6 degrees nose down, before the pilot rolled the throttle to Idle. The instruments showed 395 rpm at 8.5 first-limit indica- tor (FLI). Within 5 seconds, the FLI needle dropped to 1.75 and rotor speed decayed to 328 rpm; the only control input was slight left pedal by the pilot. The helicopter gained 12 feet of altitude while losing 4 knots of ground speed. The panel’s Horn light illuminated 1.75 seconds later when the pilot muted the low-rpm warning. Rotor rpm was down to 290 at 1.25 FLI. The helicopter hadn’t yet begun to descend but con- tinued to slow, pitched 3 degrees nose up. Four seconds later, “loose objects in the cabin showed an indication of a negative g-force.” The twist grip was still at Idle, and rotor speed was 259 rpm. Slight forward-left cyclic inputs were recorded, but it was unclear who made them; both pilots had their hands on their grips. Impact occurred 6 seconds later. The helicopter fell 600 feet in the last 10 seconds.
The Takeaway The details of the accident sequence defy ready explanation. Why did the pilot twist the throttle to Idle at 600 feet—after making 30-plus normal landings in the preceding three days?
Why did his safety pilot fail to correct that move immediately, or at least after the panel’s twist-grip annunciator lit up? And why did the pilot mute the low-rpm warning horn rather than lower collective? With the bulk of the pilot’s helicopter experience in the R44, whose low-inertia rotor system’s susceptibility to blade stall made it the subject of a Special Federal Aviation Regulation mandating specialized training, the horn might have been expected to trigger him to instantly lower collective. The survivor told investigators that both his father and the
safety pilot froze on the controls—and that he knew some- thing was wrong right away because the phone on his knee “flew up and stuck to the ceiling.” Shortly after the accident, he told a state trooper that his
father looked “like a two-year-old … sort of in shock.” He recalled both pilots “snap[ping] out of their trance” just a sec- ond and a half before the helicopter hit the water, with his father yelling, “No!”
Not at all unclear is that a high-timer’s scrutiny of a new pilot doesn’t necessarily provide the safety margin both expect—particularly if that high-timer hasn’t cultivated a flight instructor’s reflexive paranoia.
2020 Q4 ROTOR 63
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