West Coast Charters Cessna 560XL accident

The airplane was substantially damaged when it overran the departure end of the runway during an aborted takeoff. The crew attempted to reject the takeoff when the pilot flying could not rotate normally. The aircraft is equipped with a two-position horizontal stabilizer system, which acts to reduce elevator control forces by repositioning the stabilizer two-degrees down for takeoff or landing. The normal (cruise) position corresponds to one-degree up. There are no intermediate positions. The stabilizer is commanded to move to the takeoff position when the crew moves the cockpit flap handle out of the 0-degree (flaps up) detent. The stabilizer was observed in the cruise position during the post-accident inspection. Two independent warning systems are designed to alert the flight crew in the event that the horizontal stabilizer is not properly positioned for takeoff or landing. A stabilizer mis-compare (STAB MIS COMP) annunciator warning is displayed when the flap handle and horizontal stabilizer are not in corresponding positions. In addition, a no-takeoff warning (NO TAKEOFF) will be displayed when the aircraft is on the ground and the horizontal stabilizer is not in the proper position for takeoff. As the throttles are advanced forward of the climb thrust setting, the no-takeoff annunciator light (NO TAKEOFF) will begin to flash and a master caution will be displayed. A warning horn will sound associated with the no takeoff indication. During the post-accident investigation, electrical power was applied to the aircraft. Without changing any cockpit control settings, the STAB MIS COMP and NO TAKEOFF lights on the annunciator panel were illuminated. Initial attempts to reposition the horizontal stabilizer were not successful. Subsequent inspection of the aft fairing feedthru connector revealed an unseated (pushed-back) pin. The pin provided electrical power to the hydraulic arming valve in order to allow repositioning of the horizontal stabilizer. Further examination of the pin showed black marks near the tip consistent with electrical arcing. When a new pin was installed, the horizontal stabilizer repositioned from cruise to takeoff/landing position as expected. The stabilizer miscompare and no-takeoff warning systems were subsequently tested and performed in accordance with the flight and operating manual parameters. The warning horn associated with the no-takeoff indication was heard over the cockpit speaker when the thrust levers were brought above the climb thrust setting. The flight manual BEFORE TAKEOFF checklist noted that all annunciator lights should be extinguished except the ground idle light prior to initiating a takeoff. The flight manual abnormal procedures checklist stated that when illuminated on the ground a STAB MISCOMP indication must be corrected prior to flight. In addition, a no-takeoff indication required the takeoff be aborted. The cockpit voice recorder was downloaded and transcribed. The transcript revealed that the crew was aware that the horizontal stabilizer was not in the takeoff position prior to initiating the takeoff roll. In addition, a sound similar to the no-takeoff warning horn was recorded over the cockpit area microphone during the takeoff roll and sounded for approximately twelve seconds before a rejected takeoff was initiated.

Verbatim NTSB analysis and probable cause from the NTSB dataset