LATAM A320 lands with nose wheels at 90 degrees

[Escape Path]

Once again, an A320 lands with the nose gear at 90 degrees, this time at Medellín, Colombia (SKRG/MDE). Link to news (in Spanish): https://www.elcolombiano.com/antioquia/emergencia-en-el-aeropuerto-de-rionegro-por-avion-de-latam-al-que-se-le-incendio-una-llanta-CB17079784

Media is reporting the event was due to either a "wheel on fire" or burst, detected by the crew after takeoff. The flight returned to the origin airport after holding for some time. From the videos, it would seem the flight crew behaved as expected, though, as usual, the subsequent investigation will confirm or deny this. Aircraft wasn't evacuated and was deplaned via airstars.

I wouldn't think a burst tire could cause such a failure...? Maybe a mechanical failure of some sort that would trigger the WHEEL NW STRG Fault ECAM?

[DaveReidUK]

Interesting recent edition of Airbus's Safety First magazine, identifying five unrelated root causes that can result in a 90° rotation of the NLG on the A320 family: Safety first - January 2022 (https://mms-safetyfirst.s3.eu-west-3.amazonaws.com/pdf/safety+first/landing-with-nosewheels-at-90-degrees.pdf)

[compressor stall]

It's a design feature. Sacrifice the front wheel keeping the aircraft on the runway.

Read the article linked by Dave.

[tubby linton]

From photographs I have seen of this incident the RAT is extended. I wonder what other problems they were experiencing?

[compressor stall]

Yes, I saw that too - but I can't quite see it in the landing video though.....although could be the resolution.

CAA statement just says found fault in nose wheel on takeoff.
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/863x377/screen_shot_2022_03_30_at_10_12_47_pm_1c0ffefa76192739e47ca9 0f397eac46186a80e5.png

[gearlever]

If my memory serves me right RAT comes out if AC BUS 1&2 are lost. With abnormal NLG ALL ENG MASTERS OFF before the nose comes down.

[FlightDetent]

Careful, there's great pride in correctly executing a wrong checklist.
The procedure is intended for use when the nose or main landing gear fail to extend and/or lock down following the application of the L/G GRVTY EXTN procedure. ref. PRO-ABN-LG "A"

[hoistop]

It's a design feature. Sacrifice the front wheel keeping the aircraft on the runway.

Read the article linked by Dave.
In one case crew managed to TAKE-OFF with NLG at 90 degrees at the beginning of T/O roll. Didn`t know this is possible. Wow.

[compressor stall]

Careful, there's great pride in correctly executing a wrong checklist.
ref. PRO-ABN-LG "A"
true. Benefit of the doubt though that they may have had an abnormal gear down lock indication as a consequence of the original failure.

[FlightDetent]

Sure. I was only commenting on gearlever's recollection, not the case itself.

[Escape Path]

Re: RAT extended, I was baffled too when I saw some pictures that showed the RAT deployed. I remembered the Landing with abnormal LG procedure and went for my QRH to have a look at it and found the note FlightDetent mentioned and thought "oh oh, hopefully they didn't run a checklist they didn't need to". Not knowing what other indications they might have had, I went for the "benefit of the doubt" route. Let's wait and see...

It would seem that this aircraft had a similar scenario to the onehoistop mentioned. I departed this airport the very next day, once they had removed the aircraft, and there's a single very identifiable skid mark from the very threshold...

The safety first article relates one such case of taking off with the wheels at 90 degrees, and in that instance it was because of a dispatch with NW steering inop. Maybe something similar happened in this case?

[DIBO]

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/800x400/1648912013_8a2ebb0b3a2492262eee0ea9c308465d0ab34ed8.jpeg
More pic's @ https://twitter.com/AerocivilCol/status/1508911729526329354?s=20&t=x7uflj7culs8h8IbgG3pnA

[Tango and Cash]

In one case crew managed to TAKE-OFF with NLG at 90 degrees at the beginning of T/O roll. Didn`t know this is possible. Wow.

Wouldn't the additional drag, vibration, grinding noises be very noticeable during the takeoff roll/skid?

[hoistop]

Wouldn't the additional drag, vibration, grinding noises be very noticeable during the takeoff roll/skid?
That is what I would expect too, but, obviously, one crew managed to do it - it is well described in Airbus Newsletter referred above. In short: as alowed by MEL, A/C was dispatched with NLG steering off - meaning in free-castor mode, maintaining directional control by differential braking and assymetric thrust. (there are several small A/C and also tri-cycle wheeled helicopters with NLG free-castor as normal operating mode-no connection between pedals/tiller and NLG itself at all) But, in A-320, if 25 degree limit of steering angle is exceeded, wheels will not return to neutral at the end of turn, but will continue towards 90 deg. And that happened with said flight, when crew performed 180 deg turn on the runway before take-off. They did not notice they are grinding rubber and then wheel rims during take-off roll, which sounds impossible, but obviously, it is possible. Airbus intends to remove this free-castor operation from MMEL. I am a bit surprised they allowed it in the first place, as exceeding 25 deg is really easy and there is no indication to the pilot it has happened.

[oceancrosser]

That is what I would expect too, but, obviously, one crew managed to do it - it is well described in Airbus Newsletter referred above. In short: as alowed by MEL, A/C was dispatched with NLG steering off - meaning in free-castor mode, maintaining directional control by differential braking and assymetric thrust. (there are several small A/C and also tri-cycle wheeled helicopters with NLG free-castor as normal operating mode-no connection between pedals/tiller and NLG itself at all) But, in A-320, if 25 degree limit of steering angle is exceeded, wheels will not return to neutral at the end of turn, but will continue towards 90 deg. And that happened with said flight, when crew performed 180 deg turn on the runway before take-off. They did not notice they are grinding rubber and then wheel rims during take-off roll, which sounds impossible, but obviously, it is possible. Airbus intends to remove this free-castor operation from MMEL. I am a bit surprised they allowed it in the first place, as exceeding 25 deg is really easy and there is no indication to the pilot it has happened.

Sound like a poor design that Airbus and the NLG vendor have had decades to redesign.

[FlightDetent]

Sound like a poor design that Airbus and the NLG vendor have had decades to redesign.Awkard, isn't it. Sounds like the MMEL provision will get you directly into a non-airworthy state.

Always thought the whole concept was the exact opposite, only MMEL'd if the subsequent failure does not render it unflyable.
​​​​​​

[Escape Path]

That is what I would expect too, but, obviously, one crew managed to do it - it is well described in Airbus Newsletter referred above. In short: as alowed by MEL, A/C was dispatched with NLG steering off - meaning in free-castor mode(...)

The mentioned Airbus Safety First article also states that dispatch with an inoperative NWS (as you say, in free castor mode) was removed from the MMEL. This revision was published/issued in February 2022, if my memory serves me right. By the looks of it, this airline didn't have this revision in their manuals yet. I am unaware of the process of how a manual published by the manufacturer gets to an operator (i.e. how long does it take between it being issued and being accepted by the respective CAA), but I guess the question now would be "why wasn't that MEL in their approved manuals?"

I know from a good source that some days after the event, the airline published a bulletin stating that it was no longer possible to dispatch an aircraft with inoperative NWS. Go figure...

[hoistop]

The mentioned Airbus Safety First article also states that dispatch with an inoperative NWS (as you say, in free castor mode) was removed from the MMEL. This revision was published/issued in February 2022, if my memory serves me right. By the looks of it, this airline didn't have this revision in their manuals yet. I am unaware of the process of how a manual published by the manufacturer gets to an operator (i.e. how long does it take between it being issued and being accepted by the respective CAA), but I guess the question now would be "why wasn't that MEL in their approved manuals?"

I know from a good source that some days after the event, the airline published a bulletin stating that it was no longer possible to dispatch an aircraft with inoperative NWS. Go figure...

I am not with A-320 operator anymore, so I don`t have access to OSD of A-320, and I can`t check when mentioned MMEL change was actually published. But if it was implemented somewhere in February and incident happened 29th March, I can guesstimate 4-6 weeks time and not implemented yet in MELs. Maybe it souds a lot, but in some places it might not be so unusual - especially if CAA is involved in approval of MEL changes (no indirect approval procedure in place).

[Escape Path]

especially if CAA is involved in approval of MEL changes (no indirect approval procedure in place).

This is the case for Colombia. Operational manuals are approved by the CAA, including the MEL. Hmm, 4 to 6 weeks... nice ballpark. I had no idea how long it could possibly take