Air France plane missing?

[Tomtom]

Thanks Tom and Theo. I figured it would relate to that, but in a pinch, it would be better than an entire system crapping out and leaving you completely blind.

I would agree at low altitudes and low speeds. In a small piston piston driven plane you can almost play it by ear: just set the engine to certain RPM and you are relatively safe. (There's a book out, somebody told me, to learn how to fly only with power setting; title anybody?)

At high altitude, the stall speed I believe is increasing (somebody correct me splease if I'm wrong here) due to lower air density; moving closer to to Vne (Never Exceed). And therefore making the window of safe operation smaller.

Now, think of winds of 50 to 100 knots up there... your airspeed is so not equal to the ground speed delivered by your GPS...

Better and safer approach: setup the plane to a known safe setting, i.e. attitude (via attitude indicator or artificial horizon) and power setting (so much percent of thrust). Many, many pages before somebody ("dn" or something... anybody?) posted the corresponding checklist: Flying with unreliable airspeed.

Cheers
Tom

[Gabriel]

been in the jump seat witnessing the turbulence and malfunctions.? Domt tell me the 24 ACARS DID THE CONCLUSION..............

Just answer this question:

How's the fact that the "loss of cabin pressure" ACARS message was the LAST ACARS message, after 4 minutes of 24 ACARS messages (that included A/P and A/T off, PFD flags, alternate law, speed disagree, IR fault, TCAS fault, ISIS fault, rudder travel limit fault, and others) is consistent with the bomb theory?

While this sequence of ACARS message doesn't tell us what WAS, it DOES tell us that it is very unlikely that it was a bomb.

While the lack of any sign of high energy device damage is present in the bodies and parts recovered isn't a proof that it was not a bomb (acknowledged: the evidence could be in the bodies and parts NOT recovered), at least it is certainly NOT an evidence that suggest a bomb.

So whatever little evidence we have by now, while it doesn't completely rules out a bomb, either does gives hints that a bomb is unlikely or doesn't give a hint that it was a bomb.

Could you please name one, just one, solid* evidence that goes into the direction of the bomb?

* With "solid" I mean directly related with the accident investigation. That means the "France have political problems" or "It happened before" don't qualify.

So if not a bomb, what then?

I have no idea. Maybe (unlikely) it WAS a bomb. Maybe (more likely) it was one of the half dozen of competing theories, some of which, while not proved, are at least more compatible with the findings so far. But not for lack of idea I will invent something. You want one? It was suicide. The pilot killed the FO, then disconnected two ADR's, then dived the plane until overspeeding it, and then applied full rudder. Prove me wrong.

Know what? You resemble me that people who sees something odd in the sky that they can't explain, and instead of saying "it a UFO" (that is, an UNIDENTIFIED flying object, which is just a cool way of saying "I have no crap idea what it was) say "it's a spaceship from a superior extraterrestial intelligence".

[xspeedy]

Regarding the GPS (for ground speed), I would think this would be a good fallback for when the airspeed system is found to be faulty or providing conflicting data.

I'm not sure what the margin is between stall speed and overspeed when at cruise altitude, but I'd think ground speed would be better than guessing with throttle position.

This is coming from a non aviation person.

[Leightman]

Fuel tank details

Thanks Kiwi, Evan, and P3. All of it great info. Nice spar P3. How does one go about pranging a P3 spar?

[Gabriel]

Thanks Tom and Theo. I figured it would relate to that, but in a pinch, it would be better than an entire system crapping out and leaving you completely blind.

EDIT: And I mean it as just an extra tool in the toolbox. Like I work with a really nice and expensive power driver, but sometimes, its batteries go dead somewhere where I cannot get to power to charge it. The trusty screwdriver may make it a lot longer, and more of a pain in the tush, but I can at least get the job done.

It's even worse than just wind. Say that there is no wind. Then the ground speed equals the True Air Speed (TAS).

But the speed that matters for "FLIGHT" (not for navigation), which is the Equivalent Air Speed (EAS), is affected by pressure (and hence altitude), temperature and Mach number so much that at cruise the EAS will be just a fraction of the TAS, as much as 50% (that fraction being very variable depending on the factors named above).

And then you have wind, which at cruise altitudes can be pretty strong and variable, specially when flying in an area of thunderstorms like in this case.

For a more technical (but accessible) explanation, see posts 423 and 424 in this thread:

http://forums.jetphotos.net/showthread.php?p=514934

So forget it. GPS speed is of no use to avoid that a cruising jet stalls or overspeeds.

That said, if you knew what your groundspeed was when the airspeed become unreliable, in the short term you could use VARIATION of groundspeed as an indication of VARIATION of airspeed (i.e. keep the groundspeed you had and the airspeed will be more or less the same you had, as long as the wind doesn't change too much in strength or direction)

[Gabriel]

Regarding the GPS (for ground speed), I would think this would be a good fallback for when the airspeed system is found to be faulty or providing conflicting data.

I'm not sure what the margin is between stall speed and overspeed when at cruise altitude, but I'd think ground speed would be better than guessing with throttle position.

This is coming from a non aviation person.

In fact no, the best IS guessing with throttle position, well, more or less.

First of all it's not throttle position, it's actual engine performance as seen in the engine gauges.

Then, it's not guessing, its replicating what has been actually done during flight testing.

The pilots have a table that gives, for each weight and altitude, a combination of pitch attitude and engine setting that would keep constant altitude and an acceptable airspeed.

The full A-330 procedure for unreliable speed, copy past from the airplane's manuals, was posted in this thread several pages ago.

I remember the procedure said, as a memory item, "maximum continuous thrust, pitch 5 degrees nose up" as an initial target, then grab the written procedure and fine tune thrust and pitch for the actual plane's conditions.

[Tomtom]

In fact no, the best IS guessing with throttle position, well, more or less.

First of all it's not throttle position, it's actual engine performance as seen in the engine gauges.

Then, it's not guessing, its replicating what has been actually done during flight testing.

The pilots have a table that gives, for each weight and altitude, a combination of pitch attitude and engine setting that would keep constant altitude and an acceptable airspeed.

The full A-330 procedure for unreliable speed, copy past from the airplane's manuals, was posted in this thread several pages ago.

I remember the procedure said, as a memory item, "maximum continuous thrust, pitch 5 degrees nose up" as an initial target, then grab the written procedure and fine tune thrust and pitch for the actual plane's conditions.

Here's the post from DN with the checklist: http://forums.jetphotos.net/showpost...&postcount=937

Good memory. Later it should be between 2.0 to 3.5 depending on weight.

[P3_Super_Bee]

How does one go about pranging a P3 spar?

In the old saying during and in-flight there are three simple rules...

1. aviate
2. navigate
3. communicate

In this case the crew didn't think the rules needed to be accomplished in order.

They tried Navigating first...

Crew was on a training flight, with the #1 engine shutdown(for training). They had a real in-flight on #2 engine which required for the engine to be shut down. No big deal, normally plane can still cruise along fine.

The problem was they were coming up on Canadian Airspace(or restricted, can't remember), and since they didn't have clearance to enter, the PPC(PIC in civilian world) thought a left turn away from Canadian Airspace was best course. Dumb move. They turned into the dead wing. Thus causing a stall and spin, The aircraft went from 6000 AGL to somewhere around 50 AGL in about 18 seconds. They ended up pulling 5.8G's down around the bottom of the decent with roll rates of 20+ degrees per second. Initial airspeed was 125 Knots with an acceleration to 270.

In the process due to damage sustained on the starboard wing they lost all fuel in tanks #3 & #4. They did manage to relight the #1 engine during the decent, which helped pull them out of the spin.

They managed to recover and bring the plane home with an uneventful landing.

[Leightman]

Great story P3. Spinning a P3, then 5.8 on the pullout. Just had to laugh, one of those laughs when disaster is just avoided.

[Theoddkiwi]

Certainly a time when you dont want any computers in the way of getting out of trouble. Thats mad.

[Jason]

Just answer this question:

How's the fact that the "loss of cabin pressure" ACARS message was the LAST ACARS message, after 4 minutes of 24 ACARS messages (that included A/P and A/T off, PFD flags, alternate law, speed disagree, IR fault, TCAS fault, ISIS fault, rudder travel limit fault, and others) is consistent with the bomb theory?

100% agree.

first of all, if it was a bomb, there would be an immediate loss of cabin pressure - not after 4 minutes.

second, the bodies found did not show any signs that would strenghen the bomb therory.

thrid: is it was a bomb, don't you think that someone (i.e. a group) would have taken responsibility? where is the point (from the groups' point of view) to blow up an A/C without telling the world it was them?

[mfeldt]

first of all, if it was a bomb, there would be an immediate loss of cabin pressure - not after 4 minutes.

I repeat that ACARS did not report a loss of cabin pressure at all. It issued a maintenance warning for the air condition / pressurization system because pressure in the cabin was changing too rapidly. It didn't even say in which direction the pressure was changing!

m.

[Alpha Sierra]

Again, think please, a small device does not need to leave burns anywhere but is enough to rip a cell..........the rest you do can imagine at FL350 pressure levels and speeds. Disclosure: I am not an ambulance chaser, thank you for ripping my face off in public.

No offense was intended and ... you're welcome !

I believe that many of us here on this forum, and I include myself, would somehow prefer for this accident to in fact be the result of a terrorist act, as opposed to an inherent design flaw with the A330, or any aircraft for that matter. But the evidence to date just does not stack up to support this theory, as a number of posters have also tried to explain in the last few pages (thanks also Kiwi for your great post #1802 re the bomb theory). And with that I rest my case regarding the bomb theory.

[Jason]

I repeat that ACARS did not report a loss of cabin pressure at all. It issued a maintenance warning for the air condition / pressurization system because pressure in the cabin was changing too rapidly. It didn't even say in which direction the pressure was changing!

m.

well, even at this early stage of the investigations, it was found out that the a/c disintegrated in the air. therefore it can be assumed that the message "change of cabin pressure" is equal to a loss of cabin pressure.

[Spectator]

Bombs and the cabin vertical speed warning

been in the jump seat witnessing the turbulence and malfunctions.? Domt tell me the 24 ACARS DID THE CONCLUSION..............

How's the fact that the "loss of cabin pressure" ACARS message was the LAST ACARS message, after 4 minutes of 24 ACARS messages (that included A/P and A/T off, PFD flags, alternate law, speed disagree, IR fault, TCAS fault, ISIS fault, rudder travel limit fault, and others) is consistent with the bomb theory?

While this sequence of ACARS message doesn't tell us what WAS, it DOES tell us that it is very unlikely that it was a bomb.

first of all, if it was a bomb, there would be an immediate loss of cabin pressure - not after 4 minutes.

I repeat that ACARS did not report a loss of cabin pressure at all. It issued a maintenance warning for the air condition / pressurization system because pressure in the cabin was changing too rapidly. It didn't even say in which direction the pressure was changing!

m.

The ACARS message was for cabin vertical speed, which was thoroughly discussed earlier in this thread. e.g. http://forums.jetphotos.net/showpost...&postcount=248 and think there is an even more comprehensive one about how it is easier for the crew to understand rates of climb instead of actual cabin pressure.

Nevertheless, the vertical speed warning is evidently caused by a rate of change in the cabin pressure equivalent to 1800ft/min positive or negative.
Now, any breach in the aircraft's pressure vessel (with the aircraft above about 10,000ft, as is understood it was still at FL350) will cause a loss of pressure, and in turn trigger the vertical speed warning.

Therefore in my reasoning, any bomb which catastrophically damages the airframe should have triggered the cabin vertical speed (aka pressurization) warning first, or at least very near the beginning of the ACARS list.

So, although the ACARS messages cannot really be relied on the prove a specific theory, they do help to make some (i.e. the semtex chocolate bar theory) very unlikely.