Originally Posted by
thermalsniffer
From reading other forums, it appears that FPV is useful in unreliable airspeed situations.
Well, it also appears that the FPV (elaborated from the inertial/barometric parameters) is not available in a UAS (and for the AF447 crew), when the 3 ADR are disagreeing ? the basic procedure is to set the pich (not the FPV slope) and thrust.
Besides, in such a situation, usefull versus misleading parameters are given page 54 of the interim report:
This briefings booklet also provides a list of points that can help or affect the
accomplishment of the emergency manoeuvre and indicates the following in
particular:
-The factors identified as aids are: ground speeds, GPS altitude, radioaltimetric
height and STALL warning;
-The following factors, however, could be sources of confusion and
cause stress: unreliability of the FPV and of the vertical speed if the
altitude indications are affected, incorrect primary information without
any associated message on the ECAM, presence of alarms (false or real,
overspeed for example);
-The key points presented for the correct management of the situation are:
detection of the problems, interpretation of the alarms and coordination
in processing.
Jeff
PS) does the BEA formulation "There was no search for display of an attitude of 5°" refer to the application of the pich & thrust procedure ? (p 52 of the interim report #2, analysis of past cases of Pitot freezing events).