NTSB Identification: SEA04MA167.
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Nonscheduled 14 CFR
Accident occurred Saturday, August 21, 2004 in Battle Mountain, NV
Probable Cause Approval Date: 01/26/2006
Aircraft: Bell 407, registration: N2YN
Injuries: 5 Fatal.
NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.
The emergency medical services (EMS) helicopter departed for a night flight to transport an 11-day-old infant patient from a hospital in Battle Mountain, Nevada, to another in Reno, Nevada. No record was found indicating the pilot obtained a weather briefing before departure. The pilot had a choice of taking either a direct route that crossed a remote area of rugged mountainous terrain with maximum ground elevations of about 9,000 feet or a route that was about 10 minutes longer and followed an interstate highway with maximum ground elevations of about 6,000 feet. After takeoff, the pilot reported his departure to the Elko county dispatch center, stating that his estimated time en route was l hour 20 minutes. There were no further radio communications from the helicopter. Radar data, which show about 4 minutes of the helicopter's flight before coverage was lost due to mountainous terrain, are consistent with the flight following the direct route. A search was initiated about 4 hours after the helicopter did not arrive at the destination hospital, and the wreckage was located the following morning. The accident site was along the direct course line at an elevation of about 8,600 feet. Physical evidence observed at the accident site indicated that the helicopter was in level flight at impact and was consistent with controlled flight into terrain. No evidence was found of any preimpact mechanical discrepancies with the helicopter's airframe or systems that would have prevented normal operation. Rotational damage to the rotor blades and transmission components were consistent with normal engine operation at impact. The two closest aviation weather reporting stations, located 31 and 54 nautical miles (nm) from the accident site, both reported 10 miles visibility, clear skies below 12,000 feet, and no precipitation at the time of the accident. However, satellite images valid approximately 1 hour before the accident indicated cloud cover over the accident site. Additionally, weather radar images valid approximately 1.5 hours before the accident indicated light precipitation was present in the vicinity of the accident site. However, the exact weather conditions and cloud ceiling at the time and location of the accident could not be determined. If the pilot had obtained a weather briefing, he would likely have learned of the cloud cover and light precipitation present along his planned route of flight. Studies conducted by the National Transportation Safety Board and industry have shown that the urgent nature of the EMS mission can result in inaccurate/incomplete preflight planning, as well as poor pilot judgment. The fact that the patient was an infant may well have placed additional pressure on the pilot to take the direct route to arrive at the hospital sooner. The helicopter was not equipped with an enhanced ground proximity warning system (EGPWS), and none as required. If installed, an EGPWS would have alerted the pilot of high terrain ahead at least 35seconds before impact. Although the search for the helicopter was not initiated until about 4 hours after the accident (despite company flight-following procedures that indicated an aircraft should be reported missing as soon as it fails to make a required 15-minute position report), this accident was not survivable and a faster notification would not have changed the outcome.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain clearance from mountainous terrain. Contributing factors were the pilot's improper decision to take the direct route over mountainous terrain, the dark night conditions, and the pressure to complete the mission induced by the pilot as a result of the nature of the EMS mission. Full narrative available
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