737NG landing gear retraction
 

Hey fellas,

following question regarding 737NG gear retraction:

In a scenraio, you loose ENG 1 during T/O, so gear retraction during climb out is ensured through the LGTU. Then, while in-flight, you experience a loss of HYD SYS B.
Question: In this event, will the landing gear retract during an one ENG INOP go-around or not?
Looking through the books, I found alot of stuff about the LGTU and it's ability "... to raise the landing gear at the normal rate when system A engine-driven pump volume is lost." But no word about the non-normal combination of having experienced an ENG 1 failure and LOSS OF SYS B.
I guess what I'm trying to ask is: Does the SYS A ELEC pump provide enough fluid volume to opearte (retract) the landing gear?

Please enlighten me on this one. :ok:

The answer is in your post. The electric hydraulic pump it's not enough to raise the gear at a NORMAL rate, so the answer is yes, but slower than normal; in this scenario you might not be able to comply with the minimum climb gradient.
As far as I remember the volume ratio between the engine driven pump versus the electric one is 6 to 1.

FB,

thanks for your reply. I was suspecting the ELEC PUMP to be capable of retracting the gear (although at slower rates), but I could not find any written confirmation thereof.

By the way, the fluid volume ratios between ENG DRIVEN and ELEC Pumps that I came across was 4 to 1.

Again, thanks for the hint.

Out of my information:
EDP = 34 gpm
EMDP = 5,7 gpm