Gatwick closed (now reopened) - aborted take off

[fclauson]

BA seems to abort a take off for a Dubrovnik flight a bit earlier this afternoon

[2Planks]

It was 2279 to Vancouver according to the reports in the Press. FR24 had it up to 140kts ish before the abort.

[krismiler]

That's quite a high speed. probably not too far below V1 and with the distance involved, probably a widebody with a decent fuel load.

Tyre deflation may have occurred and they may have need the portable fans for brake cooling.

[Capn Bloggs]

Spotters Corner!

[OldLurker]

Brief report on AvHerald: Incident: BAW B772 at London on Jun 28th 2024, rejected takeoff (https://avherald.com/h?article=51a75e77)

[FUMR]

A passenger reported the crew told them there had been a problem on the flight deck.

​​​​​​​That made me laugh. Just waiting for the tabloids to twist that around!

[BoeingDriver99]

Another BA 777 RTO handled in a sub-prime way? Or have the lessons learned from the last major one resulted in an overly cautious new method?

Barring a catastrophic failure which obviously didn’t occur here; why not get out of the way? Brakes are certified up to max energy + a portion of taxi time after RTO. This wasn’t max energy and it would have taken two minutes to vacate and stop on a taxiway.

And I’m speaking from the experience of an RTO at 130+ knots due to a serious failure in the flight deck but not catastrophic. We were off the active within ten minutes of stabilising the situation.

[ploughman67]

I don’t know, I wasn’t there and neither were you. It’ll all come out in the wash, why not wait and see. Just because you vacated the runway doesn’t make you right/them wrong. It’s just attempted point scoring without knowing any of the facts.

Professional courtesy and all that… unless you have a particular axe to grind?

[BoeingDriver99]

BA have a trend to completely f&ck up RTOs and EFATOs. I reckon that is their own axe to sharpen.

But then again it also seems they are more concerned about the feelings of the overweight cabin crew.

lol.

[911slf]

I believe there is an emergency runway. I appreciate that a major inconvenience is not an emergency but might it have been possible to use it?

[chevvron]

I believe there is an emergency runway. I appreciate that a major inconvenience is not an emergency but might it have been possible to use it?
There's not a lot of distance between the two runways so they might have had to stop beween them thus blocking both of them.

[DaveReidUK]

There's not a lot of distance between the two runways so they might have had to stop between them thus blocking both of them.

The aircraft was stationary on 26L for the best part of 40 minutes. The ADS-B data suggests that it may have been slightly N of the centreline at that point.

[Uplinker]

There will have been a very good reason to stop and stay on the runway. No crew are just going to sit there and fill in the tech log.

I am not B777 rated, but Nose-wheel steering. Brake problems, Landing gear unlocked or a flat tyre might require staying put until an engineering inspection had been made, or a tow could be organised (very heavy aircraft). Unlocked reverser or a flight control issue would be another reason to RTO, but should still be able to taxi off.

A problem involving a chance of fire and/or emergency evac also might mean staying on the runway for better emergency services access around the aircraft, rather than having to use the grass ?
.

[MickG0105]

Simon Hradecky over on The Aviation Herald covers the incident here (https://avherald.com/h?article=51a75e77).

​​​​​The ADS-B data collected and interpreted by Flightradar24 is interesting. It shows three consecutive positive altitudes either side of the point of recorded maximum ground speed. Noting that a rejected take-off after rotation would be something extraordinary, I am curious as to whether anyone might have any information regarding the incident.

And yes, corrupted and/or spurious ADS-B data would be a leading explanation, but the timing and persistence over three transmissions covering 18 seconds is, at best, odd.

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/1920x1200/screenshot_20240629_121407_flightradar24_ebafc3b3872a253f3af 6263102657951fddfd4c9.jpg
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1750x715/screenshot_20240630_085311_sheets_bed86dd30ab20f9b5c6d4fe235 2880d7689f178d.jpg

[Maninthebar]

Another potential explanation is that the baro readings shown here are symptomatic of the cause of the reject - instrument failure during the take-off roll.

[mikeygd]

As I understand it, if the "Weight on wheels" signal is present the altitude records as zero. If the signal is not present the altitude is recorded from GPS or derived from air pressure. May not have actually lifted off.

[wiggy]

Any chance that’s an issue with the use of not of ADS data rather than an aircraft issue?

Somebody will know this - When does FR transition from assuming the aircraft is in the ground (and so displays alt of zero) and move to displaying the (uncorrected) baro data?

Edit: I see mikeygd has similar thoughts…in any event being Gatwick the crew will have been seeing 200 feet, plus or minus on their pressure altimeters on the roll. I’d be highly wary of any alt data as being valid or representative of what the crew were seeing or perhaps responded to.

[V_2]

Nothing odd about it. When the ground speed goes above a certain value, I think from about 60kts up to about 100kts for larger aircraft, the transponder changes signal from ground to air. This is so TCAS signals can be prepared in good time for an aircraft about to get airborne

however, there was a case in Canada where the controller in LVP saw an embraer “airborne” on his screen and cleared the next aircraft for takeoff. However the embraer had also rejected, and the status changed back to ground which the controller missed. This was a misunderstanding on the controllers behalf, the ADSB data should not be used in this way

https://www.tsb.gc.ca/eng/enquetes-investigations/aviation/2020/a20o0029/a20o0029.html#

[MickG0105]

Another potential explanation is that the baro readings shown here are symptomatic of the cause of the reject - instrument failure during the take-off roll.
That thought had crossed my mind.

As I understand it, if the "Weight on wheels" signal is present the altitude records as zero. If the signal is not present the altitude is recorded from GPS or derived from air pressure. May not have actually lifted off.Thank you, a weight-on/off-wheels transition could explain it.

Nothing odd about it. When the ground speed goes above a certain value, I think from about 60kts up to about 100kts for larger aircraft, the transponder changes signal from ground to air. This is so TCAS signals can be prepared in good time for an aircraft about to get airborne... Muchas gracias. That would be an explanation for the data (a quick skim of the take-off roll data from previous flights of the incident aircraft show something similar but not wholly consistent). We can debate whether that's "odd" or not. Thanks also for the TSB reference.

[DaveReidUK]

Nothing odd about it. When the ground speed goes above a certain value, I think from about 60kts up to about 100kts for larger aircraft, the transponder changes signal from ground to air. This is so TCAS signals can be prepared in good time for an aircraft about to get airborne

however, there was a case in Canada where the controller in LVP saw an embraer “airborne” on his screen and cleared the next aircraft for takeoff. However the embraer had also rejected, and the status changed back to ground which the controller missed. This was a misunderstanding on the controllers behalf, the ADSB data should not be used in this way

https://www.tsb.gc.ca/eng/enquetes-investigations/aviation/2020/a20o0029/a20o0029.html#

Interestingly, that TSB report mentions in passing that the other aircraft involved in the Toronto incident (coincidentally, a 777) also used the same somewhat shaky air/ground logic in its transponder data as the Embraer did (albeit with not necessarily the same threshold speed).

Given the QNH on the day (1017 hPa), an aircraft on the LGW runway at over the air/ground threshold speed should have been sending transponder altitudes of around 100' (± 25', AMSL, uncorrected) so those 50/'150' readouts aren't too far out, and shouldn't necessarily be interpreted as weight off wheels.

[Uplinker]

All possible. However, instrument problems or unreliable speed would not require staying parked on the runway for 40 mins - unless possibly it was a hot brake issue from a high speed RTO, with a chance of the fusible plugs going and deflating the tyres.

Surely the B777 has brake fans ? Bit daft if they have to block a runway every time they have hot brakes.

[dixi188]

There are hot brakes and HOT BRAKES! We had a hot brake on an A300 and when the fans were turned on one brake caught fire. It happened at EDI right outside the fire station.

[ploughman67]

No brake fans on a B777, the carbon brakes are very effective and under routine ops brake temperatures are rarely an issue.

Rejecting a takeoff in a 250T airplane from around 140kts at 200’ elevation +20°C is going to put you just inside the fuse plug melt zone and the QRH instruction reads…

“When in fuse plug melt zone, clear runway immediately. Unless required, do not set parking brake. Do not approach gear or attempt to taxi for one hour. Tire, wheel and brake replacement may be required.”

For whatever reason, whether external (Fire service or ATC request) or internal, captain’s decision, the crew elected to stay on the runway. Their prerogative and one that will be subject to scrutiny both within the company and outside through the AAIB. Doubtless learning points will come, but for now I think a high-speed RTO with a safe outcome is a good result.

[dixi188]

Look what happened at Manchester in 1985 when a B737 had an engine fire and they rejected TO and vacated the runway. 55 dead.