Why a vacuum failure in IMC is an emergency

Not long ago, I wrote a post trying to figure out why some pilots are more likely than others to declare an emergency. More specifically, I gave some ideas on why professional pilots are more likely to declare an emergency than other pilots. This is the opposite of what one might expect, since aren't the pros trained to handle anything?

The answer to that question is a qualified yes. However, sometimes "handling something" means recognizing when you need help, asking for that help, and then accepting that help when you get it. Marvin Gaye may have not been too proud to beg, but fortunately as pilots we don't have to beg: all we have to do is ask.

That post was sparked by a online debate with a pilot who flatly denied that losing a vacuum system—and therefore the attitude indicator and directional gyro, which are the critical sources of the information necessary to keep the shiny side up—in instrument meteorological conditions was an emergency. I have 10x the number of hours in the logbook than he does, yet I would declare an emergency immediately in that situation.

As it turns out, AOPA's Air Safety Institute has an accident case study that examines a fatal accident that happened precisely because that scenario actually happened: a pilot lost his vacuum system, yet continued on to an approach which ended up in a crash. You can watch it below:

This pilot was not stupid. He was a highly intelligent, competent, and accomplished surgeon. His story is not a case of "that could never happen to me". In fact, the first big mistake he made was doing the other pilot was saying was the correct response: being unwilling to tell ATC he had lost his gyros and therefore was in an emergency situation.

The fatal mistake he made was one that any of us could have had kill up at one time or another: instead of continuing on to his alternate, which had fine weather so failed instruments would be no problem, he wanted to complete the mission and end up where he intended to be. There isn't a pilot in the world who hasn't been strongly tempted—or even done it and gotten away with it—to do the same thing.

There but for the grace of God go any of us.


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The author is an airline pilot, flight instructor, and adjunct college professor teaching aviation ground schools. He holds an ATP certificate with a DHC-8 type rating, as well as CFI, CFII, MEI, AGI, and IGI certificates, and is a Master-level participant in the FAA's WINGS program and a former FAASafety Team representative. He is on Facebook as Larry the Flying Guy, has a Larry the Flying Guy YouTube channel, and is on Twitter as @Lairspeed.

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