The NTSB is recommending modifications of Honeywell flight management system (FMS) software that would provide warnings to pilots if they try to enter inconsistent weight and performance information.
In a letter to FAA Administrator Marion Blakey, the NTSB said the recommendation was based on two serious tailstrike incidents in which pilots entered incorrect information into FMS computers. One incident, on March 12, 2003, involved a fully loaded Singapore Airlines Boeing 747 at Auckland, New Zealand, that rotated on takeoff some 33 knots slower than the required Vr of 163 knots. The NTSB said the calculation error was the fault of the copilot, who inadvertently entered a fuel weight figure that was 220,000 pounds less than the airplane’s actual fuel weight. The Safety Board also faulted the Honeywell FMS, however, for allowing the incorrect figure to be entered and calculated in the first place.
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