Iced AoA sensors send A321 into deep dive
Join Date: Feb 2009
Location: deutschland
Posts: 72
Likes: 0
Received 0 Likes
on
0 Posts
"Passenger 9".....The nom de plume says it all.
Wingswinger is correct:
In the Habsheim event, A-FLOOR was inoperative below 100 ft RA as per design.
The A320 test flight was indeed a departure from the scheduled flight test profile (I believe due to perceived time pressures) combined with AoA issues.
Wingswinger is correct:
In the Habsheim event, A-FLOOR was inoperative below 100 ft RA as per design.
The A320 test flight was indeed a departure from the scheduled flight test profile (I believe due to perceived time pressures) combined with AoA issues.
Join Date: May 2005
Location: middle of nowhere
Posts: 312
Likes: 0
Received 0 Likes
on
0 Posts
@mockingjay:
Passenger 9 gave you the answer:
It would not have helped here. Be careful what you wish for, as per design .....
if Boeing had Alpha Floor protection, or equivalent' it is likely that Asiana 214 would not have happened
in the Habsheim event, A-FLOOR was inoperative below 100 ft RA as per design
Join Date: Apr 2004
Location: Europe
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
I the Habsheim A320 FDR showed the pilot commanding (stick position) a pitch up before they went into the trees and the flight controls moving in the opposite direction! Explain that please.
Join Date: Jun 2009
Location: somewhere
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
@Pax 9:
They were on their total energy limit (Engine thrust) at that time, any altitude gain (Potential energy) would have been traded for airspeed (Kinetic energy) resulting in a stall, it would have crashed at the tree line.
They were too low and too late....
They were too low and too late....
Join Date: Nov 2007
Location: Lancing, Sussex
Age: 92
Posts: 255
Likes: 0
Received 0 Likes
on
0 Posts
Simplistic I know, but does the AOA sensor overide all other info to the pilot.
On one previous accident, the aircraft was straight and level, engines producing normal thrust, but the pilot was convinced the a/c had stralled, and crashed.
On one previous accident, the aircraft was straight and level, engines producing normal thrust, but the pilot was convinced the a/c had stralled, and crashed.
Join Date: Jan 2001
Location: UK
Posts: 2,044
Likes: 0
Received 0 Likes
on
0 Posts
Simplistic I know, but does the AOA sensor overide all other info to the pilot
If 1 sensor provides a differing value to the other 2, in general it will be "voted out". That works well for 99% of failure cases.
The rare problem is where either all 3 sensors give differing values, or where 2 give a similar, but incorrect value. This is behind AF447 and OEB48.
AFAIK, in the A320 one out of range AoA value will generate a stall warning, but not flight protections.
It is fine to blame the aircraft for not working out the 2 failed scenarios, but pilots will not usually be much better, especially at night / IMC
Join Date: May 2000
Location: Phuket
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
Yes they would, experienced pilots will know with a given power setting at a given altitude we should see X speed more or less. If I feel a buffet with this much nose up attitude and with this power setting I will expect X. With experience I will know what to expect and will act accordingly. Experience is the key word here. Fly the freaking machine first however we need proper training and experience.
Join Date: Mar 2015
Location: Dresden, Germany
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
The A320 that crashed into the mediteranian was XL 888T on a check flight. The aircraft's lease was up and XL was in the process of returning it to its owner.
There were three problems that led to the crash:
1. the maintenance crew had washed the plane with a high-pressure hose, thus pushing water into the AoA sensors,
2. the crew did flight tests without authorization and at a dangerously low altitude and
3. the crew did not realize that their plan correctly identified the problem with the AoA sensors and fell back giving the pilots manual control over everything, including crucially the trim.
Had either the PF or the PM read the message on the annunciator and understood it (the CVR indicates that they didn't even read it) they could have trimmed the nose down and the plane would have remained entirely stable.
Also, the crew might have monitored the IAS and realized that the stall protection had not kicked in, long before the speed would have dropped so low.
The chain of problems that led to AF447's crash were: 1. flying through a thunderstorm,
2. pitot tubes freezing,
3. the PF not following procedure in the case of frozen pitot tubes and instead pulling up and
4. said pilot keeping his sidestick pulled back thoughout the stall and drop out of the sky DESPITE the more experienced PM having said several times that he was taking control and that the nose had to be brought down. (In fact FO Bonin did only announce that he was still pulling back on the stick at FL040, at which point it was far to late to do anything.)
The incident this thread is supposedly about was solved by pressing two buttons on the overhead and there was never any real danger to anyone.
Really, people should stop with the blind the hysteria. FBW has saved lots of people's lives and many disasters would not have happened, had the plane had Airbus' system.
There were three problems that led to the crash:
1. the maintenance crew had washed the plane with a high-pressure hose, thus pushing water into the AoA sensors,
2. the crew did flight tests without authorization and at a dangerously low altitude and
3. the crew did not realize that their plan correctly identified the problem with the AoA sensors and fell back giving the pilots manual control over everything, including crucially the trim.
Had either the PF or the PM read the message on the annunciator and understood it (the CVR indicates that they didn't even read it) they could have trimmed the nose down and the plane would have remained entirely stable.
Also, the crew might have monitored the IAS and realized that the stall protection had not kicked in, long before the speed would have dropped so low.
The chain of problems that led to AF447's crash were: 1. flying through a thunderstorm,
2. pitot tubes freezing,
3. the PF not following procedure in the case of frozen pitot tubes and instead pulling up and
4. said pilot keeping his sidestick pulled back thoughout the stall and drop out of the sky DESPITE the more experienced PM having said several times that he was taking control and that the nose had to be brought down. (In fact FO Bonin did only announce that he was still pulling back on the stick at FL040, at which point it was far to late to do anything.)
The incident this thread is supposedly about was solved by pressing two buttons on the overhead and there was never any real danger to anyone.
Really, people should stop with the blind the hysteria. FBW has saved lots of people's lives and many disasters would not have happened, had the plane had Airbus' system.
Join Date: May 2000
Location: Phuket
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
Ok, I am going to have to,say it. Or if people had basic flying skills. That would have saved lives. Case in point; your number 4. That was a prime example of the lack of basic flying skills.
Join Date: Sep 1999
Location: United Kingdom
Posts: 929
Likes: 0
Received 0 Likes
on
0 Posts
& as for the 330 crashed by the test pilots. Funny old thing no protections in ALT* But all the AB aeroplanes are lovely to operate, not so sure to fly. They are fascinating machines & you do need an above average knowledge of the systems to be totally safe. Again well done the crew.
Join Date: Jan 2001
Location: UK
Posts: 2,044
Likes: 0
Received 0 Likes
on
0 Posts
Yes they would, experienced pilots will know with a given power setting at a given altitude we should see X speed more or less
Join Date: May 2000
Location: Phuket
Posts: 297
Likes: 0
Received 0 Likes
on
0 Posts
Leaving the Airbus out of it, it did not work that way with the 2x 757 accidents?
Last edited by before landing check list; 29th Mar 2015 at 06:57.
I was looking into this matter tonight. And I found on this page that Airbus claims it only happened two times ever.
https://safetyfirst.airbus.com/overs...9-application/
Whereas this is clearly false.
There is this case for example where the AOA protection malfunctionned :
https://en.m.wikipedia.org/wiki/Iberia_Flight_1456
(prevented a go around that was required)
I also know from primary data that this happened at least two or three times in another european airline (this time with the same freeze as the Lufthansa 321).
The article in the first post says it happened several times at lufthansa as well.
So, why is airbus making such unsupported claims ?
https://safetyfirst.airbus.com/overs...9-application/
Whereas this is clearly false.
There is this case for example where the AOA protection malfunctionned :
https://en.m.wikipedia.org/wiki/Iberia_Flight_1456
(prevented a go around that was required)
I also know from primary data that this happened at least two or three times in another european airline (this time with the same freeze as the Lufthansa 321).
The article in the first post says it happened several times at lufthansa as well.
So, why is airbus making such unsupported claims ?
Last edited by CVividasku; 21st Feb 2024 at 00:33.
Is it perhaps more probable that Wikipedia is lying?
The good thing with wikipedia is that you can always verify their claims. Just google the report :
https://www.mitma.gob.es/recursos_mf...006_a_eng1.pdf
You even have the curves.
So my question stands
Same goes for the press articles about the lufthansa incidents. It's less reliable than this final report for an accident, but it's still something.
I also know for sure that some cases happened several times to another european airline following probe freeze, but it didn't leak in the press. The logic is simple.
The probes freeze at a given AOA, with comparable values (at least two probes frozen at the same time).
The airplane climbs. The mach number increases. The aoa limit decreases when mach increases.
The aoa limit becomes lower than the frozen AOA. The airplanes dives down.
It's sort of similar to what happened to the B737 max (sort of).
https://www.mitma.gob.es/recursos_mf...006_a_eng1.pdf
You even have the curves.
So my question stands
Same goes for the press articles about the lufthansa incidents. It's less reliable than this final report for an accident, but it's still something.
I also know for sure that some cases happened several times to another european airline following probe freeze, but it didn't leak in the press. The logic is simple.
The probes freeze at a given AOA, with comparable values (at least two probes frozen at the same time).
The airplane climbs. The mach number increases. The aoa limit decreases when mach increases.
The aoa limit becomes lower than the frozen AOA. The airplanes dives down.
It's sort of similar to what happened to the B737 max (sort of).
Oh dear, another example of Airbus 'we always know better than pilots' automation run amuck.
If a Boeing starts to do something unexpected you simply disconnect the autopilot and point it in the right direction, makes you wonder why Airbus couldn't offer that as an option
If a Boeing starts to do something unexpected you simply disconnect the autopilot and point it in the right direction, makes you wonder why Airbus couldn't offer that as an option
