B737ng Gear Access Door

[framer]

Hi,
Our FCOM says this about the Manual Extension Access Door:

Open – • manual landing gear extension is possible with landing gear lever in any position
• normal landing gear extension is still possible if hydraulic system A pressure is available
• landing gear retraction is disabled.
Closed – landing gear operate normally

Does anyone know how the opening of this door disable's retraction?
I am picturing a scenario where the aircraft gets airborne with said door open and I am not sure if the landing gear lever will move as normal ( ie does the door work through the lever-lock).
Any help appreciated,
Cheers

[otrex]

The lever will move and you will end up with three reds and three greens.

[de facto]

When you open the access door a valve makes sure all hydraulic lines go to the return line.
No more hydraulic for gear ops including if try be smart and cut off engine nr1

Ure FO or Captain?sorry its been a while since i wondered...

[RAT 5]

And I've always wondered why? This door is not on the Classics. What purpose does it serve?

[SlowAndSilly]

The door is there all right, but it doesn't inhibit the hydraulics on the NG as it does on the NG.

[propnut]

The door has a pin which keeps a microswitch (mounted under the panel)activated when closed. There a service letter to inspect the switch.This controls the PTU valve I think. I don't have my book with me.

Definitely need to ensure it's properly closed before t/off.

[Gas Bags]

Framer,

The access door has a microswitch that sends an electrical signal to the manual extend solenoid valve in the landing gear selector valve which moves the bypass valve in the selector valve to the bypass position connecting the hydraulic system to the return side. When you pull the manual extension handles in the cockpit they are mechanically connected to the landing gear uplocks, and you physically release the uplocks, allowing the gear to free fall to the down position. Without the bypass valve connecting the hydraulic fluid to the return side you would create a hydraulic lock when you manually release the gear to lower, as the fluid would not have anywhere to go.

The door switch has nothing to do with the lever lock. They are two very separate things. The lever lock solenoid is there to stop inadvertent repositioning of the gear lever in the wrong configuration (on ground - gear up). It is a physical barrier in the lever assy itself which is electrically powered to remove the lock when the aircraft is in the air to allow handle movement to the up position.