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  Reply # 1214831 14-Jan-2015 14:16
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Hmm microburst warnings would have sounded, and they can prepare for it.  At that altitude it should not bring a plane down.  On approach they are very dangerous, also I thought a microbursts only occurred lower to the ground.

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  Reply # 1216394 17-Jan-2015 00:11
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When I first picked this up it made me quite anxious, we're flying AirAsia on a big 6-week round the world trip whilst are goods are being shipped from the UK to NZ.
Initially I had also booked a Kuala Lumpur-Bali flight with them but because of their appalling customer services I was made to forfeit the flight.




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  Reply # 1218998 21-Jan-2015 12:24
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New develeopments

Half of CVR heard. Normal, nothing to report

They have found that the aircraft ascended at 6000ft per minute, then probably stalled. Could an updraft cause this? This is fighter ascent rate levels. Maybe with high headwinds, full power, pilot controlled it could have? Maybe the rest of the CVR may fill in this gap.

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  Reply # 1219017 21-Jan-2015 12:43
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tdgeek: New develeopments

Half of CVR heard. Normal, nothing to report

They have found that the aircraft ascended at 6000ft per minute, then probably stalled. Could an updraft cause this? This is fighter ascent rate levels. Maybe with high headwinds, full power, pilot controlled it could have? Maybe the rest of the CVR may fill in this gap.


The answer is yes.

From http://www.britannica.com/EBchecked/topic/594363/thunderstorm/218326/Multiple-cell-thunderstorms-and-mesoscale-convective-systems:

Updraft speeds typically peak in the range of 5 to 10 metres (16 to 33 feet) per second, and speeds exceeding 20 metres (66 feet) per second are common in the upper parts of large storms. Airplanes flying through large storms at altitudes of about 10,000 metres (33,000 feet) have measured updrafts exceeding 30 metres per second (5900fpm).

It also tells me that in Supercells, updrafts can reach 40m/s (7800fpm).

Incidentally, headwinds (or tailwinds) are irrelevant to rate of climb.



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  Reply # 1219033 21-Jan-2015 12:49
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frankv:
tdgeek: New develeopments

Half of CVR heard. Normal, nothing to report

They have found that the aircraft ascended at 6000ft per minute, then probably stalled. Could an updraft cause this? This is fighter ascent rate levels. Maybe with high headwinds, full power, pilot controlled it could have? Maybe the rest of the CVR may fill in this gap.


The answer is yes.

From http://www.britannica.com/EBchecked/topic/594363/thunderstorm/218326/Multiple-cell-thunderstorms-and-mesoscale-convective-systems:

Updraft speeds typically peak in the range of 5 to 10 metres (16 to 33 feet) per second, and speeds exceeding 20 metres (66 feet) per second are common in the upper parts of large storms. Airplanes flying through large storms at altitudes of about 10,000 metres (33,000 feet) have measured updrafts exceeding 30 metres per second (5900fpm).

It also tells me that in Supercells, updrafts can reach 40m/s (7800fpm).

Incidentally, headwinds (or tailwinds) are irrelevant to rate of climb.




Tks for the detail. I assumed a headwind would allow more airspeed over the wing, causing more lift at an angle of attack, but good to know.

Given that the stall speed at close to 40000 feet is very high, easy to see how a stall could occur in this mayhem. And possibly difficult to get the nose down to increase airspeed in varying storm wind conditions?

Lastly, good to see the journos reporting this as not possible. Typically adding to the sensationalism.

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  Reply # 1219040 21-Jan-2015 13:02
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tdgeek:

Tks for the detail. I assumed a headwind would allow more airspeed over the wing, causing more lift at an angle of attack, but good to know.

Given that the stall speed at close to 40000 feet is very high, easy to see how a stall could occur in this mayhem. And possibly difficult to get the nose down to increase airspeed in varying storm wind conditions?

Lastly, good to see the journos reporting this as not possible. Typically adding to the sensationalism.


Aircraft fly relative to the air they are in. So a headwind has no effect on rate of climb. It does reduce the groundspeed, and increase the angle of climb.

A sudden strong updraft could cause the wing to stall, because it effectively increases the angle of attack.

In conditions like this, there is also likely to be a great deal of turbulence as the aircraft flies in and out of updrafts and downdrafts. I have no doubt that the pilots requested changes of course and altitude because they were experiencing turbulence, and expected it to get worse. Conceivably, turbulence inside a thunderstorm might be bad enough to cause structural failure of the aircraft.


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  Reply # 1219451 21-Jan-2015 20:40
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The A320 has flight envelope protection and it's my understanding that it would not have been possible for it to stall unless some sort of failure caused it to switch to direct or alternate law. This might suggest blockage, icing or damage to pitot tubes or angle of attack sensors.



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  Reply # 1438968 1-Dec-2015 23:42
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So the final report says the autopilot computer had a cracked solder joint, causing the plane to be upset (pointed up), pilots disabled autopilot and caused it to gain even more altitude by incorrect response, eventually stalling [lift on wings < weight of plane] it leading to crash.

http://edition.cnn.com/videos/world/2015/12/01/report-on-air-asia-crash-released-quest-bpr.cnn




Swype on iOS is detrimental to accurate typing. Apologies in advance.


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  Reply # 1438978 2-Dec-2015 00:04
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joker97: So the final report says the autopilot computer had a cracked solder joint, causing the plane to be upset (pointed up), pilots disabled autopilot and caused it to gain even more altitude by incorrect response, eventually stalling [lift on wings < weight of plane] it leading to crash.

http://edition.cnn.com/videos/world/2015/12/01/report-on-air-asia-crash-released-quest-bpr.cnn


Watching Air Crash Investigation it blows my mind how often pilots do this.  Their stick shaker is going off and still they pull up. 



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  Reply # 1439007 2-Dec-2015 07:23
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Apparently Air Asia only train*ed their pilots to Take Off and Land, because, let's face it, nothing ever goes wrong in mid air, the plane flies itself doesn't it?

*they do now




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  Reply # 1439009 2-Dec-2015 07:25
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itxtme:
joker97: So the final report says the autopilot computer had a cracked solder joint, causing the plane to be upset (pointed up), pilots disabled autopilot and caused it to gain even more altitude by incorrect response, eventually stalling [lift on wings < weight of plane] it leading to crash.

http://edition.cnn.com/videos/world/2015/12/01/report-on-air-asia-crash-released-quest-bpr.cnn


Watching Air Crash Investigation it blows my mind how often pilots do this.  Their stick shaker is going off and still they pull up. 


Yes that's our favourite show, mind boggling eh ...




Swype on iOS is detrimental to accurate typing. Apologies in advance.


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  Reply # 1439013 2-Dec-2015 07:33
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Once again the whole Airbus flight control model rears it's ugly head.

How many Airbus crashes have we now had where the pilot and first officer have both tried to avert an incident and due to the asynchronous sidesticks and lack of haptic feedback between both sidesticks have had totally opposing inputs (one pulling back and the other pushing forward) which is then averaged out by the flight computer? You'd think pilot training globally would have improved since the AF447 crash, but clearly it hasn't.

It really makes you wonder about pilot training when in two incidents both have lost all situational awareness and believed that pulling back was the solution for a stall, not pushing the nose down.

(And now I wait for @hairy1 to comment! :p)

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  Reply # 1439023 2-Dec-2015 08:03
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No comment.




My views (except when I am looking out their windows) are not those of my employer.

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  Reply # 1439028 2-Dec-2015 08:10
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hairy1: No comment.


That's unlike you. Are your QC25's so good you didn't hear me speak?

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  Reply # 1439043 2-Dec-2015 08:23
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"the AirAsia plane had the same problem with its rudder system 23 times in the 12 months before the December crash"
If the brake or engine warnings light up on your car dashboard every couple of weeks, just ignore them.  She'll be right - just a dry solder joint.




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