Manual Gear extension - B737

[owl-attack]

Hello guys

MRG book says with the manual gear extension door open, the NWS is INOP, so close the door Manual gear extension door for the ALTN NWS to work

So this is written in MRG. I am surprised that in the QRH, Manual gear extension NNC doesn't warn the crew that if the manual gear extension door is left open the NWS will be INOP, neither does the FCOM

Why did Boeing do this, do they expect pilots to figure it out by themselves?

Thanks

P.S: if any one could help me by giving answers to my previous thread, i would be grateful (i've got zero replies) Link given below

http://www.pprune.org/tech-log/572575-b737-air-conditioning-standby-pack-average-temperautre.html

[STBYRUD]

After flipping through the AMM for a while I see no reason why the manual extension door with its associated solenoid controlling the bypass valve prevents operation of the nose wheel steering. It only redirects up pressure to the return lines to permit manual extension with the gear lever in any position (unlike on the older 737s).
The manual extension system supplies electrical signals to a
solenoid valve in the selector valve. The solenoid valve controls
hydraulic pressure to a pressure operated bypass valve. When
the bypass valve is in the bypass position, landing gear up
pressure is ported around the slide valve to return. This
prevents a hydraulic lock in the landing gear system if the slide
valve jams.
However, if you leave the gear lever in Off or Up, then you will indeed not have nose wheel steering, but as you know that is in the checklist.

[owl-attack]

Thank you for your reply

I wonder what would could be the reason. Might have to email the author and request explanation

[STBYRUD]

I just checked my MRG, I am not sure how he meant that sentence. Closing it is a good idea in any case... Especially for the unlikely case when you want to retract your gear again :D

[EW73]

Though I thought it was common knowledge, the only direct effect of leaving the manual gear extension door not fully closed is that you cannot retract your gear at all. As has been mentioned earlier, that door switch opens a port within the gear selector valve that prevents a hydraulic lock when manually lowering the gear!
With that port open, no gear retraction possible!
NWS pressure is supplied by gear down supply pressure, so that must be available on the ground, which it is via the gear being selected down!