FATAL CRASH BLAMED ON PILOT ERROR / FEDERAL OFFICIALS ALSO SAY AIRBORNE EXPRESS FAILED TO INSTITUTE ADEQUATE TEST-FLIGHT GUIDELINES.

National Transportation Safety Board officials also admonished the company for its failure to institute adequate test-flight guidelines and pilot training. The findings were part of an NTSB summary on the ill-fated flight.The cargo plane slammed into a southwest Virginia mountainside on Dec. 22, killing all six on board. Five of those who died were Airborne Express employees, including pilots Keith Leming, 37, of Lebanon, Ohio, and Garth Avery, 48, of Dayton, Ohio.

Airborne Express mechanic Kenneth Athey, 39, of Winston-Salem, and Brian Scully, 36, a mechanic with Triad International Maintenance Co. in Greensboro, also perished in the crash.

TIMCO was completing a five-month overhaul of the plane when it went down amid clouds and darkness. The company's maintenance procedures were not named in the NTSB's summary of probable causes that led to the accident.

The board made its ruling Tuesday following a hearing in Washington. It concluded that Leming, who was behind the controls of the plane, failed to use proper procedures to recover from a stall that had been initiated as part of the test flight.

A stall occurs when a plane slows to a point where its wings lose sufficient lift to keep it airborne. The pilots of the Airborne Express flight were testing the airplane's handling during a stall.

The NTSB also concluded that Avery, who was the pilot-in-command and seated beside Leming, failed to recognize the trouble and intervene.

Neither pilot had ever handled the controls of a DC-8 during an actual stall, and the board questioned the decision by Airborne Express to pair the pilots on the flight. Avery had been on similar test flights in the past, but never behind the controls, said Ben Berman, one of the NTSB investigators assigned to the crash.

The NTSB also said the accident could have been prevented if the pilots had used a revised stall recovery procedure developed after a similar incident involving an Airborne Express plane in 1991. But the airline had failed to institutionalize the procedure into its test flight guidelines.

In a statement released Tuesday evening, Airborne Express agreed with the NTSB that the pilots did not use ``stall recovery procedures as developed' by the airline, but it denied that Avery had never controlled a DC-8 during a stall.

The airline also denied that it had failed to institutionalize its procedures. ``These pilots were all extremely trained as to the proper procedures in which to perform the stall maneuver required for the functional evaluation flight,' Airborne Express said. ``In fact, the (cockpit voice recorder) clearly indicates' that the pilots were ``aware of the stall recovery procedures agreed to in 1991 to which the NTSB referred in its report.'

The plane ran into trouble about 30 minutes out of Greensboro. After initiating the stall, the plane began to vibrate, which was expected. At that point, Leming should have released the control wheel and increased power. Instead, the NTSB believes, Leming kept the wheel pulled back, which prolonged the stall and sent the airplane out of control.

A stall warning system that causes the control wheel to vibrate could have alerted Leming that the plane was in more serious trouble than he may have thought, but the system was not working, Berman said. The pilots also could not get their bearings from the ground because it was dark and cloudy outside.

As a result of its findings, the NTSB made several recommendations to the Federal Aviation Administration. Among them:

Require that Douglas Aircraft ``review and amend the stall warning test procedures in the DC-8 maintenance manual to include regular calibration and functional checks of the complete stall warning system.'

Evaluate information on stall characteristics of all air cargo planes and check simulators used in pilot training.

Ensure that Airborne Express ``explicitly incorporates' its revised flight recovery procedures into its DC-8 guidelines.