TAM A320 crash at Congonhas, Brazil

[PBL]

Concerning Waldock's observation reported in Estado de Minas (marciovp in #1642), note the Pressure Altitude is on the same page and shows no sharp variation (as Mauersegler noted). ELAC noted there is rising terrain (#1643). Need we say more?

Comparing RA with PA is so basic that I am wondering whether Estado did not quote Waldock out of context?

Concerning the reliability (or otherwise) of digital avionics systems (in particular comments by flyingnewbie10, Sdrvuss), comparing digital avionics to corporate IT systems or others seems to me to yield about as much insight as comparing the wheel construction and braking systems on (a) your bicycle, (b) your car, (c) your truck fleet, (d) the A380 bogie sitting in the entry hall of the Science Museum in London. Sure they all have similarities, but their differences invalidate the kind of analogical reasoning, especially about failure modes, that I have been reading here.

Back some 70 years ago, Frank Ramsey determined how one may rank convictions in the presence of uncertainty, by considering at what odds one would be undecided in betting on two given events. The ranking he derived is consistent with all future work. (To those who consider betting infra dignitate, I note that this stuff is highly respectable semantics ). Now, investigators don't use it (unfortunately; I have come across some pretty poor reasoning about what is "likely", even in reports from agencies with the highest reputations).

So, given that the evidence for either has disappeared, and thus that we cannot find out definitively, what are the chance of sensor-fault versus TL-really-left-in-climb? Following Ramsey, at what odds are you willing to bet on which one? Note that if you bet askew, someone will be able to offer you a bet which (a) you will take, thinking it to be advantageous, and (b) you are guaranteed to lose (a so-called "Dutch book"). Is anyone arguing for a sensor fault prepared to say what heshe thinks the relative chances are?

And to those who think "likelihood be darned, it is still *possible*", I'd like to ask how far you got in dealing with the possibility that the center wing-tank explosion of TWA 800 was caused by little green men sitting in it and playing with matches at the wrong time. You can't rule that out either.

To slip&turn, I should point out that that analysis in the 1994 braking-logic state machine paper came from FCOM of the Lufthansa machine involved in the Warsaw overrun and is not valid for more recent aircraft, which have a different logic. That current logic may be read in Section 1.32.30 of the A320 FCOM, many "for training purposes only"-copies of which one can find on the WWW.

PBL