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Cases › DEN08FA101 · Part 135 fatal

BELL 407

Huntsville, TX, USA · 2008-06-08·N416PH

4
fatal
0
serious
Fatal
highest injury
Destroyed
damage

What happened

NTSB summary, verbatim

This report was updated on August 14, 2009. An Emergency Medical Services (EMS) flight dispatch was requested from the accident operator, since a previous EMS operator had "aborted" the same requested mission flight. The EMS operator, who had "aborted" the same mission approximately one hour and 30 minutes prior to the accident flight, reported low clouds in the vicinity of the accident site. No PIREP was reported with the FAA. Official weather reporting stations in the area recorded visional flight rules weather conditions. The pilot contacted his company's operations control center and discussed observed weather and the reasoning for the "turndown" by the other EMS operator. It was agreed that weather observation stations were reporting visual flight rules weather conditions and the flight was accepted. The EMS flight powered up for the accident leg at 0244:11 and departed at 0246:56. The onboard flight tracking system recorded the flight until 0247 to an altitude of 1,016 feet mean sea level (600 feet above the ground), on a flight path of 170 degrees. The wreckage was located 2.5 miles southwest of the last known coordinates in densely forested terrain, the next morning, in the exact location where the other EMS operator had encountered low clouds and lost their reference to surface light sources. Sheared tree tops indicate initial impact occurred with the helicopter's main rotor blade system, in a straight, nose low attitude. The flight path terrain was dark, without surface reference lights, and there was no moon. The accident helicopter was equipped with the Aviation Night Vision Imaging System and radar altimeter; however the settings on the radar altimeter could not be established and the pilot was not utilizing night vision goggles. The helicopter was not equipped with Helicopter Terrain Awareness Warning System (HTAWS). The pilot was appropriately trained and certified to fly the accident flight. An examination of the helicopter airframe, engine, and related systems revealed no anomalies.

Photographs

7the aircraft, and what the investigators found
Wreckage and site documentation · 7 photographs from the docket

Photographs are NTSB docket attachments — works of the US government, in the public domain. Captions are the Board’s own.

Probable cause

the Board's determination
The pilot's failure to identify and arrest the helicopter's descent, which resulted in its impact with terrain. Contributing to the accident was the limited outside visual reference due to the dark night conditions.

Occurrence sequence

2 stepsNTSB coding · CICTT taxonomy
  1. 1 · Enroute-climb to cruise
    Loss of visual reference
  2. 2 · Enroute-climb to cruise
    Controlled flight into terr/obj (CFIT)
    defining event

Findings

3 causal · 0 contributing
  • CAUSE
    Environmental issues › Conditions/weather/phenomena › Light condition › Dark — Contributed to outcome
  • CAUSE
    Aircraft › Aircraft oper/perf/capability › (general) — Not attained/maintained
  • CAUSE
    Personnel issues › Task performance › Use of equip/info — Pilot

NTSB analysis

from the final report

This report was updated on August 14, 2009. An Emergency Medical Services (EMS) flight dispatch was requested from the accident operator, since a previous EMS operator had "aborted" the same requested mission flight. The EMS operator, who had "aborted" the same mission approximately one hour and 30 minutes prior to the accident flight, reported low clouds in the vicinity of the accident site. No PIREP was reported with the FAA. Official weather reporting stations in the area recorded visional flight rules weather conditions. The pilot contacted his company's operations control center and discussed observed weather and the reasoning for the "turndown" by the other EMS operator. It was agreed that weather observation stations were reporting visual flight rules weather conditions and the flight was accepted. The EMS flight powered up for the accident leg at 0244:11 and departed at 0246:56. The onboard flight tracking system recorded the flight until 0247 to an altitude of 1,016 feet mean sea level (600 feet above the ground), on a flight path of 170 degrees. The wreckage was located 2.5 miles southwest of the last known coordinates in densely forested terrain, the next morning, in the exact location where the other EMS operator had encountered low clouds and lost their reference to surface light sources. Sheared tree tops indicate initial impact occurred with the helicopter's main rotor blade system, in a straight, nose low attitude. The flight path terrain was dark, without surface reference lights, and there was no moon. The accident helicopter was equipped with the Aviation Night Vision Imaging System and radar altimeter; however the settings on the radar altimeter could not be established and the pilot was not utilizing night vision goggles. The helicopter was not equipped with Helicopter Terrain Awareness Warning System (HTAWS). The pilot was appropriately trained and certified to fly the accident flight. An examination of the helicopter airframe, engine, and related systems revealed no anomalies.