NTSB: Crew Failed To Deice, Citation Stalled In Fatal Crash
A Circuit City Citation business jet carrying two crew and six passengers crashed on approach to Pueblo (Colo.) Memorial Airport in February 2005 because it stalled, the NTSB said on Tuesday. All on board were killed. During the flight, the wing leading edges had picked up a layer of thin, rough ice that degraded the aircraft's performance. The crew didn't activate the deicing boots, and also didn't increase their approach speed as the flight manual dictates anytime ice is present or expected, the NTSB said. The jet's stall-warning system didn't activate until after the aerodynamic stall occurred, which the Safety Board cited as a contributing factor. The Board recommended that the FAA require modification of the Cessna 560's stall-warning system to provide an adequate warning margin in icing conditions, when the stall speed may be higher than normal. "This accident underscores the importance of flight crews carefully monitoring and cross-checking flight instruments during approach," stated NTSB Chairman Mark Rosenker. "We would also like to see more progress from the Federal Aviation Administration on major icing recommendations we issued a decade ago." A second Circuit City Citation that was following the first landed safely at Pueblo. The flight crew of that aircraft did cycle the deice boots numerous times and maintained increased airspeed during the approach and subsequently landed safely, the NTSB said. Importantly, the Board concluded that ice bridging does not occur on modern airplanes; therefore, there is no reason for flight crews to delay activation of the deice boots. The Board recommended that the FAA require that guidance for aircraft with pneumatic deice boots be revised to indicate that the leading-edge deice boots should be activated as soon as the aircraft enters icing conditions.