washingtonian
Topic Author
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Joined: Sat Sep 04, 2010 5:56 pm

Question About AF 447 Thunderstorm

Tue Dec 07, 2010 5:13 pm

I watched the NOVA special last night. I have some random questions:
One of the theories they suggested is that the A-330s weather radar picked up the first small storm, but that this small storm blocked the airplane's radar from seeing the much larger storm behind it. I guess my question is what is the normal procedure for when an airplane encounters a thunderstorm over the ocean. If they are supposed to fly a certain path and only are in HF radio contact once an hour or so, how do they know they are not flying into more dangerous territory or another airplane's path? Is the standard procedure to try to raise ATC on HF to report their new path?

Also, it appears from all of those images that the particular storm was spread over dozens of miles. So is there really any way for an airplane to go around a storm like this?

Last question: What about the 10 or so other airliners that were flying across the Atlantic that night? Did they all fly around the storm, or what?

[Edited 2010-12-07 09:14:07]
 
Utah744
Posts: 110
Joined: Mon Jul 13, 2009 10:41 pm

RE: Question About AF 447 Thunderstorm

Tue Dec 07, 2010 6:14 pm

I did a quick google search to find a reference for you and the first one I came up was from India which is fine as all countries adheare to world-wide procedures. In general if you need to deviate from your assigned track and are unable to contact ATC as pilot in command you can deviate further than 10NM from tract by climbing or descending 500' and announcing on either 121.5 or 123.45 your position and your intentions. The link below tells the correct procedures, just scroll down to 11.6.8.

http://www.scribd.com/doc/27238806/ENR-1-1-General-Rules

[Edited 2010-12-07 11:06:44]
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washingtonian
Topic Author
Posts: 749
Joined: Sat Sep 04, 2010 5:56 pm

RE: Question About AF 447 Thunderstorm

Wed Dec 08, 2010 10:50 pm

Quoting UTAH744 (Reply 1):
I did a quick google search to find a reference for you and the first one I came up was from India which is fine as all countries adheare to world-wide procedures. In general if you need to deviate from your assigned track and are unable to contact ATC as pilot in command you can deviate further than 10NM from tract by climbing or descending 500' and announcing on either 121.5 or 123.45 your position and your intentions. The link below tells the correct procedures, just scroll down to 11.6.8.

Interesting...I assume other aircraft did this that night?
 
jreuschl
Posts: 382
Joined: Tue Jul 28, 2009 3:04 am

RE: Question About AF 447 Thunderstorm

Wed Dec 08, 2010 11:05 pm

Yes, didn't an Iberia flight go around the storm?

It did: http://www.france24.com/en/20090605-...jet-spanish-aircraft-brazil-iberia

[Edited 2010-12-08 15:18:59]
 
PPVRA
Posts: 7878
Joined: Fri Nov 12, 2004 7:48 am

RE: Question About AF 447 Thunderstorm

Wed Dec 08, 2010 11:37 pm

IIRC the program did say that for that effect to happen, you need to approach the small storm from an angle that would block the bigger storm behind it. If the other aircraft weren't at just the right angle they may have seen the storm and then gone around it.
"If goods do not cross borders, soldiers will" - Frederic Bastiat
 
Dogbreath
Posts: 174
Joined: Fri Mar 28, 2008 8:49 am

RE: Question About AF 447 Thunderstorm

Sat Dec 11, 2010 9:02 am

The airlines I've flown for have always made very good use of satellite imagery and at the flight planning stage you are made aware of the potential weather issues on your planned track. Especially when flying across the ICTZ, you know that there will be CB's and thunderstorms to contend with. I have no idea how AF conduct their flight briefings and what resources they use to assess weather, but in my experience you are always prepared. Of course weather is an ever constantly changing phenomenon and can improve or deteriorate very quickly. You need to have your wits about you and be prepared to deviate. The most I've had to deviate was approx 95nm off track and once had to make a 180 degree turn to find another route through the weather as the radar wasn't able to penetrate the first CB and show further lines of CB's behind the first. I'm no stunt pilot and would never intentionally fly through a CB or TS. And until the CVR/FDR are recovered from the AF flight there will be no absolute 'conclusive' proof that these AF pilots did the same.

You mention in your question about how do you change path if only in contact on HF every hour. You are always in contact with ATC, even on HF. Of course nowadays most airlines have ACARS. If you need to deviate for weather then it's quite simple to get on the radio and get a deviation clearance. If using ACARS it's even easier by sending an ACARS message.
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