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-   -   787 bounce (https://www.pprune.org/rumours-news/618191-787-bounce.html)

overstress 10th Feb 2019 07:26

Bravohotel, I land on that runway several times a month and I don’t think it was strange.

DaveReidUK 10th Feb 2019 08:33


Originally Posted by Suvarnabhumi (Post 10385400)
Was it 27R and wind from the south ?

Yes, 27R - you can see the BA 747 hangars in the background.

METAR 10 minutes before the GA was wind SSW 210/20 kt, gusting 34 kt. In fact you can see the windsock in the video.

Akrapovic 10th Feb 2019 08:59

(

Originally Posted by old,not bold (Post 10385252)
Nice to have the AAIB on board, especially with such insight. But did you consider the possibility that all the passengers, seeing the problems the crew were having with gusts, decided to rush forward and advise them how to handle it? Not saying this is the case, but can’t be ruled out....

Very droll

For info, here’s the incident;

https://www.gov.uk/aaib-reports/airb...-february-2012

Something that actually happened, compared to your somewhat unlikely scenario....)

sleeper 10th Feb 2019 10:22


Originally Posted by OntimeexceptACARS (Post 10385451)
When do you think they pressed TOGA? Before first touchdown? Looked an impressive climb out, no doubt helped by the windspeed. Asking as SLF...

No need to press toga immediately, just push the throttles forward and climb away. Toga can be pushed anytime in that sequence. Unless they were on an autoland, but I seriously doubt that.

Midland63 10th Feb 2019 10:36


Originally Posted by Locked door (Post 10385138)
well flown windshear go around, hence the gear staying down.

Would the pro's care to explain to an SLF why gear stays down in a windshear (but not any other type of???) G/A?

wiggy 10th Feb 2019 10:39

It stays down (intially) for both a Windshear Go Around or (if down) a GPWS pull up in case of ground contact.

Locked door 10th Feb 2019 10:40

Not the only reason Wiggy

During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.

donpizmeov 10th Feb 2019 11:43


Originally Posted by Locked door (Post 10385792)
Not the only reason Wiggy

During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance. The gear raising process takes approximately ten seconds, during which time your performance is compromised.

Do you leave the gear down after an EFATO then?

Locked door 10th Feb 2019 12:03

No, because an EFATO doesn’t contain an immediately performance critical segment. The perf calculation includes the gear retraction and included in the type certification.

GPWS and windshear are immediate, unique dynamic events with no pre calculations where instantaneous max available performance may be required depending on the severity of the event.

if you don’t believe me, try googling it!

wiggy 10th Feb 2019 12:35


Originally Posted by Locked door (Post 10385792)
Not the only reason Wiggy..

Err, yes, I did appreciate that......I wasn’t sure at what level the questioner was operating at, so to speak, but thanks for providing the extra ...

and yes, FWIW I second the info in your reply to donpizmeov. :ok:

Mylius 10th Feb 2019 14:42


Originally Posted by Akrapovic (Post 10385211)
Reminds me of an incident easyJet had with an Airbus going in to Luton. FO under training for the left hand seat had a brain melt and stuffed the nose forward at low level. Not saying this is the case, but can’t be ruled out....

It can totally be ruled out because there were two Captains on this flight as well as a First Officer. Neither Captain is a trainer and the FO isn’t senior enough for a 787 command.

What happened is the handling pilot flew a textbook rejected landing followed by what looks to be a windshear go-around in tricky conditions. Great job by the guys up front. It

Locked door 10th Feb 2019 14:50

Thanks Wiggy, you’re much more sympathetic than me!

ATB

Midland63 10th Feb 2019 17:30


Originally Posted by Locked door (Post 10385792)
During a windshear or gpws event you need maximum performance from the aircraft immediately. The first thing that happens when you raise the gear is the huge gear doors open creating a large amount of extra drag before the gear legs start to move, significantly reducing the available performance.

Thanks. Didn't appreciate the thing about the gear doors creating extra drag but understand now. But there seemed to be an implication that there was a different procedure re the gear (leaving them down for longer) in a G/A due to windshear compared with other G/As. Or did I misunderstand that wrongly and gear is left down longer in all G/As, for any reason, from a very low height, or having touched, compared with a G/A from higher up.

Locked door 10th Feb 2019 17:53

The gear goes up almost immediately after a positive climb is achieved on a normal go around but stays down until the windshear is exited or positive terrain clearance is achieved ( often above msa) for gpws.

FlightDetent 10th Feb 2019 18:12

Midland63 The L/G is kept down during the wind shear escape routine (also) because terrain impact is a possibility. The loads absorbed by the collapsing undercarriage structure make survival of the occupants more likely, any straw counts.

While the doors protruding into the airflow will add drag, and the explanations above that it is accounted for in the EFATO case are sound, the mainstay B737 does not have any on the main landing gear. Go figure? The priority on both GWPS (terrain) and WSHR (loss of lift) scenarios must be to fly the aeroplane up, as the single objective. I gather that history teaches us messing with configuration might be detrimental to the crew's coordinated effort to ensure max thrust is set and peak climb performance is established (with speed-brakes retracted).

My best guess is that avoiding the doors' extra drag applies for GPWS, where the danger of impact is truly immediate. For WSHR, the impact-survival aspect would be the reason, which covers the 737 too. As well you want to keep the procedures simple and similar as much as practicable. What is seen in the video may be better described as a low-level G/A with unavoidable touchdown due to a de-stabilized flare, owing to gust (most likely). The industry standard wind shear model is probably different, though related. Still, the L/G lever is not to be touched!

FlightDetent 10th Feb 2019 18:24

Just realized that opening the NW bay, thus exposing the whell-well into the airflow at higher AoA, might in fact be quite significant.

greenfields 10th Feb 2019 19:00


Originally Posted by sleeper (Post 10385770)
No need to press toga immediately, just push the throttles forward and climb away. Toga can be pushed anytime in that sequence. Unless they were on an autoland, but I seriously doubt that.

Unless it was for WINDSHEAR, in which case the TOGA switches are pressed prior to advancing the TLs.


The L/G is kept down during the wind shear escape routine (also) because terrain impact is a possibility
This is a by product of the escape manoeuvres, not a reason for it to remain down. The gear is left down (no change to config) for one reason only - the performance of the aircraft. It is not left down in case of ground contact, rather it is left down to avoid ground contact (by not increasing drag as the doors open.)

JanetFlight 10th Feb 2019 19:57

Seen and heard from the inside...a few shouts ...


facebook.com/BigJetTV/videos/vb.168124773665425/351089042153464

BluSdUp 10th Feb 2019 20:06

Spot on Flight Detent!
 
All my Types have the same: Max Pwr NO Config change!
Industry standard for GPWS and Low level Wind Shear escape I gather:

Greenfields
I do disagree, the Gear stays as there is plenty of times the aircraft touches down after a momentary positive climb.( Microburst mostly).
Secondary touchdown with gear in transit will ruin Your day.
Also remember if You have to trade all your airspeed down towards shaker, that gear does not give you much drag as it is the old " Parasite Drag" so it gets less with less speed.

Bravohotel 10th Feb 2019 21:39

Overstress I was referring to the Aircraft and the crews action ,not the runway. 27R was in use and all other arrivals seemed normal (some crews nailed it) considering the conditions,those hangers can cause issues in SSW winds.I wish I could post the video of the second approach and landing but unable too.


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