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View Full Version : A318/319 - Gust Load Alleviation ??


used2flyboeing
23rd Jun 2003, 08:11
Jst got back from Gay Paris, Saw the flight-test A318 - I guess they added 6 or so inches to the vertical tail to make up for the reduce moment arm - and therefore rudder authority through which the vertical tail/rudder reacts through. Does anyone know if they are using a gust load alleviation system on this new bird ?

Just curious - thanks

LEM
24th Jun 2003, 00:44
A320: the Load Alleviation Function deflects the two outboard spoiler panels and the ailerons upward to decrease wing span loads.
This function is not present on the A319.
Don't know about A318, but since they've not fitted it on the minibus, probably on the 318 is not present either.

LEM;)

hooperfly
24th Jun 2003, 02:11
Nor is it present on the newer A320 with IAE engines, as flown by BA and BMI. It was found not to be necessary, following line experience with the original A320 CFM aircraft. I would be very surprised if it was fitted to the A318.

Looks a bit short to me, although it will make our A319s look less stumpy once we see it around the place. Glad I won't have to fly it - same wing as an A320 but 50 less seats - it will be a b@gger to slow down.

G Zip
24th Jun 2003, 02:17
No expert, just an A319/320 driver with an Aero-Eng Degree, but I'd guess that since LAF not on A319 with same wing as A320, it probably isn't structurally worth it at the lower certificated weights. Ergo, if the same applies to super-mini-baby A318, don't expect it to be an availble option. Sorry, for a moment there I erred dangerously into the application of logic to Airbus design - would anyone like to correct me?? :)

used2flyboeing
25th Jun 2003, 21:32
What would be removed ? you said bottles ? Cap & Stow some wires - I would imagine the only thing to remove would be a few accelerometers ? - But bottles ??

LEM
25th Jun 2003, 21:44
Probably accumulators to provide for the instantaneous spoilers deflection needed.

used2flyboeing
25th Jun 2003, 23:57
would never imagine that the AIRBUS designer's would have had to add accu,ulators for energy storage - seems like the spoiler system is under sized ? Is this the way Lockheed did it on the L1011 ? - Boeing would never carry accumulators around for this purpose - Opps - Boeing does have a pyrotechnic actuator on the spoilers that are in the path of the overwing escape slide on the 777 & 767 ( I think ) - IE to fair the spoilers following an unscheduled incident - but this thing is tiny & uses the bleed fluid from the host system ..

LEM
26th Jun 2003, 01:44
Boeing does have a pyrotechnic actuator on the spoilers that are in the path of the overwing escape slide on the 777 & 767 ( I think ) - IE to fair the spoilers following an unscheduled incident - but this thing is tiny & uses the bleed fluid from the host system ..

Interesting! Never heard about that feature. Could you give more details? thanks!:confused:

mono
26th Jun 2003, 03:00
LEM

Boeing 757/767 with over wing exits as opposed to a 4th door aft of the wing were fitted with a pyrotechnic actuator which faired #6 and 7 spoiler so that the o/wing route to the slides from the doors was clear. It was activated when the overwing doors were opened and whilst fluid was ported to return the firework knocked down the panel.

used2,

Accumulators are used for energy storage on almost every a/c I have ever worked on. Usually for Brake systems but also for HMG's, LAF's and others.

All

Yes good riddance to bad rubbish the LAF system in the 'bus was a complete waste of space and a maintenance intensive (i.e. costly item). Not on the newer 320's or the 321's and 319's.

used2flyboeing
26th Jun 2003, 03:12
Yea .. Its wired to the slide pack - arm system ..
This thing is to retract wing spoliers in the path of the slide deployement .. it is designed to work regardless of anything powered on the ship IE electrics or hydraulics - Thing was developed because slides are puncturable. Boeing did not want to add the weight of accumulators .. If the thing deploys in flight - IE lightning strike etc. one turn of the wheel canels the system.

It is basically a transfer cylinder housing like a shotgun barrell with a piston separating the charge from the hyds. Firing the cylinder causes expanding gas to force the piston to translate, thus forcing hydraulic fluid out the output port.
I believe OEA Aerospace makes , Inc. It make something like 1450 psi. in a quarter second. Cant wait to see how & where these end up in the maintenance world ..

LEM
26th Jun 2003, 04:07
Got it, thanks! :ok: