A319
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 210; Flight Crew Total 13256; Flight Crew Type 1800
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Inflight Event / Encounter Weather / Turbulence
Flight Crew Overcame Equipment Problem
Company Policy; Procedure
The ACARS runway data program is fully authorized as a stand alone source for performance data. Per our Flight Manual: 'RWY this is the only mandatory entry' and '...runway and performance takeoff limits are based on the latest sequence report from the National Weather Service. During training on our new flight planning program the impression was given that the ACARS takeoff data was foolproof. Events have shown this not to be true. [On a recent departure] ATIS provided: Winds 35017; visibility 10 SM; temperature/dew point 26/11; altimeter 29.93. Takeoff Data was requested. The takeoff data provided by ACARS was based on: TEMP 30C ALT 29.74 WIND 312/10. I would not have noticed this had it not been brought to my attention by the First Officer. The correct ATIS data was entered into the performance request and there were significant changes to the V speeds. While the incorrect data was a failure in the 'safe direction' one must assume; based on this occurrence that it could also occur on a short runway with a heavy weight aircraft and with the takeoff data based on a cooler temperature and higher altimeter. There is a serious potential for an accident caused by such an error in takeoff performance.
An A319 flight crew discovered that the takeoff performance data provided by the company's new flight planning/dispatch program was not based on current meteorlogical information. The reporter believes discrepancies such as this; if common; could be hazardous.