AF 447 Search to resume
2. then a 2min 10 sec period in which orientation varies sufficiently that ACARS is interrupted: can't send (29 sec), then can (29 sec), then can't (31 sec), then can (16 sec), then can't (17 sec), then can (12 sec). Note that the periods are roughly equivalent, but shortening. Then some unknown time, max 54 sec, to impact, but effectively flat and able to send ACARS.
If all these phases were due to loss of signal, that would indicate really severe movement of the aircraft.
As to what kind of attitude would fit to that:
Maybe a 'Falling Leaf'.
However I'm not sure if a swept wing airliner is susceptible to that. I'm not aware of any previous case of an airliner coming down in a genuine 'Falling Leaf' attitude.
A simple spin probably won't do.
On the other hand I'm a bit surprised that BEA doesn't know if it was due to weak signal. I would have assumed the SATCOM provider should be able to determine that.
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Originally posted by Graybeard ...
This credibility filter, if it existed, would logically be in the Mode S transponder, not the TCAS.
This credibility filter, if it existed, would logically be in the Mode S transponder, not the TCAS.
From Auraflyers calculations,
Incidentally, would engine power loss and switching the APU on generate an ACARS message ? Maybe loss of power and then restoration would have caused a gap in transmission.
- 2:10:04-2:12:16 - cascade of faults generated but ACARS still able to be sent - 17 received.
- (in this period, possibly 2:14:20, the cabin advisory message is generated)
- 2:15:14: latest time for impact for followup ACARS fault message not to be received.
Incidentally, would engine power loss and switching the APU on generate an ACARS message ? Maybe loss of power and then restoration would have caused a gap in transmission.
Last edited by Mr Optimistic; 10th Apr 2011 at 18:49.
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Originally posted by auraflyer ...
Some of the more recent posts have raised a few things that I thought had been settled by the two BEA reports.
Some of the more recent posts have raised a few things that I thought had been settled by the two BEA reports.
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Originally posted by Mr Optimistic ...
... a few posts back there was a question about what objects #9 and #11 where in the debris field (as they sit above the presumed resting place). Was that answered and I missed it ?
... a few posts back there was a question about what objects #9 and #11 where in the debris field (as they sit above the presumed resting place). Was that answered and I missed it ?
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Originally posted by promani ...
Crew did not respond to ACC-AO request for Tasil estimate.
Crew did not respond to ACC-AO request for Tasil estimate.
Even though Atlantico did call them, they didn't Secal them. Furthermore, the crew only gave estimates for SALPU and ORARO, and failed to report passing either. Neither did Atlantico call them at these waypoints.
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VS loss in-air unlikely
I've been following this thread from the beginning. Just some observations about some recent stuff...
All the clues you need are in the BEA report if you are able to comprehend it.
The VS was almost certainly lost on impact. Look at the photos of damage not just to the VS hardware, but the recovered galley G3, and in particular; the damage to the luggage rack fixings.
Some posters seem to have a fixation that the aircraft "dropped" into the water. High vertical speed is certain, since victims found so far showed fractures of the pelvis and vertebrae. VS component 36g's failure indicates that significant energy was involved. Humans can only take about 40g and be assured of survival. That may well have been exceeded on impact.
However, there is also evidence that the aircraft was travelling forward along it's longitudinal axis with very little yaw. The damage to the luggage rack fixings clearly show this.
What were the chances of this happening with a missing VS? Very, very slim - almost nil, I'd bet. The VS detached at impact. There's a reason the BEA assume this - they have physical evidence.
Related to this, some posters have expressed surprise that the wreckage has been found to close to the LKP. There's nothing surprising about it. You don't know what happened between the LKP and impact. There is no reason whatsoever to suppose that the aircraft's descent was in any way continuous, be it a dive, flat spin, continuous turn or whatever. It could have consisted of several stages, in any direction - or in different directions. In addition, you shouldn't assume that the aircraft hit the water directly above it's resting place on the sea-bed. Currents play a factor. Those current's could have caused a drift back towards the LKP completely by coincidence.
And finally, while I'm in rant mode...
ACARS - BEA's analysis is sound. Some messages are by-design transmitted with a follow-up message that can take place a few seconds later. Some of those expected follow-up messages are missing. BEA's report indicates from the satellite logs that signal strength was OK until the end of messages. They also state that for the signal to be blocked - it would have to be blocked line of sight between the antenna and the satellite by a flight surface. i.e. at an abnormal orientation. Given the physical evidence, that the aircraft impacted moving forwards, slightly nose-up with high vertical speed; the impact most likely occurred immediately after the last recorded message. You don't need to be Sherlock Holmes.
All the clues you need are in the BEA report if you are able to comprehend it.
The VS was almost certainly lost on impact. Look at the photos of damage not just to the VS hardware, but the recovered galley G3, and in particular; the damage to the luggage rack fixings.
Some posters seem to have a fixation that the aircraft "dropped" into the water. High vertical speed is certain, since victims found so far showed fractures of the pelvis and vertebrae. VS component 36g's failure indicates that significant energy was involved. Humans can only take about 40g and be assured of survival. That may well have been exceeded on impact.
However, there is also evidence that the aircraft was travelling forward along it's longitudinal axis with very little yaw. The damage to the luggage rack fixings clearly show this.
What were the chances of this happening with a missing VS? Very, very slim - almost nil, I'd bet. The VS detached at impact. There's a reason the BEA assume this - they have physical evidence.
Related to this, some posters have expressed surprise that the wreckage has been found to close to the LKP. There's nothing surprising about it. You don't know what happened between the LKP and impact. There is no reason whatsoever to suppose that the aircraft's descent was in any way continuous, be it a dive, flat spin, continuous turn or whatever. It could have consisted of several stages, in any direction - or in different directions. In addition, you shouldn't assume that the aircraft hit the water directly above it's resting place on the sea-bed. Currents play a factor. Those current's could have caused a drift back towards the LKP completely by coincidence.
And finally, while I'm in rant mode...
ACARS - BEA's analysis is sound. Some messages are by-design transmitted with a follow-up message that can take place a few seconds later. Some of those expected follow-up messages are missing. BEA's report indicates from the satellite logs that signal strength was OK until the end of messages. They also state that for the signal to be blocked - it would have to be blocked line of sight between the antenna and the satellite by a flight surface. i.e. at an abnormal orientation. Given the physical evidence, that the aircraft impacted moving forwards, slightly nose-up with high vertical speed; the impact most likely occurred immediately after the last recorded message. You don't need to be Sherlock Holmes.
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Originally posted by BOAC ...
... in a universe somewhere like ours, there was a finding that '36g' referred to part number?
... in a universe somewhere like ours, there was a finding that '36g' referred to part number?
In practical terms however, I have difficulties to see how an A330 @210t can arrive at the attitude described by BEA and which seems to be confirmed by the damage pattern of the wrecjage with a vertical velocity of 110fps = 6600ft/min.
That would be in the ballpark of a Cessna terminal velocity.
The terminal velocity for a flat falling A330 being somewhere around 240 - 250fps (at altitude even ~30% higher) there has to have been some discontinuity in the vertical speed during these 5 minutes.
When and how this discontinuity occured is at the moment unclear, at least to me.
Let's hope the recorders still contain usable data !
Related to this, some posters have expressed surprise that the wreckage has been found to close to the LKP. There's nothing surprising about it. You don't know what happened between the LKP and impact. There is no reason whatsoever to suppose that the aircraft's descent was in any way continuous, be it a dive, flat spin, continuous turn or whatever.
If yes please read my post carefully. That should explain why I'm a bit surprised that it is that close.
If we assume that the aircraft at LKP was still at cruise speed (which can be assumed from the average speed between the two last known positions since it was in line with the average speed between the previous ones) then it had massive kinetic and potential energy at that point. So much energy is not shed that quickly in an airliner. Even a max pull- up at LKP should require 20 - 30s before stalling the plane (at that point I assume it was not yet in Alternate 2 which might allow for an accelerated stall). Stalling should happen somewhere around 350 kts ground speed. At that point it will already have travelled ~4nm and it will still be traveling at that speed.
Being so close to LKP requires some kind of course reversal at a certain point.
It is defnitely not impossible, but in an upset any other direction would have been equally as likely or even more so.
And considering the verical velocity in these 5 mins it does not seem that it was one single continuous drop.
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36G
If this arm really broke on impact or before/after has been discussed a lot earler. A close look at enlargements of the published pictures shows:
1. Typical signs of corrosion.
2. No trace of movement of the parts relative each other after a break.
My own guess is that arm 36g is irrelevant to whether the fin broke on impact, earlier, or later. It could be a corrosion caused cracking accelerated by temperature cycling during use, which is well known for several light metal alloys. Perhaps the other half of the arm (not visible in the photos) did not break at all.
Regards
1. Typical signs of corrosion.
2. No trace of movement of the parts relative each other after a break.
My own guess is that arm 36g is irrelevant to whether the fin broke on impact, earlier, or later. It could be a corrosion caused cracking accelerated by temperature cycling during use, which is well known for several light metal alloys. Perhaps the other half of the arm (not visible in the photos) did not break at all.
Regards
henra;
Regarding the proximity of the site of the wreckage with the LKP, it may be worth reviewing the "Metron Scientific Solutions" Report to the BEA on the Search Analysis for the Location of the AF447 Underwater Wreckage the link to which was provided in February by Hyperveloce, which, now in hindsight, makes a great deal more sense in terms of 9 other accidents in which very high rates of descent obtained.
What has yet to be examined and then explained is the question of the state/condition of much of the recovered wreckage after June 6th or so, and, now, the state/condition of the wreckage, as seen in five photographs. It is not shattered as the Swissair 111 MD11 was but, relatively speaking, remains "intact". Notwithstanding other notions regarding the VS, engine thrust, attitude, etc, we have to conclude that it was not a high forward-speed impact like the SR111.
That kind of impact, (high vertical velocity, low forward velocity, slight yaw, slight NU pitch) precludes a number of theories regarding the way-of-descent.
A spiral dive almost always becomes a very high speed event. Even if it began that way, by what mechanism was the speed reduced and a stall precipitated followed by vertical descent, either from cruise altitudes or at some point on the way down?
If at altitude, (as has been asked many, many times previously), by what means did a loss of about 80kts (M0.82/279kts to M0.60/198kts) occur? In "normal" flight, it isn't easy! What makes such an event "easier"?
We know that a stall is a function of AoA. We know that it is not even necessary to "lose 80kts" to enter a stall. As has been asked, what of pitch-up, and by what methods?
At some point from the LKP, the aircraft entered a stall. Was it the initial stall or in a secondary or tertiary stall at the time of impact? It is difficult to accept that a fully stalled aircraft would also roll to the point of blanking the SATCOM antenna. And the question of the THS position as speed decayed, needs to be asked and answered.
PJ2
For review, antenna and probe locations:
If we assume that the aircraft at LKP was still at cruise speed (which can be assumed from the average speed between the two last known positions since it was in line with the average speed between the previous ones) then it had massive kinetic and potential energy at that point. So much energy is not shed that quickly in an airliner. Even a max pull- up at LKP should require 20 - 30s before stalling the plane (at that point I assume it was not yet in Alternate 2 which might allow for an accelerated stall). Stalling should happen somewhere around 350 kts ground speed. At that point it will already have travelled ~4nm and it will still be traveling at that speed.
Being so close to LKP requires some kind of course reversal at a certain point.
Being so close to LKP requires some kind of course reversal at a certain point.
What has yet to be examined and then explained is the question of the state/condition of much of the recovered wreckage after June 6th or so, and, now, the state/condition of the wreckage, as seen in five photographs. It is not shattered as the Swissair 111 MD11 was but, relatively speaking, remains "intact". Notwithstanding other notions regarding the VS, engine thrust, attitude, etc, we have to conclude that it was not a high forward-speed impact like the SR111.
That kind of impact, (high vertical velocity, low forward velocity, slight yaw, slight NU pitch) precludes a number of theories regarding the way-of-descent.
A spiral dive almost always becomes a very high speed event. Even if it began that way, by what mechanism was the speed reduced and a stall precipitated followed by vertical descent, either from cruise altitudes or at some point on the way down?
If at altitude, (as has been asked many, many times previously), by what means did a loss of about 80kts (M0.82/279kts to M0.60/198kts) occur? In "normal" flight, it isn't easy! What makes such an event "easier"?
We know that a stall is a function of AoA. We know that it is not even necessary to "lose 80kts" to enter a stall. As has been asked, what of pitch-up, and by what methods?
At some point from the LKP, the aircraft entered a stall. Was it the initial stall or in a secondary or tertiary stall at the time of impact? It is difficult to accept that a fully stalled aircraft would also roll to the point of blanking the SATCOM antenna. And the question of the THS position as speed decayed, needs to be asked and answered.
PJ2
For review, antenna and probe locations:
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God's Hand
I have followed this and previous forums since the June 1st accident happened. Now that all is about to become clearer, I would take the opportunity to congratulate all posters for their most interesting inputs and help in the understanding of flight and commercial aviation.
My input, concerning this statement
"That is a fairly likely scenario. But if they are only 10 miles away from LKP was it God's hand that appeared in front of the plane and slowed it fairly rapidly and then let it fall in a stall? Facetiousness aside, what slowed the plane down so suddenly? It wants to fly and in four minutes it was in the water from 35000'. Where did all the plane's energy go? And more importantly, why?"
is:
What are the chances of a wall of supercooled water so dense as to be able to freeze the pitot tubes, slow and stall the plane, (crack the pilot's windshields), causing an upset?
What are the aerodynamics properties of such supercooled water as compared to air? Would af447 "fly" through it?
My input, concerning this statement
"That is a fairly likely scenario. But if they are only 10 miles away from LKP was it God's hand that appeared in front of the plane and slowed it fairly rapidly and then let it fall in a stall? Facetiousness aside, what slowed the plane down so suddenly? It wants to fly and in four minutes it was in the water from 35000'. Where did all the plane's energy go? And more importantly, why?"
is:
What are the chances of a wall of supercooled water so dense as to be able to freeze the pitot tubes, slow and stall the plane, (crack the pilot's windshields), causing an upset?
What are the aerodynamics properties of such supercooled water as compared to air? Would af447 "fly" through it?
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MLG down before impact or not?
bearfoil's post did not explain why lowering the gear might be an attempt to lower the nose. The idea is that the MLG are located below the center of gravity (CG) of the aircraft and lowering them will increase drag with a corresponding change (lower relative to the fuselage centerline) in center of drag relative to CG that acts to lower the nose. I am a software engineer, not an aerodynamic engineer, so someone please correct me if I got this wrong. I know there is also a pitch moment that is the result of the change in position of the center of drag relative to the CG fore and aft (as happens when lowering flaps) and I think that if the MLG are aft of the CG then it would be a pitch up. Please correct me if I got that wrong.
A) this has been done before (with a better result TWA 841 comes to mind) - by the way, my dad flew N840TW after that incident and said it "flew crooked". That incident involved a rate of descent of over 30,000 fpm! That is greater than the rate someone here calculated from the BEA report.
B) if true, this would suggest a desperate attempt by the pilot-in-command to regain pitch control of the aircraft, implying a severe controllability problem.
Of course, a descent into the drink at high vertical velocity already tells us there was a severe controllability problem.
I am curious who thinks this was:
A) a fully developed flat spin
B) a straight ahead "deep" stall
and why two experienced airline pilots couldn't recover from it.
A) this has been done before (with a better result TWA 841 comes to mind) - by the way, my dad flew N840TW after that incident and said it "flew crooked". That incident involved a rate of descent of over 30,000 fpm! That is greater than the rate someone here calculated from the BEA report.
B) if true, this would suggest a desperate attempt by the pilot-in-command to regain pitch control of the aircraft, implying a severe controllability problem.
Of course, a descent into the drink at high vertical velocity already tells us there was a severe controllability problem.
I am curious who thinks this was:
A) a fully developed flat spin
B) a straight ahead "deep" stall
and why two experienced airline pilots couldn't recover from it.
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Hi,
I find this remark interesting ....
Source:
AF 447. BEA : volonté de tromper ! : Les dossiers noirs du transport aérien
I find this remark interesting ....
In his note of 8 April, the BEA boss JP Troadec says that BEA has determined the initial search area as a circle of radius equal to 5 minutes of flight at maximum speed (40Nm, 75Km). Troadec "forgets"to say that the A330 must at the same time, lose 35000ft in 5 minutes or an average rate vario -7000ft/mn. An airliner of 200T flying to the max speed with such vario does not exist! It takes delta wings and can finish at 650Kts low altitude ... The only way for a commercial airliner, losing in 5 minutes 35000ft is to falling like a stone.
Such a level of incompetence of engineers does not exist.
But can be explained by the desire to deceive.
Such a level of incompetence of engineers does not exist.
But can be explained by the desire to deceive.
AF 447. BEA : volonté de tromper ! : Les dossiers noirs du transport aérien
The A332 will descend very rapidly with the speed brakes out.I remember flying into a Caribbean airfield and there was a very poor handover between the sector controllers. which kept us high.Once we were eventually cleared for descent the aircraft was descending in excess of the ASI v/s limit of 6000ft/min with the brakes out.
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Hi,
I understand that.
But can you go from 35.000 feet to 0 foot in 5 minutes and covering the radius distance of 75 Km (40 Nm) ?
What will be your speed when you contact the sea ?
Once we were eventually cleared for descent the aircraft was descending in excess of the ASI v/s limit of 6000ft/min with the brakes out.
But can you go from 35.000 feet to 0 foot in 5 minutes and covering the radius distance of 75 Km (40 Nm) ?
What will be your speed when you contact the sea ?
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Taking into account the maximum possible speed of the airplane, the wreckage of the airplane must then have been within a circle with a radius of 75 km (the Circle) centred on the last known position (LKP).
The French best know the nature of cover-ups that happen in their society, and the culture behind them, hence this type of conspiracy theory. Best left where it was found - in cyber-space.
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Hi,
I understand that .. but it's to notice that pprune is also in the cyber-space .. so sometime we meet or visit our neighbors 
Best left where it was found - in cyber-space.
