Machine Design

Air travelers might be worrying about the wrong things

Since terrorists launched their attacks on the United States in September, the media have had extensive coverage of people canceling trips because they are afraid to fly.

Editorial Comment
March 7, 2002

Well, my wife and I are not among them. Since September 11, each of us has logged 15,219 miles on 14 commercial flights.

What's more, this Nervous Nellie stuff is annoying and cowardly. Rather than my being comforted by intense security measures at airports, I find them inconvenient and annoying. Passengers now know what to do when unpleasantness erupts in the cabin, and they have been handling their duties effectively. Ironically, since September 11, the worst crash in commercial aviation, the one involving an American Airlines Airbus departing JFK last November, was apparently caused by the inherent frangibility of the airplane in combination with incorrect responses on the part of the pilot.

I am, however, getting ahead of my story. First let me list my greatest concerns when I travel by commercial airlines today, mentioned roughly in order of priority. You'll note that skyjackings aren't among my greatest concerns. My biggest worry is that I won't get upgraded. Then I worry that a fussing infant or ill-behaved toddler will be seated near me. Next, I worry about inordinately long lines at security checkpoints. I also worry that security people might close the airport because of a trivial breach in their controls.

When I am finally in my (hopefully) upgraded first-class seat, I worry that the flight attendant will be slow in pouring me a glass of wine. It will help ease the aggravation of being jostled by other passengers lugging their backpacks, shopping bags, and oversized carry-on luggage past my aisle seat.

Most of all, however, I worry about the marginal design of aircraft and the propensity for their complex systems to go haywire. Highest on my worry list is that the yaw damper will, on its own volition, dump the airplane on its back. If this happens at low altitudes typical of approaches to airports, you can bend over and kiss your toenails good-bye. The last I heard, there has been no real fix for this problem, which is endemic to 737s.

Next, I worry about the brittle behavior of lightweight composite structures, which increasingly are finding their way into airframes and control surfaces. Yes, airframe builders must save weight and minimize seat-mile costs so that mom, dad, and the kids can afford the fare to Disneyland. But composite structures are not yet as trustworthy as aluminum.

I also worry about wiring and fuses in the elaborate entertainment systems we now see in airplanes. It is ironic that a fault in an electrical system, which provided nothing more than games and entertainment, caused one of the most horrific airline crashes in recent memory, the Swissair crash off Nova Scotia in 1998.

Another worry is nacelles deliberately designed to break away if an engine seizes. In theory, the breakaway feature is supposed to allow an engine to drop off rather than having it tear off a wing. The problem is that when the structure works as planned, loss of an engine usually helps bring down the whole aircraft. There are also other potentially lethal hazards, but there is not enough room in this column to list them all.

The bottom line is that it is reasonable for air travelers to be fearful. But their concern shouldn't be so selective. It should be focused just as much on the airplane as on who is coming aboard.

- Ronald Khol, Editor

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