AF447

[PJ2]

Will;

If the standby instruments fail, (which there is question of in the 447 ISIS case), there is no other system, archaic or no, and the mechanical standbys in the 320, 330 and 340 were tiny, poorly lit and would be impossible to read in heavy turbulence. These instruments are certainly not going to help you inside a thunderstorm. The B767 standbys were marginally better, (larger) and the L1011's were good, (well lit, readable). The DC8 - 60 series had a standby horizon. A standby altimeter was installed to "permit dispatch capability in the event that the air data computer or servoed altimeter fails." I don't think the DC9 had standby's but I can't recall now.

What I am pleading is the case for examining in detail the recorded issues to see the pattern or common thread if there is one, from which, I think you'd agree, the problem can be defined and if chronic, fixed, and if intermittent and statistically granular, addressed strategically. In part this has already been accomplished with the Unreliable Airspeed memory items and QRH checklist.

I think you need to understand that no bread-and-butter "archane" system presenting basic attitudes/speeds etc is going to right an aircraft or permit the crew to manually do same, that is badly upset.

What such a system must do, (and in my view it requires good flight conditions to do it for the reasons stated, "good" being in cloud, at night, no moon, no visible horizon, possible icing and moderate turbulence) is provide a horizon and a direct speed indication until the crew can stabilize the aircraft.

I can assure you that no instrumentation no matter how robust and no autoflight system will permit safe flight inside, or even offer a good chance of surviving penetration of, a large, developing thunderstorm at high altitude by a transport category aircraft. No pilot, no designer, no certification body and no regulator has a right to expect that any airliner should perform otherwise. If one enters a thunderstorm, one is, for all intents and purposes, in test-pilot territory with an unknown outcome.

If I read you correctly, those are however, the assurances you seek. That correct? If not, we're misconnecting and you need to be more specific and clear.