What happened
On January 27, 2015, an EC2LLP helicopter, registration PR-BGA, operated by Brazilian Helicopter Services Táxi Aéreo S.A., was performing a passenger transport flight from the Garoupa Oil Rig to the Farol de São Tomé Helipad in Campos dos Goytacazes, Rio de Janeiro. The aircraft was carrying two pilots, one flight attendant, and 18 passengers.
After landing at the helipad, the aircraft began taxiing when the crew observed low oil pressure in the number-2 engine. Shortly thereafter, the engine caught fire. The flight crew responded by shutting down the affected engine and activating the helicopter's onboard fire extinguisher. While the crew's actions helped manage the situation, ground personnel were also required to assist in extinguishing the remaining flames. The incident resulted in no injuries to the 21 occupants, though the aircraft sustained minor damage to the engine and its fairing.
The investigation
CENIPA investigators examined the engine components and maintenance history of the aircraft. The investigation focused on the disconnection between the rear bearing lubrication pipe and its duct. Physical examination of the thread fillets revealed soot, confirming that the components were already disconnected when the fire started.
Testing of a similar engine on a test bench failed to replicate a total disconnection of these parts, leading investigators to look toward maintenance practices. The investigation noted that the manufacturer had performed the initial assembly of these specific items on PR-BGA. Furthermore, the committee reviewed a previous incident involving another aircraft in the same fleet, PR-BGK, which had experienced a loss of oil pressure in flight due to a similar leak.
Findings
- The fire was caused by lubricating oil leaking from a disconnected pipe and igniting upon contact with hot engine parts.
- The investigation identified insufficient torque application during the assembly of the lubrication pipe as the likely cause of the disconnection.
- There was evidence of managerial oversight regarding the inspection and release of the aircraft for service, as the disconnected line was not detected prior to flight.
- The crew's decision to use the onboard fire extinguisher, while standard for critical emergencies, was noted as not being specifically prescribed in the flight manual for an engine fire occurring while the aircraft is on the ground and external firefighting resources are available.