BAE 146 speed brakes.
 

Watch a BAE146 lining up for t/off at begining of active with what looks like spoilers deployed. Was driving pass so did not actually see it t/off. Was my eyes playing tricks on me. Maybe some large wing top add on HF aerials. Any 146's to comment.Thanks :confused:

Lift spoilers and the airbrake are two different secondary flight controls on the Bae-146/AVRO. Obviously the lift spoilers are on top of the wing and the airbrake is the 'opening' arse.

However, when the hydraulics are pressurized the airbrake will be retracted and the lift spoilers down. The AVRO RJ has an automatic lift spoiler function and spoilers will come up when WOW.
But also if taxi speed is more than 33kts.

Maybe this was the case with this particulier aircraft.

Flight control check?

There may be different reasons for that.

The AVRO has the AUTOSPLRS which deploy with speeds >33kts.

But we also use the Airbrake and Spoilers on our 146s during taxi to slow it down and keep the brakes cool. You see that especially in FRA on TXY S to RWY18.

And during lineup it sounds like the flightcontrolcheck.
With full handwheel deflection you have a pretty big rollspoiler deployed. And that thing is awsome big.

Was there a cross-wind?

A large amount of into-wind aileron would result in a single roll spoiler being extended. However, this would only appear on one of the wings - in a similar manner to the control check described by 'loader'.

If you saw a series of spoilers above both wings then these are lift spoilers as opposed to roll spoilers.

The wings have four panels each about the size of a house door(ish). The inner three on each wing are lift dump spoilers and the outer ones are differential roll spoilers only. On a control check, you unlock the column, ( a small clip on bracket on the left column ) and while the PF pushes the rudder each way, the PNF will push to all four corners or more usually push to front, left and right then back into skipper's fat gut. This will produce different external effects depending on relative wind and strength as main flight controls are servo tab controlled, with limit direct control.

On the 146, you'd need to pull the lever right back for first airbrake and then spoiler, in that you will never see the dump spoilers out without airbrake fully out as well. On the RJ you may see spoilers deploy at high speed, but this usually indicates an unprofessional **** driving as going that fast is damn right stupid.

I query the logic of pulling all the spoilers to help keep taxi speeds down as well. If you are going that fast that they'd help, again hand your licence over please.

The 146/RJ suffers from light weight keeness to go, and the old school technique of shutting outers down on taxi in, works wonders. We got stopped from doing that when our management went from common sense to **** by numbers. Tyre and brake wear has now gone up loads.:ugh:

The brakes drag, so taxi-ing SLOWLY is how you keep speeds down and brakes from getting too hot. Brake down to walking pace, then let it go for a minte and do the same again. That's how I was taught by an old Gentleman, now retired.

Hope the info helps.

"We got stopped from closing down the outers on the taxi-in".

Point out to the management that not shutting down the outers on the taxi-in increases the fuel bill by about 50 kgs per sector. Multiply the number of sectors flown per day by the number of aircraft in the fleet and the extra fuel burnt in a year is very considerable.

As you say, it also increases brake and tyre wear.

Your company obviously has money to burn!

Sorry to but in (just a humble piece of SLF) but if keeping the outers running during taxi increases fuel burn and brake and tyre wear, where is the perceived saving?

Sorry if that's a daft question.

You can only shut down the outers if the APU and its generator are working (since only Nos 1 and 4 engines on the BAe146 are fitted with generators).

There is of course a very slight risk that should the APU generator fail after shutting down the outers then it could be mildly embarrassing.

In 20 years I have only ever heard of this happening twice.

Saving fuel is a much bigger issue.

Exactly so; you would now be down to the standby generator which, as you know, is powered by the green hydraulic system which in turn means that all normal green hydraulic systems have now been lost (i.a.w. QRH Card 30A).

That would indeed mean loss of nosewheel steering so you might have to get a tug to get you on to stand.

On the other side of the coin, if we were to imagine a small fleet of 5 aircraft and make the assumption that each aircraft flew 6 sectors per day then the fuel saving would be 5 x 6 x 50 = 1500 kgs per day (which is about the fuel burn for one aircraft from London - Brussels).

If we then take a 360 day year (allowing for public holidays) then 180 round trips from London - Brussels are being p*ssed against the wall for no good reason.

IMHO it's far safer to shut only #1 or #4 down (shutting down the engine most likely to be inboard of most turns during taxi) after the mandatory cool-down period.

In my 6years on type one learned never to rely on the APU without a backup. :\

Oh come on JW411/Clarrie. If you lose the APU gennie, just reach up and switch off the STBY GEN, you get your hydraulics back and on you go to the parking bay! :) :ok:

Quite true but it is going to go very dark and it ain't going to do the battery a lot of good.

Bloggs, why didn't you teach me than technique then? :p I thought you taught me everything I know. :D

I did, Claret. It's just that I didn't teach you everything that I know! :}

In my 19 years it never happened! Perhaps we had better APUs?

JW411,

Perhaps it was not operating the APU at ISA +30.

Bloggs,

Hmm, it never occurred to me that you'd hold back. :(

Good point Capt Claret!