Accident Analysis: Consider the consequences

The CFI who retards the throttle of a typical slow, stable trainer at 3,000 feet agl has several minutes in which to recognize and arrest any unfavorable trend in the interplay between altitude, airspeed, and landing site. A helicopter CFI teaching autorotations in a machine with a low-inertia main rotor system, however, has at most a few seconds to counter any tardy, confused, or simply inappropriate student reactions (see “Technique: Autorotations,” p. 26).

Worse, to be of any use, the autorotation exercise has to be continued until the ship nears terra firma. (Go-arounds are possible, of course.) Power recoveries are initiated within 10 yards of the ground, ending in a three- to five-foot hover. “Full-down” autorotations, carried out until the helicopter lands—preferably upright and within the designated target zone—ratchet the pucker factor up at least one more notch. Autos are the drill most essential to saving lives if ever actually needed, and for the models most often used for primary—and even commercial training—no realistic simulators exist. There’s no choice but to do them in the aircraft.

Crisp pedal work is crucial to keeping an attempted recovery from deteriorating into a carnival ride.The risks are real, first and foremost that of failing to get the collective down within the five seconds or less it takes a low-inertia main rotor to stall. Main rotor stalls are unrecoverable and nearly always fatal, so this is a big deal. Once rotor rpm is stabilized, there could be 10 seconds or more in which to calibrate the glidepath and assess prospects for reaching the designated touchdown point. The flare must be initiated high enough to avoid a tail strike if the student’s overly aggressive, but close enough to the ground to prevent the bottom from dropping out if the engine doesn’t respond in a power recovery. And crisp pedal work is crucial to keeping an attempted recovery from deteriorating into a carnival ride.

Helicopter CFIs have a couple of strategies to defend their precarious position. The first is to simply never get far from the flight controls—far meaning more than a quarter of an inch from the collective and cyclic, maybe half an inch from the pedals. It can be a little off-putting to advanced students or established helicopter pilots, but look at it from the instructor’s viewpoint: When the time scale is seconds, not expecting the worst requires a level of trust that can’t be built up in the first few hours of dual. And until that trust is established, frequent verbal coaching helps keep the student’s understanding of the situation in line with the instructor’s: “Not yet. OK, start a gentle flare.”

Still, accidents do happen, and they’re not always the student’s fault. In Tampa, Florida, in February 2020, the CFI had to execute an unplanned full-down autorotation after he accidentally shut off the engine during a practice autorotation. Both he and his student escaped unhurt, but the helicopter was rather the worse for wear.