Autopsies suggest Air France jet broke up in sky

[StreetScooby 5]

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The current theory is that icing on the pitot tubes or static pressure ports rendered one or more ADIRU's inoperable, and this lead to control law reversion and the disabling of several features (like flight envelope protection, rudder limiter etc.)

So, the guys flying the plane didn't turn around in time.
Is that a reasonable statement?

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[billvon 3,120]

>So, the guys flying the plane didn't turn around in time.
>Is that a reasonable statement?

I don't think "turning the plane around" is a common strategy for icing, for a few reasons:

1) Over the ocean, that could result in running out of fuel and having to ditch.

2) Icing is most common at certain altitudes, so climbing or descending to a different altitude is a more common approach to dealing with it. (Climb = get to an altitude where all the water is already frozen, descend = get to an altitude where it melts.)

3) The A330, like most modern airliners, have icing systems certified to handle icing.

3) Normally icing occurs when supercooled water hits a cold airplane and freezes on contact. However, there isn't much possibility of supercooled unfrozen water at those altitudes, so this was not a "normal" case of icing. (35,000 feet, -40C.)

If icing was an issue, it might be due to free ice (crystals) clogging things. Hail is unlikely at those altitudes, and in any case would be immediately evident on leading edges of stabilizers, wings etc.

Another possibility is simply that the aircraft hit such extreme turbulence that the flight computers started rejecting reported airspeeds/attitudes as impossible. It would be akin to a cypres seeing a sudden descent from 13,000 to ground level and then back to 13,000; the earlier cypreses (cypres 1) would shut off in that scenario to avoid a misfire.

[StreetScooby 5]

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3) Normally icing occurs when supercooled water hits a cold airplane and freezes on contact. However, there isn't much possibility of supercooled unfrozen water at those altitudes, so this was not a "normal" case of icing. (35,000 feet, -40C.)

If I understood what the pilot was saying, at the TCZ there's alot of warm water that causes the icing zone to be higher than usual. Hopefully, I'll see him before he heads out of country, and replay the chat with what I've learned here.

Thanks.

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