Tuesday, November 8, 2011
The Dangers Of Noise Fatigue
Noise fatigue may be an often-overlooked cause of aircraft accidents in general aviation
I had flown a nine-hour leg from St. Johns, Newfoundland, to Santa Maria, Azores, refueled and continued on the four-hour leg to Lanzarote, Canary Islands, off the coast of Morocco. I had slept for five hours at the nearest hotel, and lifted off at 0 dark thirty the following morning for the trip across the Western Sahara to Abidjan, Ivory Coast, 10 hours en route. I had made a semi-quick stop for fuel, and flown another five hours across the Gulf of Guinea to Libreville, Gabon. That's 4,500 nm in two days, none of it at much over 150 knots.
By the time I entered the pattern at Libreville, my brain was basically fried. (Video paraphrase: "This is your brain without sleep.") The constant drone of the Pratt & Whitney PT-6A had dulled my senses to a kind of somnambulistic confusion. This was several years before the first ANR headset, so I had
been dealing with two days of high decibels, well beyond any reasonable tolerance. As I rolled out on final for Libreville, I was grateful the Caravan was such a simple airplane with forgiving landing characteristics.
Still, there was a voice far back in my head saying, "Bill, you are REALLY dumb." I was too tired to care.
Somehow, I managed to get the airplane on the ground without leaving pieces on the runway. I parked at Air Gabon, cleared customs in a daze, and sleep-walked across the street to the Atlantique Hotel. I slept for about 11 hours, and woke with partially restored hearing and a brace of sanity. The Mirage would have to wait.
I took a full day off in Libreville, then continued 11 hours to Windhoek, Namibia, the following day, got a good sleep and flew on to Johannesburg a day after that. Two days later, when I returned to Florida, the first new production Mirage was still waiting for me in Vero Beach.
Of such mistakes are accidents made. Fortunately, I had avoided one, despite my best efforts to the contrary.
Fatigue, noise fatigue in particular, is a special enemy of general aviation pilots, specifically because we're our own worst enemies. I certainly was on that trip.
Back in the days of full-contract ferry pricing (whatever money you had left over at the end was yours), some pilots used to press the limits of human endurance, especially on long trips to the opposite side of the planet. Some pilots flying Pacific ferry routes to Australia, New Zealand and Japan in particular, used to fly nonstop from Florida to California, refuel in Santa Barbara, sleep on a couch at the FBO for three or four hours, continue to Honolulu, do the same thing there, continue to Majuro, and make it to Australia or Japan in three or four days. No, I was never that stupid. What I did was dumb enough.
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