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@takata: Eh bien, you're right the timestamp of the ACARS message is not necessarily related to when the fault occurred. The sequence of events up to the ADR disagree message however would be conducive with a disabled pitot and the corresponding crew action such as manual AP OFF.
@chaz: You don't need that high a speed. The point is I don't know how fast a flat spinning A330 will descend. Any number between 7000 to 20000 ft/min sounds reasonable to me: If you assume FL350 to FL0 in 5 minutes, you just need 7000ft/min ROD. If you take the highest number I've seen (taken from someone elses calculations on the previous page, look for the diagram with velocity vectors), the numbers can still be plausible.
Hopefully we'll know for sure soon. I was just (for my own curiosity) trying to satisfy possible events between LKP and what we now know as the wreck position.
@chaz: You don't need that high a speed. The point is I don't know how fast a flat spinning A330 will descend. Any number between 7000 to 20000 ft/min sounds reasonable to me: If you assume FL350 to FL0 in 5 minutes, you just need 7000ft/min ROD. If you take the highest number I've seen (taken from someone elses calculations on the previous page, look for the diagram with velocity vectors), the numbers can still be plausible.
Hopefully we'll know for sure soon. I was just (for my own curiosity) trying to satisfy possible events between LKP and what we now know as the wreck position.
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@takata: Eh bien, you're right the timestamp of the ACARS message is not necessarily related to when the fault occurred. The sequence of events up to the ADR disagree message however would be conducive with a disabled pitot and the corresponding crew action such as manual AP OFF.
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Engine damage
Re Chaz: Pulkovo flight 612 stall. From FDR data; stall from 11,677m reached vertical velocity of 94m/s around 5730m, decreasing to 72m/sec just prior to impact. Time of decent was 126sec.
Re the engines. Unless I am very much mistaken, the LPC fan blades are gone, the front sections of the outer nozzle containment shroud ring has gone, and what we see in both pictures are the remnants of the guide vanes which form the rear part of the bypass nozzle. Surely, this level of destruction is suggestive of a high engine shaft rpm at impact.
Compare this with the crush damage sustained on engine 2 for TW 800 and the still intact nature of the LPC fan, where the NTSB concluded that there was minimal amount of low-pressure rotor rotation at impact.
General Electric cf6-80
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CROSS SECTION
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FLIGHT INTERNATIONAL: DETAILED SECTION
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REAR VIEW OF FAN SECTION
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TW800 ENGINE 2 - IMPACT CRUSH DAMAGE
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Re the engines. Unless I am very much mistaken, the LPC fan blades are gone, the front sections of the outer nozzle containment shroud ring has gone, and what we see in both pictures are the remnants of the guide vanes which form the rear part of the bypass nozzle. Surely, this level of destruction is suggestive of a high engine shaft rpm at impact.
Compare this with the crush damage sustained on engine 2 for TW 800 and the still intact nature of the LPC fan, where the NTSB concluded that there was minimal amount of low-pressure rotor rotation at impact.
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TW800 ENGINE 2 - IMPACT CRUSH DAMAGE
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@Chris Scot I believe he means the catapult launch from an aircraft carrier.
Chris Scot
For the benefit of this pedestrian pilot, what is a "cat shot", and are you talking about a F-102/ F-106 (delta-wing)?
Chris Scot
For the benefit of this pedestrian pilot, what is a "cat shot", and are you talking about a F-102/ F-106 (delta-wing)?
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By takata:
"Well. but the late triggering of "ADR disagree" at 02.12 is obviously what caused ALT2, Autopilot OFF, Autothrust OFF, Rudder limiter control, etc. And this is what happend in the first place at 02.10 because of those Pitots reading errors... There is not so much possibility for the system to switch to ALT2 in any case."
Rudder Limiter. Fast Vertical Speed fall. Did the vertical stab last untill impact?
"Well. but the late triggering of "ADR disagree" at 02.12 is obviously what caused ALT2, Autopilot OFF, Autothrust OFF, Rudder limiter control, etc. And this is what happend in the first place at 02.10 because of those Pitots reading errors... There is not so much possibility for the system to switch to ALT2 in any case."
Rudder Limiter. Fast Vertical Speed fall. Did the vertical stab last untill impact?
I don't agree with the post above engine assessment.
Suffice it to say that the high quality photos available to the investigators would be enough for them to make a determination. The photos we are looking at do not have resolution to assess the blade condition
The TWA engines came off during the spin to the ground and thus would be no higher in RPM than a very low windmill (they fall flat).
My interest is the ten or so seconds of flight before the error codes were set and not at what the engines looked like when they hit the water.
Suffice it to say that the high quality photos available to the investigators would be enough for them to make a determination. The photos we are looking at do not have resolution to assess the blade condition
The TWA engines came off during the spin to the ground and thus would be no higher in RPM than a very low windmill (they fall flat).
My interest is the ten or so seconds of flight before the error codes were set and not at what the engines looked like when they hit the water.
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I think the only things you can conclude from the photos of the one engine are these:
1. The fan rotor and fan casing are both gone.
2. Most of, if not all of, the fan bypass stator vanes are gone.
3. The titanium fan frame and struts are visable but damaged.
4. The one piece turbine rear frame containing the rear engine mounts (attachment point to the pylon) is gone as well as the rear portion of the LPT casing exposing some turbine rotor blades.
TD
1. The fan rotor and fan casing are both gone.
2. Most of, if not all of, the fan bypass stator vanes are gone.
3. The titanium fan frame and struts are visable but damaged.
4. The one piece turbine rear frame containing the rear engine mounts (attachment point to the pylon) is gone as well as the rear portion of the LPT casing exposing some turbine rotor blades.
TD
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Originally Posted by jcarlosgon
Rudder Limiter. Fast Vertical Speed fall. Did the vertical stab last untill impact?
The structural analysis is telling that the damages were mostly due to vertical compression all over the airframe (and symetrical) with secondary horizontal forces and very few rotational forces. It doesn't mean "Fast vertical speed fall" but that the vertical pressure was higher than horizontal forces.
This is consistent with a stalled level slightly pitched up airframe at impact.
Now, what caused this end stall?
Did this aircraft departed from controled flight at cruise level or did something else happened in between that we are still not aware of?
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I think the only things you can conclude from the photos of the one engine are these:
1. The fan rotor and fan casing are both gone.
2. Most of, if not all of, the fan bypass stator vanes are gone.
3. The titanium fan frame and struts are visable but damaged.
4. The one piece turbine rear frame containing the rear engine mounts (attachment point to the pylon) is gone as well as the rear portion of the LPT casing exposing some turbine rotor blades.
TD
1. The fan rotor and fan casing are both gone.
2. Most of, if not all of, the fan bypass stator vanes are gone.
3. The titanium fan frame and struts are visable but damaged.
4. The one piece turbine rear frame containing the rear engine mounts (attachment point to the pylon) is gone as well as the rear portion of the LPT casing exposing some turbine rotor blades.
TD
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Now, something else than the "deep stall theory" should not be ruled out at this point.
Even if unpowered, such an airframe can glide very far (more than 120 NM from FL350) when it is able to trade off altitude vs distance. It would defintively not fall from the sky like that if it could remain wings level, with all its thrust or if it had enough altitude.
It would take a fair amount of structural damages or an incapacited crew to go down like that (like that?). More likely, before impact, she was left at low altitude without thrust and may have unexpectedly stalled at some point (hence no preparation for ditching).
There was already in the past some problems related with those engines (CF6-80E1 in this case CF6-80E1A3) ice/water ingestion:
Even if unpowered, such an airframe can glide very far (more than 120 NM from FL350) when it is able to trade off altitude vs distance. It would defintively not fall from the sky like that if it could remain wings level, with all its thrust or if it had enough altitude.
It would take a fair amount of structural damages or an incapacited crew to go down like that (like that?). More likely, before impact, she was left at low altitude without thrust and may have unexpectedly stalled at some point (hence no preparation for ditching).
There was already in the past some problems related with those engines (CF6-80E1 in this case CF6-80E1A3) ice/water ingestion:
FROM : AIRBUS CUSTOMER SERVICES TOULOUSE
TO : ALL A330 OPERATORS
OPERATORS INFORMATION TELEX - OPERATORS INFORMATION TELEX
AND
FLIGHT OPERATIONS TELEX - FLIGHT OPERATIONS TELEX
TO: ALL A330 OPERATORS
SUBJECT: ATA 72 - A330 DUAL ENGINE FLAME OUT
OUR REF: SE 999.0069/JS dated 09 JUNE 2006
CLASSIFICATION: INCIDENT - ADVICE (FLIGHT OPERATIONS)
REFERENCE
- OIT SE 999.0067/06/JS dated 02 JUNE 2006
1. PURPOSE
The purpose of OIT/FOT is to provide latest update and to provide operational recommendations on the dual engine flame out event reported through OIT ref. SE 999.0067/06/JS dated 02 JUNE 2006.
2. EVENT DESCRIPTION
On 1 June 2006 an A330-200 aircraft, equipped with General Electric (GE) CF6-80E1 engines, experienced a dual engine flame out during descent around flight level 200.
Both engines quickly recovered and a safe landing was performed.
3. INVESTIGATION STATUS
The investigation into this event is led by the Investigation Authorities with assistance from Airbus. The investigation is still in its early stages, however, DFDR preliminary analysis has shown that:
- During descent, while engines started to accelerate for aircraft altitude capture, both engines flamed out simultaneously.
- Both engines automatically relit after flame out, and recovered within approximately 45 seconds.
- Engine Anti Ice had been selected ON during the descent, and Wing Anti Ice had been selected ON shortly prior to the event.
- Aircraft systems behavior was normal including automatic RAT extension.
Boroscope inspections have been performed on both engines without significant findings.
Based on the above, the initial Airbus/GE view is that this event is similar to other power loss events at altitudes above 10 000 ft attributed to inclement weather as experienced on CF6-80 engines installed on various aircraft types.
The aircraft returned to service on 7 June 06.
4. OPERATIONAL RECOMMENDATIONS
Waiting for final investigation results, in order to increase the fuel/air ratio in the engine so as to mitigate the possibility of experiencing an engine flame out, the following provisional procedure is recommended:
. If inclement weather/icing conditions are expected at any time during descent or if convective activity is identified by the weather radar in the vicinity of the aircraft flight path:
At top of descent:
- ENG ANTI ICE__ON
- WING ANTI ICE_..ON
- PACK FLOW___HI
Below 10000 feet :
Resume normal anti ice and pack flow operation according to weather conditions.
Note that the fuel consumption and the idle thrust will slightly increase when selecting ENG ANTI ICE_ON, WING ANTI ICE_ON, and PACK FLOW_HI.
Final operational recommendations will be implemented in the FCOM/QRH via OEB or TR.
5. FOLLOW-UP PLAN
An update will be provided by 16 June 06.
TO : ALL A330 OPERATORS
OPERATORS INFORMATION TELEX - OPERATORS INFORMATION TELEX
AND
FLIGHT OPERATIONS TELEX - FLIGHT OPERATIONS TELEX
TO: ALL A330 OPERATORS
SUBJECT: ATA 72 - A330 DUAL ENGINE FLAME OUT
OUR REF: SE 999.0069/JS dated 09 JUNE 2006
CLASSIFICATION: INCIDENT - ADVICE (FLIGHT OPERATIONS)
REFERENCE
- OIT SE 999.0067/06/JS dated 02 JUNE 2006
1. PURPOSE
The purpose of OIT/FOT is to provide latest update and to provide operational recommendations on the dual engine flame out event reported through OIT ref. SE 999.0067/06/JS dated 02 JUNE 2006.
2. EVENT DESCRIPTION
On 1 June 2006 an A330-200 aircraft, equipped with General Electric (GE) CF6-80E1 engines, experienced a dual engine flame out during descent around flight level 200.
Both engines quickly recovered and a safe landing was performed.
3. INVESTIGATION STATUS
The investigation into this event is led by the Investigation Authorities with assistance from Airbus. The investigation is still in its early stages, however, DFDR preliminary analysis has shown that:
- During descent, while engines started to accelerate for aircraft altitude capture, both engines flamed out simultaneously.
- Both engines automatically relit after flame out, and recovered within approximately 45 seconds.
- Engine Anti Ice had been selected ON during the descent, and Wing Anti Ice had been selected ON shortly prior to the event.
- Aircraft systems behavior was normal including automatic RAT extension.
Boroscope inspections have been performed on both engines without significant findings.
Based on the above, the initial Airbus/GE view is that this event is similar to other power loss events at altitudes above 10 000 ft attributed to inclement weather as experienced on CF6-80 engines installed on various aircraft types.
The aircraft returned to service on 7 June 06.
4. OPERATIONAL RECOMMENDATIONS
Waiting for final investigation results, in order to increase the fuel/air ratio in the engine so as to mitigate the possibility of experiencing an engine flame out, the following provisional procedure is recommended:
. If inclement weather/icing conditions are expected at any time during descent or if convective activity is identified by the weather radar in the vicinity of the aircraft flight path:
At top of descent:
- ENG ANTI ICE__ON
- WING ANTI ICE_..ON
- PACK FLOW___HI
Below 10000 feet :
Resume normal anti ice and pack flow operation according to weather conditions.
Note that the fuel consumption and the idle thrust will slightly increase when selecting ENG ANTI ICE_ON, WING ANTI ICE_ON, and PACK FLOW_HI.
Final operational recommendations will be implemented in the FCOM/QRH via OEB or TR.
5. FOLLOW-UP PLAN
An update will be provided by 16 June 06.
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@takata - You're clearly right that if the aircraft can maintain wings level at a suitable attitude, it can glide for a long time from FL350.
What if the aircraft entered a storm cell? The huge updraft/downdraft velocities inside the storm system could make the level aircraft lose altitude very rapidly?
I only fly gliders, not large aircraft, but I've flown in pretty rough conditions where we were wings level at normal attitude experiencing 10kt downdrafts (which is a very big downdraft for a glider at little more than 1000ft!). Under those conditions you can lose altitude very rapidly even if the aircraft is in a normal, non-upset condition.
What if the aircraft entered a storm cell? The huge updraft/downdraft velocities inside the storm system could make the level aircraft lose altitude very rapidly?
I only fly gliders, not large aircraft, but I've flown in pretty rough conditions where we were wings level at normal attitude experiencing 10kt downdrafts (which is a very big downdraft for a glider at little more than 1000ft!). Under those conditions you can lose altitude very rapidly even if the aircraft is in a normal, non-upset condition.
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Another speculation
Hello everyone – first time here - always wanted to be a pilot, but became an electronic engineer, then a teacher.
This is a fascinating thread, and I've learned a huge amount, especially about stalls in the last few pages. I have a question for the experts:
I recently saw a program on TV that explained the phenomenon of super cooled water vapour which can exist in very pure air, in the absence of particles to condense around. The program narrator shower how ice spontaneously form around an object (he used a real pitot tube) when introduced to supercooled water vapour in the lab
If this did happen, it would be more than a pitot tube or three that iced up, especially the wings and the leading components of the entire craft. (Some manner of) stalling would have occurred, but the subsequent loss of altitude would have cause the ice build-up to melt, and the possibility would exist for the aircraft to become manageable again, would it not?
What are the chances that the plane crashed in a belated but vain attempt by the pilots to pull out of a dive? Is it true that ACARS transmits error conditions, but not the reversal of a error condition back to OK?
This is a fascinating thread, and I've learned a huge amount, especially about stalls in the last few pages. I have a question for the experts:
I recently saw a program on TV that explained the phenomenon of super cooled water vapour which can exist in very pure air, in the absence of particles to condense around. The program narrator shower how ice spontaneously form around an object (he used a real pitot tube) when introduced to supercooled water vapour in the lab
If this did happen, it would be more than a pitot tube or three that iced up, especially the wings and the leading components of the entire craft. (Some manner of) stalling would have occurred, but the subsequent loss of altitude would have cause the ice build-up to melt, and the possibility would exist for the aircraft to become manageable again, would it not?
What are the chances that the plane crashed in a belated but vain attempt by the pilots to pull out of a dive? Is it true that ACARS transmits error conditions, but not the reversal of a error condition back to OK?
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Originally Posted by eugenefraxby
@takata - You're clearly right that if the aircraft can maintain wings level at a suitable attitude, it can glide for a long time from FL350.
What if the aircraft entered a storm cell? The huge updraft/downdraft velocities inside the storm system could make the level aircraft lose altitude very rapidly?
I only fly gliders, not large aircraft, but I've flown in pretty rough conditions where we were wings level at normal attitude experiencing 10kt downdrafts (which is a very big downdraft for a glider at little more than 1000ft!). Under those conditions you can lose altitude very rapidly even if the aircraft is in a normal, non-upset condition.
What if the aircraft entered a storm cell? The huge updraft/downdraft velocities inside the storm system could make the level aircraft lose altitude very rapidly?
I only fly gliders, not large aircraft, but I've flown in pretty rough conditions where we were wings level at normal attitude experiencing 10kt downdrafts (which is a very big downdraft for a glider at little more than 1000ft!). Under those conditions you can lose altitude very rapidly even if the aircraft is in a normal, non-upset condition.
All those pitot tubes don't freeze in normal/severe weather conditions, neither a dual engine flameout would be caused, neither such an aircraft would be lost with all hands from its cruise level.
This is why we should learn much more from the recorders (if they are found) and the wreckage analysis (including those engines remants).
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Missing fan assembly
@Lomapaseo
Sorry, missed your earlier post about non visible blades. Missing fan assembly and casing could also be explained by shearing forces as you suggest, rather than high rotational energy disintegration.
As you say, let's wait for better photos.
Sorry, missed your earlier post about non visible blades. Missing fan assembly and casing could also be explained by shearing forces as you suggest, rather than high rotational energy disintegration.
As you say, let's wait for better photos.
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takata
I doubt very little controlled gliding was done during the descent. Rather I suspect that immediately following the onset of their upset, the airplane was quick to begin a loss of altitude, with a corresponding increase in vertical speed as forward ground speed declined. The apparent fact that flight attendant stations (seats) were not occupied (on impact) and the lack of any kind of cabin preparedness gives credibility to the quickness of events and the violence of the upset .
I doubt very little controlled gliding was done during the descent. Rather I suspect that immediately following the onset of their upset, the airplane was quick to begin a loss of altitude, with a corresponding increase in vertical speed as forward ground speed declined. The apparent fact that flight attendant stations (seats) were not occupied (on impact) and the lack of any kind of cabin preparedness gives credibility to the quickness of events and the violence of the upset .
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Originally Posted by wes_wall
I doubt very little controlled gliding was done during the descent. Rather I suspect that immediately following the onset of their upset, the airplane was quick to begin a loss of altitude, with a corresponding increase in vertical speed as forward ground speed declined. The apparent fact that flight attendant stations (seats) were not occupied (on impact) and the lack of any kind of cabin preparedness gives credibility to the quickness of events and the violence of the upset.
At 02.15, 02.16, 02.17? Nobody knows actually.
Just before 02.15, at least one engine was obviously still running (certainly both) as ACARS were still transmitted...
Now, at impact time, this aircraft seems to be controlable in the case she was still powered. Was she?
How could we know for sure that she impacted at this exact time if she was not powered anymore?
I'm just pointing that this airframe is able of gliding unpowered but will need some altitude to do so, as well as being able to build up some speed to restart its engines.
When short of both, she certainly will go down.
Per Ardua ad Astraeus
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Come on everyone - we have VERY LITTLE more information now than we had 3000 posts ago. Let's focus on the 'search' and now 'recovery' rather than another 3000 'maybes'. I don't think I could face wading through another 3000 flat spins/stalls/ glides/turnbacks etc etc while trying to find mm's gems.
Personally I suspect the tail section (and FDR) are sadly a long way away from this wreckage - I hope I am wrong.
Personally I suspect the tail section (and FDR) are sadly a long way away from this wreckage - I hope I am wrong.
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Originally Posted by ZeeDoktor
Only alpha floor is lost in alternate law 2.
Alt 1: At low speed, a nose down demand is introduced in reference to IAS, instead of angle of attack, and alternate law changes to direct law. It is available, whatever the slats/flaps configuration, and is active from about 5 knots up to about 10 knots above the stall warning speed, depending on the aircraft's weight and slat/flaps configuration. A gentle progressive nose down signal is introduced, which tends to keep the speed from falling below these values. In addition, audio stall warning (crickets + "STALL" synthetic voice message) is activated at an appropriate margin from the stall condition. The PFD speed scale is modified to show a black/red barber pole below stall warning. Vα prot and Vα max are replaced by Vsw (stall warning speed). The α floor protection is inoperative.
Alt 2 is identical to protections in Alt 1, except that:
1. There is no bank angle protection in Alt 2 law.
2. In case of failure of 2 ADRs, there is no low speed stability.
3. In case of failure of 3 ADRs, there is no high speed stability.
Alt 2 is identical to protections in Alt 1, except that:
1. There is no bank angle protection in Alt 2 law.
2. In case of failure of 2 ADRs, there is no low speed stability.
3. In case of failure of 3 ADRs, there is no high speed stability.
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Originally Posted by BOAC
Personally I suspect the tail section (and FDR) are sadly a long way away from this wreckage - I hope I am wrong.
If the tail separated from the airframe before impact, why was the cabin still pressurized? Do you mean that it happened at low altitude or that it separated without releasing the oxygen masks or without compromising the cabin pressure?
If so, it would not be that far from the main debris field anyway.