AF447
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singpilot:
We all forget one additional 'factor' in the sea surface search. The immediate area has every afternoon, evening and night, been subject to massive thunderstorm activity, with rain, localized downdrafts and wave-creating winds impacting the surface. Location of the storms are as variable as the winds they create as they 'migrate' across the region
We all forget one additional 'factor' in the sea surface search. The immediate area has every afternoon, evening and night, been subject to massive thunderstorm activity, with rain, localized downdrafts and wave-creating winds impacting the surface. Location of the storms are as variable as the winds they create as they 'migrate' across the region
All this for saying that it is very improbable that the drift was North one day, South the following day, East, the day after and so on...
S~
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Elt on Impact
Hi Gentlemen,
I flew three hours behind the AF on that day and never even heared one blip on 121.5. My question as a non Airbuspilot, isnt there a elt installed that radiates on impact/certain g-loads? If so, Boeing A/C have them, at least a few ELT Blips should have been heared/picked up by me and other A/C in the vicinity. Can you shed some light on this?
Many thanks,
I flew three hours behind the AF on that day and never even heared one blip on 121.5. My question as a non Airbuspilot, isnt there a elt installed that radiates on impact/certain g-loads? If so, Boeing A/C have them, at least a few ELT Blips should have been heared/picked up by me and other A/C in the vicinity. Can you shed some light on this?
Many thanks,
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Elt on Impact
cws:
I flew three hours behind the AF on that day and never even heared one blip on 121.5. My question as a non Airbuspilot, isnt there a elt installed that radiates on impact/certain g-loads? If so, Boeing A/C have them, at least a few ELT Blips should have been heared/picked up by me and other A/C in the vicinity. Can you shed some light on this?
I flew three hours behind the AF on that day and never even heared one blip on 121.5. My question as a non Airbuspilot, isnt there a elt installed that radiates on impact/certain g-loads? If so, Boeing A/C have them, at least a few ELT Blips should have been heared/picked up by me and other A/C in the vicinity. Can you shed some light on this?
Did you read in the interim report that they have recovered one AF447's ELT intact?...It was off.
They got three on board, and I guess, at least two in the cockpit with other survival equipment, but they are not automaticaly emitting "on impact". They have to be switched ON manualy. Are you sure yours are automaticaly working in this case?
S~
Olivier
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Drifters in area of crash of Air France flight # 447
The Global Drifter Program - Information
Jeff
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The Amsterdam recent incident crashed much like that landing flat but with a high sink rate. If they were in a spiral dive and saw the ocean coming towards them in the final seconds they would attempt to pull out wings level but if they couldn't they might hit flat or even nose up with a very high sink rate at impact.
I’m fairly certain that the A330 is not susceptible to them; otherwise it would have a stick pusher
The A330 was certified with FBW and if I understand other posters, doesn't require stick pusher because of that. The FAA wouldn't require stall protection after multiple failures and degradation for FBW status. The A330 in baseline configuration will not enter a stable stall without gyroscopic forces for stabilization. Not to say the HS didn't depart or any of a number of other things to change the airplane from baseline. The aft CG at cruise could be enough for a spin to go flat and if that's the case, then it's unlikely the HS would be enough to overcome the condition. The VS would be blanketed by the HS, i.e., lack of rudder area below the HS, and would be useless for upright spin recovery.
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@Takata
Hi, thank you for your reply, I read it but could not really comprehend it completely since I am not familiar with airbus. We have also two mobile elt which have to be manually activated but the third one is build in and is in the position armed at all times in flight, meaning it will start once a certain g-force was applied, happened even on some really hard landings...
That was the reason I was asking. I did not know that the Airbus has only mobile ELTs and no stationary built in ELT. In Boeing A/C the ELT has a own switch on the overhead panel with a three position switch on, off and armed, armed position being guarded.
Greetings
Hi, thank you for your reply, I read it but could not really comprehend it completely since I am not familiar with airbus. We have also two mobile elt which have to be manually activated but the third one is build in and is in the position armed at all times in flight, meaning it will start once a certain g-force was applied, happened even on some really hard landings...
That was the reason I was asking. I did not know that the Airbus has only mobile ELTs and no stationary built in ELT. In Boeing A/C the ELT has a own switch on the overhead panel with a three position switch on, off and armed, armed position being guarded.
Greetings
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cws:
Hi, thank you for your reply, I read it but could not really comprehend it completely since I am not familiar with airbus. We have also two mobile elt which have to be manually activated but the third one is build in and is in the position armed at all times in flight, meaning it will start once a certain g-force was applied, happened even on some really hard landings...
Hi, thank you for your reply, I read it but could not really comprehend it completely since I am not familiar with airbus. We have also two mobile elt which have to be manually activated but the third one is build in and is in the position armed at all times in flight, meaning it will start once a certain g-force was applied, happened even on some really hard landings...
I was previously talking about the mobile ones, and it is the same as yours, two are locked in overhead panel with survival equipment in case of ditching.
S~
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@ Hyperveloce:
Thanks for this link. I checked all this buoys before, too bad that none were drifting at the right place and, as you can see here and even on the SHOM map, this area drift is fairly different North, South, East & West from this place!
On the other hand, the drift is mostly continuous in direction for days (but not the speed) with slight variations until the reversal zone above 5N which is showing erratic and spiral drift. I'm still hoping they will be able to find the wreck soon. The deep sea relief is the main obstacle as they have to use towed sensors listening very close to the bottom.
S~
Olivier
Thanks for this link. I checked all this buoys before, too bad that none were drifting at the right place and, as you can see here and even on the SHOM map, this area drift is fairly different North, South, East & West from this place!
On the other hand, the drift is mostly continuous in direction for days (but not the speed) with slight variations until the reversal zone above 5N which is showing erratic and spiral drift. I'm still hoping they will be able to find the wreck soon. The deep sea relief is the main obstacle as they have to use towed sensors listening very close to the bottom.
S~
Olivier
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einhverfr, way back someone posted structural drawings (or links to images of them) of the internal structure of the tail section below the VS including the very end of the pressurized section. By all appearances the tail section is flimsy compared to the rest of the plane. I'm not trying to say it was too weak to do its job. It appears just quite weak relative to the rest of the plane.
As you note the VS is attached to it securely enough but not with structural steel girders. This suggests the tail assembly is a little stronger near the pressurized section than the rear.
Suppose the rear hits first or at least in such a way that the tip of the tail is pushed upwards relative to its normal position. The nose is still pretty much unmoved. The raised tail damages the rudder and pries the VS off the rest of the tail section.
The concept of the tail hitting slightly before the rest may not be needed. But it helps visualize the process. The action of the elevators would help lever the rest of the plane into its appearance of nearly flat encounter with the water. It might also serve to further lever the VS away from the rest of the tail assembly after the middle portion was torn away from the initial tail cone collapse.
JD-EE
As you note the VS is attached to it securely enough but not with structural steel girders. This suggests the tail assembly is a little stronger near the pressurized section than the rear.
Suppose the rear hits first or at least in such a way that the tip of the tail is pushed upwards relative to its normal position. The nose is still pretty much unmoved. The raised tail damages the rudder and pries the VS off the rest of the tail section.
The concept of the tail hitting slightly before the rest may not be needed. But it helps visualize the process. The action of the elevators would help lever the rest of the plane into its appearance of nearly flat encounter with the water. It might also serve to further lever the VS away from the rest of the tail assembly after the middle portion was torn away from the initial tail cone collapse.
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ARFOR, as a non-pilot that summary looks good. One thing to consider, as an EE who digs RF communications and antennas, is that as long as the plane was nearly horizontal, within 20 degrees or so, more ACARS messages COULD go out if they were generated. That coupled with the high vertical speed component to its encounter with the water in normal flight orientation suggests to me that the flight of AF447 may have ended somewhere depressingly close to the last message at 0214.
(I am (rashly?) presuming that the damage encountered is consistent with the plane hitting with the wings nearly level, at the very least. As soon as one digs in the leverage should produce a distinctive damage profile. I am not sure we can say nose or tail first or purely horizontal, though. My guess, as a preceding message indicates, is that the VS was levered off the plane by the collapsing tail cone from a slightly tail first encounter with the water.)
JD-EE
(I am (rashly?) presuming that the damage encountered is consistent with the plane hitting with the wings nearly level, at the very least. As soon as one digs in the leverage should produce a distinctive damage profile. I am not sure we can say nose or tail first or purely horizontal, though. My guess, as a preceding message indicates, is that the VS was levered off the plane by the collapsing tail cone from a slightly tail first encounter with the water.)
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takata, there is one problem with your analysis of the SHOM chart (I assume you are referring to the chart in post 3138) and the initial northward drift of bodies and wreckage that you calculated occurred between June 1 and 5. This drift lies within an area that was repeatedly overflown and searched by the Brazilian Air Force over this period, and nothing was recovered belonging to the plane.
Here are the cumulative search grids by the Brazilian Air Force June1-5:
Note, the circle in the image above does not denote a search grid, only a radius for a subsequent search focus once bodies and wreckage were discovered on June 6.
It is no accident that the search for the FDR and CDR extends west 65 NM from the last position report, and south for only 40 NM from that position. (40 NM being the standard minimum radius for all quadrants in the search grid.)
I agree that surface winds can alter the direction and speed of objects being carried by surface ocean currents. The SIGMETS issued for this area on May 31 - June 1 describe the CBs as stationary. As I read the detailed French meteorology report, a similar pattern of CB complexes occurred daily between May 30 and June 3 over this general area.
Here are the cumulative search grids by the Brazilian Air Force June1-5:
Note, the circle in the image above does not denote a search grid, only a radius for a subsequent search focus once bodies and wreckage were discovered on June 6.
It is no accident that the search for the FDR and CDR extends west 65 NM from the last position report, and south for only 40 NM from that position. (40 NM being the standard minimum radius for all quadrants in the search grid.)
I agree that surface winds can alter the direction and speed of objects being carried by surface ocean currents. The SIGMETS issued for this area on May 31 - June 1 describe the CBs as stationary. As I read the detailed French meteorology report, a similar pattern of CB complexes occurred daily between May 30 and June 3 over this general area.
Sur la période de quatre jours du 30 mai au 3 juin 2009, l’évolution des zones nuageuses observées est typique de ce qui est fréquemment observé dans la ZCIT, qui s’étend sur une largeur moyenne de l’ordre de 500 km
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SaturnV:
takata, there is one problem with your analysis of the SHOM chart (I assume you are referring to the chart in post 3138) and the initial northward drift of bodies and wreckage that you calculated occurred between June 1 and 5. This drift lies within an area that was repeatedly overflown and searched by the Brazilian Air Force over this period, and nothing was recovered belonging to the plane.
takata, there is one problem with your analysis of the SHOM chart (I assume you are referring to the chart in post 3138) and the initial northward drift of bodies and wreckage that you calculated occurred between June 1 and 5. This drift lies within an area that was repeatedly overflown and searched by the Brazilian Air Force over this period, and nothing was recovered belonging to the plane.
It doesn't picture in any way how many times they flew above each area, what the aircraft crews actually were able to spot/detect because of the bad weather, luminosity, and plenty of other parameters. But maybe you are not very familiar with this kind of operation and it is pretty hard to see something fairly immersed like aircraft wreckage (or victims) when flyng at 200 kts above the sea for very long hours. A good example of the difficulty is when they tried to relocate some wreckage they spoted the day before without success during several days. Certainly, they would not have missed embarcations with survivors, but the wreckage... this is another story.
(Moreover, the SHOM map for the 5th is clearly pointing a very eastern surface current at the location where the bodies were recovered June 6, but their actual drift was still full North for 5 consecutive days...)
S~
Olivier
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AF Flight Plan Proc
how does AF follow up on the computer flight plan?
they are highly accurate and by comparing their FP times with the FMS times ,speed errors of such a magnitude should have become apparent to the crew,not needing Atlantico to realize it.
they are highly accurate and by comparing their FP times with the FMS times ,speed errors of such a magnitude should have become apparent to the crew,not needing Atlantico to realize it.
surplus1, re #3147.
AFAIK there is no ‘big switch’ enabling the pilot to select Direct Law. However, it appears that the law could be invoked by selecting off an appropriate selection of sensors (e.g. IRS) or flight control computers, but I don’t know the exact details.
Undesirable flight states; stall appears to be prevented in Alternate law (ALTN 1) by the low speed protection, IAS replaces the AOA function, but in this accident it appears that there was no IAS. AFAIK this gives ALTN 2 law – no speed protections; I don't know about any alerts.
The architecture of the A330 control system provides an adequate level of ‘fail safe’ for aviation, as defined by aviation requirements – based on experience. In this sense Airbus wasn’t the first to test these regulations as there were many test aircraft and military experience beforehand.
Many people appear to have overlooked the point that when the A330 is flown direct law it is essentially the same as the older generation aircraft excepting that, like them on occasions, you might lose VMO/MMO and Stall warnings, and if applicable stick push; in which case you took extra care at low speed.
The one significant difference that I am pursuing is the trim operation. In direct law it is via the hand wheel – the old way, but in ALT law the trim operation appears to be in some quasi state attempting to operate normally (auto-trim / follow-up trim), but not associated with the of the loss of protections, and thus may be ‘auto’ active in a stall. Furthermore, the crew may unaware of this (isolated from trim activity).
Re pilot interface with automation; one of the major issues is the crew’s understanding of the differences in the levels of automation – what are the crew responsible for and when, and then relating these states to a previous or clearly understandable method of operation; but rule 1 still applies – fly the aircraft.
I agree that nothing should be ruled out or in. We all appear to have crossed the bounding rules. The search for understanding is perhaps better achieved by questioning, opposed to statements of ‘fact’ seen elsewhere in this thread.
AFAIK there is no ‘big switch’ enabling the pilot to select Direct Law. However, it appears that the law could be invoked by selecting off an appropriate selection of sensors (e.g. IRS) or flight control computers, but I don’t know the exact details.
Undesirable flight states; stall appears to be prevented in Alternate law (ALTN 1) by the low speed protection, IAS replaces the AOA function, but in this accident it appears that there was no IAS. AFAIK this gives ALTN 2 law – no speed protections; I don't know about any alerts.
The architecture of the A330 control system provides an adequate level of ‘fail safe’ for aviation, as defined by aviation requirements – based on experience. In this sense Airbus wasn’t the first to test these regulations as there were many test aircraft and military experience beforehand.
Many people appear to have overlooked the point that when the A330 is flown direct law it is essentially the same as the older generation aircraft excepting that, like them on occasions, you might lose VMO/MMO and Stall warnings, and if applicable stick push; in which case you took extra care at low speed.
The one significant difference that I am pursuing is the trim operation. In direct law it is via the hand wheel – the old way, but in ALT law the trim operation appears to be in some quasi state attempting to operate normally (auto-trim / follow-up trim), but not associated with the of the loss of protections, and thus may be ‘auto’ active in a stall. Furthermore, the crew may unaware of this (isolated from trim activity).
Re pilot interface with automation; one of the major issues is the crew’s understanding of the differences in the levels of automation – what are the crew responsible for and when, and then relating these states to a previous or clearly understandable method of operation; but rule 1 still applies – fly the aircraft.
I agree that nothing should be ruled out or in. We all appear to have crossed the bounding rules. The search for understanding is perhaps better achieved by questioning, opposed to statements of ‘fact’ seen elsewhere in this thread.
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Search areas for the actual crash site
At 420 knots the plane is going 7 miles a minute.
At 0210 we have a position. Presuming the plane was still aimed "roughly" along the planned flightpath and presuming perhaps some pushes by storm winds where could the plane have gotten to by 0214 plus maybe a little Kentucky Windage for surviving a bit past 0214?
"Where could the plane possibly be?" might be a better search criterion than "where do the currents extrapolate backwards to at the time of the crash?"
And, of course, I am fastened on to the apparent fact that the plane was either deceased or was no longer even approximately horizontal after 0214.
Aiming of the satellite antenna is somewhere between a TV yagi on a rotator and a pair of rabbit ears in a high signal area for reference. You can be a whole lot off and it still works. Plus or minus maybe 60 degrees of vertical for a 3dB (half power) loss. Within about 35 degrees you'd have trouble picking the optimum direction without automation.
This is why "what is the region it could have reached in 5 minutes or less is my search criterion. Then match that with the currents to try to refine it all. And I have an untutored hunch that turning an A330 or anything else at FL350 is not "sharp" by any stretch of the imagination unless you are purposely entering a dive as for a bombing run.
JD-EE
At 0210 we have a position. Presuming the plane was still aimed "roughly" along the planned flightpath and presuming perhaps some pushes by storm winds where could the plane have gotten to by 0214 plus maybe a little Kentucky Windage for surviving a bit past 0214?
"Where could the plane possibly be?" might be a better search criterion than "where do the currents extrapolate backwards to at the time of the crash?"
And, of course, I am fastened on to the apparent fact that the plane was either deceased or was no longer even approximately horizontal after 0214.
Aiming of the satellite antenna is somewhere between a TV yagi on a rotator and a pair of rabbit ears in a high signal area for reference. You can be a whole lot off and it still works. Plus or minus maybe 60 degrees of vertical for a 3dB (half power) loss. Within about 35 degrees you'd have trouble picking the optimum direction without automation.
This is why "what is the region it could have reached in 5 minutes or less is my search criterion. Then match that with the currents to try to refine it all. And I have an untutored hunch that turning an A330 or anything else at FL350 is not "sharp" by any stretch of the imagination unless you are purposely entering a dive as for a bombing run.
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Remember, the 0214 time is the last received time for any datalink from AF447. Reversion to anything other than 'Normal AC Power' would have turned the ACARS system off. The plane could have been airbourne for some time after that, expanding the search area requirements.
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In Summary then.......
Surplus1 said
I accept what surplus1 says about a maintained stable stall being unlikely, however his arguments don’t apply to a spin scenario. Once entered and stabilized (for whatever reason), some aircraft will remain in a sustained stick-free spin until impact. It’s the nature of the beast and a function of the momentum built up by the couples in autorotation (hence the “auto”). The most recent precedent is the TU154 crash in Donetsk. It was a very similar situation except that the pilots had attempted to outclimb the storm clouds – rather than suffered an autopilot disconnect and pitch-up. They rode it down, attempting recovery, and even managed to punch out a distress call or two.
However I don’t believe that the aerodynamic forces in play at spin entry (or during a spin) would’ve been anywhere near that required to generate fin failure/detachment. The four minutes of ACARS messages stemming from that initial failure would have started at autopilot “kick-out”.
So if we now apply Occam's Razor and then summarize:
Can't rule out pilot incapacitation yet but it's more likely that the two copilots were minding the shop and were caught out when the autopilot suddenly kicked out and they faced a severely out-of-trim aircraft pitching up into a stall/spin situation (thanks to the faulty pitot tubes and auto-trim and a confounded ADIRS).
If the auto-trim progressively wound in lots of back-trim as a result of the pitot supplying increasingly false air-data, the A330 may not have been recoverable in Alternate Law (which they were suddenly in). It's one of the unattractive aspects of a trimmable horizontal stabilizer and an autopilot that's capable of holding large out-of-trim loads.
One big fallacy is that you cannot stall a FBW Airbus. That law is trumped by a dynamic pitch-up into the tenuous aerodynamics of coffin corner flight. i.e. to say that no further pro-spin flight control inputs are required. Thanks to the high nose attitude and the couples, the stall/spin scenario is the only logical aerodynamic outcome (with or without an engine hiccup). That's what can happen in a thin air regime that pilots very very rarely fly manually in. And you can reflect upon the likelihood that such corners of the operating envelope would never have been pursued by Airbus test-pilots. Engines that are suddenly exposed to a high AoA at high power in coffin corner are also likely to stall (due intake blanking). One engine stalling would have provided the asymmetry for rapid instantaneous entry into a flat spin.
Why could it have remained a flat spin? As the aircraft descended and the air thickened, the engine would have unstalled itself (that's what happens with N over root T stalls), provided high symmetric thrust and kept the spin flattened. Distracted pilots may not have noted that the auto-thrust had also dropped out and that the throttle positions were now dictating thrust directly (after all, during a developed spin there's lots of centrifugal force and the pilots were probably not able to focus on the ECAM). They'd have been trying stick and rudder inputs for recovery. The nature of a flat spin is that recovery via unsustained flight control inputs is highly unlikely and, because of that high centrifugal force, anything not tied down in the cabin or holds would've migrated aft, further exacerbating the aft CofG complication for a flat spin.
The nature of spins generically is that the correct flight control anti-spin inputs must be made AND HELD to be ultimately effective in recovery. CRM just doesn't operate in a terminal spin - and in a FBW Airbus there's got to be a formal hand-over/take-over and a pressing of side-stick buttons, or control inputs are either negated or reinforced. The galvanic nature of a spin is not conducive to two pilots caught by surprise, agreeing on the correct throttle and stick/rudder positions and holding them static - at least not long enough for their inputs to overcome the spin's considerable inertia. Coherent analysis, communication and trouble-shooting is just not possible in a full-blown spin. AF447 has likely been one of those "points of no return" developments that lurk beyond aviation's rarely visited thresholds.
A sudden lunge into the deep recesses of coffin corner, courtesy of the triple ADIRUs finally rejecting erroneous pitot-derived data - and reacting and rejecting- is to swiftly and unexpectedly cross one of those thresholds. When examining the hazards of a known deficiency, and the urgency of any need to correct it, both EADS and the FAA should be looking at the possible complications arising at (or just outside) the edge of the operating envelope - and extrapolate from there.
.
If a stall is approached in that mode, when the AP disconnects and power is applied there will be a severe pitch up that the elevator may not have the authority to overcome in a timely manner unless (and until) the trim is removed by the pilot.
Undesirable flight states; stall appears to be prevented in Alternate law (ALTN 1) by the low speed protection, IAS replaces the AOA function, but in this accident it appears that there was no valid IAS. AFAIK this gives ALTN 2 law – no speed protections;
However I don’t believe that the aerodynamic forces in play at spin entry (or during a spin) would’ve been anywhere near that required to generate fin failure/detachment. The four minutes of ACARS messages stemming from that initial failure would have started at autopilot “kick-out”.
So if we now apply Occam's Razor and then summarize:
Can't rule out pilot incapacitation yet but it's more likely that the two copilots were minding the shop and were caught out when the autopilot suddenly kicked out and they faced a severely out-of-trim aircraft pitching up into a stall/spin situation (thanks to the faulty pitot tubes and auto-trim and a confounded ADIRS).
If the auto-trim progressively wound in lots of back-trim as a result of the pitot supplying increasingly false air-data, the A330 may not have been recoverable in Alternate Law (which they were suddenly in). It's one of the unattractive aspects of a trimmable horizontal stabilizer and an autopilot that's capable of holding large out-of-trim loads.
One big fallacy is that you cannot stall a FBW Airbus. That law is trumped by a dynamic pitch-up into the tenuous aerodynamics of coffin corner flight. i.e. to say that no further pro-spin flight control inputs are required. Thanks to the high nose attitude and the couples, the stall/spin scenario is the only logical aerodynamic outcome (with or without an engine hiccup). That's what can happen in a thin air regime that pilots very very rarely fly manually in. And you can reflect upon the likelihood that such corners of the operating envelope would never have been pursued by Airbus test-pilots. Engines that are suddenly exposed to a high AoA at high power in coffin corner are also likely to stall (due intake blanking). One engine stalling would have provided the asymmetry for rapid instantaneous entry into a flat spin.
Why could it have remained a flat spin? As the aircraft descended and the air thickened, the engine would have unstalled itself (that's what happens with N over root T stalls), provided high symmetric thrust and kept the spin flattened. Distracted pilots may not have noted that the auto-thrust had also dropped out and that the throttle positions were now dictating thrust directly (after all, during a developed spin there's lots of centrifugal force and the pilots were probably not able to focus on the ECAM). They'd have been trying stick and rudder inputs for recovery. The nature of a flat spin is that recovery via unsustained flight control inputs is highly unlikely and, because of that high centrifugal force, anything not tied down in the cabin or holds would've migrated aft, further exacerbating the aft CofG complication for a flat spin.
The nature of spins generically is that the correct flight control anti-spin inputs must be made AND HELD to be ultimately effective in recovery. CRM just doesn't operate in a terminal spin - and in a FBW Airbus there's got to be a formal hand-over/take-over and a pressing of side-stick buttons, or control inputs are either negated or reinforced. The galvanic nature of a spin is not conducive to two pilots caught by surprise, agreeing on the correct throttle and stick/rudder positions and holding them static - at least not long enough for their inputs to overcome the spin's considerable inertia. Coherent analysis, communication and trouble-shooting is just not possible in a full-blown spin. AF447 has likely been one of those "points of no return" developments that lurk beyond aviation's rarely visited thresholds.
A sudden lunge into the deep recesses of coffin corner, courtesy of the triple ADIRUs finally rejecting erroneous pitot-derived data - and reacting and rejecting- is to swiftly and unexpectedly cross one of those thresholds. When examining the hazards of a known deficiency, and the urgency of any need to correct it, both EADS and the FAA should be looking at the possible complications arising at (or just outside) the edge of the operating envelope - and extrapolate from there.
.
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JD-EE:
At 420 knots the plane is going 7 miles a minute.
At 420 knots the plane is going 7 miles a minute.
At 0210 we have a position. Presuming the plane was still aimed "roughly" along the planned flightpath and presuming perhaps some pushes by storm winds where could the plane have gotten to by 0214 plus maybe a little Kentucky Windage for surviving a bit past 0214?
This hard flying condition are not documented anywhere and all we can verify by sattelite IR imagery is that she was pretty close to the coldest part of the convective CB cells around her, but we are left without a single clue about how bad or good the real situation was. LH507 crossed 20 mn before with a 10 NM deviation West and reported only moderate turbulences. There is a strong evidence by F-GZCP thrust setting that she was not in severe turbulences at 0210. Please, give a little credit to the pilots and consider first that they will do what they were supposed to do, weather avoidance and turbulence procedures, until we got something like a hard proof that they failed to do so. The next Air France flight, 37 mn later, deviated 80 NM as it is not in the company policy to fly strait into bad weather for saving fuel. If they picked this way, it would have been painted safe (right or wrong) on their radar and they are supposed to have been trained well enough to use it, or we need evidence they were not.
"Where could the plane possibly be?" might be a better search criterion than "where do the currents extrapolate backwards to at the time of the crash?"
And, of course, I am fastened on to the apparent fact that the plane was either deceased or was no longer even approximately horizontal after 0214.
And, of course, I am fastened on to the apparent fact that the plane was either deceased or was no longer even approximately horizontal after 0214.
All the facts we know for sure about the real weather situation is resumed in one word: ice. How we know it? The ACARS are telling us that the probes are freezing, that's all and we should stick with it as the primary weather issue encountered.
Aiming of the satellite antenna is somewhere between a TV yagi on a rotator and a pair of rabbit ears in a high signal area for reference. You can be a whole lot off and it still works. Plus or minus maybe 60 degrees of vertical for a 3dB (half power) loss. Within about 35 degrees you'd have trouble picking the optimum direction without automation.
This is why "what is the region it could have reached in 5 minutes or less is my search criterion. Then match that with the currents to try to refine it all. And I have an untutored hunch that turning an A330 or anything else at FL350 is not "sharp" by any stretch of the imagination unless you are purposely entering a dive as for a bombing run.
This is why "what is the region it could have reached in 5 minutes or less is my search criterion. Then match that with the currents to try to refine it all. And I have an untutored hunch that turning an A330 or anything else at FL350 is not "sharp" by any stretch of the imagination unless you are purposely entering a dive as for a bombing run.
Air Transat Flight TS236, was en route at FL390 when at 05:36 UTC, the crew became aware of a fuel imbalance between the left and right-wing main fuel tanks. Five minutes later the crew concerned about the lower-that-expected fuel quantity indication, decided to divert to Lajes Airport in the Azores. At 05:48 UTC, when the crew ascertained that a fuel leak could be the reason for the possible fuel loss, an emergency was declared to Santa Maria Oceanic Control. At 06:13, at a calculated distance of 135 miles from Lajes, the right engine (Rolls-Royce Trent 772B) flamed out. At 06:26, when the aircraft was about 85 nm from Lajes and at an altitude of about FL345, the left engine flamed out. At 06:39 the aircraft was at 13,000 feet and 8 miles from the threshold of runway 33. An engines-out visual approach was carried out and the aircraft landed on runway 33. Eight of the plane's ten tyres burst during the landing.
Investigation has determined that a low-pressure fuel line on the right engine, had failed probably as the result of its coming into contact with an adjacent hydraulic line.
S~
Olivier
Last edited by takata; 7th Jul 2009 at 06:10.