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A320 how to save this landing

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A320 how to save this landing

Old 6th May 2010, 00:10
  #21 (permalink)  
 
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Never mind... found it... it is a FCOM bullitin not an OEB.
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Old 6th May 2010, 00:48
  #22 (permalink)  
 
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I felt a 1.98Gs the other day... it did hurt a bit, but aircraft was fine. AFAIK only above 2 or 2.6 requires maintenance action. In any case, we had the mechanic check the aircraft and it was fine.
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Old 6th May 2010, 01:00
  #23 (permalink)  
Beau_Peep
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Friends, thanks for your responses..

first, I was the captain myself

Second, change of tailwind to nil wind was reported by my first officer, after reaching the bay. at 50ft my attention was all outside. so there could be a possibility of erroneous reporting.

third, ROD upto 50ft was about 700fpm. 3 deg descend, 2 whites 2 reds, GW about 61T. autothrust was on all the time. I disconnected AP at about 1000ft.

fourth, I did feel the increase in sink after crossing the threshold at 50ft.

my initial response to it was to pitch up a little bit to arrest the ROD. but it failed to respond. controls were sluggish.

I cut the power , because landing with power on with uncontrolled sink would have lead to greater bounch.

Now I recall we had a little bounch. And an aural 'PITCH' at touchdown.

post flight inspection, no sign of tailstrike.

of course I know, a go around would have been an ideal solution. but I started the thread with an objective to know what could have been done to reduce the g load on touchdown, assuming that a pilot would continue.

I feel g load could have been lesser if I had relaxed the pitch up demand, after finding no response intially. I dug the main wheels with constant demand.
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Old 6th May 2010, 01:09
  #24 (permalink)  
 
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Maybe you should learn to actually handfly the airplane and never have to embarass yourself again with a suck landing because of automation. Don't recall any landings going bad in the last several years of landings doing it manually. Actually it is kind of fun.
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Old 6th May 2010, 01:30
  #25 (permalink)  
 
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Did the aircraft produce a LOAD <15> report?

Did you mention this to anyone, logbook entry etc?

If you feel that the incident was bad enough to come on PPRuNe and talk about it like this.. I really hope you did.

Just been reading back over some hard landing reports on the 320.. that were not reported and went undetected and these have caused some serious issues on subsequent flights.

In short, if the landing feels overly hard report it! The 320 may not always produce a LOAD <15> depending on exact circumstances at the time of touch down / bounce it can mislead the software to the actual G load that was attained.

With regard to the winds.. would make a lot more sense if it shifted to a tailwind at 50 feet as opposed to the other way around.

You had a very lucky escape from your own account, and I just hope that the airplane that at a guess is back out flying has had a full inspection and is safe to be doing so.

Otherwise we could be looking at another report!

Well said P51

Last edited by PT6A; 6th May 2010 at 01:47.
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Old 6th May 2010, 01:37
  #26 (permalink)  
 
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Why did you do that?
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Old 6th May 2010, 01:55
  #27 (permalink)  
 
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As difficult as it can be to accept it, it's never too late to go around, even if you've touched down
The best advise given thus far!
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Old 6th May 2010, 02:27
  #28 (permalink)  
 
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Careful PappyJ, some have come to grief by touching around, attempting to stop, then going around. VERY bad outcomes, usually a fireball! Now, if one touches down while "on the go", quite agree.

GF
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Old 6th May 2010, 02:39
  #29 (permalink)  
 
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Unless you've opened reversers, you can always go around.
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Old 6th May 2010, 03:55
  #30 (permalink)  
 
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Regarding manual increase of thrust levers above detent:

In SOME aircraft (dependant on mod status) if you are below 100' RA with the autothrust engaged and you nudge the levers above the detent, the autothrust will disconnect and you will get a huge increase in thrust as the engines chase the thrust lever position.

See FCOM 1.22.30 P62- subtlely hidden in the detail !

This will invariably lead to an unstable approach.
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Old 6th May 2010, 06:35
  #31 (permalink)  
 
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controls were sluggish and didn't respond.
In this case wouldn't it be better just to accept a hard landing vs a go around?
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Old 6th May 2010, 07:30
  #32 (permalink)  
 
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The controls will of worked just as they were ment to... otherwise the poster would of been talking to the investigation team and not to PPRuNe.

It was just a classic case trying to make the best out of a bad approach and not making a go-around.

It is easy to blame the aircraft - when in most cases the problem is with the pilot, his training, the airline safety culture and the Aviation Authority.

In India at the moment the airlines are being forced to upgrade local co-pilots due to political pressure - these co-pilots have very very limited experience because as a co-pilot in India you are not released like a western co-pilot... You are NOT allowed to takeoff and land... unless with a TRE/TRI Line Training Captain... have x number of hours on the aircraft and both the Captain and FO have done further training.

In the western world you would of never been released to go out and fly with a line captain unless you could takeoff and land satisfactorily... that is where the system is flawed.

An Indian pilot having 500 hours on type is nothing like a western pilot with 500 hours on type... as the former will only have a fraction of the takeoffs and landings... Thus only part of the western pilots skillset.

Mastering the aircraft in various weather conditions takes practice, time and exposure - in the correct environment.

Otherwise we end up with a Captain and Co-pilot.. neither of which are overly proficient at handling the aircraft in all stages of flight.

PT6A
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Old 6th May 2010, 09:19
  #33 (permalink)  
 
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Commiserations on your experience. You are not the first A320 pilot to be caught out in this situation.

As I see it, the autothrust system would have reduced power to compensate for increasing airspeed as you descended out of the tailwind .In consequence you commenced the flare with less thrust set than you had anticipated and the aircraft behaved differently from what you had expected. Because your attention would not have been focussed on the engine instruments coming into the flare you would not have been aware of the low thrust level.

One solution (as others have already suggested) would have been to commence the flare slightly earlier and to a slightly higher pitch attitude while still avoiding a last-second snatch overpitch . Probably this would have still given you an uncomfortable arrival, but not as rugged as the one you describe.

Low level tailwinds and consequent shear are often encountered unexpectedly, and therefore may not be planned for in one's mental model of how to fly the approach and landing. So one has to be ready to adopt a different model. In this particular situation an early reversion to manual thrust as soon as a tailwind is identified would be beneficial. This would ensure full pilot control over power settings immediately prior to and in the flare, which of course you do not have when autothrust is in use.
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Old 6th May 2010, 10:01
  #34 (permalink)  
 
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The only thing that's gunna save you in a swept wing jet aeroplane when the arse drops out of it close to the ground is a handful of thrust, enough to feel it kick you in the back. If you don't feel the aeroplane accelerate you haven't used enough.

I've had a couple of events during the last few years when I got that ugly sinking feeling close to the ground and have flared and pushed up the thrust at the same time and the resulting touchdowns were quite good but if I hadn't done what I did then there would have been a couple of really hard landings.

Regards,
BH.
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Old 6th May 2010, 11:27
  #35 (permalink)  
 
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Hi IFLY-INDIGO,

The sensation which you thought was sluggish around 50 feet, was probably because :

"FLARE MODE

The flight mode changes to flare mode when the aircraft passes 50 feet RA as it descends to land.

The system memorizes the attitude at 50 feet, and that attitude becomes the initial reference for pitch attitude control.
"

Unlike a conventional aircraft which is trimmed to be speed stable in pitch, the Airbus below 50 feet is "trimmed" for the attitude you had then. So if it felt like you were sinking around 50 feet, because your attitude was too low, then you are stuck with that reference attitude, and it will "feel" heavier no matter what your speed is. Unlike a Boeing, which naturally pitches up with the application of power - your Airbus won't and it will still feel heavy.

Last edited by rudderrudderrat; 6th May 2010 at 14:35. Reason: typo & pitch power couple
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Old 6th May 2010, 11:48
  #36 (permalink)  
 
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Hi again, IFLY INDIGO,

Some of the recent responses seem to me to be a bit alarmist.

However, if your airline had a SESMA programme − or equivalent − in which certain events (where one or more QAR parameters are outside normal limits) automatically trigger a report, and the crew concerned are contacted confidentially by the SESMA representative; the “Pitch” auto-call would undoubtedly result in you hearing from him or her in a week or two. He/she would be at your disposal to discuss the flight-recorder traces. Later, the event would be added to a database to analyse possible trends in pilot handling on your fleet. If it was considered sufficiently important as an example, a summary would be published in-house, again with the flight date and crew names omitted.

You say the “controls were sluggish”, but you are unable to say if the IAS was above or below VLS. The “Pitch” call suggests that, having started the flare late, you over-flared. In that case, it was not the CONTROLS that were sluggish, but the wing itself, which was unable to generate enough lift to arrest the ROD in the short time you seem to have given it. This may have been partly due to a lack of airspeed.

But closing the throttles would also have robbed you of a useful vertical component of thrust (as well as putting you in a position where a go-around from a severe bounce would have been hampered by a lack of thrust for several seconds, at least).

You write: “I feel g load could have been lesser if I had relaxed the pitch up demand, after finding no response intially. I dug the main wheels with constant demand.”

Yes, definitely you should have relaxed it. It seems you were already at a pitch attitude higher than desirable if you had been initiating a go-around from a rejected landing. I don’t have that procedure to hand, but recommend you look for it in your FCOM or, if necessary, elsewhere.

In answer to your other question, “what could have been done to reduce the g load on touchdown”, it is also true that − if the nose is high − a small, brief, forward movement of the stick, just before main-wheels touchdown, can reduce their impact. But it is vital not to overdo it, and the pitch-down rate must be arrested with some back-stick as soon as the main-wheels touch down, to stop the nose-wheels thumping down. This is not a technique, however, that I would recommend to anyone in your scenario.

To summarise.
If you don’t like the look of it at any stage, go around. (Be prepared for possible main-wheels contact with the runway.)
But once the throttles have been closed, this may not be possible.
So never close the throttles until a safe landing is assured.

Get as much value as you can from this experience.

Chris

Last edited by Chris Scott; 6th May 2010 at 12:50. Reason: Third-last paragraph clarified.
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Old 6th May 2010, 13:10
  #37 (permalink)  
 
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Hello IFLY INDIGO,

First of all, congratulations to you for sharing your experience with us and for seeking advice.

I would like to question many major airlines' policy about auto thrust use. (and Airbus' recommendations about A/T use)

I fly A320 in a company where manual flight skills are still intensively trained and encouraged by the training department and I am very glad about that. The large majority of the landings in our company are -conditions permitting- done with F/D, A/T and AP off!

So our company is really not concerned by what Airbus captain Jacques Drappier has to say about manual flight skills. (Jacques Drappier, like myself, is a former SABENA-pilot BTW) Read also this thread: Pilot handling skills under threat, says Airbus

In my company all pilots will fly the approach to Funchal, Madeira with A/T off, while most other companies forbid their pilots to disconnect A/T over there.

All pilots in my company will agree that we, as pilots, can do a better job then the A320 autothrust system. It's my experience that if you fly the A320 by hand but with A/T engaged in stormy and gusty conditions, the A/T is a very foolish "speedchasing device". For instance: when you're a little low, but a litlle high on speed -due to shifting winds for instance- the A/T will reduce thrust too much and not anticipate fast enough to stop you from getting in a nose high, low speed condition when you pull the sidestick to recover from your low trajectory. It appears to me that that is what happened to you during your flare.

Originally Posted by Bullethead
The only thing that's gunna save you in a swept wing jet aeroplane when the arse drops out of it close to the ground is a handful of thrust, enough to feel it kick you in the back. If you don't feel the aeroplane accelerate you haven't used enough.
Of course, "giving a handful of thrust" is not easy in the Airbus when your thrust levers are immobile in the CLB detent and you are "at the mercy" of the A/T system! In manual thrust it's a piece of cake!

Now I'm getting ready to be flamed about the fact that I dare to go against Airbus' recommendations about A/T use, but really guys, it's time that pilots relearn how to handfly an airliner, especially Airbii! Make life easier on yourself by using the AP and AT when there's a good reason to do so but make sure you keep your basic skills in good shape!!

Best regards,
sabenaboy
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Old 6th May 2010, 13:31
  #38 (permalink)  
 
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IFLY INDIGO, thanks for sharing. Can you tell us more about the wx conditions ie the pressure altitude and temperature?
As the ldw is below max the other things that could be significant in this situation is ref to Vls, field temperature and alt density. (aircraft will react differently at 7000 asl and +35C then at sl 15C)
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Old 6th May 2010, 13:46
  #39 (permalink)  
 
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Of course, "giving a handful of thrust" is not easy in the Airbus when your thrust levers are immobile in the CLB detent and you are "at the mercy" of the A/T system!
can't agree more. I like the Boeing moving thrust levers much better. Need more thrust? Just move it up a little then release the pressure. Makes it more instinctive.

Flame incoming.
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Old 6th May 2010, 14:17
  #40 (permalink)  
 
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if winds dying down,either delay the thrst reduction to idle or goround without any hesitation
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