What happened
Between 0130 and 0355 on May 3, 2011, an Aerospatiale AS350B2, registration N916AM, sustained substantial damage while performing maneuvers at Woodward Field in Camden, South Carolina. The flight was part of a night vision goggle training session conducted under 14 CFR Part 91. The two pilots on board were not injured.
The training session included two flights between 2130 on May 2 and 0355 on May 3. The maneuvers performed during these flights included simulated hydraulic failures, sloping ground landings, rapid decelerations, and various types of autorotations, such as hovering and turning autorotations. The instructor pilot reported that no abnormal vibrations or heavy landings were felt during the maneuvers, and that the aircraft had been inspected prior to the second flight with no discrepancies found.
The investigation
An inspection by an FAA inspector and a company mechanic identified that the tail boom was buckled approximately 42 inches in front of the horizontal stabilizer. The investigation also found that the tail rotor gearbox input seal was leaking oil excessively. Additionally, the tail fin stinger (referred to by Eurocopter as the lower fin tail guard) showed fresh marks from contact with the ground. While a mechanic had inspected the aircraft at 1900 on May 2 and found no such damage, the post-accident inspection confirmed the presence of these new contact marks.
Findings
Although the instructor pilot did not report any hard landings or ground contact with the tail fin stinger, the physical evidence—specifically the buckled tail boom and the ground contact marks on the tail fin stinger—was consistent with a hard landing.