Dash 8 question

[RedDogC130]

When a Dash 8 is configured for takeoff...are there spoliers or some kind of tabs on the top of the wings that stay up for any reason?

 

[Sig]

Yes.

But if they stay up as power is set, it should get awful danged noisy up front and an RTO is about to happen.

It is normal. It's the Trash8 version of lift dump on landing, as you're seeing the roll spoilers extend with WOW and "flight mode" before takeoff.

 

[T-prop]

Spoilers armed+WOW+power to idle=spoilers deploy

Kinda looks goofy. When power is added for takeoff the spoilers retract.

 

[FirstMate]

Note: -200 and -300 models are the exception

 

[Singlecoil]

The system is designed so that as you advance the power levers for takeoff, the spoilers will shift from taxi mode to flight mode automatically. However, for some reason just about everybody wants to manually position the switch into flight mode, extend the spoilers, then advance the power levers for takeoff and have them retract. It never made any sense to me. As the system was designed, they would stay retracted until WOW on landing and then deploy.

 

[T-prop]

The system is designed so that as you advance the power levers for takeoff, the spoilers will shift from taxi mode to flight mode automatically. However, for some reason just about everybody wants to manually position the switch into flight mode, extend the spoilers, then advance the power levers for takeoff and have them retract. It never made any sense to me. As the system was designed, they would stay retracted until WOW on landing and then deploy.

Probably due to some program manager's fear of trusting anything automatic.

 

[NCFlyer]

However, for some reason just about everybody wants to manually position the switch into flight mode, extend the spoilers, then advance the power levers for takeoff and have them retract. It never made any sense to me. As the system was designed, they would stay retracted until WOW on landing and then deploy.

Not wants to, but required to by SOP & checklist.

In fact for years PDT operated just the way you suggest. Leave the flight/taxi switch in the taxi mode keeping the spoilers retracted, upon power lever advancement the flight/taxi switch would "snap" in to the flight position. It was done that way for years to reduce the total number of cycles on the spoiler actuators.

However some higher up in YYZ decided that PDT was operating the system contrary to the way it was designed and our POI insisted that we return to the previous/current way of utilizing the flight/taxi switch.

 

[zasca]

Every few months some guy waiting in line will make a comment about them when we are in position and hold. Live and learn.

 

[Hikoushi]

The reason you (should) manually set the spoilers switch to "FLIGHT" and cycle the spoilers prior to takeoff power application is to verify that the spoilers do, in fact, all deploy symmetrically in the ground mode in the event of a subsequent takeoff abort. If you have an assymetric spoiler deployment during a rejected takeoff, stopping distance and directional control will both be adversely affected. Nice to know stuff if you are about to take off fully loaded from a 2900 foot strip on an 85 degree day.

 

[check6]

The Q400 works the same way.