Let me get this right. ISIS is a system on the A330 which is a redundant back-up to pitot tubes?Does the 757 have this? I think it was a 757 that crashed years ago because of pitot blockage.Daniel

I don't know about ISIS, but jets have redundant pitot tubes, static ports and temperature probes (all inputs to the ADC - Air Data Computer) which is also often triple-redundant (Left, Center, Right ADC).Cheers,- jahman.

I don't know about ISIS, but jets have redundant pitot tubes, static ports and temperature probes (all inputs to the ADC - Air Data Computer) which is also often triple-redundant (Left, Center, Right ADC).Cheers,- jahman.

Yeah thanks J, I know that they have multiples. If you have no pitot tubes working wouldn't the ISIS or INS systems provide a good idea of your heading/altitude and airspeed?Daniel

Yeah thanks J, I know that they have multiples. If you have no pitot tubes working wouldn't the ISIS or INS systems provide a good idea of your heading/altitude and airspeed?Daniel

on the A320 anyway, ISIS is not a replacement for the Pitot Static system. It uses the Pitot static system, as well as ADIRU 1 and 3, the ILS, and can be powered by the DC ESS Bus, or Hot Bus 1.It's really designed to keep going for an electrical failure more than anything else. If you lose both engines and the generators go out, everything of utter importance (Including the ISIS) has to be powered via Hot Bus 1, or Hot Bus 2 (Batteries). The RAT doesn't just fly out and start spinning instantly, you can count the seconds between Everything going black and the "Power" coming back on :).ISIS is still very Dependant on Pitot/static, like everything else in aviation.

Yeah thanks J, I know that they have multiples. If you have no pitot tubes working wouldn't the ISIS or INS systems provide a good idea of your heading/altitude and airspeed?Daniel

With zero wind you could convert INS ground speed plus static port altitude plus outside air temperature into Indicated Airspeed. With wind, all bets are off.Cheers,- jahman.

"Pitch plus power equals performance", Taught to student pilots. otherwise known as flight with unreliable airspeed QRH.Also ,I forgot this site,Air France Flight 447:A detailed meteorological analysishttp://www.weathergraphics.com/tim/af447/Lesson #2, don't fly thru thunderstorms,also taught to student pilots.

"Pitch plus power equals performance", Taught to student pilots. otherwise known as flight with unreliable airspeed QRH.Also ,I forgot this site,Air France Flight 447:A detailed meteorological analysishttp://www.weathergr....com/tim/af447/Lesson #2, don't fly thru thunderstorms,also taught to student pilots.

The Airbus config for redundant flight is 5% pitch up and 85% engine thrust when AIS/Pitot tubes fails.Daniel

Lesson #2, don't fly thru thunderstorms

Sometimes this is unavoidable: If you use weather radar, you might see a channel through the thunderstorm wall where the thunderstorm is thin, so you fly there. The problem is you have been lured straight into the mouth of the beast, as the "channel" you thought you saw where the thunderstorm seemed thin actually is the core of the thunderstorm, where precipitation is strong enough to block radar from penetrating any further, which is why the thunderstorm looked thin in the first place. This could have happened to AF447.

The Airbus config for redundant flight is 5% pitch up and 85% engine thrust when AIS/Pitot tubes fails.

This type of golden rule could save your life. Good to know!Cheers,- jahman.

Pitch + thrust is the correct way to fly if IAS is unreliable!I think that if the black boxes are found, and are readable I'm certain that the crew chose not to deviate thinking they could get through it(I think that probably no mention may even have been made in the cockpit). The weather returns were absolutely massive and that the crew either misread the weather reports or discounted them. I don't believe that a radar return was hidden and thus they flew into an imaginary gap! The storm system was huge and was active long before they took off. Absolutely everybody else that night in both directions diverted or delayed (correctly).If this hypothesis were to be correct then Air France will probably go bust as full blame would ultimately fall on them as failing to apraise their pilot of the dangers of flying through storms!The weather analysis link posted above is very thorough and clearly suggests that the a/c at least partially broke up. Look at the BOAC flight 911 in 1966 that broke up over Mount Fuji in clear air turbulence ( a tropical convergence storm would have shredded it!!!). There is a photo taken which clearly shows it to be in a flat spin see here I remember this photo in the newspapers of the time! So the Air France Airbus could certanly have suffered the same fate.It is absolutely essential to try to recover the wreckage not just to determine the crew activities but also to check whether there are any airframe weaknesses.The BEA suggest that the Airbus hit the water in level attitude and this would correlate with a flat spin.vololiberista

I don't believe that a radar return was hidden and thus they flew into an imaginary gap! The storm system was huge and was active long before they took off.

At the ITCZ - Inter-Tropical Convergence Zone the lines of squalls can be so long it is not possible to circumvent them: You must pick a spot on your radar screen radar and punch through. Again, it's not that the stomrs are hidden from radar by something else, rather the storm can hide itself when storm precip is dense enough so you only see intense radar returns for the first few miles and then nothing at all behind, so you think the air there is clear when in fact that's the worst part of the storm you are heading for.Cheers,- Jahman.

At the ITCZ - Inter-Tropical Convergence Zone the lines of squalls can be so long it is not possible to circumvent them: You must pick a spot on your radar screen radar and punch through. Again, it's not that the stomrs are hidden from radar by something else, rather the storm can hide itself when storm precip is dense enough so you only see intense radar returns for the first few miles and then nothing at all behind, so you think the air there is clear when in fact that's the worst part of the storm you are heading for.Cheers,- Jahman.

I understand that but others "did" make very wide detours. When I see stuff like that I don't go anywhere near it. Whether in the temperate zone or the tropics.vololiberista

The big question is why they didn't deviate when everyone else did?