IFR Fix: The vertigo vaccine

August 12, 2013

Are you vaccinated against vertigo?

That would be useful, but don’t look for the cure within the health care system. Start in your logbook.

For example, what percentage of your flight time is instrument time? And what percentage of that is during night flight?

For most non-working pilots, that answer is not much. But night flight mimics instrument conditions, as every student pilot learns before the introductory night-dual session in primary training.

Nov. 1, 2012, was a foggy night in San Marcos, Texas—so murky that the FBO employee who gave a twin Cessna pilot the way to the runway lost sight of the aircraft soon after it taxied away. Video footage shortly captured the airplane crashing, less than a mile from the airport. The noninstrument-rated pilot lost control in the night instrument conditions—unfortunately, not an uncommon result.

If that doesn’t hit close to home for an instrument pilot, this will. The pilot of a Cessna 210 had been airborne for about 15 minutes when he responded to an ATC query about his heading by saying that he was "a little disoriented." Control problems continued during vectors for an ILS approach. A missed approach and a low-altitude alert followed.

On another try, "the pilot unknowingly deviated well right of the localizer course and was instructed to climb immediately due to another low altitude alert." That’s when the pilot reported complete gyro failure, and dizziness.

The aircraft spiraled to the ground. The pilot had received his instrument rating six weeks prior; the National Transportation Safety Board reported that he was an insulin-dependent diabetic, but "was unable to determine if the pilot’s glucose level affected his performance."

Probable cause was given as loss of control due to spatial disorientation and “the pilot’s lack of experience in actual night instrument conditions.”

The reality is that there’s no way to become inoculated against spatial disorientation because it is “normal perception.” Training teaches you why (and to a lesser extent, how) to disregard the misleading cues.

"The sensations that lead to illusions during instrument flight conditions are normal perceptions experienced by pilots," explains the Instrument Flying Handbook. "These undesirable sensations cannot be completely prevented, but through training and awareness, pilots can ignore or suppress them by developing absolute reliance on the flight instruments."

Now add night conditions, and gyro failure. Will your proficiency stand up to that?