A320 how to save this landing

[IFLY_INDIGO]

friends, I was shooting a VOR approach today with 8 kts tailwind. things were fine upto 50ft, when suddenly wind died to zero. airplane started dropping, I pull the stick little up to increase the lift but controls were sluggish and didn't respond. just a second before touchdown airplane pitched up (may be the late response) and I cut the throttle. I had a 1.72g landing. :sad:
What could be ideal technique to save or rather reduce the 'damage' on this landing?

[Fright Level]

A go around?

[Flash2001]

Why would the aircraft drop if the tailwind dropped to zero?

After an excellent landing etc...

[b737NGyyc]

Just pulling back without increasing the thrust is inviting a tail strike. This is basic high rate of sink landing recovery. If it is really bad then a go around would be in order.

[Permafrost_ATPL]

Don't close the thrust levers so early if you feel you have run out of energy. If you end up leaving them on too long and float deep, go around.

P

[Permafrost_ATPL]

b737NGyyc, the autothrust (that would normally be ON even for manual landing on a Bus) should have taken care of that. I assume the problem was that the thrust levers were closed just as the autothrust reacted.

[wiggy]

Why would the aircraft drop if the tailwind dropped to zero?


My simple non- Airbus twopence worth: Down to 50' (in this case) higher than normal Groundspeed due to the tailwind, so you have a higher than normal ROD to hold the glideslope, so the power's is back below normal headwind figures . Then at 50' you run into what is an effectively increasing headwind, Ground speed drops, ROD is still high, power's back ...if you or the AT don't increase the power you may start dropping short, if you pull the power off....

Standing by to be corrected.

[b737NGyyc]

b737NGyyc, the autothrust (that would normally be ON even for manual landing on a Bus) should have taken care of that. I assume the problem was that the thrust levers were closed just as the autothrust reacted.

As you can see from my pseudonym I don't fly the Airbus and never have but my experience with autothrust (throttles) is that they are rarely responsive enough to react to a situation such as this.

Having no experience on the Airbus I can only presume that they can be manually overridden if required by pushing the thrust levers forward. If the autothrust on the Airbus is responsive enough to handle this situation then that is great but from my experience pulling back and expecting the automation to save the landing is too much of a leap of faith for this stick and rudder guy.

All the bells and whistles are great but in some situations, such as this one, manual intervention is the way to go IMHO. More and more I see it on the line that there is too much reliance on the automation and more and more erosion of basic piloting skills.

[PT6A]

What did your Captain say?

He might be your best bet for some ideas on how to "save" the landing.

You have some very high time airbus drivers at Indigo, who I'm sure would be more than willing to share their experience with you.

I agree with some of the other comments made so far.. In that you can't rely on the automation to save the landing.

Keep a good eye on what the winds are doing... or have your PM to do that... watch for a trend and be ready to respond.

At what point did you take out the A/P? If you are low time, esp with the silly rules in India... where you as a F/O can't takeoff and and land unless on a special list (yes that right! a FO can NOT take off and land unless with a TRI/TRE)

You should consider taking out as much automation as you can... learning how to fly the aircraft by hand.. and building up the reflexes so it is second nature and you will see a trend developing much sooner.

Also, if things start to look bad... offer control back to the left... or GO AROUND.

If you ever fly something bigger... you really need to think about a tail strike as from what you say happened that was on the cards...

Just my 2 cents.

PT6A

[muduckace]

I do not know the center of lift in relation to the gear in the A-320, often a pitch up at this hight to reduce the rate of decent can result in a higher rate of impact for the gear if it is aft of the axis the aircraft is pitching on. But as a few have said before, you did not have a resolution for the problem presented to you a GO-AROUND should have been the first instinct.

[rudderrudderrat]

Hi IFLY_INDOGO,

My two pennies worth:

.. with 8 kts tailwind. things were fine upto 50ft, when suddenly wind died to zero. - If wind suddenly died to zero, air speed should have increased - Good.

airplane started dropping, - result of reducing ground speed and maintaining original ROD - Bad.

I pull the stick little up to increase the lift but controls were sluggish and didn't respond. - with increased airspeed, controls should have behaved normally - possibly an illusion due concentrating on touch down point -need to look further down the runway.

just a second before touchdown airplane pitched up (may be the late response) and I cut the throttle. - initiation of the flare was too late with high ROD.

I had a 1.72g landing. - Ouch.

What could be ideal technique to save or rather reduce the 'damage' on this landing? - With a tail wind and higher ROD - be prepared to flare a bit earlier and look further down runway to judge flare attitude change.

If you get into a similar situation again - do a "TOGA 10". Set TOGA power and rotate to 10 degs pitch up. This will prevent a tail strike on A320 / 319. After touch down, and when safely climbing away - do the normal "Go Around Flaps" rotating towards SRS / 15 degs.

[sharpclassic]

As difficult as it can be to accept it, it's never too late to go around, even if you've touched down (although deciding to 'go around' when you're down to 50kts may not be such a good idea!)

If you feel the lift start to drop off, do NOT close the thrust levers, even if it's yelling retard. Keeping the thrust on (be it in SPEED or Manual), even until you touch down, can turn a heavy landing into just an uncomfortable landing.

Phase Advance is a great tool on the approach but remember that it doesn't work below 100ft RA.

Listen to others, learn from it and move on. Don't dwell on it and let it get you down!

[fredgrav]

I was shooting a VOR approach today with 8 kts tailwind. things were fine upto 50ft, when suddenly wind died to zero

Just out of curiosity, didn't you get any help from GS Mini here ?? AC energy should have remained as high as needed for sudden wind changes ...

[rudderrudderrat]

Hi fredgrav,

didn't you get any help from GS Mini here

"Ground speed mini" holds a suitable minimum ground speed based on the reported wind entered. With a tail wind on the approach you have a bigger ground speed - so GS Mini does nothing.

[IRRenewal]

Is a 1.72G landing within limits? I.e. was an engineering inspection required? Not a bus driver myself so just wondering.

[fredgrav]

Hi rudder & studi,
sure, erroneously interpreted the decrease of TW as a lack of HW on final ... :sad:

[PT6A]

If my memory serves me correctly its 1.8G that needs MX.

However a pilot SHOULD report a hard landing... as per the advice from the UK CAA as I don't think those readings are always spot on.

Would be curious if the orginal poster reported his landing.....

[Chris Scott]

Hi IFLY INDIGO,

As has been said, the loss of tailwind would, everything else being equal, give an increase of IAS.

Did she bounce?

With VS higher than normal, flare needs to be started earlier (higher), and thrust retarded later (as has been said above), unless you are “fat” on IAS. If you realise you’ve left it too late, the only safe option is a go-around, because flaring will dig the main wheels in on the A320, just as on most aeroplanes with tricycle L/G.

A last-moment attempt to arrest the sink with a big burst of thrust is not something I would recommend − even if you are using manual thrust (my preference for most manual landings on the A320). It can lead to all kinds of problems, particularly on a short runway. If you do decide to continue, better to leave the power alone, but, if you have to ignore the “retard” call initially, don’t forget to do it once you are safely on the ground… Many of us have.

Yes, it’s easy for us to be wise while we ponder at our keyboards, or watch you from the briefing room window, but it doesn’t necessarily mean we would have done a better job than you did!

Chris

[MD83FO]

why is there a last FCOM engineering bulletin recommending not to move the thrust levers above climb?

[PT6A]

I don't have that in my manual... Do you have the number and I can look it up...

PT6A

[PT6A]

Never mind... found it... it is a FCOM bullitin not an OEB.

[PA38-Pilot]

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.

[IFLY_INDIGO]

Friends, thanks for your responses..

first, I was the captain myself :ouch:

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.

[p51guy]

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.

[PT6A]

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:D

[p51guy]

Why did you do that?

[PappyJ]

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!

[galaxy flyer]

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

[PappyJ]

Unless you've opened reversers, you can always go around.

[drop bear ten]

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 !:eek:

This will invariably lead to an unstable approach.:{

[Neupielot]

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?

[PT6A]

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

[Tagron]

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.

[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.

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.

[rudderrudderrat]

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.

[Chris Scott]

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. :ok: (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

[sabenaboy]

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 (http://www.flightglobal.com/articles/2009/09/09/331991/aa09-pilot-handling-skills-under-threat-says-airbus.html). (Jacques Drappier, like myself, is a former SABENA-pilot BTW) Read also this thread: Pilot handling skills under threat, says Airbus (http://www.pprune.org/rumours-news/388573-pilot-handling-skills-under-threat-says-airbus.html)

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.

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

[Flexable]

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)

[Neupielot]

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.

[bauangupta]

if winds dying down,either delay the thrst reduction to idle or goround without any hesitation

[G-SPOTs Lost]

I fly a 21st Century Designed mid sized chunky bizjet with airliner derived avionics. It does not however have autothrottle.

I was taught to have a hand on the TL's within 1000ft of the ground just in case, forgive me but it just appears to reinforce the lack of basic airmanship and stick and throttle skills that seems to be apparent on these types.

Too much reliance on automatics in an ever changing weather environment with too many variables with a A/T system that by everybodys reckoning isn't able to cope.

Training and basic airmanship issue imho ......a small addition of power and its prompt removal would have made all the difference here - why didn't it happen?

[rudderrudderrat]

Hi,

a small addition of power and its prompt removal would have made all the difference here - why didn't it happen?

There seems to be a common agreement that a quick burst of power would have made all the difference.

But how much extra flying speed might you expect to gain from a quick burst? 5kts or so? I don't think 5 kts would make a significant difference to the total lift available from the wing. A pitch change makes a bigger difference.

If I was flying a conventional aircraft, then the burst of power would help raise the nose, and the extra 5 kts would make the aircraft feel lighter in pitch. Unfortunately when Bernard Ziegler designed the A320, he didn't put the aircraft into Direct Law during landing, so we are stuck with the feel it has with a reference pitch attitude remembered at 50 feet.

[Max Angle]

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.

I have flown the Airbus for 10 years and 737 before that and I quite agree with you. Love the aircraft in general but the autothrust system was wrong from inception.

[G-SPOTs Lost]

But how much extra flying speed might you expect to gain from a quick burst? 5kts or so? I don't think 5 kts would make a significant difference to the total lift available from the wing. A pitch change makes a bigger difference.

If I was flying a conventional aircraft, then the burst of power would help raise the nose, and the extra 5 kts would make the aircraft feel lighter in pitch. Unfortunately when Bernard Ziegler designed the A320, he didn't put the aircraft into Direct Law during landing, so we are stuck with the feel it has with a reference pitch attitude remembered at 50 feet.

Nobody mentioned 5 knots, try not to quantify this - this is part of the problem. Basic Airmanship taught to people in Cessna 152's the world over, sense the sink add power and pitch, reduce the rate of descent. As opposed to blind faith that automatics will sort out all enviromental occurences.

I remember being parked on RS1 at Heathrow very early one morning when an A340 came into land it was very gusty and the aircraft was flown onto the ground with lots of additional power on a number of occasions at very low level. I remember thinking that a lovely approach could be flown under difficult conditions especially having "been on the road" for possibly 12 hours + (inc crew rest etc etc)

[p51guy]

The previous C 152 post was right on. If you can't fly a C152 you will be very dangerous in an airbus because you will let it do things you wouldn't do. After thousands of landings with a handful of go arounds, only one in an airliner, except for minimums approaches with no lights at DH using proper power and pitch entering a flair is not difficult even with windshear below 50 ft. Nobody should be flying an Airbus or any large aircraft if they have a problem with a C152.

[IFLY_INDIGO]

Hi Chris & other fellows,

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.

I didn't start the flare late. due to sudden drop at 50ft, the center point of this thread, any flare would be called late eventually.

I agree a little bit of derotation could have reduced the impact.

When I said controls were sluggish, I meant the control input didn't give me required increase in the lift.

It was a stabilised approach with steady 8 kts tailwind upto 50ft.

I don't agree with the suggestion Moving thrust lever out of CLB detent a bit in this case. first it is too much of addition of thrust. And moving the levers through the detents, while adding thrust or reducing thrust, has its own precious time element. Detent resists the movement. As I told you all in the very beginning, reaction time was very little, due to sudden sink. So I think it would not have saved this landing.

I totally agree the use of manual thrust is a far better option then relying on ATHR. But such decision is to be taken well before stabilisation altitude, not at 50ft ! I started this thread not to debate manual thrust VS ATHR. My intention was to discuss the possibilities of 'how to save this landing' IN THIS PARTICULAR SITUATION.

[IFLY_INDIGO]

PA was 3100ft , OAT 34deg C

[galaxy flyer]

PT6A

If the situation is thus in India, they are in for a very hard and unsafe time. It is F/O experience that builds Captains. Not giving 50% of the landings to F/Os is simply criminal.

GF

[PT6A]

GF,

It sure is... It is a DGCA rule.. I have the list for Indigo and the amount of Captains who are allowed to even allow FO's to land is very very few.

I know some F/O have to go to the sim in India because they dont have legal landing currency as they get to do so few.

PT6A

[DesiPilot]

I am assuming that you were at VOBL RW27 approach?

How do you know it was 1.76 g landing? If you are getting your number from the load report, you may want to call either safety department or the FDR monitoring team and get the actual numbers. I've had smoothest of landings and the load report was 1.65 and had a very firm landing and load report was only 1.2. So it all depends on what you were doing one second before touch down.

Were you performing Config 3 landing? Not that it is going to make a difference but lack of drag could have saved you but than again you are a lot closer to tail strike as you approach with higher pitch attitude.

On the approach I always check the VLS calculated by FMGS and FAC (on the PFD). I make sure that the difference is minimum and that the FAC calculated VLS is not higher than FMGS. I have seen it in the past that the actual VLS (on PFD) was only 1 knot below Vapp and that calls for some interesting landing.

Like the others have said it earlier, I'd have increased the pitch, reduce the rod and hold it there until thrust starts spooling up, if you were in BLR runway length is not a problem. I know the reaction time is less, but if you do not go around, this would be your next best option. Have you ever landed with thrust? May be next time you fly with a TRI/TRE ask them if you could practice it, it will give you more insight on how aircraft reacts.

For hard landings, the bus will print the load report if it was above the parameters, you may have to check it with your engineering department since the report printing is inhibited in IndiGo aircrafts.

[DesiPilot]

You are rght about the DGCA regulation. The regs says that the first officer need a minimum of 50 hours on type a sim check and to fly with a captain who is cleared for assisted take off and landing before they are allowed to t/o and land. For captains, if it is their first command they require 1000 hours on type.

When I joined airlines in India I had close to 4000 tt, previous experience of flying CRJ but I was not allowed to land A320 until I completed 300 hours on type. In 2006-7 requirement was 300 hours on type which is reduced to 50 now. Typical :mad: dgca

[FlightDetent]

OAT 34deg C
Here's my suspect to why it happen. Not loss of tailwind (momentary IAS increase), but perhaps entry to overheated layer of air over threshold? Madrid (elev 2000) 33R (displaced thr) produces some quite interesting sinkers on a sunny day. Change in density would reduce lift available in line with Chris Scott's comment.


Sincerely,
FD (the un-real)

[sabenaboy]

My intention was to discuss the possibilities of 'how to save this landing' IN THIS PARTICULAR SITUATION.

Well, perhaps it wasn't "saveable". Of course reverting to manual thrust at 50' is not option and I think that perhaps a Go-around was the only possibilty to avoid a firm landing. But then again: who cares about firm landings? It's not because it's firm that it's not a good landing! (Despite what most pax will be thinking :sad: )

So my advice would be not to use A/T for landing unless it's necessary (or unless your company says you HAVE to use A/T all the time. :( ) To me "necessary" means that I use A/T for autolands only or every once in a while for training. (After all I still want to be able to use all the automatic gizmo's :ok: ) I personally NEVER use A/T for landings in gusty or stormy conditions.

Have fun and safe flights,
Sabenaboy

[Tom355uk]

Now, I'm not a driver (I hope to be, one day in the distant future :)) but I have studied fluid dynamics and I also have an intense interest in the flight controls and laws of all Airbus FBW.


With reference to:


When I said controls were sluggish, I meant the control input didn't give me required increase in the lift.
Do you mean the ROD did not reduce commensurate with what you would expect during the flare, or what you would expect during final approach? Remember, when the aircraft is in Flare mode, at 30' RA the reference attitude is 'washed out' over 8 seconds (Which, I assume means that a nose down trend is introduced) to ensure the PF progressively flares the aircraft. Now, would I be correct in assuming, at this point the control input required to reduce the ROD will be greater than that required during the other flight regimes (Climb/Cruise/Descent/Approach)?

However, if that has been taken into account, and you are very sure you didn't flare late then I would tend to agree with FlightDetent about a low density, high temperature pocket at the threshold. Might seem a real silly question, but are there any watercourses or streams just before the threshold? High localised humidity would decrease the density even further.

Just $0.02.

Tom

[kijangnim]

Greetings
What was the wind given by the Tower?

[G-SPOTs Lost]

I don't agree with the suggestion Moving thrust lever out of CLB detent a bit in this case. first it is too much of addition of thrust. And moving the levers through the detents, while adding thrust or reducing thrust, has its own precious time element. Detent resists the movement. As I told you all in the very beginning, reaction time was very little, due to sudden sink. So I think it would not have saved this landing.


You're suggesting that you dont think adding power on short finals as required to avoid a heay landing (and if that wasn't going to work a G/A) is a good idea. Forgive me if Im putting words into your mouth or twisting the words that came out.

I dont care whether its a 152/787/320 its up to you to putting the aircraft where you want it at all times using all the assets you have, if you disregard the thrust this is going to happen again. Use whatever power is required to arrest the ROD and fly level if required if you have any doubt that you wont make it in go around. In the landing config there should be enough thrust available to arrest the rate of descent thats a certification issue.

I'm not suggesting you practice on revenue flights but Level D sims do a crap job of accurately recreating close to the ground events, maybe ask your skipper if you can do a non A/T approach next time the weathers good

[sabenaboy]

You're suggesting that you dont think adding power on short finals as required to avoid a heay landing (and if that wasn't going to work a G/A) is a good idea. Forgive me if Im putting words into your mouth or twisting the words that came out.


G_SPOT,

Looking at your profile, I assume that you're not familiar with the Airbus A/T system. Unlike in Boeing the thrust levers in an Airbus stay immobile in the CL(im)B detent the whole time until they are retarded during the flare. The A/T system will then adjust thrust as necessary between idle pwr and climb thrust. (I like my airbus very much and got used to this design, but I have to admit Boeing's system with moving levers is a better design.)

What IFLY_INDIGO was probably trying to say is that at 50' it's not easy -nor is there time- to first adjust the thrust levers in the necessary position and then push the A/T disconnect button on the thrust levers.

That's just one of the reasons why I hardly ever keep A/T on for landing in my 320.

Regards,
Sabenaboy

[IFLY_INDIGO]

perhaps entry to overheated layer of air over threshold? Madrid (elev 2000) 33R (displaced thr) produces some quite interesting sinkers on a sunny day. Change in density would reduce lift available

this sounds plausible. it felt as if all lift was gone at that moment and we were a dead stone falling free.. and if that is the case, I feel even a go around would not have prevented the hard touchdown before lifting off again..

[Chris Scott]

'Morning, IFLY_INDIGO,

I see I was wrong to infer that you started the flare late - sorry. Hope you take my point, however, that - in a nose-high attitude - any engine thrust is contributing to lift.

The problem we all have in this discussion is that we will never know what happened to the IAS in the last 100 ft of your approach. That's why it's such a pity that your airline does not seem to monitor QAR-recorded 'events' as I described in my previous post.

Despite that, it's been an interesting and valuable exchange of views, and I agree with much that has been said. Very glad to see that so many younger guys agree with my preference for using manual thrust for manual landings, PROVIDED you are visual fairly early, so you can disengage the A/THR in a smooth and leisurely fashion. (We lost the battle against non-driven thrust levers in 1986, I'm afraid...)

Happy future landings!

Chris

[p51guy]

All aircraft, no matter who made them, needs a pilot to fly them. They may or may not have experience in this plane but they can fly it. They all fly basically the same so the throttle hand and the yoke hand should be coordinated by now. If you are flying any aircraft you should be able to do a 3 degree approach and land without a lot of procedures. Just learn how to fly any airplane and use basic pilotage and forget about the special Airbus procedures. A lot of Boeing guys actually transitioned to Airbus and did ok with Boeing procedures. As I said before if you let automation cause an incident you lose credibility as a pilot.

[Tipsy Barossa]

I heard this from a former SEA colleague about this quirk in flying the scare bus. He had transitioned to the T7 and was discussing or rather giving some tips about his experience to some new A330 drivers.....he cautioned against " fighting the controls " via the side stick especially pitching motions in gusty weather when close to touchdown. According to him, if you fight the controls with pitch down inputs, the autotrim will trim down and when this cuts out below 100 ft RA as the flight control law transitions to flare law, you lose a lot of pitch authority to flare and there it goes into a crunch unless you're fast enough to take momentarily take the thrust levers out of climb detent and back to get a boost of raw power to cushion the thump. And only if there is sufficiently runway to play around with........the temporary power boost can be considerable if one is not quick enough to " retard ":{

[Pugilistic Animus]

John Farley put an excellent flow chart and explanation regarding 'flight path stable' FBW aircraft and POI's --in the FT forum:)

[Wingswinger]

My Twopence: Don't forget that the F/CTL system in normal law trims the aircraft 2 degrees nose down when it's in flare mode (below 50ft RA) and if back pressure is not applied to the side stick to maintain the descent path a hard landing will result.

Unfortunately when Bernard Ziegler designed the A320, he didn't put the aircraft into Direct Law during landing, so we are stuck with the feel it has with a reference pitch attitude remembered at 50 feet.

I'm amazed at that comment. Why would anyone prefer direct law for landing? Astonishing. Direct law exists because there is no flare mode in alternate law so when in alternate law due to failures direct law is entered when the gear goes down (or you have a double failure). The aircraft (if simulator fidelity is to be taken as a given) is decidedly more difficult to land in DL.

I think the root problem is the modern over-reliance on technology and automation. The A320 can be flown just like any other aircraft. Airbus itself says so. the only difference is in the F/CTL system which takes out the trim changes for the pilot in response to slat/flap, speedbrake, gear and power changes. In training young pilots to land the 320 I have lost count of the number I have to persuade to stop concentrating their scan on the PFD once they have gone visual. The focus should then be on the touchdown point with glances inside to monitor and correct speed. Keep the touch down point 1/3rd of the way up the windscreen. If it moves up you're going low; if it moves down you're going high. Correct the flight path with power adjustments as required. Simple really.

[rudderrudderrat]

Why would anyone prefer direct law for landing?

Hi wingswinger,

I bet you use ground mode for take off.

It was meant to explain the difference between a conventional aircraft's feel with a quick burst of power when below 50 feet versus FBW feel.

e.g. Consider a normal 3 deg approach. If the nose was briefly allowed to drop by up to one and a half degrees (so ROD increase from 700 fpm to 1050 fpm) just as you passed 50 feet:

1) Conventional aircraft will feel correct after a quick burst of power and attitude re-established to original 3 deg trajectory.
2) A320 now uses -4.5 degs as reference attitude (despite anything done with thrust) and when below 30 feet also gradually feeds in an additional feel of 2 degs nose down. No wonder it can feel "sluggish" and "heavy" and can be very confusing.

I've spent 5 years on A320 type in intensive European Operations after over 25 years on Boeings / Lockheed. I still prefer the "feel" of a conventional aircraft, & I especially miss moving thrust levers with autothrust, & the control wheel feed back from the other pilot's input when close to the ground.

FBW is very clever in some areas - but it's far from perfect.

[Chris Scott]

Hello PA,

Presume that was a typo: do you mean “PIO”? Any chance of a link to John Farley’s post? Am currently on a dial-up connection at 20kb/s, so searching difficult.

A couple of years ago, when we were discussing a Lufthansa cross-wind incident at Hamburg, you may remember the subject of sidestick technique came up? My thoughts on the avoidance of “sidestick abuse”, refined in the light of comments from others, were posted here (http://www.pprune.org/tech-log/316096-lh-a320-rough-landing-hamburg-24.html#post3979423).


Back to the main topic, and Tipsy Barossa’s post. Haven’t flown the A330, unfortunately, but don’t remember ever experiencing inadequate pitch authority in the flare on the A320 in 14 years line flying, despite the features of flare law described by Wingswinger and rudderrudderrat. On an average day, if landing is assured and the speed on target, you can even retard the throttles at 50 feet, before starting the flare (as is done for certification).

Tipsy Barossa’s other point refers to the difficulty of adding a burst of extra thrust to what the A/THR is providing, but which the throttle levers − parked in the CLB detent − are not reflecting. This facility was not available in the early days, and I’m not keen on it.

By advancing the levers the slightest amount from the CLB detent, you are effectively calling for more than climb thrust. If you actually needed and achieved that much power in the late stages of an approach, you would be going around. So it’s only the relatively slow acceleration of the big fans that enables the approach to be continued, provided you quickly return to the CLB detent. On the other hand, if you return too quickly, the energy deficit may not have been corrected. It is a very crude tool, which is one of the reasons I prefer manual thrust for manual landings.

Chris

[CONF iture]

Tipsy Barossa’s other point refers to the difficulty of adding a burst of extra thrust to what the A/THR is providing, but which the throttle levers − parked in the CLB detent − are not reflecting. This facility was not available in the early days, and I’m not keen on it.
... and for good reasons Chris :

This strange procedure came up only in 2004 I believe (?) through a FCOM BULLETIN :
AIRCRAFT HANDLING IN FINAL APPROACH

Above 100 feet
The purpose is to reduce the A/THR response time. This will temporarily deactivate and arm the A/THR.
"This possibility should be used in exceptional circumstances, and should not become a routine flying technique."

Below 100 feet
The story is different too, and can get pretty interesting ...

Overall, many agree that it is much more simple to be in manual thrust by 1000 feet and forget about this mascarade.

[G-SPOTs Lost]

So are all you bus veterans saying its not practical to add power close to the ground to avoid a hard landing.....

Yes or No???

So you're at 50ft and experience perf decreasing windshear - what do you do?

Im sure its not as bad in reality as the picture you're painting

[Pugilistic Animus]

Hey Chris
http://www.pprune.org/flight-testing/399480-time-new-edition-handling-big-jets.html#post5434108

:)

[tubby linton]

Pugilistic-Would you be able to provide a link to John Farley's flow chart please?

[Pugilistic Animus]

http://www.pprune.org/flight-testing/399480-time-new-edition-handling-big-jets.html#post5432833:)

post #7:)

[p51guy]

Reading the old version of Flying the Big Jets would answer 98% of the posts in this thread.

[Chris Scott]

Thanks for the link, PA.

p51guy,

I'm not sure I would put it as high as 98%, but I'm not inclined to dispute your figure either. Since 1988 it's been evident to me that the A320 is a very ordinary aeropane, and handles conventionally with no particular vices.

But I agree with John Farley's comment that you need to give the relevant FBW computer a moment to correct a displacement, before chasing it yourself.

G-SPOTs Lost,

If you are using it, the A/THR normally sorts it out pretty well. If not, and you are very low, I suggest a go-around is a wiser move than trying an uncontrolled burst of thrust, followed by reversion to A/THR (see CONF_iture's post). A late switch to manual thrust is also not to be recommended.

Chris

[rudderrudderrat]

@ BarbiesBoyfriend,

Instead of looking for a solution on PPRuNe, why not learn to fly?
We've all been there and done that at "our local aerodrome" - FBW is the next step in evolution.

If the Wright Brothers had started with side stick controls - how would the invention of a "big control wheel" have been greeted?

The comprehension of the pilot reflex required when converting from conventional aeroplane control to FBW is brilliantly aired on this sort of forum.

[Wingswinger]

Hello rudder,

Ground mode of Normal Law, yes. - for about 5 seconds until flight mode has blended in. Direct Law it ain't. Next time you're in the simulator have the rad alts failed, select flap 2, put the gear down and raise the flap to 1. Fly along at about F speed and then rotate to 15 degees nose up with TOGA. That should demonstrate the difference between Normal Law Ground Mode and Direct Law.

[rudderrudderrat]

Hi wingswinger,

I've flown the equivalent of "Direct Law" for over 25 years on Boeings etc. It's beautifully simple and very instinctive.
As you correctly point out "The A320 can be flown just like any other aircraft. Airbus itself says so."

[G-SPOTs Lost]

G-SPOTs Lost,

If you are using it, the A/THR normally sorts it out pretty well. If not, and you are very low, I suggest a go-around is a wiser move than trying an uncontrolled burst of thrust, followed by reversion to A/THR (see CONF_iture's post). A late switch to manual thrust is also not to be recommended.

Chris

Thanks Chris

So an expensive possible once around again 30 minute go around instead of adding some power to arrest a decreasing performance gust of wind.

Nobodys suggesting an "uncontrolled burst of thrust" just enough to keep the desired speed whilst arresting the ROD a tad.....forgive me this is what we get paid for no?

I've never flown Airbus as you can probably tell and it cant be this bad otherwise we'd see more go arounds from Airbi, you're comments fan the flames of the accusations that FBW degrade core skills...

In many ways Im slightly flabbergasted that we're heaping ultimate speed control onto the AT in circumstances that by the sounds of it it cant always cope with, when it cant cope we're advocating a go around rather than flying the aircraft close to the ground because its unwieldy to manipulate the thrust levers

[DiagonalLeg]

I may (well probably :}) be too far beyond my primitive knowledge level but I think the issue seems to be the transition from autothrust to manual thrust, specifically in respect to thrust levers which are not backdriven.

So, when changing to manual thrust one has to move the lever back from climb detent to find the level where the levers would have been had they been "normal" driven levers, then add power, then reduce again? Is this actually the case? Not an ideal proposition at 50ft if so...

Hence I think folks are saying that switching off the autothrottle much earlier is the way to go - keeping the PF much more "in the loop" - and not scrabbling to switch from one mode to another at the last minute.

I await correction!!

[Chris Scott]

Hi, G-SPOTs Lost,

Quote:
Nobodys suggesting an "uncontrolled burst of thrust" just enough to keep the desired speed whilst arresting the ROD a tad.....forgive me this is what we get paid for no?

I agree with most of your interpretation of my previous post, but am not entirely convinced that you understand why I’ve used the phrase: “uncontrolled burst of thrust”. If in any doubt, refer to the last paragraph of my post #69, and CONF_iture’s post #70.

As you know, on a conventional (driven) auto-throttle, a controlled, short-term thrust increase − for example, to add the right amount of energy (by increased GS) to recover from a sustained loss of headwind − is a simple matter of pushing the throttles forward, as much as you judge necessary, against the clutch mechanism. Once you’ve recovered airspeed, you allow the throttles to do their own thing again.

With the current Airbus system (unlike the A300 and A310), how much energy you add depends on how quickly the engines spool up towards the very high thrust setting you have commanded − something over which you’ve no control − and how long you dare to keep the levers forward of the CLB detent. If you overdo it, not only will you find yourself with too much energy, but the big fans will take another couple of seconds to slow down. This may result in the A/THR selecting idle, to correct an excessive IAS. Not something you want at 100ft.

As I said in an earlier post, the battle some of us putative A320 pilots waged − to persuade Bernard Ziegler that we needed conventional (driven) thrust levers, when in A/THR mode − was lost circa-1986. Our concerns included the issue of A/THR cancellation, but concentrated mainly on the loss of tactile information in A/THR with the non-driven thrust lever. The latter criticism was ruled out of order on the spurious, but undeniable, pretext that no pilot should assume that thrust is changing − without reference to the gauges − just because the throttles are moving. (I guess the B777 accident at LHR might appear to lend credence to that argument.)

Having said all that, the A320 throttle levers provide the smoothest thrust changes when operated in Manual Thrust: the best of the six jet types I flew. Left to its own devices, helped by the excellent GS-MINI system, the A/THR is also pretty good.

Chris

[sigler]

How can you guys tell the G-load on landing?

[1cap]

sigler,

There's a complicated formula:

You take the average change of height of all occupants, multiplied by the square root of pi and the difference in the local elevation before and after the landing.

Or you can print a load report via the MCDU :)

[kijangnim]

Greetings
It is not the first one and not the last hard landing you shall experience.
Next time verify, Wind given by Tower, and compare with wind displayed on your ND if the difference is important then monitor your speed, because if the wind drops by X Kts, so will your speed , have a look at your C of G if it is Forward then Flare a bit higher.
:ok:

[sigler]

But where do you find this load report? In the print function menu? CFDS? I've never seen it.

[Citation2]

I have noticed that the A320 flies very bad in tail wind . A321 flies much better in that condition and is more stable.

As for the 320 with a Tail wind adding few knots to your Vapp will help the aircraft fly better , you would have more lift and better control for the flare .
In Leaving the Vapp "incorrected " and retarding at the Retard call will definitely result in a positive or sometimes a high g landing.



Now If you see that the aircraft starts sinking and that controls are sluggish and not really responsive . The only way to recover is :

Disconnect the Auto thrust in the "wrong way " . I mean Leave the Thrust lever in Climb and Disconnect the Auto-trust using the instinctive red button and then immediately Retard.
By doing so , Thrust would start to increase on its way to Climb thrust and stop the pitch down moment , then immediately followed by retard .

So these 2 actions are almost done in the same time: disconnect Auto thrust and Retard "

Excuse me Captain "fly indigo" but retarding when your aircraft starts sinking is poor airmanship and this could lead to a tail strike and high G landings

What I have just described above , is not an airbus procedure but common sense is not written in the FCOM.

A 737 pilot would simply increase the thrust when his aircraft starts sinking during the flare so airbus pilots should not forget basic jet flying skills.

[ceightoz]

Hello guys.

I found this thread today so I must be a little bit late to cut in but I can’t resist. Because it is quite interesting subject and As an newbie in airbus operation( I just have been in Beoing for more than decade before moved into airbus) I also feel little bit strange and twisted feeling to adopt in Airbus system.

First of all, I totally agree that manual flight with manual thrust is better choice than lagging A/THR chasing behind IAS which make more turmoil on gusty wind.

But I’m confusing that I found some strange comment in Training manual. I have genuine Airbus Training manual (REF No. U0T25TI ). And it says “Use of A/THR is recommended during the entire flight” in section 01.030, APR 11/07,page 11of 17. It doesn’t make any difference in my company’s TRM.

I also know that each company can establish its own policy for A/P, A/T usage. But why Airbus does say “Use of A/THR is recommended during the entire flight” in thierTRM?

Since I don’t know Capt. Indigo’s situation, I can’t insist use manual thrust. It can be more serious problem if his company wants to blame someone, instead of finding cause for high G landing. You guys know what I mean.

I also got confusing on G/S mini protection. The reason for G/S mini in Airbus defined by “Keeping certain amount of energy during approach” but…what the hell is that mean? Does airplane fly on aerodynamics regardless of G/S?
When I was flying Boeing, I always keep IAS between Vref to Vref + 15kts( depending on report tower wind).

What if…Hmm…A/TRH keep G/S mini in tailwind situation? The power should be keep minimum to maintain Vls (it must be same around G/S mini). On reverse, in head wind situation the power should increase to keep G/S mini (because headwind will slow A/C G/S without increasing power and IAS .)

What about Capt. Indigo’s case?

He told us that He got steady tailwind ( Can I assume that he just got tailwind not gusty wind?) until 50ft then sudden loss of tailwind. If we apply theoretically…..power should be increase until he cut the thrust lever to idle( nose goes up for flare and G/S decrease against head wind)

I’m not sure but can it be better? ..in… a little bit late retraction to idle power can help high G ROD?

Anyway Theory is not always a perfect answer for real life.:uhoh:

Please give me some light if anybody can explain G/S mini and A/THR power management on landing.
I like to try manual thrust with manual landing. But I’m afraid because Airbus A/THR reaction is much behind of Beoing A/Throttle, and the length of A/THR movement is much shorter than Beoing, It must be not easy maintain precise target speed in gusty wind.
So here is my expression of respect to airbus expert on manual thrust. Please share the secret.:D

Happy flight and happy landings to you guys.

[PBL]

Whatever caused this problem, I doubt it's down to differential ROD. IFLY INDIGO says he was 700 ft/min with a tailwind of 8kt on a 3° GS. That equates to a ground speed of 135 kts, if I am doing my arithmetic right (3° is about 1 in 19, and 1kt is about 100ft/min), which means AS of 127 kts, so Vapp was 127 kts for him. Still wind, GS 3°, Vapp 127 kts yields ROD of 660 ft/min.

The difference, 40 ft/min, is not by itself enough to have a crunch almost to inspection levels. And lift when the tailwind went would have been increased, so some of this 40 ft/min difference would have been compensated.

PBL