Airbus crash/training flight
Join Date: Jan 2005
Location: France
Posts: 2,315
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by On Guard
...pressing a big red button that merely gives us control of an a/c.
As they say at school: "discuss".
"merely..." ???
Do you really want the aircraft dumped in your lap in Cessna 152 mode when you're already knee-deep in the soft brown matter?
I was hoping for a serious discussion rather than the usual A vs B session.
As an engineer, I have no axe to grind. I was just hoping for some intelligent input.
CJ
Cessna 172 Mode
Would any Captain want that much responsibility (by pressing said button) on his/her shoulders?
Join Date: Jan 2005
Location: W of 30W
Posts: 1,916
Likes: 0
Received 0 Likes
on
0 Posts
At Habsheim, that 'big red button' would simply have caused the aircraft to do a wing-over into a big fireball
Originally Posted by Safety Concerns
An Airbus can be flown manually and the whole argument has no place here in a discussion about a dreadful accident
Would any Captain want that much responsibility (by pressing said button) on his/her shoulders?
(None of this is in reference to the German crew, just to the above quote)
Join Date: Feb 2007
Location: i don't know
Posts: 320
Likes: 0
Received 0 Likes
on
0 Posts
@ TeachMe
Well, there is such possibility (allthough not a button) on the fly by wire 777. Now look at it's record. There has been no incident where the automatic overriding capability was used and as a consequence a situation was worsened. On the other hand the QF72 incident could be directly linked to the automation giving wrong inputs and the pilot not beeing able to intervene fast enough due to absence of such feature.
Hypothetical arguments as yours are very delicate. As you said, we might never know. But real incidents with findings exist and they stay awkwardly in the room to cry for a SOLUTION.
'How may accidents has the automation and design philosophy prevented?'
Unfortunately that is obviously a question that can never be answered, therefore it is hard to make a good argument for or against that automation. Really, would a big red override button have saved this plane, but have resulted in two other accidents? We will never know.
Unfortunately that is obviously a question that can never be answered, therefore it is hard to make a good argument for or against that automation. Really, would a big red override button have saved this plane, but have resulted in two other accidents? We will never know.
Hypothetical arguments as yours are very delicate. As you said, we might never know. But real incidents with findings exist and they stay awkwardly in the room to cry for a SOLUTION.
One thing that's sure is that it wasn't trainning, but rather post-maintenance test flight. Sud747 or moderators, please change the topic title accordingly, thank you.
There was no mention in media that ATC was told that anything out of the ordinary happened on the flight, it wasn't cut short, there was no communication of changed intentions, so whatever happened, manifested itself suddenly and unexpectedly on approach and that's not something you'd see with ports taped over or probes blocked.
There was a leak from the state prosecutor (although this might be mistranslation and fellow might actually be the investigating judge) that there was pitchup, surge in power, stall and crash. Some have used this statement by complete aviation amateur to theorise about FBW Airbus protections gone awry. Well the only protection that gives you pitch-up is high-speed protection and I have reasons to believe that the aeroplane was nowhere near its Vmo of 350 kt on DME arc. Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors. There was also a question of pitch-power coupling in A320. In normal law, there's always ample and timely application of autotrim to counter any pitch changes with power, whether flying manually or with AP engaged. If you're out of normal law, alpha floor is deactivated i.e. there's no automatic TOGA power to fight with.
However, we still don't know what happened and everything and anything I've written may or may not be related to the accident and for the time being, this accident absolutely cannot be used as an argument to move Airbus approach to flight controls and automation in any direction.
If you're reffering to some old accident, please check out Aviation Safety Network and acquaint yourself with the facts about it. There are database entries for each and every accident and significant incident that happened to transport category aeroplane from 1943 onwards, FBW Airbi included. I'd especially recommend the site to PPRuNers peppering their posts with "QF72" - it might help them include "MH124" into their vocabulary. And while browsing through the reports, bear in mind that it is not the responsibility of the accident investigators to answer to a question "why did it happen?" What they're telling us is what happened, how it happened and what we have to do to prevent it from reccuring. They never, ever blamed anyone or anything.
There was no mention in media that ATC was told that anything out of the ordinary happened on the flight, it wasn't cut short, there was no communication of changed intentions, so whatever happened, manifested itself suddenly and unexpectedly on approach and that's not something you'd see with ports taped over or probes blocked.
There was a leak from the state prosecutor (although this might be mistranslation and fellow might actually be the investigating judge) that there was pitchup, surge in power, stall and crash. Some have used this statement by complete aviation amateur to theorise about FBW Airbus protections gone awry. Well the only protection that gives you pitch-up is high-speed protection and I have reasons to believe that the aeroplane was nowhere near its Vmo of 350 kt on DME arc. Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors. There was also a question of pitch-power coupling in A320. In normal law, there's always ample and timely application of autotrim to counter any pitch changes with power, whether flying manually or with AP engaged. If you're out of normal law, alpha floor is deactivated i.e. there's no automatic TOGA power to fight with.
However, we still don't know what happened and everything and anything I've written may or may not be related to the accident and for the time being, this accident absolutely cannot be used as an argument to move Airbus approach to flight controls and automation in any direction.
If you're reffering to some old accident, please check out Aviation Safety Network and acquaint yourself with the facts about it. There are database entries for each and every accident and significant incident that happened to transport category aeroplane from 1943 onwards, FBW Airbi included. I'd especially recommend the site to PPRuNers peppering their posts with "QF72" - it might help them include "MH124" into their vocabulary. And while browsing through the reports, bear in mind that it is not the responsibility of the accident investigators to answer to a question "why did it happen?" What they're telling us is what happened, how it happened and what we have to do to prevent it from reccuring. They never, ever blamed anyone or anything.
Join Date: Sep 2000
Location: England
Posts: 303
Likes: 0
Received 0 Likes
on
0 Posts
Why COULD there be a protective PITCH-UP?
Well the only protection that gives you pitch-up is high-speed protection and I have reasons to believe that the aeroplane was nowhere near its Vmo of 350 kt on DME arc. Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors.
All on here would be surprised by how quickly the IAS winds back to zero in the climb, once water freezes in the static lines. Similarly, how very quickly it winds UP after the aircraft descends below the height at which it freezes and blocks static pressure changes reaching the ADIRU's, In fact, does it even need to freeze? Maybe water can just quickly flow to and collect at a low-point due to the attitude change of a descent/config change inducing a flow and a blockage.
.
Now I'm guessing that the A320 doesn't have independent static pressure line systems for each of its ADIRU's - so there'd be an effect upon all threeADIRU's and no shut-off of protections per:
Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors.
.
Just a theory but........ any arguments against the logic and feasibility?
.
Maintenance => aircraft repaint and/or aircraft wash => water in static system......... => freezes at height (maybe during system checks on pressn system).
Join Date: Sep 2000
Location: England
Posts: 303
Likes: 0
Received 0 Likes
on
0 Posts
Similar Scenario (Static Ports compromised)
from this link
.
Incident: Boeing 747-200, N520UP, Dublin Airport,12 May 2000: Report No 2004-004
.
6 February 2004
SYNOPSIS
The aircraft took off from Dublin Airport for a check flight following the completion of C check maintenance at Team FLS. After take-off, significant airframe vibration was encountered. The crew then deduced that both airspeed indicators were under-reading significantly. Following declaration of an emergency, and trouble-shooting by the crew off the east coast of Ireland, the aircraft returned safely to Dublin. After landing it was discovered that the flap system had suffered damage. It was found that the static drain ports in the Avionics and Electrical (A&E) bay, connected to both the Captains and the First Officers instruments, were left open after maintenance. This resulted in both airspeed indicators under-reading by a significant amount.
.
.
Incident: Boeing 747-200, N520UP, Dublin Airport,12 May 2000: Report No 2004-004
.
6 February 2004
SYNOPSIS
The aircraft took off from Dublin Airport for a check flight following the completion of C check maintenance at Team FLS. After take-off, significant airframe vibration was encountered. The crew then deduced that both airspeed indicators were under-reading significantly. Following declaration of an emergency, and trouble-shooting by the crew off the east coast of Ireland, the aircraft returned safely to Dublin. After landing it was discovered that the flap system had suffered damage. It was found that the static drain ports in the Avionics and Electrical (A&E) bay, connected to both the Captains and the First Officers instruments, were left open after maintenance. This resulted in both airspeed indicators under-reading by a significant amount.
.
Join Date: Jan 2008
Location: Around the corner
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
Quote:
Well the only protection that gives you pitch-up is high-speed protection and I have reasons to believe that the aeroplane was nowhere near its Vmo of 350 kt on DME arc. Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors.
Another protection that gives you pitch up, even though as a byproduct, is if you are close to stall and the protection gives you full power. With the engines at full power and slow speed, you will get a pitch up. Even though the alpha floor is not designed to give you pitch up, the pitch up at very slow speed might not be overrideable.
Well the only protection that gives you pitch-up is high-speed protection and I have reasons to believe that the aeroplane was nowhere near its Vmo of 350 kt on DME arc. Protections are also designed to shut themselves off if there are discrepancies between all three air data or inertial reference sensors.
Another protection that gives you pitch up, even though as a byproduct, is if you are close to stall and the protection gives you full power. With the engines at full power and slow speed, you will get a pitch up. Even though the alpha floor is not designed to give you pitch up, the pitch up at very slow speed might not be overrideable.
Join Date: Aug 2002
Location: SE Asia
Age: 39
Posts: 137
Likes: 0
Received 0 Likes
on
0 Posts
excuse my ignorance ....but is there no kind of stick pusher on the airboos?
or something similar ?
i understand its designed so that it 'cant' stall ...but what happens if it actually does get into a stall due to some combination of windshear/failures/errors etc? will the 'systems' reduce the angle of attack ..wait ..and then add power ?
or something similar ?
i understand its designed so that it 'cant' stall ...but what happens if it actually does get into a stall due to some combination of windshear/failures/errors etc? will the 'systems' reduce the angle of attack ..wait ..and then add power ?
Last edited by camel; 29th Jan 2009 at 13:25.
Join Date: Jan 2008
Location: Around the corner
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
As far as I know (and I study the airbus manuals regularly), there is no mentioning of any stick pusher. The idea behind an airbus is, that it cannot stall (?!). So why should they design something against a situation, that cannot happen? (not that I myself belief, that the aircraft cannot stall).
As far as I know (and I study the airbus manuals regularly), there is no mentioning of any stick pusher. The idea behind an airbus is, that it cannot stall (?!). So why should they design something against a situation, that cannot happen? (not that I myself belief, that the aircraft cannot stall).
Join Date: Jan 2001
Location: UK
Posts: 2,044
Likes: 0
Received 0 Likes
on
0 Posts
but is there no kind of stick pusher on the airboos?
or something similar ?
or something similar ?
See QF72 for this coming into effect - aircraft "percieves" it is at Alpha far in excesss of Alpha max, and pushes hard to reduce Alpha...
NoD
Join Date: Mar 2005
Location: England
Posts: 730
Likes: 0
Received 0 Likes
on
0 Posts
excuse my ignorance ....but is there no kind of stick pusher on the airboos?
or something similar ?
or something similar ?
Join Date: Jan 2001
Location: UK
Posts: 2,044
Likes: 0
Received 0 Likes
on
0 Posts
No stick pusher or shaker on the A320 , the aircraft will repeatedly shout "Stall,Stall" at you though
Why ? To rub salt in the wound? Would I PA to the back... "Stall......
NoD