Packer Backer

Why would you enter clouds at 390 that had tops at 41? The risk of encountering hail and other bad stuff is to great. Just go around.

Captain Bligh

It is starting to look more and more like AF might have done well with some better preflight planning. Perhaps even a call to the dispatcher while still standing in the weather planning center to inquire about a avoidance routing would have if nothing else given them relief. Even if it turns out that the accident had nothing to do with weather perhaps they would have been in better conditions to deal with whatever problem(s) they did have.

Some pilots are just less prone to deviate. Do they perceive that it wastes time, or fuel, or maybe is it that to do so often requires a PITA call to a minimally cooperative center on an HF radio? I often find they are also pilots who have never inadvertently entered sever embedded or shadowed convection and regretted it.
Why not plan to avoid massive areas of convection? I don’t even want to have the diminished ITCZ reflectivity argument, because I don’t buy it. Given state of the art tools like satellite, IR maps and variable gain, I have to agree with Packer Backer on everything but his choice of sports teams.

ce650

I asked myself that same question. nice avtar pic by the way.

upndsky

The problem with flying along a track, whether it's organized (like the North Atlantic) or random, is that to make a change pretty much requires an act of God.

I remember once being on a random track, which AF would have been, and trying to move our next waypoint over one degree to get around some weather that was over our original waypoint. By the time the Oceanic Controller got back to us with our new clearance, we were already past the waypoint we had wanted to avoid. Another time, it took 10 minutes to get a clearance to climb 2,000 feet to get out of turbulence.

It really is a PITA to request a change or deviation. Unless it's really, really bad, most guys will just slog it out. I can certainly understand why those guys stayed at FL039.

As far as AF picking a different route prior to departure, the ITCZ is way to dynamic to be able to do that. What looks clear now may not be five hours later, which is when you would be passing through the area.

Packer Backer

Agreed. And that is probably what AF encountered. But the NW flight this thread is about was entering Japan's airspace (and presumably in vhf range). I don't want to throw the BS flag yet, but it's out of my pocket.

upndsky

Yeah, I don't know. I've never done the Pacific, so I have no idea what the coverage is between HKG and NRT. I also don't know anything about the 330. Could they have been to heavy to go to FL410?

Packer Backer

As far as coverage, pretty much VHF. They could have been to heavy to climb above the top's but they were never to heavy to ask for vectors around. Who in their right mind would fly through the top of a thunderstorm? That's what we are talking about here. With heavy rain and top's above 410, it's a thunderstorm!

Desperado

That must be a "Monday morning quarterback's helmet" in your avatar. If you weren't there, how can you be so critical??? Did you see their radar? Do you know for sure what their options were???

FDXLAG

I disagree. In fact we shouldn't fly at night because we can't see when we are entering clouds at 390 when we could simply fly over them at 410.

And for the record, I agree with Carl. You can lose your vertical stab and safely land most any aircraft. Assuming of course you are in stablized flight before you lose it, while you are losing it, and after you lose it. Does anybody know, when it peels off the airbi does it go straight back?

LivingInMEM

I think a structural failure caused by excessive dynamic loading is a result of anything but stabilized flight!

The assumption (from the AA flight and probably this one too since the focus is on the rudder limiter being given inaccurate inputs with a pitot malfunction) is that the vert stab is lost due to excessive side-loading caused by a yaw condition combined with excessive rudder input.

The initial rudder input creates a yaw condition, the opposite instantaneous rudder input starts the yaw movement in the opposite direction but the resulting side-loading on the vert stab structure causes it to separate from the aircraft.

The condition of the aircraft at the immediate moment of separation is at least a steady yaw condition and more likely a transition in yaw, with the nose position of the aircraft certainly reacting to the loss of the yaw input that was being created by the previously intact vert stab.

Any aileron input after the failure causes adverse yaw.