Enstrom Helicopter has resumed flight tests of its TH-180 with a May 26 flight of the second prototype and the objective of pursuing an accelerated schedule for certification of the two-seat, piston-powered trainer.
The wholly owned subsidiary of Chongqing General Aviation Group said test pilot and Senior Technical Fellow William Taylor took the No. 2 TH-180, registration N181TH, "through a standard production-type acceptance, including all the hover and forward flight checks" and tracking and rigging checks.
A third TH-180 flight test vehicle is expected to be completed before late September, the company said. It added that, with two aircraft flying, it "is focused on an accelerated certification flight test schedule."
Certification was delayed from the 2016 target when the No. 1 prototype was damaged substantially in a Feb. 12 accident. Enstrom said the first prototype, registration N180TH, experienced a mechanical problem. Taylor, at the controls, made a forced landing near Menominee-Marinette Twin County Airport in Menominee, Michigan, where the company is based.
According to a preliminary report by the NTSB, the TH-180 was on a right base to land on Runway 32 on Feb. 12 when the pilot felt a "jolt" in the airframe and noticed a sudden reduction in rotor rpm. The engine continued to run. Taylor entered an autorotation and touched down.
The main rotor blades struck the pole as the helicopter slid about 300 ft down the street and came to rest upright, the NTSB said. The skid landing gear collapsed, and there was substantial damage to the tail cone, the pylon center section and the lower section of the cockpit structure.
Enstrom said in March that a preliminary investigation indicates a piece of flight test instrumentation in the main drive system failed, disconnecting the engine from the drive train.