What caused Mercy Flight helicopter crash in Elba? NTSB releases final report on double-fatal accident

A Bell Helicopter flight instructor was in town to provide factory training of the Bell 429 helicopter, intended to give an extra layer of comfort and security for the pilots of the Cheektowaga-based nonprofit provider of emergency air medical transport.

But on the second training flight of the day, something went terribly wrong just before 1 p.m. while over rural Genesee County.

A just completed final report from the National Transportation Safety Board – released nearly 20 months after the double-fatal accident – sheds light on what was Mercy Flight’s darkest day, when one of its pilots, James E. Sauer, and Bell flight instructor Stewart M. Dietrick were killed when their helicopter crashed in the Town of Elba. Sauer and Dietrick were longtime pilots with thousands of hours of flight experience.

In the report, the NTSB said the cause of the crash boiled down to errors made by one or both of the pilots – the helicopter had dual controls – during a training maneuver that required the pilot to pull the aircraft out of an unstable flight condition known as a “vortex ring state.” In a matter of seconds, the helicopter’s main rotor blades struck the aircraft’s tail, causing it to break up in flight. Also causal, the agency noted, was the “flight instructor’s inadequate monitoring of the flight.”

NTSB investigators keyed in on an 18-second window from 12:59:26 to 12:59:44 that day, when the helicopter entered into vortex ring state, which is characterized by an “unstable condition in which a helicopter experiences uncommanded pitch-and-roll oscillations, has little or no collective authority” and reaches a rapid descent rate. 

The NTSB’s report noted that, on the first training flight that day, Dietrick had another Mercy Flight pilot perform a vortex ring state recovery maneuver. The information gathered, the NTSB said, indicates Dietrick also had Sauer…