Accident Overview
On August 23, 2015, at approximately 1645 mountain standard time, a Schweizer 269C helicopter, registration N315TV, was substantially damaged when it landed hard at Falcon Field Airport (FFZ) in Mesa, Arizona. The helicopter was registered to Canyon State Aero LLC. and operated by the pilot under Title 14 Code of Federal Regulations Part 91. The commercial pilot was not injured, and the passenger sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which originated from FFZ around 1615.
Pilot Report
The pilot reported that during the approach to the ramp area in front of the operator's hangar, he noticed erratic cyclic control movements. During the landing, the helicopter landed hard.
Examination Findings
Initial examination by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the main rotor blades and tail boom. The helicopter was later moved to a secured local storage facility for further examination.
A subsequent examination by the National Transportation Safety Board (NTSB) investigator-in-charge, an FAA inspector, and a representative from Sikorsky showed the helicopter sitting upright on its skids with the tail boom separated. All three main rotor blades remained attached to the main rotor head, but the main rotor mast was tilted.
The flight control system was generally intact, with all rods and bellcranks properly attached. Flight control continuity was established with the cyclic and collective controls in the cockpit. Continuity to the tail rotor was established from the cockpit pedals to the forward end of the control rod, where a fracture was observed, and from that fracture point to the tail boom. The electric cyclic trim system operated normally with no anomalies.
The main rotor mast support structure, including the lower transmission housing, sustained damage, causing the mast to tilt. Scratches and marks on the mast indicated its movement. Additional damage was noted on the aft cabin bulkhead. The main rotor head was intact and attached to the drive shaft, and the swashplate was intact. The rotor head rotated freely in the mast bearing, and the pitch housings remained attached and correctly installed.
Rotor Damper Condition
The main rotor head dampers were removed and examined. All three dampers displayed compression contact marks on the interior of the barrel end caps, indicating excessive lead-lag motion. Additionally, the dampers had internally separated. Further examination revealed that one damper had become dis-bonded, which would result in degradation of its damping capability.
Engine and Systems
The engine was intact but slightly displaced due to damage to the mast and main gear box mounting. Continuity with all engine controls was established. When the starter was engaged, the engine rotated normally, with suction observed on the cylinders and fuel servo inlet.
No additional evidence of a mechanical malfunction that would preclude normal operation was found.
Maintenance Records
A review of maintenance records showed that the last annual inspection occurred on June 14, 2015, at 2,368 hours. The dampers were determined to be the original units. The main rotor damper inspection would have been complied with during the August 28, 2011, inspection at 2,319 hours. Although not required, no specific results of the damper check dimensions were documented.