Recently, an issue was reported by a King Air operator whose Aviation Communication and Surveillance Systems (ACSS) Terrain Awareness Warning System (TAWS+) system faulted when the flap override mode was selected in flight. Analysis of the downloaded fault data revealed that the flap override mode was selected on descent while the airplane was traveling at greater than 200 knots. This is per design and normal operation, but is not a published limitation. Pro Line 21 King Airs equipped with the ACSS TAWS+ system are configured through the Aircraft Configuration Data (ACD) and the Aircraft Specific Database (ASDB), which reside in the Aircraft Personality Module (APM). This data configures the TAWS+ computer for operation in a specific airplane model as it initializes. One of the limitations programed into this system for King Airs will fault the TAWS+ computer if flap override is selected when airplane speed is greater than 200 knots. This value coincides with the 200-knot maximum flap extension speed on the airplane. This article is to inform operators of this condition. Depending on the interpretation of the pilot’s operating handbook flaps up landing procedure, an operator could select the mode too early and see the reported issue. Deselecting the mode will clear the fault and it can then be reselected after the airplane is below the limiting airspeed. For questions concerning this issue, please contact Beechcraft Corporation customer support at (800) 429-5372, (316) 676-3140 or by email at kingair_support@txtav.com.
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