Final Report: Citation crew ignored stabilizer problems

 - December 11, 2007, 10:04 AM

Cessna Citation 560XL, Wheeling, Ill., Nov. 11, 2003–Citation N789CN was substantially damaged when it overran the end of the runway during an aborted takeoff at Palwaukee Municipal Airport (PWK).

The NTSB blamed the accident on the crew’s intentional operation with known aircraft deficiencies and on their delay in aborting when a no-takeoff warning was given. The Safety Board listed as an additional cause the crew’s failure to comply with flight manual procedures concerning stabilizer miscompare and no-takeoff indications. Contributing factors were the inoperative two-position horizontal stabilizer system, due to the intermittent electrical connection at the aft fairing connector, as well as the runway approach lights struck during the overrun.

The crew had noted problems with the horizontal stabilizer system inbound to PWK. A maintenance discrepancy report on Dec. 23, 2002, had stated that the stabilizer miscompare annunciator light had illuminated during flight. Maintenance personnel performed a functional check of the stabilizer and could not duplicate the problem.

When the pilot flying could not rotate normally at PWK, the crew attempted to reject the takeoff. The aircraft has a two-position horizontal stabilizer system, which reduces elevator control forces by repositioning the stabilizer leading edge two degrees down for takeoff or landing. The cruise position is one degree up. When the crew moves the flap handle out of the zero degree (flaps-up) detent, the stabilizer moves to the takeoff position. After the accident, the stabilizer was found in the cruise position.

Two independent warning systems alert the crew if the stabilizer is not properly positioned for takeoff or landing. A stabilizer miscompare annunciator warning is displayed when the flap handle and horizontal stabilizer are not in corresponding positions. In addition, a no-takeoff warning is displayed when the aircraft is on the ground and the horizontal stabilizer is not in the proper position for takeoff. As the throttles advance forward of the climb thrust setting, the no-takeoff annunciator light will begin to flash and a master caution light will be displayed. A warning horn will sound.

According to the transcript of the cockpit voice recorder, the crew was aware that the horizontal stabilizer was not in the takeoff position. In addition, a sound similar to the no-takeoff warning horn sounded for approximately 12 seconds during the takeoff roll before the crew initiated a rejected takeoff. During the investigation, electrical power was applied to the aircraft and the stabilizer miscompare and no-takeoff lights were illuminated. The horizontal stabilizer could not be repositioned. A pin that provides power to reposition the stabilizer was found unseated. Black marks near the tip indicated electrical arcing. With a new pin installed, the horizontal stabilizer repositioned correctly.

The stabilizer warning systems were subsequently tested and worked properly.
The Citation Excel was operated by West Coast Charters and flown by an ATP pilot. The charter Part 135 flight was on an IFR flight plan and VMC prevailed.

After the overrun, the aircraft stopped approximately 300 feet past the end of
the pavement, striking eight approach lights. The right main landing gear and nose gear collapsed. The two pilots and three passengers reported no injuries.