"A" pumps off for pushback -737MAX & NG
Thread Starter
Join Date: May 2006
Location: N/A
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
"A" pumps off for pushback -737MAX & NG
I'm curious as to how many operators out there turn the Hyd A pumps 'off' for pushback on the 737NG and MAX.
At my previous operator (737-800) we had all Elec and ED hyd pumps 'on' for pushback -- given the nose gear steering lockout pin, having the pumps on seemd a non-issue (also Boeing procedures).
At my current outfit (737Max), the sop is to turn both 'A' pumps off for pushback.
thoughts on this? Unnecessary? Surely this would result in excessive wear on the EDP?
This outfit used to fly the -200 many years ago, perhaps just cut and pasted procedures. Thoughts?
At my previous operator (737-800) we had all Elec and ED hyd pumps 'on' for pushback -- given the nose gear steering lockout pin, having the pumps on seemd a non-issue (also Boeing procedures).
At my current outfit (737Max), the sop is to turn both 'A' pumps off for pushback.
thoughts on this? Unnecessary? Surely this would result in excessive wear on the EDP?
This outfit used to fly the -200 many years ago, perhaps just cut and pasted procedures. Thoughts?
Join Date: Apr 2010
Location: IRS NAV ONLY
Posts: 1,230
Likes: 0
Received 0 Likes
on
0 Posts
Why would there be any wear on the EDP itself? The EDP keeps running regardless of whether the EDP switch is ON or OFF...
The "A pumps off" just adds an extra safety barrier in place, might be useful if operating to places with unreliable ground crew. Not in use at my airline currently...
The "A pumps off" just adds an extra safety barrier in place, might be useful if operating to places with unreliable ground crew. Not in use at my airline currently...
Join Date: Jan 1999
Location: north of barlu
Posts: 6,207
Likes: 0
Received 0 Likes
on
0 Posts
This is a throwback to the early B737-200 that had no steering lock out pin fitted to the nose leg , it’s all part of aviation’s inertia and a totally pointless procedure on the -800.
Without knowing the circumstances, my guess is that the operator in question had a close shave when a steering pin was either not fitted or malfunctioned, and the steering hydraulics became pressurised. So the SOP was probably changed to ensure the steering hydraulics remained unpressurised until the push crew had removed the tow-bar.
At one time we used to switch the nose-wheel steering off during pushback (Airbus), but in later years we we left it on, I think there was a software update.
At one time we used to switch the nose-wheel steering off during pushback (Airbus), but in later years we we left it on, I think there was a software update.
