Dash 8 spoilers during line up

[The Red Max]

Just curious but having watched some Dash 8 line up, the speed brake/spoilers seem to deploy until the aircraft starts rolling, what is the point of this?:sad:

[hetfield]

Just curious but having watched some Dash 8 line up, the speed brake/spoilers seem to deploy until the aircraft starts rolling, what is the point of this?:sad:

Sorry, but we've had this here several times.

BTW, it's normal.

[lgw bean flicker]

We've also had plenty of "helpful" replies like yours!! As helpful as a chocolate kettle,............:}

[excrab]

You will see it on the D8 - 400 and also I believe on the 100 series. The spoilers deploy as ground spoilers for an RTO if the power levers are retarded below a set angle (can't remember it off hand and it isn't important). They are armed prior to take-off and as this is normally done at low power when at the hold or taxying they will pop up at that point, to retract when the power is applied for take-off. It is possible to start the t/o roll without arming them as they will do it automatically anyway, but one of our trainers suggested to me that the reason for arming them is to check that they will actually work if you need them, which makes sense. All that is applicable to the 400 - possibly someone who flies a 100 can confirm if it is the same or not.

Hope that helps.

[AerocatS2A]

The 100 has a ground/flight switch. I think (I fly a 200 which doesn't have this) that in flight mode the spoilers will be up on the ground at low power settings. Ground mode can be selected to retract the spoilers and allow you to check that they deploy with aileron when you check the controls. Flight mode does not get selected automatically but the configuration horn will sound if you apply power with ground mode selected.

[hikoushi]

On both the 100 and 400 series the spoilers flight/taxi mode switch will automatically pop over to "flight" if the power levers are advanced with the switch in "taxi" position. This actually happens at a fairly low power lever angle. The takeoff warning horn sounds when a seperate power lever microswitch is tripped at a higher power setting if one or more spoilers remains deployed (stuck) at the takeoff power setting. So before takeoff we unlock and check the controls with the switch at taxi, observing the spoilers deflect in the proper direction; then flight/taxi to flight, check all spoilers deploy; then, as we advance the power on takeoff, quick check that all spoilers have retracted, then off we go.

[BOAC]

Like hetfield says, try these two pages.


http://www.pprune.org/forums/showthread.php?t=242414&highlight=spoilers

[The Red Max]

Hetfield
Thanks ever so much for your really helpful reply. Forgive me but I have neither the time nor the inclination to search through all the archives on pprune, I just had a technical querry and wanted a technical answer.
ps, are you a member of the "on-guard" police aswell?