TAP Portugal Airbus A320 Strikes Wingtip

[Dimitri Cherchenko]

It seems that a TAP Air Portugal A320 struck the runway with a wing tip and struggled to climb away in a go-around while attempting to land at Copenhagen airport.

Read news here. (https://simpleflying.com/tap-a320-wingtip-strike/?fbclid=IwAR065veSu4Ik5GDeAyRpfoUkfnk5JzFB03a8xkeJqaUBH5NzQx bUJ8Xmkjo)

[procede]

Seems there is no damage. Go around does seem to have been botched.

Incident: TAP A320 at Copenhagen on Apr 8th 2022, possible wing tip strike on landing, overflew buildings at very low height on go around (http://avherald.com/h?article=4f73f634&opt=0)

[8029848s]

Well it is always tricky to fly with one thrust reverser deployed......simple lesson, when you select reverse you are staying on the ground.

[shared reality]

We landed ahead of TAP on that day in CPH. Rwy in use 30, which is quite unusual and only used in gusty NW winds. Challenging landing with said gusty conditions. As we were asking for pushback some 35-40 min later we were asked to hold the push due to a "situation" at the airport. We listened in to twr freq and heard TAP being vectored for a second approach on 22L (winds had calmed a bit). TAP stated 107 or 109 souls onboard and having flown from LIS to CPH with that load I doubt they were especially heavy. Once TAP landed (normally) we were pushed back and as we requested taxi, we were to taxi and hold short of taxiway Y to let TAP pass ahead. We got a good look at the aircraft (with rescue services in tow) and the reverser on engine nr.1 was clearly not in the stowed position.

[EDMJ]

Using time and altitude data from the play-back function on Flightradar 24, from the go-around until the aircraft stops climbing and turns south, you get an average climb rate of 750 ft/min.

Is this indicative of a go-around on (eventually) one engine only?

[EDMJ]

There's a video of the aircraft's second landing in the link below; the thrust reversers on both engine being open after landing, but not closing and remaining open on one engine.

https://www.bt.dk/samfund/alvorlig-haendelse-i-koebenhavns-lufthavn

[Equivocal]

There's a video of the aircraft's second landing in the link below; the thrust reversers on both engine being open after landing, but not closing and remaining open on one engine.I have only a passing interest in this incident and no dog in the fight, but it looks to me like both reversers closed - right is visible closing on the runway, left is closed as it taxis in.

[DIBO]

3 out of 4 TR-doors remaining open, would be my guess. 2 inboard can be seen on the RWY, 1 lower outboard clearly visible on TWY, with the edge of the lower inboard also just visible.
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1172x367/a320_tr_8aa950c72bbc441feeee8366a857d66feb2a5dd7.jpg

[D Bru]

Apparently neither wingtip nor pod strike (according to Havarikommissionen 11/4), but No 1 T/R petals not (fully) stowed (either on G/A or landing). IF theory that No 1 T/R petals already didn't close after the aborted landing were to be correct, a number of things would have had to occur at that time. A 320 would have needed WOW on both MLGs AND engines retarded to idle to allow T/R deployment in the first place (contrary to e.g. 737 where T/R depl. is possible below 10 ft RA). Big Q is then why they didn't pursue that initial landing. They obviously didn't and they likely engaged TO/GA THR. Another big Q is then why subsequently only the No 2 T/R petals fully closed. At least this allowed full fwd THR on eng No 2 to develop, while, as per design with petals not fully stowed, No 1 automatically switched to fwd idle. To note that in this situation (also as per design) A/T would have been disengaged automatically. This, plus perhaps momentary crew confusion up front and some delay of spooling up No 2 from idle, plus the drag inducing No 1 deployed petals could explain the feeble fwd and vertical speed profile in the G/A. One already knew it is apparently possible to fly and land an 320 with idle fwd THR and petals/sleeves open on one eng. At least with V2500 engines and already at a good speed (March 2004), but if it can be avoided IMO the better...

[Mike_UEM]

Why does FR24 only show a minimum of 750ft on the first approach and also 750ft on the 2nd. It only turns to zeroo when vacating?

[heavydane]

My guess would be that FR24 runs of STD QNH and actual pressure that day was pretty low.

[DaveReidUK]

My guess would be that FR24 runs of STD QNH and actual pressure that day was pretty low.

Your guess would be correct.

[172_driver]

On Apr 15th 2022 the HCL reported the captain decided to initiate a go around, upon applying TOGA one thrust reverser inadvertently opened causing control problems during the go around.

[Nightstop]

Unlikely imho. I suspect reverse thrust on at least one engine was selected on touchdown, after which a go-around is not SOP but they decided to anyway.

[Say Mach Number]

I agree with Nightstop, highly unlikely TOGA caused reverser deployment.

If 172 Drivers theory was correct I suspect every A320 worldwide would be bulletined for grounding.

Reversers opening on selection of TOGA would be a game changer and would scare the pants of out any airbus driver Im sure.

[DaveReidUK]

If 172 Drivers theory was correct I suspect every A320 worldwide would be bulletined for grounding

To be fair, that's not the poster's theory, it's an unattributed quote from Avherald of a statement reportedly made by the Danish Havarikommissionen. I have no idea whether it's correct or not.

A more likely scenario would seem to be the sequence of events surrounding the TNT A306 incident (https://assets.publishing.service.gov.uk/media/5422fe4540f0b613420008a3/Airbus_A300-B4-622R_TF-ELK_05-12.pdf) at EGNX in January 2011.

[vilas]

Unlikely imho. I suspect reverse thrust on at least one engine was selected on touchdown, after which a go-around is not SOP but they decided to anyway.
Moving from forward idle to TOGA there's no possibility of reverse getting deployed. But some pilots have this habit of prematurely moving the hand on to reverse before touchdown. In that case while moving the hand from reversers to behind thrust levers for TOGA can inadvertently engage one them.

[FlightDetent]

And others can move to REV gate while still airborne on a long float. If the PM took over at that point one lever might remain latched to REV IDLE detent, until rectified by crew by resetting the REV paddle.

Does not explain the petals extended after the second landing, nor flying the GA with REV open.

Looks like some darn mechanical failure that was really not supposed to happen in a post-Lauda 767 world. (cometh forward, the Master of the combustion chamber?)

[tdracer]

And others can move to REV gate while still airborne on a long float. If the PM took over at that point one lever might remain latched to REV IDLE detent, until rectified by crew by resetting the REV paddle.

Does not explain the petals extended after the second landing, nor flying the GA with REV open.

Looks like some darn mechanical failure that was really not supposed to happen in a post-Lauda 767 world. (cometh forward, the Master of the combustion chamber?)
You called? :E
Not too familiar with the T/R system on Airbus. Is it possible to advance the thrust lever (damn, almost wrote throttle lever :ooh:) off idle with the reverse lever extended? On Boeings, there is a mechanical interlock that locks the forward lever to idle if the reverse lever isn't stowed - don't know about the A320. If it is possible to advance the forward lever with the reverse lever not stowed (or there was a failure of the interlock), it could explain what happened (depending on the specifics of the A320 auto-restow system). If they had to stow the reverse lever before selecting TOGA, then there would need to have been some sort of mechanical fault that prevented the reverser from completely stowing.
While Boeing specifically states that performing a go-around after reverser deployment is not recommended, it is a design requirement that the reverser will successfully stow.

[FlightDetent]

It's been a flaming success the last time, many thanks for coming to clarify again. What I missed then same as now: was there any industry-wide change in design requirements and certification standards for TR installation in the aftermath?

The TLs in the cockpit are very simple. The arc of travel has separate positions for IDLE, REV IDLE and REV FULL. The revers selection paddles mounted on the front side of TLs are mechanical interlocks that prevent the TLs from travelling below the IDLE stop. Then you need to pull the paddles up, unlatching the movent into the REV range. A similar concept applies in the opposite direction - "stowing" action is required to move forward of the REV IDLE notch.

I am looking at the FCOM description (dumbed down to pilot level) and 3 out 1 in looks only possible under a "fail to open" scenario which does not match the chronological course of reported events.

[tdracer]

It's been a flaming success the last time, many thanks for coming to clarify again. What I missed then same as now: was there any industry-wide change in design requirements and certification standards for TR installation in the aftermath?

Boeing implemented a 'third lock' on all their thrust reverser systems to prevent inadvertent deployment in-flight (retrofit to the existing fleet) - prior to Lauda it only took two failures (the T/R directional control valve - DCV, and T/R isolation valve). Unfortunately, Boeing had added something called "auto-restow" after the 737 Cranbrook crash (737-200, landed in a snowstorm, after T/R deployment a snowplow appeared out of the snow - crew did an aborted landing but one T/R hadn't completed the stow cycle before they lifted off again - the isolation valve had air/ground logic and closed the isolation valve - the aero forces forced the T/R back open and they crashed due to the yaw and loss of thrust (clamshell style T/R on the JT-8D). Auto-restow sensed if the T/R wasn't stowed and bypassed the air-ground logic to open the isolation valve allowing the T/R to stow.
On Lauda, a miss-rigged sensor was causing auto-restow to cycle (sensor would go target far, auto-restow would snug the reverser up tight, sensor would indicate target near, auto-restow would close the isolation valve, vibration and flight loads would move the T/R a bit and cause the sensor to go target far and the cycle would repeat). On one of those cycles, for reasons that were never firmly established, the DCV changed state to 'deploy'. The aircraft was at ~24k, Mach 0.78, max climb - with the engine at power, the eflux from the deployed reverser effectively destroyed the lift on that entire wing and they rapidly rolled into a dive. Although the FADEC commanded the thrust to idle, at those conditions it takes well over 10 seconds for a PW4000 engine to decel to idle - by which time it was already too late and the aircraft was coming apart.
The addition of the third lock, along with stricter maintenance requirements, pushed the probability of an in-flight deployment from ~10-8 out to ~10-13/flight hour. Prior to Lauda, a T/R deployment in flight wasn't considered to be catastrophic - and had happened multiple times with the older low bypass and pure jet engines - no body appreciated how the introduction of big, high bypass engines tucked up relatively close to the wing had changed the impact. They had actually tested an in-flight T/R deployment during 767 flight test - but they'd done it at 10k, 200 knots, with the engine already at idle - 24k/Mach .78/climb power was completely different.

Interestingly, the relevant FAR still says a T/R deployment in-flight must be shown to be controllable - so the Boeing cert basis is an "Equivalent Level of Safety" - basically showing it'll never happen (in regulatory lingo, 'never' is "extremely improbable" - a probability of 10-9/hr or less). EASA has changed their CS to basically say 'controllable or 'extremely improbable'.

[Mike_UEM]

Couldn't the T/R just have been deployed on the 2nd landing with a shutdown #1? Low LH hydraulic pressure (PTU unable to cope) resulting in the partial stow.
The sloppy go-around could be a flameout of #1 on balked landing at low energy/high drag condition?

[FlightDetent]

Does not really fit the FCOM limited explanation
- there is an accumulator on the system
- the four petals are operated by a single (?) hyd valve
- by the looks of it, each petal is hinged to the actuator to weathervane shut if not energised

[India Four Two]

tdracer,

Thanks for your informative post on the TR history. It’s always been of a subject of interest to me since the Cranbrook crash. The FO was a friend of mine.

[tdracer]

Thanks for your informative post on the TR history. It’s always been of a subject of interest to me since the Cranbrook crash. The FO was a friend of mine.

You're definitely welcome. That post is obviously very top level - if I went to much into the gory details the result would have been so long, few people would bother to read it.
I was heavily involved in the Lauda investigation - by far the most difficult thing I had to do during my career. It was the only fatal crash investigation that I was directly involved in, and it really started getting to me emotionally, particularly as it quickly become obvious that engineering wise we'd missed something - and made all the worse that (as I've noted on other threads) you're basically under a gag order during the investigation - I was only allowed to discuss it with other people involved in the investigation. I could never have been an accident investigator - emotionally it was just too difficult to isolate the impact of what had happened.
If you want more details of the TR history, PM me...

[cavuman1]

Heartfelt post, tdracer. Many of us tend to forget that engineers are human and have deeply-felt emotions. It's not all equations and experimental results.

My father, who held a Mechanical Engineering degree from the Georgia Institute of Technology and a Masters degree in Marine Architecture from The U.S. Naval Academy at Annapolis, designed aircraft carrier hulls, specifically the Essex class.

I never saw Dad cry often, but every once in awhile, when there was a carrier accident (e.g. Forrestal CV-59), he would stand staring out of our library's bay window for a long time, then turn, wet-eyed, to embrace me and my mother.

Engineers have brains - big ones. Engineers have hearts - bigger ones.

- Ed

[SMT Member]

DAIB preliminary notification (press release) is out; 3 out of 4 TR doors on the no. 1 engine did not stow when TOGA was applied.

https://havarikommissionen.dk/media/12851/l_2022_alvorlig-haendelse_2022-150_cstnv_motorfly_ekch.pdf

Whilst the press release doesn’t say, one can maybe infer that the crew elected to go-around after deployment of thrust reversers. If TR were not selected by crew, and the doors “decided by themselves" to open asymmetrically on one engine only, that’s a whole different - and much scarier - scenario.

Press release doesn’t say why crew decided to go-around.

[vilas]

Whilst the press release doesn’t say, one can maybe infer that the crew elected to go-around after deployment of thrust reversers
This is the precise reason for reverse thrust is full stop. One at TOGA and other at reverse. The worst case scenario.