Fairbanks takeoff in '99 had stabilizer problem

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Fairbanks takeoff in '99 had stabilizer problem

The Arizona Republic

PHOENIX--Potential problems with horizontal stabilizers emerged Wednesday as a common thread in at least three cases involving MD-80 aircraft, including Monday's fatal crash of Alaska Airlines Flight 261 off California.

The stabilizer, at the rear of the craft, which helps a plane fly level, was cited as a potential problem:

In Wednesday morning's emergency landing of a Dallas-bound American Airlines flight at Phoenix Sky Harbor International Airport (story on Page A-7).

In a similar emergency landing nearly a year ago of an Alaska Airlines flight at Fairbanks International Airport.

In an earlier flight of the Alaska Airlines MD-83 that crashed this week in the ocean near Los Angeles.

On Wednesday, investigators with the National Transportation Safety Board recovered one of Flight 261's flight recorders. Officials said they will expand their probe of Flight 261 to check reports that the horizontal stabilizer was a problem on the aircraft's earlier flight to Mexico. That flight carried a different crew and pilots.

In Phoenix, NTSB officials plan to examine the flight-data boxes aboard American Airlines Flight 1538, which made an emergency landing at Sky Harbor after the pilots reported problems with the stabilizer trim. The crew members also will be interviewed.

The pilots on that Phoenix-to-Dallas flight said they were having intermittent problems with the stabilizer trim at 8:20 a.m., shortly after leaving Sky Harbor.

There were 59 passengers and six crew members.

Wednesday's incident has parallels to a Feb. 5 emergency landing at Fairbanks International Airport.

In that case, the pilot of an MD-82 owned by Alaska Airlines had trouble getting the plane's nose to rise on takeoff, according to a preliminary NTSB report. However, after using an "excessive amount" of pressure on the control that lifts the nose, the plane was able to take off.

The pilot declared an emergency in flight and touched down at Anchorage, complaining that the elevator control was "sluggish and slow to respond to control inputs."

That flight, carrying 138 passengers and crew, ended uneventfully. The NTSB is still investigating.

Although there seems to be a link, aviation experts cautioned against a rush to condemn the horizontal stabilizer. Until more is known, it is difficult to pin aircraft problems on one part.

The MD-80 series jets have two engines attached to the fuselage near the tail. The models, depending on configuration, usually carry 144 to 152 passengers.

"I think everybody has jumped on this stabilizer issue like a duck on a June bug," said Bill Waldock, director of the Center for Aerospace Safety Education at Embry-Riddle Aviation University in Prescott.

Even without a functioning stabilizer, a plane can fly, he said.

Fueling the speculation is the fact that the stabilizer, as part of the airplane tail, is subject to a Federal Aviation Administration inspection order.

The May 1999 directive orders operators of the MD-80 series of planes to inspect them for signs of corrosion around the hinges that connect parts of the plane's tail. Inspections must be completed by November.

On Wednesday, FAA spokesman Paul Turk said it is unlikely that the FAA would move up the inspection deadline, unless there was some serious reason to do so.

Waldock said the last time the FAA changed a directive to an emergency order was 20 years ago, when a DC-10 crashed at Chicago. The order grounded every DC-10 in the nation for more than two weeks, causing huge financial losses.

Waldock said until more is known about the emergency landing Wednesday at Sky Harbor, it's hard to say what role, if any, the horizontal stabilizer played.

The American Airlines pilot may have been very cautious, a normal reaction after a crash, Waldock said. "If you think back to Swissair, we had a whole lot of people turning back because they were smelling smoke," Waldock said. Swissair Flight 111 filled with smoke and crashed in the Atlantic Ocean off Nova Scotia in 1998, killing 229.

In the first six months after the Swissair crash, there were more flights turning back due to smoke complaints than had been registered in the previous three years.

Link:

http://ajr.newslink.org/cgi/goto.cgi?2=001330

-- Carl Jenkins (Somewherepress@aol.com), February 03, 2000

Answers

Carl, this board has some amazing threads discussing what might have happened in regards to stabilizers. One tidbit I picked-up from an aviation safety board mentions "...unless the glass display that you are watching is providing you with erronous bank/pitch information and you don't notice that fact (by means of cross checking) before you have entered a spiral dive and for all practical purposes already lost the aircraft. The word is out that there have been instances of malfunctioning EFIS displays before."

Today, in his press conference, Jim Hall mentioned the NTSB's investigation of "...an in-flight occurrence involving another MD-83 that occurred yesterday morning near Phoenix, Arizona." He said that a preliminary analysis of the flight data recorder of the airplane found, among other things, that "Position of the stabilizer trim is recorded on the FDR, but pilot trim inputs are not." Wonder what that means?

-- Rachel Gibson (rgibson@hotmail.com), February 03, 2000.


Link to previous MD80/DC-9 trim problems.

-- Rachel Gibson (rgibson@hotmail.com), February 04, 2000.

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