Bell 407 N771AL

Summary

On 15 December 1997 at about 05:00 local time, a Bell 407 registered N771AL was involved in an accident near Littleton, Colorado, United States. 4 people were on board and 4 died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

15 December 1997 at 05:00

Classification

Accident

Location

Littleton, Colorado, United States

Coordinates

39.5904, -105.0090

Aircraft

Bell 407

Registration

N771AL

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Aurora → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Night/Dark

NTSB number

FTW98FA068

4 people died.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.