Winnerhofer,
You seem to be implying that had AF447 been equipped with BUSS, the accident could have been avoided. An old posting friend of mine jogged my memory regarding the BUSS system which was discussed in previous AF 447 Threads. Having it on AF447 may not have made a difference. First of all, the crew had to recognize the problem was UAS, it seemed that they did recognize the loss of speed, i.e., "We've lost the speeds", but then the AF447 crew never performed the memory UAS/ADR check procedure nor did they recognize what alternate law they were in. The BUSS system simply replaces the pitch and thrust tables which would have been part of the trouble shooting and isolation procedure after UAS recognition and aircraft stabilization, if stabilization corrections were required. The BUSS system becomes active only after all ADRs are shut off. By shutting off all three ADRs with the BUSS, the stall warning protection remains active. Without the BUSS, shutting off 2 ADRs, the stall warning protection remains active. However, if the remaining ADR is affected as in the case with multiple pitot tube icing, the data generated may be inaccurate and flying the pitch and thrust table settings would be the only safe thing to do. In earlier thread discussions regarding the BUSS, my posting friend pointed out that he recalled the BUSS isn't available in altitudes above 25K and once it is enabled, the flight laws can't be change from the direct law it reverts to (a technical discussion item?).
UAS can be a difficult problem to recognize as it can be caused by multiple scenarios which lead to it. IMHO, rapid UAS recognition training is the key ingredient to enhance the crew's ability to quickly detect a UAS situation and then correctly handle it. While the BUSS system is helpful, so were the pitch and thrust tables that were never used…
Last edited by Turbine D; 9th Dec 2014 at 17:05.
Reason: Content correction and addition