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Farrell
22nd Jan 2020, 04:39
Ouch.

https://www.aviation24.be/airlines/international-airlines-group-iag/british-airways/airbus-a350-1000-damaged-during-hard-landing-at-tel-aviv-airport/

KelvinD
22nd Jan 2020, 06:12
The aircraft returned to Heathrow yesterday as a cargo flight.

esscee
22nd Jan 2020, 14:34
Not an automatic landing at Tel Aviv then?

Airbubba
22nd Jan 2020, 15:45
The aircraft returned to Heathrow yesterday as a cargo flight.

Are you sure it wasn't a ferry? I saw the note on BA Source but I'm not sure how the plane could operate a revenue flight even as a freighter if it wasn't OK to carry pax before maintenance work back at LHR. Were some of the passenger service units unserviceable perhaps when panels fell from the aft cabin ceiling?

Don't the BA cargo flights normally use 3000 series numerics? I realize that this was an ad hoc situation.

https://flightaware.com/live/flight/GXWBD/history/20200121/1625Z/LLBG/EGLL

oliver2002
22nd Jan 2020, 16:04
No major harm done, unexpected tail wind at the wrong time.




On Jan 22nd 2020 The Aviation Herald received information that the approach had been stable until about 70 feet AGL. At 70 feet AGL the sink rate increased to 1000 fpm, the pilot monitoring called "SINK RATE". Corrective inputs were made on the pilot flying's side stick, however insufficient to arrest the sink rate. According to flight data a loss of 5 knots of IAS occurred as result of a gust (increasing tailwind) which prompted a nose down input and high rate of descent. Maintenance travelled to Tel Aviv to assess the aircraft, the damage was assessed minor. The aircraft is estimated to return to service on Jan 22nd 2020 as flight BA-163 to Tel Aviv again

https://avherald.com/h?article=4d23c7df&opt=0

NWA SLF
22nd Jan 2020, 16:23
Am I interpreting that wrong, but doesn't it say that the 5 knot gust created an unexpected (by the PF) software input pushing the nose down that couldn't be corrected in time by the PF with side stick input resulting in a hard landing causing enough damage that it needed to be ferried back to the UK for repair? If the pilot had full control at the time of a 5 knot wind change, would he have been able to avert the hard landing? Keep thinking of MAX and software causing a pitch down with more dire results.

DaveReidUK
22nd Jan 2020, 18:24
Are you sure it wasn't a ferry? I saw the note on BA Source but I'm not sure how the plane could operate a revenue flight even as a freighter if it wasn't OK to carry pax before maintenance work back at LHR. Were some of the passenger service units unserviceable perhaps when panels fell from the aft cabin ceiling?

The aircraft wasn't necessarily unsafe to carry passengers, it just didn't have any on board.

It's not unusual when a service is severely delayed for BA to re-accommodate pax on other flights, but still to carry any originally-booked cargo, so technically a cargo flight albeit with a regular passenger flight number.

There were a couple of similar instances in October.

FreezingDrizzle
22nd Jan 2020, 21:23
Am I interpreting that wrong, but doesn't it say that the 5 knot gust created an unexpected (by the PF) software input pushing the nose down that couldn't be corrected in time by the PF with side stick input resulting in a hard landing causing enough damage that it needed to be ferried back to the UK for repair? If the pilot had full control at the time of a 5 knot wind change, would he have been able to avert the hard landing? Keep thinking of MAX and software causing a pitch down with more dire results.

I’d say you’re interpreting that wrong. During manual flight in normal speed range (most likely at least VLS+5KT in this case) there will be no ”software” nose down inputs with a 5 kt increase in tailwind.

FlareArmed2
22nd Jan 2020, 23:05
In my experience with Airbus, below a certain RA the autothrottle will not respond to a speed loss below Vref. This can lead to quite a surprise with a gusty tailwind in flare. As the thrust levers are still in the detent there is nothing you can do to spool the engines up except go-around. Difficult to recognise and deal with in a short space of time: note this is not a criticism of the aircrew in this situation.

stilton
23rd Jan 2020, 02:34
In my experience with Airbus, below a certain RA the autothrottle will not respond to a speed loss below Vref. This can lead to quite a surprise with a gusty tailwind in flare. As the thrust levers are still in the detent there is nothing you can do to spool the engines up except go-around. Difficult to recognise and deal with in a short space of time: note this is not a criticism of the aircrew in this situation.



Not flown the AB but I find this statement hard to believe, no choice between idle and go around power in the flare ?!

Clandestino
23rd Jan 2020, 04:16
In my experience with Airbus, below a certain RA the autothrottle will not respond to a speed loss below Vref. This can lead to quite a surprise with a gusty tailwind in flare. As the thrust levers are still in the detent there is nothing you can do to spool the engines up except go-around.

In my experience with Airbus, I have never seen an autothrottle installed and I'm pretty sure 350 doesn't have one either (unlike A300 and A310). Also I have never flared with thrust levers in CLB detent, as company policy (not often found in the Airbus world, though) was "manual flight - manual thrust" so it was "the balls on the needles" and autothrust off usually around 1000 AAL. Below 100 RA, alpha floor is inhibited, not SPEED and this FUD BS about ATHR not working properly is with us ever since Asseline tried to clear himself of the blame for driving his 320 into the woods near Habsheim by blaming the aeroplane and the engines. Pilot who insists on flaring his Airbus with trust levers outside the idle detent will be quickly reminded by HAL what he is.

Uplinker
23rd Jan 2020, 06:52
In my experience with Airbus, below a certain RA the autothrottle will not respond to a speed loss below Vref. This can lead to quite a surprise with a gusty tailwind in flare. As the thrust levers are still in the detent there is nothing you can do to spool the engines up except go-around. Difficult to recognise and deal with in a short space of time: note this is not a criticism of the aircrew in this situation.

If you don't move the thrust levers to idle as you flare, the auto-thrust will increase thrust to keep Vapp. (Remember it allows +5 and -5 kts around the speed bug). So you will continue down the runway at Vapp !!

@Clandestino; what do you mean you have never seen auto-thrust installed in an Airbus except A300/310? Every Airbus FBW I have flown has it. Is the A350 different? Oh wait, you mean auto-throttle is the wrong word. I get it now.

safelife
23rd Jan 2020, 07:11
Autothrust, which has no moving levers.

FlareArmed2
23rd Jan 2020, 07:32
It is supposed to keep VAPP as a minimum; however I have seen significantly below VAPP below 50 ft RA. There is no alpha floor protection below 100 ft RA, and no windshear warning below 50 ft RA. All this may depend upon Airbus type and modification, of course, so I hesitate to be definite about this for all tails. Nonetheless, below 50 ft RA if my speed decays more than a few knots below VAPP I go-around. I know of no way to simply increase thrust slightly to reduce or ameliorate the speed decay. If you know of a better technique please let us know.

Sick
23rd Jan 2020, 08:30
Surely one is supposed to slow down from VApp over the threshold to touch down at Vref (or Vref-x it's depending on type) - NOT stay at VApp - that would exceed predicated landing distance. That said, younger pilots (non AB) do seem to be paranoid about getting below VApp, and I have even seen them ADDING thrust while they flare to prevent speed going below VApp (and rolling out very very long or with heavy braking) It would seem to me that an Airbus would rightly chastise this dodgy practice, and correct technique of closing the thrust during the flare would work just fine,

Another slightly unusual aspect is that a tailwind normally slightly increases airspeed in ground effect, not decreases.

FlareArmed2
23rd Jan 2020, 08:52
The problem with moving thrust levers to idle too early is that the auto-throttle has got no authority to exceed the thrust lever position, ie any decay in speed has no correction because the thrust levers are already at idle. Please note my careful choice of words "too early". Without AT authority, no alpha floor, no windshear warning and an early thrust lever closure, any gust in TW sets you up for a hard landing. As I said, I have experienced this.

Although the FCOM doesn't mention it, I have seen little to no AT reaction to speed decay at low RA. The FCOM says it will maintain VAPP as a minimum as long as AT has authority, but I believe, and have noticed this in actual flights, that below a certain RA that doesn't happen. It's like the undocumented behaviour of the stall warning not announcing below a certain speed that was only discovered by Airbus pilots after the AF crash. There's a lot going on that's not in the FCOM.

Having said all that, it is very difficult to keep an eye on airspeed while simultaneously flaring and moving thrust levers to idle. I try to do so but it is high workload. If in doubt about gusty conditions I add a few knots; if crosswind exceeds 15 knots I add a few knots there as well. In my operations I am never constrained by runway length so I accept the additional touchdown speed.

For the pedants: a few knots.
For non-pedants: please share your techniques if you think there is a better way.

FlareArmed2
23rd Jan 2020, 08:54
Another slightly unusual aspect is that a tailwind normally slightly increases airspeed in ground effect, not decreases.

Ground effect, I believe. Reduced downwash => less drag => same thrust => speed increase.

There may be position errors as well. (edited, added) Perhaps the ADC correct for position error, but I really don't know

Clandestino
23rd Jan 2020, 10:26
It is supposed to keep VAPP as a minimum; however I have seen significantly below VAPP below 50 ft RA. There is no alpha floor protection below 100 ft RA, and no windshear warning below 50 ft RA. All this may depend upon Airbus type and modification, of course, so I hesitate to be definite about this for all tails. Nonetheless, below 50 ft RA if my speed decays more than a few knots below VAPP I go-around. I know of no way to simply increase thrust slightly to reduce or ameliorate the speed decay. If you know of a better technique please let us know.

Obviously I am using inferior technique of arriving at 50 ft with proper speed (Vref+additons planned during approach preparation, rechecked during descent and approach) , proper flight path angle and appropriate thrust, config needs not be mentioned. At typical approach speeds, there will be a bit less than 3 seconds between "FIFTY" and flare initiation, which is the last point I'm interested in my speed tape indication and whatever happens after that, inertia will deal with it, which is incidentally one of the reasons why windshear alerts are inhibited at that point (if you got this low, they are already useless). I really admire experten who are so multitasking capable they are able to check continuously their speed below 50RA and perform windshear escape outta flare. I hope some day I'll be like them.





If you are wondering, yes, I'm taking a :mad: at hilarious flight technique advice that is best left to be tried at MSFS only; it's too risky even for X-plane.

Seems that Speedbird pilot tried to exchange altitude for airspeed. Might be a good idea but you need some of it available for exchange.

Sick
23rd Jan 2020, 10:44
. . I really admire experten who are so multitasking capable they are able to check continuously their speed below 50RA and perform windshear escape outta flare. I hope some day I'll be like them. Ha ha, I like your brand of irony. That said, many inexperienced pilots do try and do exactly this. Whatever happened to coming into the flare at the correct speed ... then just looking out of the window at the attitude, using the seat of the pants, stick and trust, and landing it like any other plane, (mitigating gusts and dips with usual control inputs) It seems just when the Airbus finally gives the pilot full direct control, it induces a mild state of panic!

FlightDetent
23rd Jan 2020, 10:49
Not flown the AB but I find this statement hard to believe, no choice Red tween idle and go around power in the flare ?! I am clueless about the 350, with the smaller ones your choices are
- Idle
- present thrust as commanded by the A/THR
- anything above CL which you need to then reduce using MAN thr (an obscured mode reversion)

The range between the commanded thrust and CL+ is not readily available with a reflex action. Also, it is not possible to prevent the a/thr from reducing unwisely with a handy intervention.

Uplinker
23rd Jan 2020, 11:29
Hi FlareArmed2,
Maybe I have been lucky, but we always check and adjust Vapp to at least Vls+5kts on approach, since we are often heavier than we think, and if so Vapp might not be quite right.

We also used to have "phase advance" available; where you pushed the thrust levers forward, just out of the CLB gate for literally a second, then back in the CLB gate. This was particularly useful on the A330 whose auto-thrust gains are not increased in the lower levels* - to just give a small 'blip' of power to prevent speed washing off too much. Airbus took phase advance away though, which was a shame, because it was very useful.

* Were not. Perhaps newer airframes do?

hans brinker
23rd Jan 2020, 16:06
The decision by AB to not have the thrust levers move with auto thrust definitely doesn't make it easy to control/adjust power in the flare. I often see pilots start to flare relatively early, not reducing TLA while the nose comes up. Thrust increases (speed mode), landing is long, max reverse and hot brakes as a result. I just flew with a new guy, and when I explained you could wave off from the flare without touching the thrust levers (TL in CLB detent, AT on and in speed mode, AT will keep Vapp regardless if you climb or descend) he definitely hadn't realized that was possible.

Also if you do need a little power in the final part of the approach due to a change in wind, everyone's instinctive reaction would be to advance the thrust lever, leading to a quite drastic increase in thrust. Even if you were aware enough to reduce the TLA and push the IDB, getting the right amount of power is not nearly as easy as it would be if the thrust levers moved, and you could just bump them up a bit.

Because of this I have gotten in the (bad?) habit of not using the AT on the approach often. If I do use the AT I start reducing TLA towards 1.05 EPR (mostly by muscle memory, same spot as for the T/O) before I start raising the nose. At that point I should not need full CLB power, and if I did need it, I would select TOGA and GA.

Romasik
23rd Jan 2020, 18:15
Yep, after certain (low) altitude thrust will not increase automatically. You will see loong decreasing speed trend and most probably use full backstick to flare. And it still may by not enough. Two solutions:
- manual thrust in gusty conditions
- move thrust levers momentarily forward from CLB and immediately back to the detent. It works and definitely better then helplessly watching speed decaying.

hans brinker
23rd Jan 2020, 20:11
Yep, after certain (low) altitude thrust will not increase automatically. You will see loong decreasing speed trend and most probably use full backstick to flare. And it still may by not enough. Two solutions:
- manual thrust in gusty conditions
- move thrust levers momentarily forward from CLB and immediately back to the detent. It works and definitely better then helplessly watching speed decaying.

The first part is definitely wrong for the A320 I fly. I often see people start to flare with the lever in the detent and invariably I will see an increase in thrust. This will happen all the way down to touch down.
Moving the lever forward of the CLB detent will give you full climb power if you leave it too long, IMHO it is asking for trouble.

FlightDetent
23rd Jan 2020, 21:16
That apart from the reason the CLB+ "bump" had been removed from the manuals.

If it's done too low, the A/THR will not re-engage and the pilot is left with CLB thrust once the TLs are set back into the detent. Not compatible with landing.

Max Angle
24th Jan 2020, 11:58
After 10000+ hours on the A320 I still wish it had a conventional auto throttle, it is the weakest part of the aircraft.

Uplinker
24th Jan 2020, 14:22
Noooooooo !

Please don't start that.

Uplinker
24th Jan 2020, 14:39
Re phase advance: As FlightDetent reminds us, if you use it below 100', auto-thrust will not re-arm, and thrust will therefore rapidly increase to the TLA position.

To use phase advance properly, you push the thrust levers forward out of the CLB gate by only about 1 cm for 1 or 2 seconds maximum, then click them straight back into the CLB gate: Click...click, like that. Auto-thrust will re-engage above 100'.

I think phase advance was poorly taught, then attempted by some who do not understand the Airbus auto-thrust logic, so they got themselves into trouble and Airbus took it away. I still use it if I need to on 'lazy' A330s, but remember if you do so below 100' RA, you will then be in manual thrust, so will then need to control thrust and speed yourself until the flare.:ok:

Probably safer, if you're not sure about phase advance, to add a couple of knots to Vapp during approach on hot, thermally days, when A330s can wallow a bit and get caught out.

FlightDetent
24th Jan 2020, 17:27
As Uplinker reminds us, unlike the benign single-aisle models the Airbus wide bodies have a history of inadequate reactions by the A/THR. Report here. (http://www.aviation-accidents.net/report-download.php?id=75)

Hopefully the present models have it well sorted out, though there is probably only so much you can do given the inertia of the airplane as well as the rotating masses inside the engines on the wide-chord installations.

Greek God
24th Jan 2020, 21:52
One of the reasons I also generally use man thrust on normal landings. A/T in association with GSmini can produce unpredictable and undesirable results at the gravy strokes.

Uplinker
25th Jan 2020, 14:11
It might say in that report @ #29 above, but I don't have time at the moment to check all 80 pages: I was told recently that narrow body Airbus FBW increase the gain of the auto-thrust below 3000', making it more responsive. For some reason the A330 doesn't or didn't have this mod, which is why it often seems lazy about correcting minus delta V's

Anybody know more?

Clandestino
25th Jan 2020, 14:57
After 10000+ hours on the A320 I still wish it had a conventional auto throttle, it is the weakest part of the aircraft.

Hours? As if hours count for anything; after 1200+ hours on autothrust equipped MRJTs and 4200+ (and counting) on the ones with autothrottle, I have no preference for either. Both have their quirks one just needs acquaint oneself with in order to have happy operational life. Still I maintain any kind of automatic thrust/power control is better than none (5000+ hrs, if you wonder).

vilas
25th Jan 2020, 15:55
I was told recently that narrow body Airbus FBW increase the gain of the auto-thrust below 3000', making it more responsive
From A320 FCOM below:
APPROACH AUTOTHRUST:
Below 3 200 ft RA, with at least CONF 1, the A/THR logic is modified to be more responsive to speed variation. This is referred to as approach autothrust

FlightDetent
25th Jan 2020, 17:36
Ref: FCOM A320 (all engine types) DSC-22_30-90 "H": A/THR MODES - Speed/Mach Mode.

swh
26th Jan 2020, 03:01
Are you sure it wasn't a ferry?

It was a normal flight back, just cargo onboard to reposition for the next outbound flight. It operated the next day as BA163 to TLV.

The landing was a crew reported suspected hard landing, analysis of the electronic landing data was within normal parameters.

Uplinker
26th Jan 2020, 08:47
Oopps, I could have just looked up auto-thrust myself. Sorry guys.:ok:

EcamSurprise
26th Jan 2020, 18:14
Basically a non-event causing an online discussion, with the usual criticisms from people who obviously know better, by a conscientious crew who correctly reported a suspected planter.

Sometimes I really wish that information didn’t leak as much as it did.

iceman50
27th Jan 2020, 01:23
EcamSurprise

My only comment would be who initiated the nose down input! According to flight data a loss of 5 knots of IAS occurred as result of a gust (increasing tailwind) which prompted a nose down input and high rate of descent..

FlexibleResponse
27th Jan 2020, 02:49
EcamSurprise

My only comment would be who initiated the nose down input! .

I would assume that the A350 (which I haven't flown) is pretty much the same as the A330 and A340 (which I have flown) in that the Stabilizer (auto trim) freezes at 100 feet RA for the FCS Flare Mode. That leaves only the elevators controlled by the sidestick to flare the aircraft.

At the instant that the Stabilizer freezes, it could be out-of-trim, depending on the conditions experienced passing 100 feet RA. That is, if a large up or down pilot sidestick command was taking place, thrust was above or below the mean, airspeed was above or below VAPP, and rate of descent higher or lower than the mean.

With the Stabilizer in an out-of-the trim position, unusual push or pull force is required on the sidestick to maintain the required vertical profile and again, unusual stick force to accomplish the desired flare manoeuvre.

With due regard to the control system Flare Mode action of the Stabilizer, in gusty conditions, the aircraft response can surprise pilots with an unexpected change in rate of descent, especially when the Stabilizer is frozen Aircraft Nose Down, and then the arse falls out of it.

If the A350 does not have the same FCS Flare mode as the A330/A340 regards the Stabilizer...then please ignore all above.

iceman50
27th Jan 2020, 05:15
FlexibleResponse

I should have included in my quote at 70'RA

I have flown A330/A340 and A350 and understand what you are saying. My question was why input nosedown at 70' for a loss of 5 kts?

Busbuoy
27th Jan 2020, 06:56
330 and 350 FCOMs present the same picture of Flare Law using different wording save the 350 not mentioning the slight pitch down elevator order at 50ft.
The 330 generates Reactive Windshear Warnings based on predicted AOA excursions (couldn't find it mentioned in 350 FCOM). I am aware that smooth stick inputs to recover an increasing descent rate can help prevent warnings being generated but I wouldn't have thought unloading initially to be warranted. But perhaps that's what transpired....

Uplinker
27th Jan 2020, 09:31
Basically a non-event causing an online discussion, with the usual criticisms from people who obviously know better.......

I must be reading a different thread. I can see no criticism of the A350 crew, and the thread has moved onto a discussion about auto-thrust and Vapp at very short finals.

Basically the Airbus FBW auto-thrust and G/S mini combination works extremely well. There are a couple of provisos to that statement: One is that the aircraft we fly can be heavier than we think from the load sheet. +2 tonnes is common, I did see nearly +4 tonnes once! So beware that Vapp might not be correct for your weight. Always check that Vapp bug is at least Vls+5kts, and adjust if necessary.

If you are in an A330, its auto-thrust is "lazy". On certain days it might let the speed dribble down to 3-4kts below bug, and this is something to be avoided, otherwise a heavy landing can result. My advice is to do something about that. On approach, if LDA is not limiting, you could adjust Vapp to be Vls+6 or Vls+7. Or simply use phase advance or go manual thrust.

Don't be afraid of manual thrust - Airbus say to take over if the system response is unsatisfactory - just make sure you understand what will happen when you use it, and practice using it on easy good weather days, so you are confident.

Once you are over the threshold, accept the speed you have and concentrate on the landing. Having said that, if speed is below Vapp-5kts, a baulked landing would probably be safer, unless you are totally confident about using manual thrust.

I am not a trainer, nor an authority, just what works for me. I have not flown A350 or A340.


Enjoy !

FlareArmed2
27th Jan 2020, 14:22
Good summary, Uplinker and I agree a good discussion I have learnt a lot.

i would disagree with this however:



...Or simply use phase advance...



...since Airbus has recommended this not be used. My airline banned it about ten years ago, never knew why until this thread explained the reason.

Agree with everything else you said. I treat A330 AT with suspicion particularly on short finals in any sort of gusty conditions. My rule of thumb is to add a few knots in these cases

FlexibleResponse
28th Jan 2020, 03:13
If you find the AutoThrust is "lazy" on an approach you will probably find that the conditions are smooth and your sidestick inputs are also "slow" and smooth.

To "wake" the AutoThrust up and have it respond quickly, simple make some rapid (tiny) sidestick pitch inputs.

The way it was explained to me was that rapid sidestick pitch inputs cause a phase/gain shift in the AutoThrust response. This in turn makes thrust change response time quicker and magnitude larger.

Don't be over-smooth, fly it like a Navy carrier approach, hold the glide slope as accurately as possible with lots of tiny and timely sidestick pitch inputs.

You'll have that sucker eating out of your hand in no time!

misd-agin
28th Jan 2020, 16:52
Exactly. Needlessly push and pull on the side stick to make it really fly. The thrust already goes up and down on it's own so adding in sidestick inputs might bring everything into harmony. Besides, being smooth is overrated. (sarcasm).

Surprisingly enough the AB products fly like regular airplanes with the autothrust/throttles off.

A 5 kt speed loss is being blamed for a hard landing?? Vicious winds, we should be damaging airplanes every day across the world.

Uplinker
31st Jan 2020, 14:30
A 5 kt speed loss is being blamed for a hard landing?? Vicious winds, we should be damaging airplanes every day across the world.

No. I said that 5kt below bug CAN cause problems in an A330. And, yes, a colleague in a previous airline did a very hard landing in an A330 as a result of exactly this situation. After which our company recommended phase advance (since removed by Airbus).

It seems to be an A330 problem when there is no significant wind, so no G/S mini addition, but a hot day with thermals on finals. Not to me - I have hammered-in the occasional A321 due to stupidity on my part, but not an A330 (yet).:ok:

FlightDetent
31st Jan 2020, 14:51
The standard bugged speed is Vref +5 kt buffer for A/THR deficiencies.

If eating into this margin and arriving at Vref, +1/+2 i.e. just above the normal and certified approach speed results in a slammer, it sounds a bit of an incomplete story to an outsider.

While you are not the first one to say so, I wonder what are the blanks that need filling.

THS freeze at 100?