By Stephen Young
By Stephen Young
By Stephen Young
By Jim Schutze
By Rachel Watts
By Lauren Drewes Daniels
Near New Orleans, if Taylor's electrically powered partial panel was operating properly, he should have been able to level the airplane and get out of trouble. At least that's the theory. But in training conditions, Taylor and other pilots fly with a partial panel that they are certain is working properly. They can also see exactly when their other two instruments go "out." They don't spend time using readings from dying or dead instruments the way pilots who crashed airplanes seem to have done in real blind conditions.
It's uncertain how long Taylor "corrected" his airplane to failing instruments (that would have been illuminated and functioning by all appearances) before he realized he wasn't flying level anymore. By then, Taylor was probably already so disoriented that he didn't believe what the remaining instruments were telling him.
Vacuum pumps have no warning system, and pilots like Taylor have no way of determining the health of a pump, says an expert who testified as part of a lawsuit filed by the families of New Orleans crash victims against North American Flight Academy Inc. (the Denton company that owned the rental airplane) and Parker Hannifin Corp., maker of the pump. What's more, he testified, the effect of a pump failure on airplane instruments is slow, heightening the danger. (North American had no comment.)
The FAA insists that a partial panel represents a backup system and that a vacuum pump failure in severe conditions is survivable. But NTSB has records showing eerily similar crashes that suggest flying out of blind conditions after a failure and sudden loss of the artificial horizon and directional gyro is difficult if not impossible. Here's a small sample of crashes linked to vacuum pump failures and "spatial disorientation."
··· Baxter, California, 1992: The pilot says he has an "unusual attitude" (artificial horizon reading) and can't figure out why. About 15 seconds later the pilot says, 'OK, I'll, ah, we might be in a spin." Someone saw the airplane fly out of the clouds with its wings coming off from the stress of an uncontrolled dive. A family of five dies.
··· Delight, Arkansas, 1993: In low visibility the pilot says, "We've lost our vacuum. We're in the clouds. We're in a hell of a bind...Nothing's working." He says his electrical turn and bank indicator is also out. Then in a way similar to Taylor, the pilot says, "I need to get above these clouds. I'm fixing to get vertigo." He crashed minutes later. Three adults and three children were killed.
··· Marlow, Oklahoma, 1993: In severe weather, the pilot tells the air traffic controller that his vacuum pump is out and he's trying to fly using a partial panel. "I'm going to have to fly the airplane," he told the controller. Then he crashed. Three people, including an aide to U.S. Senator Don Nickles, were killed.
The Aircraft Owners and Pilots Association (AOPA), like the FAA, maintains that a pilot like Taylor should be able to fly on a partial panel after a vacuum pump failure, although the association found that 50 percent of pilots in a flight simulator could not fly an airplane safely after an unannounced failure. But the AOPA is now testing pilot reaction in real airplanes and is finding a lower rate of pilot failure, says Warren Morningstar, vice president of communications for the association.
"We've done some research with pilots in a simulator. We're now replicating that research in a real aircraft to see if we can develop data one way or another to see how difficult that is," he says.
The owners association does not "see a call for additional regulatory action," Morningstar says. He characterizes vacuum pump failures as "pretty low on the list" of aviation safety priorities, particularly considering that pilots need to use instruments on only about 10 percent of all flights and because the accident rate related to vacuum pumps is relatively low. Of higher concern is the danger of pilots who don't know how to fly using instruments traveling into clouds where they can get disoriented, Morningstar says.
"The bottom line is that when we look at the number of spatial disorientation accidents there are usually about 30 a year. Out of those 30 or so spatial disorientation accidents, there are only about two or three that are attributable to vacuum pump failure or instrument failure."
The cost of installing a backup pump would be anywhere from $1,000 to $10,000 per airplane, he guesses.
Parker Hannifin, the manufacturer of the vacuum pump in Taylor's Piper Cherokee, has been telling the FAA since 1986 that the pumps can fail without warning and that a backup system should be installed. Parker Hannifin has also issued warnings to aircraft owners, pilots and others about replacing the pumps after a set length of time and urges aircraft owners to install a backup system.
"This pump has a good life, it has a specific life, and we tell people that every so many hours they have to be changed regardless," says Jim Cartwright, corporate communications manager for Parker Hannifin. "We tell them also that they should fly it with a backup system whether it's vacuum or electronic. Whatever they want to use is immaterial."