Dash 8-2/300 Pressurisation Question
 

Hi Guys,

Just going through some paperwork and came across a questions that had me stumped.

During takeoff the normal outflow valves begin to meter when the:
A. PSEU is in the flight mode.
B. Powerlevers are set 15 degrees above flight idle.
C. Bleed switches are turned on.
D. Power levers are set to climb.

I know this is a very ambiguous question but no where can I find reference in the ODM or flight manual to the actual way they come on. With power levers on take off in AUTO mode and past 15 degrees, the pressurisation system commands the aircraft's pressurisation system to pump up to 140 feet below. But there is another reference to having one or more bleed switches on before this will occur. In MAN mode this will not occur. So either answer B or C in theory would be correct but in the spirit of multiple choice, which would be "more correct"

Cheers,

SO :ok:

That´s a peculiar question...

The question seems to be strictly about the function of the outflow valves, not about the effect of their actions. As soon as the PLA exceeds 15°, they will start to work in the described manner, but what this results in depends on whether the bleeds are on or off during T/O. So I would rather lean to answer B here. If the question was about when the cabin will begin to pressurise as a result of this, I would think C might be better.

Now, I am not sure whether there is a supplement for a Bleeds on T/O on the -300 (it is a while ago since I last flew this type); my company did not apply it and bleeds were switched off during the Before T/O check and back on at 400´ AAL.

Cheers for that, I was leaning towards C originally but then spoke to a few other people about it and they just said that B is the "correct" choice regarding the power levers. Company has the supplement for bleeds on take off. Makes things so much cooler some days. Thanks again for the answer :ok: