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-   -   787 Dreamliner late undercarriage retraction (https://www.pprune.org/spectators-balcony-spotters-corner/564413-787-dreamliner-late-undercarriage-retraction.html)

wub 11th Jul 2015 14:04

787 Dreamliner late undercarriage retraction
 
I live close to Edinburgh Airport where there is a daily Qatar 787 service to Doha. I have noticed that occasionally the aircraft does not retract its gear right after takeoff but will leave it until it is well over 4,000 feet and several miles from the airport. Does anyone know why this happens, is it 787 SOP for cooling?

HEATHROW DIRECTOR 11th Jul 2015 14:26

Cooling brakes and can happen with any type.

wub 11th Jul 2015 14:33

Thank you, thought as much but never seen it at EDI on anything but the 787.

HEATHROW DIRECTOR 11th Jul 2015 16:16

Happened to me years ago with an Air France A310. AS it climbed away I said "You still have the gear down"...... "Affirmative, we use it for ze take-off". I never lived that down.

Green Guard 11th Jul 2015 17:30

787 Dreamliner late undercarriage retraction
 
They are from Qatar
so its not b'cos hot brakes after TO in Edinburgh but because "home habits"

El Bunto 11th Jul 2015 18:27

On early 787s the wizzo-magic brake & tyre pressure monitoring system ( mounted on the gear ) often overheated, forcing operators to resort to the old-school technique of dangling the gear in the airstream since they didn't know how hot the brakes were...

Are Qatar 787s early-builds?

MarcJF 11th Jul 2015 21:19

Why would the brakes be hot after departure?

Hotel Tango 11th Jul 2015 22:23

From the sometimes frequent braking during taxy from terminal to runway.

greybeard 12th Jul 2015 02:45

It could be an anti-skid fault which may prevent the brakes being applied during retract.
So you let the wheels spin down before retracting them.

3+ minutes on the older A-310

:confused:

DaveReidUK 12th Jul 2015 06:48


Originally Posted by greybeard (Post 9043200)
It could be an anti-skid fault which may prevent the brakes being applied during retract.
So you let the wheels spin down before retracting them.

3+ minutes on the older A-310

Three minutes for the wheels to spin down ?

You're having a laugh.

dixi188 12th Jul 2015 08:55

A300B-4 was 1 min. if anti-skid fault. Same for 1 brake inop.
Don't know why the A310 would be any different.

AndoniP 13th Jul 2015 08:49

I'd assume that if you follow the departure speed on flightradar or whatever it'll show that being below VLO, then speed up after gear is up

One Outsider 13th Jul 2015 10:12

Is the Pope catholic? Do bears **** in the woods?

But hey, you got to show you know about VLO.

asw28-866 13th Jul 2015 10:20

'VLO', didn't they have a hit with 'Don't Bring Me Down' in the 70's? Rather appropriate really :}

'866

AndoniP 13th Jul 2015 11:05


But hey, you got to show you know about VLO.
That's what I crave when I post on internet forums, recognition *has made it finally*

Chesty Morgan 13th Jul 2015 11:12

Yeah but you could go up to Vle to accelerate the cooling then reduce to below VLo before you increase to Vne.

Flying Fred 13th Jul 2015 11:21

It's probably got a wheel brake deactivated because of a fault, which is allowed in the 787 Dispatch Deviations Guide (DDG)

From the 787 DDG:-

Wheel Brakes may be inoperative on one main landing gear wheel per truck provided (amongst other things) the inoperative brake is deactivated and after takeoff, the gear remains down for two minutes before retraction.

As part of the normal retraction sequence, the wheel brakes are applied to stop the wheels spinning before they enter the gear bay. If a brake is deactivated, the affected wheel cannot be braked so the gear is left down for 2 minutes to ensure the wheel has stopped spinning

FF

One Outsider 13th Jul 2015 11:24

I doubt it was that kind of recognition you were looking for.

AndoniP 13th Jul 2015 11:31

Yeah I don't think you quite got it.

fujii 13th Jul 2015 16:33

DaveReid,
Three minutes for the wheels to spin down ?

You're having a laugh.


No laughing matter. If one wheel is still spinning, it's one hell of a massive gyroscope. The precessional forces would be pretty large.


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