On June 27, 2001, a Bell 212 (registration N5017H) operated by State OF Alaska, Division OF Forestry was involved in an aviation accident near Clear, AK. Investigators recorded the probable cause as: The pilot's selection of an unsuitable landing site following a partial loss of power during approach to landing in a multiengine helicopter. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A twin-engine helicopter experienced a loss of engine power in the number two engine while waiting near a helipad. The pilot executed an immediate landing into a confined area, colliding with trees and sustaining substantial damage. Investigation revealed an improper bleed air flow jet in the AFCU.
Accident Sequence
A pilot was operating a twin-engine helicopter that was lightly loaded. While flying in close proximity to a helipad and waiting for another helicopter to depart, the pilot reported a loss of engine power in the number two engine. According to the helicopter's operations manual, the aircraft was capable of sustaining flight and initiating a rate of climb between 550 and 700 feet per minute on one engine. Despite this capability, the pilot elected to make an immediate landing into a confined area. During the descent, the helicopter collided with trees, resulting in substantial damage.
Investigation Findings
An examination of the engines revealed that an improper bleed air flow jet had been left installed in the engine's automatic fuel control unit (AFCU). This installation was contrary to a service bulletin issued by the manufacturer. The presence of the incorrect bleed air flow jet resulted in substandard fuel flow pressure, creating a potential for a loss of engine power.