Air Asia Indonesia Lost Contact from Surabaya to Singapore
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6000 fpm unexpected in an Airbus with a change of Outside Air Temperature? Not at all impossible indeed its happened before.
For 18 seconds after the autopilot disengaged the aircraft remained within 200 feet altitude of FL
360 but once AoA law was invoked at 14:21:50 hrs, the aircraft's attitude began to pitch nose-up.
The pitch-up trend continued for 17 seconds reaching a peak of 15° nose-up shortly before the first
nose-down sidestick command was applied. Throughout this phase the aircraft climbed rapidly
(reaching a peak rate of about 6,000 ft/min) due to the increase in lift created by the flight control
system's capture of alpha prot. The aircraft reached its apogee at FL 384 at 14:22:28 hrs where the
airspeed had decayed to 205 KIAS and 0.67 Mach even though full thrust had been applied.
Throughout the turbulence encounter, the normal g fluctuations were between 0.5g and 1.5g. The
recorded wind direction remained within 20° of the mean of 240° but the wind speed varied
between 67 kt and 108 kt and the static air temperature fluctuated between -42° C and -52°C. There
were 7 cycles of temperature change, the second cycle being the most severe. The mean air
temperature before the AIRPROX event was -46.5° C and afterwards it was -44.5°C. The crew
subsequently descended back to FL 360 and successfully re-engaged the autopilot and autothrust
systems.
360 but once AoA law was invoked at 14:21:50 hrs, the aircraft's attitude began to pitch nose-up.
The pitch-up trend continued for 17 seconds reaching a peak of 15° nose-up shortly before the first
nose-down sidestick command was applied. Throughout this phase the aircraft climbed rapidly
(reaching a peak rate of about 6,000 ft/min) due to the increase in lift created by the flight control
system's capture of alpha prot. The aircraft reached its apogee at FL 384 at 14:22:28 hrs where the
airspeed had decayed to 205 KIAS and 0.67 Mach even though full thrust had been applied.
Throughout the turbulence encounter, the normal g fluctuations were between 0.5g and 1.5g. The
recorded wind direction remained within 20° of the mean of 240° but the wind speed varied
between 67 kt and 108 kt and the static air temperature fluctuated between -42° C and -52°C. There
were 7 cycles of temperature change, the second cycle being the most severe. The mean air
temperature before the AIRPROX event was -46.5° C and afterwards it was -44.5°C. The crew
subsequently descended back to FL 360 and successfully re-engaged the autopilot and autothrust
systems.
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Pick a number- pick a source
Geeze ...
AirAsia Jet Climbed at Rate Beyond Design of Commercial Planes
Plane Climbed at Rate of More Than 8,000 Feet a Minute, Transport Minister Says
The Airbus Group NV. A320 jet turned left away from its assigned flight path en route from Surabaya to Singapore, climbed at more than 8,000 feet a minute—six to eight times the normal rate—descended and finally disappeared within three minutes, Mr. Jonan said, citing data from the plane’s automatic dependent surveillance-broadcast, or ADS—B, system.
Note it is not from the FDR!
Pitot problems ??
AirAsia Jet Climbed at Rate Beyond Design of Commercial Planes
Plane Climbed at Rate of More Than 8,000 Feet a Minute, Transport Minister Says
The Airbus Group NV. A320 jet turned left away from its assigned flight path en route from Surabaya to Singapore, climbed at more than 8,000 feet a minute—six to eight times the normal rate—descended and finally disappeared within three minutes, Mr. Jonan said, citing data from the plane’s automatic dependent surveillance-broadcast, or ADS—B, system.
Note it is not from the FDR!
Pitot problems ??
That's one credible scenario to account for the 2000' odd overshoot of assigned altitude and the eventual stall. You often get temp changes in CBs, however it could also be sensor icing and autopilot pitchup or pilot error. There's not enough data yet to factor out all the possibilities.
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That's one credible scenario to account for the 2000' odd overshoot of assigned altitude and the eventual stall. You often get temp changes in CBs, however it could also be sensor icing and autopilot pitchup or pilot error. There's not enough data yet to factor out all the possibilities.
It seems that we are back to square one if he's just quoting the ADS-B figures because all these variables like temps and extreme gusts may adversely affect the accuracy of the sensors supplying that ADS system.
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this may answer your question
Crashed AirAsia A320 undertook rapid climb: minister
By: DAVID KAMINSKI-MORROW Source: in 5 hours
Indonesia’s parliament has been told that the Indonesia AirAsia Airbus A320 which crashed into the Java Sea last month climbed rapidly before its fatal descent.
The aircraft climbed at 6,000ft/min and then descended 7,900ft in the space of 45s, transport minister Ignasius Jonan stated.
He was briefing the parliament on the latest findings in the flight QZ8501 investigation on 20 January.
There is no immediate indication as to the reason behind the rapid climb or the subsequent descent, nor any details on the flight-control law under which the A320 was operating at the time.
The aircraft’s crew had requested a climb to 38,000ft from its assigned altitude of 32,000ft, while in the vicinity of poor weather, during the service to Singapore on 28 December.
Investigators have previously stated that the aircraft had been cleared to climb only to 34,000ft
By: DAVID KAMINSKI-MORROW Source: in 5 hours
Indonesia’s parliament has been told that the Indonesia AirAsia Airbus A320 which crashed into the Java Sea last month climbed rapidly before its fatal descent.
The aircraft climbed at 6,000ft/min and then descended 7,900ft in the space of 45s, transport minister Ignasius Jonan stated.
He was briefing the parliament on the latest findings in the flight QZ8501 investigation on 20 January.
There is no immediate indication as to the reason behind the rapid climb or the subsequent descent, nor any details on the flight-control law under which the A320 was operating at the time.
The aircraft’s crew had requested a climb to 38,000ft from its assigned altitude of 32,000ft, while in the vicinity of poor weather, during the service to Singapore on 28 December.
Investigators have previously stated that the aircraft had been cleared to climb only to 34,000ft
Last edited by Longtimer; 20th Jan 2015 at 15:19. Reason: forgot to indicate that this was a reply to NARBOS
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How used to the local weather we're these pilots? On AF447, Bonin was spooked by St Elmo's Fire and the "Electrical Smell" from lightening. It was new to him. He'd never even heard of either phenomenon before. These two things, along with his leader, Captain Dubois, leaving the cockpit, made him so uncomfortable and nervous, that he was using his reptilian brain and was in fight or flight mode, even before the pitot tubes iced up. To put it in medical terms, he was already "freaked out".
These Air Asia pilots may have already been familiar with the weather and it's associated sights, sounds, and smells they encountered. They may have done all the right things. Investigators may find that there is nothing they could have done to save the aircraft. The storm may have affected the flight with specific combinations (up/downdrafts, ice, etc), that were beyond the capacity of the aircraft, crew, and flight computer to handle, even if everything was handled correctly. Could have been a combination that almost never happens, and didn't happen to the flights ahead of them or the flights behind them. It might just be, "The storm got 'em".
I think the Indonesians will find out soon enough, and I think they're doing a good job with the investigation. They may have learned from the missteps of their neighbors on the MH370 issue, on getting their ducks in a row, before they issue statements. I join those who laud the Indonesian divers. They have put their lives at risk, pushing the envelope on getting the Bends, and fighting strong currents, in order to move the investigation and recovery along.
These Air Asia pilots may have already been familiar with the weather and it's associated sights, sounds, and smells they encountered. They may have done all the right things. Investigators may find that there is nothing they could have done to save the aircraft. The storm may have affected the flight with specific combinations (up/downdrafts, ice, etc), that were beyond the capacity of the aircraft, crew, and flight computer to handle, even if everything was handled correctly. Could have been a combination that almost never happens, and didn't happen to the flights ahead of them or the flights behind them. It might just be, "The storm got 'em".
I think the Indonesians will find out soon enough, and I think they're doing a good job with the investigation. They may have learned from the missteps of their neighbors on the MH370 issue, on getting their ducks in a row, before they issue statements. I join those who laud the Indonesian divers. They have put their lives at risk, pushing the envelope on getting the Bends, and fighting strong currents, in order to move the investigation and recovery along.
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Non-pilot here but just a question. (Which hopefully doesn't come across as blatantly ignorant.)
Is it possible, or even likely, for a severe updraft to carry a commercial airliner to that rate of ascent? Just curious.
Is it possible, or even likely, for a severe updraft to carry a commercial airliner to that rate of ascent? Just curious.
Assuming the data comes from the pressure instruments (IAS/VSI/ALT) these would be indicated values.
Within an active CB there are big pressure variations which will affect these instrument indications.
The a/c may actually have been doing something different.
Personally I don't like this drip feed of information. Better to wait and hear all the facts.
Within an active CB there are big pressure variations which will affect these instrument indications.
The a/c may actually have been doing something different.
Personally I don't like this drip feed of information. Better to wait and hear all the facts.
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It will be where the ocean currents took it either as it floated or the undersea currents. 6Kts times however many hours/days it took to wedge into the seabed. How far is 6kts for 24hours? Difficult to prove much from that isn't it. More interesting will be the damage and estimates of how that would have been caused.
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I remember (obviously unintentionally) reaching +6000fpm in a 737 while the autopilot was climbing in VNAV SPD passing FL360 - we suddenly gained 35 knots of headwind within 1000 feet, what we did was leave the autopilot attempt to fly the speed and kept the thrust levers where they were but pulled the speed brake in anticipation of losing that headwind component again to reduce the climb rate - eventually levelled off at FL400... Quite the experience, V/S pegged and Mach approaching 0.82 with the autopilot wanting to pitch past 10°.
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Radome
The visible portion of the radome pic
http://www.pprune.org/rumours-news/5...ml#post8832757
shows a similarity to the earlier pic of the fuselage frame that retained its circular shape but was neatly stripped of skin. Rivets pulled through without gross deformation seems less consistent with an impact than with an impact overpressure blowoff where pressure is applied internally and uniformly over the part. Thanks training wheels for including sources.
http://www.pprune.org/rumours-news/5...ml#post8832757
shows a similarity to the earlier pic of the fuselage frame that retained its circular shape but was neatly stripped of skin. Rivets pulled through without gross deformation seems less consistent with an impact than with an impact overpressure blowoff where pressure is applied internally and uniformly over the part. Thanks training wheels for including sources.
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re 8000 ft/min
So where did SAMPUBLIUS get his info from re 8000'/min and the ADS-B?
I'll post the headlines
World News
AirAsia Jet Climbed at Rate Beyond Design of Commercial Planes
Plane Climbed at Rate of More Than 8,000 Feet a Minute, Transport Minister Says
By
I-Made Sentana And
Gaurav Raghuvanshi
Updated Jan. 20, 2015 12:15 p.m. ET
15 COMMENTS
JAKARTA, Indonesia—The AirAsia jet that crashed on Dec. 28 into the Java Sea stalled after apparently climbing far too steeply, Indonesia’s Transport minister said Tuesday, in the first public comments by a high-level official on what likely happened.
“The plane may have climbed in the last minutes at a speed beyond normal limits. After that, it stalled. Why did it stall? I don’t know,” Transport Minister Ignasius Jonan said, elaborating on an statement he made earlier in a hearing in the parliament....
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Originally Posted by rgbrock1
Is it possible, or even likely, for a severe updraft to carry a commercial airliner to that rate of ascent? Just curious.
Wind power may cause only raise the nose of the aircraft and than speed (which initially is big) is transformed into altitude. For a time.
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It's not a controlled rate of climb. 6000'/min is impossible at that altitude and type. It's a pitchup zoom climb possibly aided by updraft with reducing IAS into a stall; then we are guessing.
I saw 4500'/m in an A320, FL330, recently, nowhere near a CB, nor with an updraft, but with "windshear". Think through flying towards a Jetstream, you are in say a 50K HW, climbing at 290KIAS transitioning to .78M, OP CLB.
As you fly into the 110K jet stream the HW increases. To maintain IAS the AP pitches up, and provided the HW keeps increasing, high RoC is possible, outside the conventional "performance limits" of the type. And totally iaw the SOPs.
On the occasion above I "hinted" to my colleague "was this wise?" - they were oblivious to the "issue"... I requested they select V/S, a reasonable RoC, even though this kept us in the turbulence for longer... since in time the HW would not only stop increasing, but potentially reduce as we flew out of the Jetstream upper level. Were you to do this, the IAS fall off could be dramatic, and could see IAS fall below VLS (or worse), an uncomfortable nose lowering pitch rate required (even manually), and a descent (back into the Jetstream
) required to recover IAS.I am not suggesting this occurred in this accident i.e. a HW change led to zoom climb, then HW fell off so drastically stall etc. - although possible? But 6000'/m is feasible without failure, and iaw SOPs.
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I am not sure if the sheer speed of the updraft would be too much of a problem. As long as you are in a consistent airmass. I have flown gliders in mountain wave, as long as I allow the updraft to carry me and I hold same 'speed' and attitude all is well....
But, along with the updraft, close by is an equally strong downdraft.. and, inbetween, extremely rough rotor and disturbance that can break your craft by exceeding G forces.
Add to that, HAL trying to maintain the programmed flight plan and getting overwhelmed by the external changes....
In a CuNimbus scenario you will have extreme airflows up and down. Trying to poke a hole in that cloud at speed will give you extremes of G and not to mention super cooled air, icing etc for your wings, pitot tubes etc.
Best to thread your way around them as most do.
They asked for permission but left it too late and drove into a super cell perhaps
But, along with the updraft, close by is an equally strong downdraft.. and, inbetween, extremely rough rotor and disturbance that can break your craft by exceeding G forces.
Add to that, HAL trying to maintain the programmed flight plan and getting overwhelmed by the external changes....
In a CuNimbus scenario you will have extreme airflows up and down. Trying to poke a hole in that cloud at speed will give you extremes of G and not to mention super cooled air, icing etc for your wings, pitot tubes etc.
Best to thread your way around them as most do.
They asked for permission but left it too late and drove into a super cell perhaps
Last edited by Swedishflyingkiwi; 20th Jan 2015 at 19:13. Reason: HAL
