Jet Engine, Wing Flaps Under Study : Lift Indicator Was in Wrong Position, Crash Probers Say

GRAPEVINE, Tex. —  Engine failure--or a combination of engine failure and improperly deployed wing flaps--emerged Thursday night as prime suspects in the continuing investigation into what caused the crash of a Delta Air Lines jetliner here Wednesday morning that killed 13 of the 108 people aboard.

Cockpit conversations heard on a recording recovered from the wreckage and statements from a variety of witnesses indicated that at least one of the Boeing 727’s three engines failed as the plane was lifting off from the Dallas-Ft. Worth International Airport on a flight to Salt Lake City.

Probe in Early Stage

However, investigators have yet to offer any explanation as to what may have caused that failure, pointing out that the investigation is still in a preliminary stage.

Thursday night, National Transportation Safety Board member Lee V. Dickinson Jr., who is heading up the federal investigation into the crash, said that the handle controlling the plane’s flaps and slats was found in the “up” position after the crash, not in the “down” position, as might normally be expected.

Flaps and slats are flat-metal extensions of the wings that normally are extended in the down position to give a plane extra lift needed on takeoff.

Dickinson did say, however, that the handle may have been moved after the crash, perhaps to facilitate the removal of the injured crew members from the cockpit.

Because of their serious injuries, the pilot, Larry Lon Davis, 48; the co-pilot, Carey Wilson Kirkland Jr., 37, and the flight engineer, Steven Judd, have yet to be interviewed about Wednesday’s crash. Dickinson said investigators hope to talk with Judd today.

Detroit Crash Cited

Failure to deploy flaps and slats properly caused the crash of a Northwest Airlines MD-80 in Detroit in August, 1987, that killed 156.

Earlier in the day, Dickinson said that “a one-time listen” to the cockpit voice recorder recovered from the wreckage revealed the “buzzing sound” of the plane’s stall-warning device moments after liftoff.

“The stick shaker gave some kind of communication,” he said. A stick shaker is a warning device that gives a dual warning when a plane is close to an aerodynamic stall--it makes a buzzing sound and vibrates the plane’s controls.

“Shortly after that, there was some sort of conversation about an engine problem,” Dickinson said.

Moments later, Delta Flight 1141 slammed into the ground about two-thirds of a mile beyond the end of Runway 18L.

Sources close to the inquiry said the Boeing 727 could not lift off properly if two of the plane’s three engines had failed.

“It’ll fly on one (engine), but it won’t take off on one,” said one of the sources, himself a veteran 727 pilot.

“It’s the sort of thing a guy wakes up in a cold sweat dreaming about,” another pilot said.

The fuselage of the big jet--which had stopped here on a flight from Jackson, Miss., en route to Salt Lake City--broke into three sections and two of them burst into flames.

The huge gashes that opened in the fuselage--together with regular emergency exits--allowed 95 survivors to escape the smoke and flames, officials said. The number was revised upward Thursday from 94 when it was discovered that one infant not previously counted had been carried to safety.

Death Toll

Twelve adults and one infant died. Thirty-five people remained in hospitals. One was in critical condition and three were in serious condition.

Dickinson refused to elaborate Thursday night on the conversation about engine problems that was found on the cockpit voice recorder. He stressed that it was far too early for his agency to come to any conclusions as to what may have caused Wednesday’s crash.

But the sources close to the investigation--who asked not to be identified--said attention has been focused from the outset on the three Pratt & Whitney JT8D engines mounted at the rear of the 727. These engines are used on a variety of airliners in service today.

Earlier Disasters

At least two earlier air disasters involved the explosive disintegration of a JT8D engine--the flaming destruction of a British Airtours Boeing 737 on Aug. 22, 1985, at Manchester, England, which claimed 54 lives, and the crash of a Midwest Express DC-9 less than a month later at Milwaukee’s Mitchell Airport with the loss of all 31 people aboard.

However, the engines have been modified under federal order since then--specifically to prevent the sort of catastrophic destruction that may have occurred in Wednesday’s crash.

There were initial reports Thursday that one of the engines on Flight 1141 may have exploded, hurling shrapnel that disabled a second engine as the big plane struggled to become airborne. However, Dickinson cited evidence Thursday night that tended to dispute this theory. He said preliminary examinations of all three engines Thursday afternoon showed that the outer casings of all three were still intact.

Multiple Engine Failure

But multiple engine failure remained a possibility, one that investigative sources said could still explain the plane’s ability to take off.

The sources cited the reports of several witnesses--among them some professional pilots--who said they saw a flame and heard explosions as Flight 1141 prepared to take off.

“One pilot said he saw parts flying off the plane as it was lifting off,” a source said.

Nonetheless, sources said, the man at the controls--either Davis or Kirkland--apparently stuck with the commitment to go ahead with the takeoff.

Such a decision, they said, would be consistent with the failure of a single engine. But should a second engine have failed moments later, they said, the big plane would have been in serious trouble.

“When you try to fly out with only one engine left, you’re not going to go anywhere,” one of the sources said.

Witnesses said the plane began to falter after climbing no more than 30 feet into the air. One wing tip and the tail of the fuselage struck the ground first.

‘Trying to Keep Airborne’

“It was obvious the pilot was still trying to keep her airborne,” one source said. “When you hit the ground tail-first, you’re still grabbing at the sky.”

Thursday, in a strange twist, Delta’s Flight 1141 was again involved in takeoff trouble at the same airport.

The airline said that one of the plane’s engines experienced a compressor stall--described as a “slight burp” from an otherwise-smoothly-turning turbine--as the jet was heading down the runway at about 30 m.p.h.

A spokesman said that because of the brief stall--possibly caused by a gusting crosswind--the pilot aborted the takeoff, the plane returned to the gate and the passengers, including six who had survived Wednesday’s crash, were placed on another aircraft for continuation of the flight.

“We figured this would be the safest flight we could ever take today,” said passenger Louise Cox, of Baton Rouge, La., as she waited to board another 727 for Salt Lake City. “Evidently not.”

Dickinson said the members of the NTSB investigative team--assisted by representatives from the FAA, Delta, the Air Line Pilots Assn., the Boeing Co., Pratt & Whitney, the airport and the American Assn. of Airport Executives--had been assigned to 10 field teams

Activities of Teams

These teams, and their activities Thursday, included:

--Operations: Began photographing the cockpit to help reconstruct the final minutes of flight.

--Air traffic control: Began lining up interviews and tape-recordings to determine what role, if any, the FAA’s air traffic control system played.

--Witnesses: Prepared a list of witnesses to be interviewed.

--Survival factors: Began photographing wreckage to determine what caused the injuries, and what can be done to minimize future injuries.

--Structures: Began to measure and catalogue debris.

--Power plants: Began photographing and cataloguing the remains of the three engines.

Checking Systems

--Systems: Began checking the plane’s hydraulic and electrical systems to see if they played a role.

--Flight data recorder/cockpit voice recorder: Began checking, in Washington, the two “black boxes” recovered from the wreckage.

--Maintenance records: Began checking, in Delta’s home base of Atlanta, the plane’s maintenance records.

--Airplane performance: Began collecting additional data, much of it from instrumentation, on how the plane performed in the last moments of flight.