make and model; 39 in the last 90 days; 11 in the last 30 days; 3,832 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 464 hours
- Last inspection: approved inspection programme, December 6, 1997; 130 hours since
- Maximum gross weight: 5,000 lb
- Seats: 4
- Landing gear: fixed
- Engine: Allison 250-C47B (turboshaft); 0 hours total
The flight
- Departed from: N/A Aurora CO at 5:40 am
- Destination: N/A
- Runway 0
Weather at the time
- Light: night, dark
- Wind: from 130° at 7 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 39°F (4°C), dew point 48°F (9°C)
- Altimeter: 30.00 inHg
- Observation at 5:45 am from APA, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 3 | |||
| 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.