Pilots have come to accept that aircraft fuel gauges just don’t work well. In fact, many pilots simply assume the fuel gauge is wrong, believing it’s safer to rely on their own calculations concerning the amount of fuel remaining rather than on the gauge. As the old saw goes, “never trust your life to a gauge.”
Good idea. Usually. But sometimes skepticism about fuel gauges can lead to an accident.
The pilot and one of his passengers were killed when the Cessna 172 crashed in Tennessee. The second passenger survived. The NTSB determined that the plane ran out of gas. How can this happen? According to the NTSB report, it seems the pilot may have miscalculated the amount of fuel necessary for the trip because he didn’t know the engine horsepower had been increased by an STC, and thus burned more fuel than an unmodified aircraft..
But still, the aircraft did have a working fuel gauge. What the NTSB’s report does not discuss is why the pilot ignored it.
The pilot and passengers were apparently from the U.K. Last week, the Welch coroner held an inquest, at which the surviving passenger testified. The passenger explained that he had been sleeping in the back seat. He woke up and:
I glanced over to look at the instruments and just noticed the fuel gauge had a low indication. I brought it to the knowledge of [the pilot]. He said ‘I’ve done a maths calculation about the distance and I trust my maths more than a 1969 fuel gauge’.
Was the pilot arrogant? Or was he just sucked in by the common belief that aircraft fuel gauges are seldom accurate?