The fatal 2020 crash of a Houston Police MD Helicopters MD530E has stumped NTSB investigators. In its final report on the accident issued this week, the Board found the probable cause to be “an uncommanded right yaw that occurred for reasons that could not be determined based on the available evidence, which resulted in a loss [of] control.”
According to the NTSB, the helicopter—manufactured in 2008—went down shortly before 2 a.m. on May 2, 2020, while responding to reports of bodies in the water near the Biscayne at Cityview apartment complex. Video of the crash shows the helicopter hovering and then spinning before impact. Post-crash photos show the helicopter had clipped part of the apartment complex’s clubhouse before coming to rest on its side.
The NTSB was able to rule out a slew of potential causes for the accident, including loss of tail rotor effectiveness, vortex ring state, and any discoverable mechanical problem. Just before the accident, the pilot reported “strong vibration” in the controls while in a right-hand orbit. The helicopter then began to spin and he initiated the emergency procedure for loss of tail rotor function, lowering the collective and pushing the cyclic forward. The accident sequence appears to have begun when the helicopter was at a forward speed of 10 knots.