B747, A340 Leading Edge Devices

[Spektor]

Gentlemen and Ladies A340 and B747 Specialists,

Once again I would like to tap into the vast well of your technical knowledge on these two beautiful aircraft.

What kind of Leading Edge High Lift Devices do they employ? Are they Leading Edge Flaps, Slats or a combination of them? Are the Flaps Krueger type or Variable Camber type? Also, any insights on their workings and deployment sequence would be greatly appreciated.

Thank you so much in advance!

Spektor,
the Cathay Pacific hopeful.

[Intruder]

747: LE Flaps. Inboard section Kreuger; remainder vairable camber.

Deployment sequence differs between Classic and -400:

Classic:
Flaps 1 => Inboard + 3rd section of LE flaps, plus some TE flaps.
Flaps 5 => Remaining 2 sections of LE flaps, plus some more TE flaps.

-400:
Flaps 1 => 3 inboard sections of LE flaps only.
Flaps 5 => Remaining outboard section of LE flaps, plus some TE flaps.

Net effect is the same for all -- 20 KIAS reduction in maneuvering speed for each increment of flaps.

[Spektor]

Mr. Intruder,

Thank you, Sir!

Spektor.

[spannersatcx]

LE flaps are pneumatically operated (ok an electrical signal is sent to operate a pneumatic motor) with alternate electric operation, time to deploy/stow 9secs by air 30secs electrically. Trailing edge flaps are hydraulically driven and the inboard and outboard flaps are split in that inbd 1 motor outbd 1 motor they can (on classic) be operated independantly (in alternate) electric mode. On the 744 if you operated the flaps by their normal source (air & hyds) and they don't go because there is no air or hyd they will automatically operate electrically. This is a simplistic view and not intended to be overly detailed (keeping it simple)