Whizz Air 320 gear unsafe landing FCO
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I guess there will be a few red faced technocrats in Koln crying into their coffee on Monday morning, questioning the effectiveness of AD 2011-0069R1 at mitigating the long standing MLG door actuator issue.
EASA Airworthiness Directives Publishing Tool
This particular can has been kicked down the road for well over a decade.
Time for GE and Airbus to take definitive action?
EASA Airworthiness Directives Publishing Tool
This particular can has been kicked down the road for well over a decade.
Time for GE and Airbus to take definitive action?
Last edited by Busbert; 9th Jun 2013 at 09:23.
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Originally Posted by AD No.: 2011-0069R1
Some operators reported slow operation of the MLG door opening/closing sequence, leading to the generation of ECAM warnings during the landing gear retraction or extension sequence.
Investigations showed that the damping ring and associated retaining ring of the MLG door actuator deteriorate. The resultant debris increases the friction inside the actuator which can be sufficiently high to restrict opening of the MLG door by gravity, during operation of the landing gear alternate (free-fall) extension system.
This condition, if not corrected, could prevent the full extension and/or downlocking of the MLG, possibly resulting in MLG collapse during landing or rollout and consequent damage to the aeroplane and injury to occupants.
Investigations showed that the damping ring and associated retaining ring of the MLG door actuator deteriorate. The resultant debris increases the friction inside the actuator which can be sufficiently high to restrict opening of the MLG door by gravity, during operation of the landing gear alternate (free-fall) extension system.
This condition, if not corrected, could prevent the full extension and/or downlocking of the MLG, possibly resulting in MLG collapse during landing or rollout and consequent damage to the aeroplane and injury to occupants.
I wonder whether or not Airbus has done any flight tests of methods to improve getting a down & locked indication? It would sure be a shame to have the means to get all rollers down but not the information on how to do it.
Perhaps positive g? Perhaps less than 1 g flight? Perhaps yaw?
Seems they have a new door actuator, but that too has problems. Lets hope the insurance companies get tired of this and put their feet down. Maybe the airlines need to bolt some oak runners to the bottom of the engine pods as an interim measure.
Where are all the real engineers when you need one? (And I'm not talking wrench turners, these are the ones with the pocket protectors.)
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What are your thoughts about landing totally wheels up, belly landing , on grass in this case? Some airports do have adjacent grass surfaces for this purpose, I think. Would the damage be less or more? The low slung engines on the B737 may make this option undesirable but not for the A320 family. Just thinking, easy with your flame throwers!
Ut Sementem Feeceris
What's the significant difference between 737 and A320? They're both under slung (with 73 having a slightly lower "C of G") but chances are that the engines will dig in on a soft surface with resultant massive deceleration and probably ripping off of the engines. At least on a runway the secondary damage will be less.
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Kilda Ste Hilda. It may or may not be better to land gear up, but the specific advice of the Flight Crew Training Manual is as follows:
'If one landing gear is not downlocked, the flight crew must perform the LDG WITH ABNORMAL L/G QRH procedure. In this case, it is always better to land with any available gear rather than carry out a landing without any gear.'
Therefore the crew had no choice as that is the official guidance, presumably because Airbus have considered the various options and concluded this is the best way. Hope that helps.
'If one landing gear is not downlocked, the flight crew must perform the LDG WITH ABNORMAL L/G QRH procedure. In this case, it is always better to land with any available gear rather than carry out a landing without any gear.'
Therefore the crew had no choice as that is the official guidance, presumably because Airbus have considered the various options and concluded this is the best way. Hope that helps.
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The low slung engines on the B737 may make this option undesirable but not for the A320 family. Just thinking, easy with your flame throwers!
The airbus' cowlings project a little further below the fuselage line than those of the 737.
737 engines only appear lower when the aircraft is on the ground...due to its shorter legs
this might help.....
(It might also help the chap earlier who cant seem to grasp why the tail could sit down if one main gear collapsed on the Bus)
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Kilda Ste Hilda
I am not sure if the fuselage has the strength to withstand the impact. B737NG broke up even on water but due to spongyness of water people survived. Also when landing without gear the impact will be at higher speed also it will be very difficult to execute proper flare, less will surely breakup the aircraft and more will break the tail and subsequent snap will breakup the aircraft. No I do not think it is a good idea. Landing with partial gear end trying to hold up as long as possible will reduce the speed and the force. It is the only way.
I am not sure if the fuselage has the strength to withstand the impact. B737NG broke up even on water but due to spongyness of water people survived. Also when landing without gear the impact will be at higher speed also it will be very difficult to execute proper flare, less will surely breakup the aircraft and more will break the tail and subsequent snap will breakup the aircraft. No I do not think it is a good idea. Landing with partial gear end trying to hold up as long as possible will reduce the speed and the force. It is the only way.
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I gave it a go:
The blue dot in the middle is the CoG. In normal ops, the green line is the axis where the MLG supports the aircraft. This axis is AFT of the CoG, hence no problem at all.
In the second case, the right MLG is not extended. So the aircraft will sit on the left MLG and the engine pod. The orange line illustrates this. It is the axis through which the aircraft is supported now. This axis is forward of the CoG, so the airplane will start tipping backwards.
Bear in mind, this is a rough sketch. If I have time tonight, I might make a more detailed version, with actaul Airbus drawings. For now, I hope this explains what might have happened in my eyes.
The blue dot in the middle is the CoG. In normal ops, the green line is the axis where the MLG supports the aircraft. This axis is AFT of the CoG, hence no problem at all.
In the second case, the right MLG is not extended. So the aircraft will sit on the left MLG and the engine pod. The orange line illustrates this. It is the axis through which the aircraft is supported now. This axis is forward of the CoG, so the airplane will start tipping backwards.
Bear in mind, this is a rough sketch. If I have time tonight, I might make a more detailed version, with actaul Airbus drawings. For now, I hope this explains what might have happened in my eyes.
Last edited by KriVa; 10th Jun 2013 at 10:29.
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KriVa
Thanks. I had figured that was the geometry. Still doesn't stop me being surprised though, and I would be REALLY interested to see the accurate plan!
From the pictures of Wizzair, the suggestion is that the front door on the 'higher' side was unsuitable for evac?? It wouldn't be unreasonable to consider there to be a real fire hazard on the 'collapsed' side, and evac there inadvisable??
This effectively leaves one rear door (plus overwings - only one on most 319s) for evac of the entire a/c. Anybody know if this how the certification is calculated????
Thanks. I had figured that was the geometry. Still doesn't stop me being surprised though, and I would be REALLY interested to see the accurate plan!
From the pictures of Wizzair, the suggestion is that the front door on the 'higher' side was unsuitable for evac?? It wouldn't be unreasonable to consider there to be a real fire hazard on the 'collapsed' side, and evac there inadvisable??
This effectively leaves one rear door (plus overwings - only one on most 319s) for evac of the entire a/c. Anybody know if this how the certification is calculated????
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Right, having found a half hour of free time, this is what I came up with. I had to link the picture, since it would be too big to put it in the forums.
https://dl.dropboxusercontent.com/u/...izzA320Top.jpg
Some explanation:
I had to estimate the place where the aircraft is resting on the engine pod. While I am pretty certain it is within the red cone, I'd say it is probably within the cyan line and the aft red line.
The blue line indicates where the CoG could be during flight.
NOTE: I am NOT a licensed pilot, so I might have slipped up calculating the actual location of the CoG. (I did do the calculations twice though ;-) )
According to this, if the CoG was pretty far AFT, but still within limits, the theory still stands.
Oh, and copyright for this diagram remains with Airbus, of course.
https://dl.dropboxusercontent.com/u/...izzA320Top.jpg
Some explanation:
I had to estimate the place where the aircraft is resting on the engine pod. While I am pretty certain it is within the red cone, I'd say it is probably within the cyan line and the aft red line.
The blue line indicates where the CoG could be during flight.
NOTE: I am NOT a licensed pilot, so I might have slipped up calculating the actual location of the CoG. (I did do the calculations twice though ;-) )
According to this, if the CoG was pretty far AFT, but still within limits, the theory still stands.
Oh, and copyright for this diagram remains with Airbus, of course.
Last edited by KriVa; 10th Jun 2013 at 18:40.
