Paging DemoTex

[WilliamPitt]

I know you're in your Oregon firewatch tower and your connectivity is sporadic, but if you see this, I'd love to hear your take on the Air France disaster.

(for those not in the know, DemoTex has been a pilot forever, and is as close to a resident aviation expert DU will ever have)

[Hassin Bin Sober]

1. k and r

[MercutioATC]

2. In his absence, I'd be happy to contribute.

(air traffic controller for 18 years)

Anything in particular you're looking for or just a general opinion?

[WilliamPitt]

4. Well

There's a thread on DU claiming the flight was downed by a bomb, and some others repeating righty talking points in the same vein.

Tell me about the timeframe of this crash, the radio broadcasts that were sent and received, and your opinion on what happened.

Many thanks! Air traffic controllers rule.

[MercutioATC]

8. From what I've read (which is the same as what everybody else as read...I have no inside sources):

There's no evidence that a bomb didn't cause the disaster. There's also absolutely no evidence that it did.

Here's what we all know (in no particular order):

1) There was a bomb threat on another Air France plane earlier, but no bomb was found. This doesn't evidence anything to me...bomb threats are occasionally called in. The threatened flight wasn't AFR447 nor was it departing from Rio de Janeiro.

2) The plane wasn't in radar contact. This is perfectly normal. Radar has a limited range and there's no radar coverage over oceans. Position is verified by radio report.

3) The plane was an Airbus 330 with fly-by-wire controls. Some people have a problem with the degree to which the fly-by-wire system removes the pilot from the loop...especially in critical situations...but the fly-by-wire system's software will provide a better solution to a given problem than a human pilot's the vast majority of the time. However, if the fly-by wire's redundant systems all fail, it's practically impossible to control the aircraft. That said, the A330 is no more inherently "dangerous" than any other wide-body commercial aircraft. Some might disagree, but I believe that's mostly attributable to a "Boeing vs. Airbus" thing (think the "Chevy vs. Ford" argument).

4) Wreckage has been found. True, but it's a deep ocean and there's a great likelihood that the data recorders will never be recovered.

5) There was convective activity in the area. Pilots receive weather briefings before flights, but that's not even close to a surefire solution for avoiding turbulence. Neither is onboard weather radar, because it only sees precipitation...not turbulence.

6) Lightning poses very little danger to aircraft, especially commercial aircraft. The fly-by-wire system in the A330 is hardened against power fluctuations...as are all commercial aircraft, fly-by-wire or not. A given large commercial plane will be hit by lightning once every two years, on average. Smaller regional jets will be struck once or twice per year (because they generally fly at lower altitudes). The vast majority of these lightning strikes cause no damage whatsoever.

7) AFR447 left a large debris field. That could be attributed to a couple of things...either the plane came apart before it hit the water (bomb or airframe stress) or ocean currents and wind have spread the debris.

8) AFR447's ACARS system sent an automated message indicating electrical failure and a loss of cabin pressure. That suggests a failure of multiple systems.


What some people know:

1) AFR447 was within the confines of the Intertropical Convergence Zone (ITCZ) when it crashed. The ITCZ is characterized by, among other things, particularly strong convective activity. (for more info on the ITCZ: http://geography.about.com/library/weekly/aa050301a.htm )


Taking all of that into consideration, I think the most plausible explanation (with the data we have right now) is that AFR447 got a weather breifing and knew that convective activity was both known and forecast along its proposed route of flight. In the air, it saw high-intensity precipitation on its onboard weather radar and, as all flight crews will do, planned to alter course if necessary to avoid the worst of it (it's also possible that, based on reports, they planned to top it rather than fly around it). At some point, AFR447 encountered severe to extreme turbulence (explanation of "severe" and "extreme" here: http://www.bayareapilot.com/turbulencereportingcriteriata.htm ) possibly combined with a lightning strike. The turbulence and/or lightning strike either caused both electrical system damage and structural damage resulting in a loss of cabin pressure OR it caused structural damage sufficient to both depressurize the cabin and disrupt electrical systems. The loss of cabin pressure suggests that the aircraft could have come apart before impact, but is not definitive proof.

That's it in a (rather verbose) nutshell. As a pilot, DemoTex will probably have more to add, but I think he'll agree with most of what I said.

[WilliamPitt]

10. Many thanks. n/t

[MercutioATC]

11. De nada

...and DO get feedback from DemoTex. As a pilot, he has an entirely difference knowledge base to draw on.

[DemoTex]

12. Excellent nutshell MercutioATC .. thanks for the briefing

Before reading this thread I knew very little about the Air France disaster. I haven't been able to contact my buds in the accident investigation community or NTSB. I did listen to a BBC World Service report last night on the 25 meter band (12.095 mHz) that focused on lightning. I think that may be a reach, given the HERF (high-energy radio frequency) protection of the Airbus. As a former ALPA accident investigator, I know that a little information is a dangerous thing, and I have far less than a little information on this crash. I'll chime in if any of my buds who are working on this check in with me.


Fog again this morning!

[MercutioATC]

18. Thanks! I've been keeping up with your adventures...

...and I envy you!

[KoKo]

22. You will be all over this one...considering the "Field of Debris" doesn't belong

to the Air France Plane. Lot's of teasers coming out for a sleuth who had Fires, Dog Needs and "other stuff" like SILENCE on their mind.

[havocmom]

3. Plus lots of us just wanna know how he is doin

Another DemoTex Fact: he had a dog with a penchant for crapping on Cheney's lawn years ago.

[WilliamPitt]

5. He checked in yesterday

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=389&topic_id=5774170&mesg_id=5774170

[havocmom]

7. Thanks, Will. Not in here much yesterday and missed that

[SidDithers]

6. He had a couple of posts 2 or 3 days ago...

with a few pictures from the lookout tower.

http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=389&topic_id=5774170
http://www.democraticunderground.com/discuss/duboard.php?az=show_topic&forum=389&topic_id=5767009

Sid

[havocmom]

17. Thanks Sid. Waited till I got home from work for those links

Always like to keep up with DemoTex's leatest exploits.

[KoKo]

13. I wanna' know how his dog is doing going up and down those many steps...

It's gotta be hard for dog body taking a piss and crap to keep going up and down...up and down.

DemoTex looks in fit shape...but how many times a day do he and his buddy have to do those stairs...Daunting!

[havocmom]

16. Bet the Nick figures out fast:

Poop and piss off the catwalk and forget the damned stairs. ;)

[KoKo]

21. lol's...I bet he has a Litter Box Up there ............fire hydrant..whatever..

[Blue_Tires]

9. we have another 2-3 longtime aviation experts here

but of course i'm hard-pressed to remember who they are....

[A HERETIC I AM]

14. In case DemoTex had not heard, Airbus issued a warning to operators of its aircraft today.

regarding possible unreliable airspeed data.

From the New York Times;
http://www.nytimes.com/2009/06/05/world/europe/05plane.html?_r=2&hp&loc=interstitialskip

[Duer 157099]

15. Here's an interesting post over at Salon

http://www.salon.com/tech/col/smith/2009/06/02/askthepilot322/index.html

[MercutioATC]

19. Damn! I could have just linked to that and saved some time.

He says pretty much everything I did.

[Duer 157099]

20. But how about this now: Brazilian air force says debris was not from Air France crash

from CNN:

http://www.cnn.com/2009/WORLD/americas/06/04/plane.crash/index.html

RIO DE JANEIRO, Brazil (CNN) -- The Brazilian air force said Thursday night that debris picked up near where officials believe Air France Flight 447 crashed Monday into the Atlantic Ocean was not from the plane.

The news came after the Brazilian navy began retrieving debris Thursday that it believed was wreckage from the flight, which disappeared over the Atlantic Ocean.

On Wednesday, searchers recovered two debris fields and had identified the wreckage, including an airplane seat and an orange float as coming from Flight 447. Officials now say that none of the debris recovered is from the missing plane.

[trof]

23. So...I'm freakin' chopped liver in the Aviation Expert Department?

I've been a pilot foreverer than he has.
He'll tell you that.
Got my USAF wings in 1964.
TWA in 1968.

My take?
We may never know.
It happens like that sometimes.
10 years after TWA (my former employer) Flight 800, Boeing 747, went down in Long Island sound, controversy still rages about what happened.

I bet y'all thought I was dead.
Not. Yet.
:-)

[havocmom]

24. Actually, I almost suggested that Pitt look you up

But I am getting bad on my follow through in my old age.

[DemoTex]

25. I just asked about you tonight in the Lounge

PM me your email trof, and I'll add you to my daily blast from the lookout tower.

[Skittles]

26. LOL.............TROF

I was gonna post, WHAT ABOUT The Retired Old Fart? :D