Input Error Triggers Stall Warning On Regional Jet
Investigators have found that the crew of a QantasLink Boeing 717 with roughly 100 passengers experienced stick shaker activation during a 2010 flight on two of three approaches, because of pilot error prior to takeoff. The flight was out of Perth for Kalgoorlie and on the first approach, the stick shaker activated as the jet descended through 1,100 feet. The crew elected to go around and experienced the stick shaker again on a second approach as the aircraft passed through 350 feet. The third landing attempt was successful but not without difficulty. According to investigators, the captain had entered improper data that resulted in a weight calculation that was off by more than 21,000 pounds.
The problem went unnoticed by the pilots because of the crew's failure to observe standard cross-checking technique, according to investigators, and the pilots had assumed their control problems were due to turbulence. The error left the crew with undetected incorrect guidance for the aircraft's approach. And, according to investigators, the flight crew "did not follow the prescribed stall recovery procedure and did not perform an immediate go around." The crew flew the third approach even though the aircraft appeared to be unstable and increasingly difficult to control. Investigators noted that the captain had been subject to multiple schedule changes that challenged his ability to manage fatigue, but stated he was "well rested" for the event.