WASHINGTON -- Airlines should at least periodically make passengers step on a scale to make sure they have an accurate assessment of the weight a plane will be carrying, federal investigators said yesterday.
The recommendation arose from the National Transportation Safety Board's investigation of the crash of US Airways Express Flight 5481 at North Carolina's Charlotte-Douglas Airport. All 21 people aboard were killed in the Jan. 8, 2003, crash.
The twin-engine plane, operated by Air Midwest, was virtually uncontrollable because of two fatal mistakes, the safety board concluded.
First, the airline's guidelines for estimating the weight of passengers and baggage were inaccurate. The pilots, therefore, didn't realize the plane's rear section was too heavy.
Second, mechanics had improperly rigged cables connected to the elevator, the tail flap that controls the up-and-down direction of the aircraft's nose. The errors meant the elevator's downward motion was restricted to half its normal range, according to the NTSB.
Without a fully maneuverable elevator, the pilots couldn't force the nose of the plane down to compensate for its heavy tail, investigators said.
As a result, the plane pitched sharply upward just seconds after takeoff for Greer, S.C., then fell out of the sky.
"The simultaneous existence of these two errors resulted in a virtually uncontrollable airplane," NTSB chief investigator Lorenda Ward said in a report presented to the NTSB, which voted to accept the findings.
After the crash, the Federal Aviation Administration ordered 15 airlines to weigh a certain percentage of passengers to determine if the current guidelines were correct. Checked bags, for example, were estimated to weigh 25 pounds, and adult passengers in winter were calculated to weigh an average of 185 pounds.
The survey showed what many suspected: Passengers and their bags had gotten heavier. The FAA issued temporary guidelines adding up to 10 pounds to its estimate for passengers and 5 pounds to luggage.
The NTSB said those guidelines don't go far enough. The board recommended the FAA identify situations where airlines should actually weigh passengers and bags instead of using estimates.
It also recommended the FAA require airlines operating planes with 10 or more seats to weigh passengers from time to time to determine when they might be heavier -- for example, people wear heavier coats and carry presents in December.
Terry McVenes, executive air safety vice chairman for the Air Line Pilots Association, said the challenge will be to come up with a survey method that's acceptable to airlines.
"The idea of having people getting on scales before they get on airlines won't make a lot of people happy," said McVenes, who represents the largest pilots' union.
Grant Brophy is an air safety investigator and director of flight safety and security programs at Embry-Riddle Aeronautical University in Daytona Beach, Fla. He said airlines ought to adopt technologies that weigh passengers unobtrusively -- for example, putting scales under pads that passengers stand on at ticket counters.
"They've just got to bite the bullet and recalculate this stuff," Brophy said.
The FAA has been working on that. Since June, a committee has been examining the average weights of passengers and baggage and how they vary according to season or geography.
The committee is expected to make recommendations at the end of March.
NTSB investigators also found flaws in the way mechanics were trained and supervised, the way their work was checked, and the way Air Midwest controlled the quality of its maintenance.
"There were a lot of mistakes made here," said NTSB board member Mark Rosenker. "I'll call it sloppy."
The NTSB recommended the FAA require improvements to training, oversight, and procedures for maintenance personnel. Among them: requiring that work on key flight control systems, including elevator cables, be checked upon completion.
FAA spokeswoman Laura Brown said the agency is already working on the issues raised by the investigation.