On August 16, 1992, a Mbb BO 105CBS-4 (registration N295EH) operated by Era Aviation, Inc. was involved in an aviation accident near Ship Shoal 90. Investigators recorded the probable cause as: The pilot's failure to switch on the forward and aft main fuel boost pumps, which resulted in the loss of power to both engines despite adequate fuel quantity remaining in the main tank. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 3 related events involving the same aircraft type or operator are linked below.
A helicopter experienced sequential engine power loss over the Gulf of Mexico, forcing an autorotation into the water. Investigation revealed the pilot failed to switch on the main fuel boost pumps, despite eighty gallons remaining in the tank.
What happened
The aircraft was operating in a cruise flight configuration over the Gulf of Mexico when it experienced a critical mechanical failure. The number one engine lost power first, which was immediately followed by the loss of power in the number two engine. With both engines non-functional, the pilot initiated an autorotation procedure to attempt a controlled descent and landing on the water surface.
The investigation
A post-accident examination of the helicopter was conducted to determine the root cause of the dual engine failure. The inspection revealed that there were no mechanical anomalies or defects noted within the helicopter's systems that would explain the loss of power. However, the investigation found that the forward and aft main fuel boost pumps had not been switched 'on' by the pilot during the flight.
Findings
The primary finding was that the fuel boost pumps were not activated. These pumps are responsible for directing fuel to the supply tank. Despite the lack of pump operation, the examination confirmed that eighty gallons of fuel remained in the main fuel tank at the time of the incident. The failure to switch on the boost pumps is identified as the critical factor leading to the engine power loss.
Probable cause
The pilot's failure to switch on the forward and aft main fuel boost pumps, which resulted in the loss of power to both engines despite adequate fuel quantity remaining in the main tank.