Airliner Pilots Aren’t Mechanics

Since an Alaska Airlines MD-83 jet crashed off the California coast last week, killing all 88 people aboard, federal inspectors have been struggling to determine what caused the failures reported by the pilots in the horizontal stabilizer, a device that controls the plane’s upward and downward pitch.

On Thursday, Alaska Airlines mechanics in Seattle and Portland, Ore., found problems on two other MD-80-series jets that could help explain the mystery. They reported finding metal shavings in and around the jackscrew, a corkscrew-like device that moves the horizontal stabilizer up and down.

The discovery led the Federal Aviation Administration Thursday to order mandatory inspections in the next three days of stabilizers in all MD-80 aircraft, as well as in similarly designed MD-90s, DC-9s and 717s.

The Alaska Airlines crash, however, also highlights underlying problems that can be solved only with more vigorous oversight from the FAA.

There is discussion now, rightly so, about tightening mechanical inspections. Of equal importance is the need to keep pilots’ decisions freely focused on safety. The Alaska Airlines pilots may have struggled for up to two hours trying to resolve the problem of their malfunctioning stabilizer. Even so, it’s highly premature to suggest that the pilots erred. Pilots have the authority to request emergency landings if following a standard checklist fails to resolve a mechanical problem. But that bears repeating within the industry, especially in light of the pressure to remain on schedule amid increasing air traffic. Aircraft captains are not mechanics.

The U.S. aviation system is among the world’s safest, carrying an average of 1.6 million passengers a day with few major accidents. But the fleet is aging; horizontal stabilizers are not the only parts subject to corrosion, stress fractures and other wear and tear. The typical “design life” of an airliner is 20 years or 60,000 cycles (each set of takeoffs and landings). Of the 4,000 jets in the U.S. airline fleet in 1996, some 1,500 were more than 20 years old.

The FAA can’t mandate prompt and major maintenance checks on all jets with reportable malfunctions--such an order would trigger industrywide chaos. But Thursday’s tough directive should be a first step toward providing the kind of sharpened oversight that commercial aviation increasingly needs.