On the 18 February 2018 Bristow USSikorskyS-76C+N860AL suffered a landing gear collapse during taxy at Acadiana Regional Airport (ARA), New Iberia, LA. The aircraft was performing an offshore oil and gas flight for Talos Energy with 2 crew and 3 passengers.
Bristow US Sikorsky S-76C+ N860AL at ARA, New Iberia: Note Degraded Paving (Credit: FAA via NTSB)
The Accident
In their safety investigation report, the US National Transportation Safety Board (NTSB) say:
The pilot reported that, while the copilot was taxiing the wheel-equipped helicopter to the runway for departure, he saw a “bump” on the concrete. The copilot reported that he attempted to stop before the “bump,” which turned out to be a pothole, but the helicopter struck the pothole with the right main landing gear, which collapsed. The pilot and the copilot both reported that the taxi speed was less than 5 knots.
All 5 persons on board escaped uninjured. The NTSB say that:
The helicopter sustained substantial damage to the internal fuselage structure.
Bristow US Sikorsky S-76C+ N860AL Structural Damage (Credit: FAA via NTSB)
The operator’s accident report form describes that this was a “non-maintained but commonly used taxiway/ramp” that was “made up of concrete sections that are approximately 12′ x 12′.”
The NTSB documentation does not discuss why the surface was not previously identified as damaged and there is no follow up with the airport authority. It is relatively unusual for an S-76 to operate from ARA so its just possible it was ground taxing along a route in which skidded helicopters would normally hover taxi and so the degraded paving was not normally an issue. No safety actions are reported.
Probable Cause
The NTSB determined the probable cause to be:
The helicopter’s striking of a pothole while taxiing, which resulted in the right main landing gear collapsing.
Taxonomies of Flight Safety
The NTSB classified this occurrence as an accident as per the following US legal definitions:
830.2 Definitions. As used in this part the following words or phrases are defined as follows:
Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage. For purposes of this part, the definition of ‘‘aircraft accident’’ includes ‘‘unmanned aircraft accident,’’ as defined herein.
Substantial damage means damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling, dented skin, small punctured holes in the skin or fabric, ground damage to rotor or propeller blades, and damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wingtips are not considered ‘‘substantial damage’’ for the purpose of this part.
However, in the Bristow annual report for FY2018 (which ended 31 March 2018) the CEO oddly stated that the company “finished FY18 with no Class A or B air accidents” (implying no accidents with >$500k of damage). This is an adaption of a US military designation system, not usually used in civil industry.
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