Q400 question?

[Salukipilot4590]

I fly the 400 and we put the Flight/Taxi (spoiler) switch to "Flight" when we taxi into-position-and-hold, and the spoilers (all 4) go 'up' as a self-test. They will stay in the 'up' position until we advance the power levers above a 12-degree power lever angle switch, then they're automatically stowed.

You should be in the training department. That was an excellent explanation!

 

[Snaab]

Thanks! Btw, Olbermann is the man!

 

[Singlecoil]

Not saying that I think it's cool that they sound cocky.

But -- I think it is very bizarre that the manufacturer designed it like this.

They didn't. As previously stated, the switch automatically moves to flight as the power levers advance. The system was designed so that during ground ops, the spoilers stay down because the taxi switch is in taxi. As you advance the power levers on takeoff, the spoilers will still stay down because the power lever angle switch is tripped before the power levers automatically flip the taxi switch to flight.
I can't think of any reason why you would want to see if your spoilers all deploy in the ground mode before you takeoff. Are you going to land on an aircraft carrier? Is this a Dash-8 or an A-380? Why don't jet pilots check the ground mode operation of their spoilers prior to takeoff?
I guess you could argue that there is a manual lever to deploy the spoilers in a jet should the auto deploy fail, but do you ever absolutely need the spoiler to deploy in a Dash?

 

[FirstMate]

I can't think of any reason why you would want to see if your spoilers all deploy in the ground mode before you takeoff. Are you going to land on an aircraft carrier? Is this a Dash-8 or an A-380? Why don't jet pilots check the ground mode operation of their spoilers prior to takeoff?
I guess you could argue that there is a manual lever to deploy the spoilers in a jet should the auto deploy fail, but do you ever absolutely need the spoiler to deploy in a Dash?

I wouldn't think of this as a 'spoiler check' when switching from 'taxi' to flight'...the actual check is when the f/o does a flight control surfaces check (the usual up, down, letf right, etc) while watching the boards go up and down on the control surfaces display and watching for any control surface lights to illuminate). Not to mention, there is a t/o warning horn that will make you jump if any of the boards are deployed.

Only had limited experience on unimproved short fields on the dash, but there are some good videos out there that show -100's landing on ~2000' gravel runways in Canada where every foot probably counts.

 

[Quimby]

They didn't. As previously stated, the switch automatically moves to flight as the power levers advance. The system was designed so that during ground ops, the spoilers stay down because the taxi switch is in taxi. As you advance the power levers on takeoff, the spoilers will still stay down because the power lever angle switch is tripped before the power levers automatically flip the taxi switch to flight.
I can't think of any reason why you would want to see if your spoilers all deploy in the ground mode before you takeoff. Are you going to land on an aircraft carrier? Is this a Dash-8 or an A-380? Why don't jet pilots check the ground mode operation of their spoilers prior to takeoff?
I guess you could argue that there is a manual lever to deploy the spoilers in a jet should the auto deploy fail, but do you ever absolutely need the spoiler to deploy in a Dash?

Not a problem in a Dash 8-100/200, no hook required.

 

[Striptyler]

As it was said before, our spoilers are also flight control surfaces, so yes we do want to check to make sure they all work. Below 185kts we use all four boards, above that the aircraft transitions to the inboards only.

The flight/taxi switch is magnetically clutched, so it will move to the flight position automatically, but it is prudent to move it manually. It's not hard to do, and it takes 1 more mechanical system out of the failure loop. On a sub V1 cut, the last thing you want is for part of your control systems to "not" work, simply because a switch. Also, the Q seems to skid the nose wheel very easily, so removing all lift during landing helps maintain directional control, and the brakes stop like a wall when they have good weight on them - so i would assume that they are just doing their job of spoiling lift... nor so much slowing us down

 

[vectorvictor]

What else does the flight/taxi switch control?

What would happen if you tried to take off with the switch in the taxi position?

You can't. advancing the power levers releases the switch to flight.