History of Flight
On May 23, 2014, at 1602 Pacific daylight time, a Williams Helicopter Corporation UH-1H helicopter, registration N260TA, crashed immediately after takeoff near Waitsburg, Washington. The commercial pilot, who was the sole occupant, received minor injuries. The helicopter sustained substantial damage to the rotor system and tail boom. The flight was conducted under 14 Code of Federal Regulations Part 137, and visual meteorological conditions prevailed. No flight plan had been filed.
The pilot stated that the initial takeoff into a hover felt normal, and he increased hover altitude to escape the dust cloud. As he transitioned forward, he felt a vertical 1:1 vibration. Expecting it to dissipate, he continued forward, but the vibration intensified, throwing him against his shoulder straps. He attempted to land, but the helicopter rolled right and impacted the ground.
Witnesses reported seeing the helicopter stir up dust during takeoff, then descend tail-first seconds later, rolling onto its left side. Surveillance video captured the takeoff and immediate descent. The video showed the helicopter lifting into a hover amid dust, then moving up and forward out of frame. Additional cameras recorded the helicopter descending with the tail low and right side toward the ground; the rising dust obscured the impact.
A Federal Aviation Administration inspector examined the wreckage, collected maintenance records and surveillance video, and gathered witness statements.
Aircraft Information
The helicopter featured two cockpit seats and an agricultural application hopper tank in the cabin. Two data plates were affixed: one from Williams Helicopter Corporation indicating model UH-1H, serial number 70-15750, and another from Bell Helicopter Company listing model 205, UH-1H, serial number 10507 with customer serial number 70-15750. The Bell plate showed three locations where numbers had been stamped over previous digits. A Bell Helicopter technical representative noted that company records indicated the data plate serial number was inconsistent with information on either plate.
Maintenance records indicated the most recent maintenance was performed on May 23, 2014, at hobbs time 2,843.7 hours. Total aircraft time was 8,314.5 hours, and total engine time was 3,265.9 hours. This maintenance included repairs to the tail fin skin and ribs, the tail rotor drive shaft cover, and a 25-hour inspection.
Wreckage and Impact Information
On October 1, 2014, the NTSB investigator-in-charge and a Bell Helicopter technical representative examined the wreckage. The helicopter was on the recovery trailer. The tail boom had separated from the fuselage just aft of the fuselage-to-tail transition. The rotor head, main rotor blades, and tail rotor were stored separately in a hangar.
Control continuity was confirmed by moving cockpit controls and observing sequential movement at the stationary swash plate and tail rotor control bell crank/cables. Elevator control continuity was also verified.
The tail rotor angle drive (42° gearbox) was seized due to drive shaft misalignment, and the gearbox was fractured, exposing the drive gear. Preimpact drive continuity to the tail rotor was confirmed.
Drive train continuity to the main rotor was confirmed. The main drive shaft k-flex was fractured, consistent with transmission aft displacement. No heat distress was visible. The transmission rotated freely with no binding when the rotor mast was turned manually. The rotor mast exhibited a fracture surface and oval deformation consistent with torsional overload. The transmission had separated from all four mounting points and was displaced aft and left. The main mast stabilizer bar pitch arm had separated, and the damper reservoir was empty with dirt and oil near the pitch arm mount. The other stabilizer bar pitch link had detached from the damper rod end. The forward two transmission mount inserts were removed for examination.
Both main rotor blades were attached to the hub; balance weights for both were located. One blade had five large weights in the outboard pocket and none in the inboard pocket. The other blade had its outboard weights intact and 15 weights that would have occupied the inboard pocket. Both rotor mast stabilizer bars were present.
The tail rotor and gearbox remained attached. Rotor blade pitch links were attached, and the blades showed rotational leading edge and skin damage.