ATR Spoiler deflection

[RHS]

Today when lining up I noticed an ATR 42 in front with something sticking up from the into wind wing. Looked like a spoiler, which made sense as it was into wind, however I couldn't see the aileron up at all. As they rolled it went down gradually then seemed to go into a downward deflection (although that could have been my eyesight admittedly!)

I'm sure it's totally normal, just interested to know if it was indeed into wing aileron being held and spoiler deflection?

[sithfighter]

Maybe you saw a Dash8 Q400?

The Q400 is designed with three modes of spoiler operation:

Flight: The spoilers operate in proportion with the up aileron to provide roll control. When one turns the control wheel, it operates both the aileron and spoiler. There are two sets of spoilers, the inboard and outboard spoilers. The outboard spoilers are disabled above 170 KIAS and re-enabled below 165 KIAS.

Ground: Each spoiler has a set "lift-dump" valves that cause the spoilers to fully extend when the following conditions are met:

-Flight/Taxi Switch is in the FLIGHT position
-Both Power levers are less than Flight Idle + 12 degrees
-Main Landing Gear are on the ground
-Hydraulic Pressure is available

Taxi: All spoilers are retracted when the Flight/Taxi Switch is in Taxi mode. This switch is spring loaded to the flight position and magnetically held in the taxi position. The magnetic latch will disengage when the power levers are brought above Flight Idle + 12 degrees.


I hope it helps.

[C_Star]

ATR needs a handful of into-wind aileron at takeoff. Bue to it's narrow wheelbase and high cg it tends to bank to the leeward side.

IIRC, spoilers deflect whenever aileron deflection is greater than 2.5 degrees. It's not unusual to have more than that at the start of t/o roll - so probably that's what you saw...

[RHS]

If I was looking at a dash maybe I should hand my type rating back ;)

Thanks C star, that was probably it, just seemed bizarre because I couldn't see any aileron deflection just the very apparent spoiler deflection. Both of us commented that we thought it unusual.

[Crashlanding]

Yes 2.5 degrees roll lifts the roll spoiler, some airlines as you enter the runway deflect left then right one checking the spoiler came up while the other checks the light in the cockpit shows deployment, the roll other way and repeat with the other guy checking there wing for the spoiler and again the spoiler light.

[JammedStab]

Correct. It is done at this time as that is when the gust locks are removed. It is a little strange at first taxing and turning onto the runway and swinging your head back and forth, up and down at the appropriate time for the spoiler and then at the spoiler light. May have screwed it up looking the wrong way a couple of times in the beginning.

The ailerons would have to move with control wheel deflection to ensure that they are free.

[no-hoper]

From the maintenance manual:

Spoiler deflection/aileron deflection kinematic law on ground without
aerodynamic load kinematic is linear :
- spoiler extension is initiated for 2.5° aileron/tab input lever
deflection
- spoiler maximum deflection 57° for 14.9° aileron/tab input lever
deflection (corresponding to an aileron 14° deflection and a spring
tab 2,25° deflection).

[JammedStab]

Thanks. The spoilers move a lot more than the ailerons do which explains why the OP did not see any aileron deflection.

ATR needs a handful of into-wind aileron at takeoff. Due to it's narrow wheelbase and high cg it tends to bank to the leeward side.


The C-130 is the same with near full aileron deflection used at relatively low crosswind components. Plus its wingspan is longer although it doesn't have the spoiler sticking up into the wind creating more drag like the ATR.

[Hussar 54]

Quote:
Originally Posted by C_Star
ATR needs a handful of into-wind aileron at takeoff. Due to it's narrow wheelbase and high cg it tends to bank to the leeward side.

Doesn't it just....

Just me, perhaps, but this also bites me landing in even the slightest crosswind...

After 20+ years on F27's, I could count on one hand the number of times I didn't grease it....Afters 3+ years on the ATR, I can count on one hand the number of times I did grease it !!

[JammedStab]

It might be you. I went onto it from a quite different type and found it to be quite reasonable to land under normal conditions. Perhaps you are still using a technique from being on a different type for 20 years. That happened to me many years back on one type where I was using a big flare instead of a fly-on technique.

Initially on the ATR, I had some crosswind difficulty on the rollout due to it not having any nosewheel steering through pedal input and did a couple of landings that had me behind the aircraft directionally on rollout. This did have me worried but at one point it finally came together and that was that. My approach technique was to crab into the flare followed by the big kick with plenty of coordinated wing down for touchdown.

Overall, most landings should be reasonable with the occasional one that aint so great. Greasers...maybe not that many.

It has been a while since I flew it but I will go out on a limb and say that in my experience, if you flown certain types before where you have used this technique, you may find that like those aircraft, the -42 can respond well in the flare with a slight control wheel relaxation after it was moved aft for the flare, although maybe not on an upslope runway.

I did find a few times where I seemed to be putting in corrections via nosewheel steering on the takeoff roll while the other pilot was counteracting with rudder input. Probably was my fault.

[Hussar 54]

Sure you're right - old habits die hard !!

And yes, with me it's the roll out - too easy to get that sudden lurch to right or left as soon as we have all three down and engaged....Even when I'm expecting it, still manages to make me look as though I don't know what I'm supposed to do....

Then again, most of my time on the F27, I was in my pomp - nowadays just part-time....So I suppose as far as ATR's are concerned, sadly it's probably already about as good as it's likely to get...Dohhh !!

[C_Star]

ATR is in my opinion quite peculiar to handle - especially during takeoff/landing roll and flare... It took me a good 500 hrs to be able to make consistent landings in all conditions/weights.

Once you get the knack of it, you can fairly easily make some nice greasers. Unlike my current type, you actually fly the thing all the way to touchdown and can fine-tune/finesse the landing.

On the -320 you just cut the power and flare at approx 30 ft and the beast sort of lands itself, with better, or worse result :}

@JammedStab

Good info on the C-130. That's one of the type I always wanted to fly and never had a chance...

[error_401]

Flew ATR 42 and 72 for nearly 4 years. About as nice to grease as the AVRO RJ today.

Crosswind needs aileron but got decent landings in all conditions.

[JammedStab]

One last thing I would say is that some people seem to stop flying the aircraft in pitch when the mains touch down and therefore let the nosewheel come falling down onto the runway firmly which I never liked. Fly the nosewheel on just like in a jet with appropriate aft elevator input so that it touches down normally.