Hydraulic pumps- on or off during turnaround??
Thread Starter
Joined: Oct 1999
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From: europe
Hydraulic pumps- on or off during turnaround??
Does anyone have experience at leaving hydraluic pumps on during a turn around on B757 B767 acft? I believe it is sometimes done on B737 acft?
What about fuel pumps during a turn around?
Turn around = less than one hour...
Can you pls advise your experiences? thks!
What about fuel pumps during a turn around?
Turn around = less than one hour...
Can you pls advise your experiences? thks!
Joined: Oct 2001
Posts: 308
Likes: 1
From: Australia.
We've been advised by our technical dept that the flight controls can not be damaged by wind. Apparently there is enough dampening effects in the control system to prevent that from happening.
However because the B737 has Manual Reversion (direct cable link between the control wheel/column and ailerons/elevators, it's good to leave the hydraulics pressurised during turn arounds in windy conditions to prevent the control column from moving about between your legs. (The ailerons aren't usually the problem, it's the elevator flapping up and down with tailwinds causing the control column to move backward and forwards that's the problem.)
If it's the last flight of the day and there's a moderate wind blowing from behind the aircraft, I just leave it to the engineers to shut the hydraulics down after they've done their overnight checks. If I was securing the aircraft at a non-maintenance airport and it was windy, I would wait until I was out of my seat before shutting the hydraulics off.
However because the B737 has Manual Reversion (direct cable link between the control wheel/column and ailerons/elevators, it's good to leave the hydraulics pressurised during turn arounds in windy conditions to prevent the control column from moving about between your legs. (The ailerons aren't usually the problem, it's the elevator flapping up and down with tailwinds causing the control column to move backward and forwards that's the problem.)
If it's the last flight of the day and there's a moderate wind blowing from behind the aircraft, I just leave it to the engineers to shut the hydraulics down after they've done their overnight checks. If I was securing the aircraft at a non-maintenance airport and it was windy, I would wait until I was out of my seat before shutting the hydraulics off.
Joined: Jan 2008
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From: All at sea
By keeping hydraulic pumps on you have a better chance of spotting any leaks on the walkaround and you reduce risk to ground personnel (slats droop with them off, so you then have the hassle of getting a clearance to re-pressurize). Fuel pumps? Engineers tell me they don't seem to have any less life if they run continuously, so you may as well leave them on (main tanks only!). One less thing to forget at start-up. KISS. I am talking B737 classic - no idea for 767, but am guessing same basic reasons for leaving it all in go position.
Joined: Feb 2008
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From: Wingham NSW Australia
Hydraulics pressurised - Fuel system pressurised ???
As a retired F/E I find it interesting that you guys would even suggest leaving the hydraulics pressurised and the fuel pumps running during ground time. Fuel pumps do have a finite life and running them whilst they are not feeding an engine is certainly not good practice in my view. Some of you may recall a Phillipine Airlines B737 burning on the ground in the late '80s at Manilla. Running CWT pumps without fuel in the tank was cited as the cause. As for hydraulics being kept pressurised during turnarounds it is simply dangerous. I am darn sure there is a very good reason for getting a clearance from your friendly ground engineer before pressurising hydraulics whilst ground personnel are moving around the aircraft. I know I wouldn't be sticking any part of my body in a wheel well or near any hydraulically powered component without knowing that (a) the system is depressurised or (b) if it was pressurised I was in contact with the cockpit. Quote: "One less thing to forget at start-up" in relation to these issues. You have got to be joking! 
Joined: Dec 2007
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From: I know EXACTLY where I am..
Old feller, concur
On my outfit, hydraulics depressurized.
I hate to think of a ground engineer putting a screwdriver to some component, only to have it propelled out of his hand and through his skull by 3000psi. (and, to add insult to injury, being hosed down by fluid, although he might not care anymore)
yuk. OORW
I hate to think of a ground engineer putting a screwdriver to some component, only to have it propelled out of his hand and through his skull by 3000psi. (and, to add insult to injury, being hosed down by fluid, although he might not care anymore)
yuk. OORW
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
On groundstays with less than 60 minutes planned hydraulics and fuel pumps (main, not center) have to stay on as per Boeing recommendation (737 classic and NG). Our engineers know that and they are not allowed to just walk up to the aircraft and stick a screwdriver into parts without visiting us chaps in the front office first and make sure everything is as they want it and we are briefed as how systems have to be configured during whatever maintenance they do. Otherwise the risk that we don't even notice they're there is way too big.
Joined: Jul 2007
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From: outside
E145 hydraulics OFF during turnaround.
We have a gustlock for the elevator so no worries there, but the rudder and ailerons are free to flap about. In my experience however, they dont. Both are reasonably stiff in what is essentially the manual reversion mode.
Of course, we should all be following the company Ops Man and FCOM when it comes to this
We have a gustlock for the elevator so no worries there, but the rudder and ailerons are free to flap about. In my experience however, they dont. Both are reasonably stiff in what is essentially the manual reversion mode.
Of course, we should all be following the company Ops Man and FCOM when it comes to this
Joined: Dec 2007
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From: I know EXACTLY where I am..
Does Boeing give a reason as to why fuel and hydraulics should remain pressurized? As stated previously in the thread, possibly to stop control surfaces flapping in the wind? (Although ive never seen that on the 'bus)
OORW
OORW
Joined: Oct 2004
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From: oop north
Blue belly ,i cannot really see any good reason why you would wish to have the boost pumps and hyd pumps running during a turnround, whats the point ? as well as being a major safety issue theres wear and tear on the pumps, plus extra load on the APU to consider, (not to mention the bloody racket those AC hyd pumps make).
We look after a fair few 757/767 operators apart from our own A/C and ive never known any crews to leave the pumps on as a matter of routine
We look after a fair few 757/767 operators apart from our own A/C and ive never known any crews to leave the pumps on as a matter of routine
Joined: Feb 2008
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From: Wingham NSW Australia
Pumps on during turnaround
Denti, I would be interested to see a copy of the Boeing recommendation that hydraulics be kept pressurised and main tank fuel pumps be kept running during turnarounds of less than 60 minutes duration. Frankly, I believe it is a load of rubbish and as Smudgethecat asks, what reason is given by Boeing?
Joined: May 2008
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From: United Kingdom
On groundstays with less than 60 minutes planned hydraulics and fuel pumps (main, not center) have to stay on as per Boeing recommendation (737 classic and NG).
Joined: Jul 2000
Posts: 942
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From: Thailand
Final answer.
Taken directly from the Boeing FCOM
Very clearly, Hydraulic and Fuel pumps remain ON during transit stops.
Centre tank pumps will remain ON if fuel is present.
737 Flight Crew Operations Manual
Normal Procedures -
Amplified Procedures
Copyright © The Boeing Company. See title page for details.
1 Jun 2007
Transit Shutdown Procedure - Pilot Flying
After the airplane has come to a complete stop, perform the following
actions:
Parking brake ............................................................ ................... Set
Parking brake warning light – Illuminated
Electrical ............................................................ ..................... On___
Verify APU powering busses. If APU is not to be used, connect
external power.
Start levers...................................................... ........................CUTOFF
If possible, operate the engines at idle for three minutes prior to
shutdown to thermally stabilize the engine hot sections. Operating
times at or near idle, such as taxiing before shutdown, are applicable
to this three–minute period. If operational requirements dictate, the
engines may be shut down with a one–minute cooling period.
FASTEN BELTS switch ............................................................ ....... OFF
PA (captain) ..................................... “DISARM SLIDES AND OPEN DOORS”
ANTI COLLISION light switch .......................................................... OFF
At 20% N2 place the ANTI-COLLISION light switch OFF.
WING and ENGINE ANTI–ICE switches .............................................. OFF
Air conditioning PACK switches...............................................As required
APU fuel flow is reduced with both pack switches off.
ISOLATION VALVE switch – OPEN
APU BLEED air switch...................................................... ............... OFF
Exterior lights ............................................................ .........As required
Cockpit door........................................................ .....................Unlock
The PF calls “TRANSIT SHUTDOWN CHECKLIST.”
Very clearly, Hydraulic and Fuel pumps remain ON during transit stops.
Centre tank pumps will remain ON if fuel is present.
737 Flight Crew Operations Manual
Normal Procedures -
Amplified Procedures
Copyright © The Boeing Company. See title page for details.
1 Jun 2007
Transit Shutdown Procedure - Pilot Flying
After the airplane has come to a complete stop, perform the following
actions:
Parking brake ............................................................ ................... Set
Parking brake warning light – Illuminated
Electrical ............................................................ ..................... On___
Verify APU powering busses. If APU is not to be used, connect
external power.
Start levers...................................................... ........................CUTOFF
If possible, operate the engines at idle for three minutes prior to
shutdown to thermally stabilize the engine hot sections. Operating
times at or near idle, such as taxiing before shutdown, are applicable
to this three–minute period. If operational requirements dictate, the
engines may be shut down with a one–minute cooling period.
FASTEN BELTS switch ............................................................ ....... OFF
PA (captain) ..................................... “DISARM SLIDES AND OPEN DOORS”
ANTI COLLISION light switch .......................................................... OFF
At 20% N2 place the ANTI-COLLISION light switch OFF.
WING and ENGINE ANTI–ICE switches .............................................. OFF
Air conditioning PACK switches...............................................As required
APU fuel flow is reduced with both pack switches off.
ISOLATION VALVE switch – OPEN
APU BLEED air switch...................................................... ............... OFF
Exterior lights ............................................................ .........As required
Cockpit door........................................................ .....................Unlock
The PF calls “TRANSIT SHUTDOWN CHECKLIST.”
Joined: Jul 2000
Posts: 942
Likes: 0
From: Thailand
To clarify
Just to clarify, to those of you who will say that the above post doesn't specifically say anything about the pumps in question, I add the following which should answer the questions raised. It also answers the question regarding HYD pumps in windy/gusty conditions.
737 Flight Crew Operations Manual
Normal Procedures -
Amplified Procedures
Copyright © The Boeing Company. See title page for details.
1 June 2007
Shutdown Procedure - Pilot Flying
After the airplane has come to a complete stop, perform the following
actions:
Parking brake ............................................................ .................... Set
Parking brake warning light – Illuminated
Electrical ............................................................ ..................... On___
Verify APU powering busses. If APU is not to be used, connect
external power.
Start levers ............................................................ ................CUTOFF
If possible, after high thrust operation, including reverse thrust, run
the engines at or near idle for three minutes before shutdown to cool
the engine hot sections. Time at or near idle, such as taxiing before
shutdown, is applicable to this three minute period. If needed, the
engines may be shut down with a one minute cooling period. Routine
cool down times of less than three minutes before shutdown are not
recommended.
FASTEN BELTS switch...................................................... ...............OFF
PA (captain) .........................“DISARM SLIDES AND OPEN DOORS”
ANTI COLLISION light switch ...........................................................O FF
At 20% N2 place the ANTI-COLLISION light switch OFF.
FUEL PUMP switches ............................................................ ..........OFF
CAUTION: Do not operate the center tank fuel pumps with the
flight deck unattended.
GALLEY power switch (as installed) ......................................... As required
WINDOW HEAT switches ............................................................ .....OFF
WING and ENGINE ANTI–ICE switches ................................................OFF
ELECTRIC HYDRAULIC PUMP switches ............................................... OFF
CAUTION: To avoid unwanted control column movement during
gusty tailwind conditions, leave the B electric
hydraulic pump switch ON until completing the
Secure procedure.
RECIRCULATION FAN switches ........................................................AUTO
Air conditioning PACK switches.................................................As required
APU fuel flow is reduced with both pack switches off.
ISOLATION VALVE switch – OPEN
Engine BLEED air switches ............................................................ .....ON
APU BLEED air switch...................................................... ................ OFF
Exterior lights ............................................................ ..........As required
AUTO BRAKE select switch ............................................................ .. OFF
Flight deck lights ............................................................ .......As desired
SPEED BRAKE lever ............................................................ DOWN detent
Parking brake ............................................................ ....................SET
It is not necessary to release the parking brake after the chocks are in
position, unless the captain is of the opinion that the brakes are
unusually hot, then only for 5 to 10 seconds and reset the parking
brake. Inform engineering/services if hot brakes are suspected.
Cabin door ............................................................ .....................Unlock
The PF calls “SHUTDOWN CHECKLIST.”
The PM accomplishes the SHUTDOWN checklist.
CAUTION: To avoid the possibility of shoulder harness buckles
snapping back and pulling or damaging circuit
breakers, hold both straps before releasing and then
allow straps to retract slowly to the stowed position.
IRS mode selectors................................................... ...................................OFF
CAB/UTIL, IFE
GALLEY POWER switches (as installed) ................................... As required
EMERGENCY EXIT lights switch ........................................................OFF
Air conditioning PACK switches ........................................................OFF
Trim air switch ............................................................ .................OFF
APU switch/GROUND POWER switch..................................................OFF
If APU was operating:
Delay approximately 2 minutes after the APU GEN OFF BUS
light extinguishes before placing the BATTERY switch OFF.
BATTERY switch ............................................................ ..............OFF
The PF calls “SECURE CHECKLIST.”
The PM accomplishes the SECURE checklist.
End of discussion, or is it?
737 Flight Crew Operations Manual
Normal Procedures -
Amplified Procedures
Copyright © The Boeing Company. See title page for details.
1 June 2007
Shutdown Procedure - Pilot Flying
After the airplane has come to a complete stop, perform the following
actions:
Parking brake ............................................................ .................... Set
Parking brake warning light – Illuminated
Electrical ............................................................ ..................... On___
Verify APU powering busses. If APU is not to be used, connect
external power.
Start levers ............................................................ ................CUTOFF
If possible, after high thrust operation, including reverse thrust, run
the engines at or near idle for three minutes before shutdown to cool
the engine hot sections. Time at or near idle, such as taxiing before
shutdown, is applicable to this three minute period. If needed, the
engines may be shut down with a one minute cooling period. Routine
cool down times of less than three minutes before shutdown are not
recommended.
FASTEN BELTS switch...................................................... ...............OFF
PA (captain) .........................“DISARM SLIDES AND OPEN DOORS”
ANTI COLLISION light switch ...........................................................O FF
At 20% N2 place the ANTI-COLLISION light switch OFF.
FUEL PUMP switches ............................................................ ..........OFF
CAUTION: Do not operate the center tank fuel pumps with the
flight deck unattended.
GALLEY power switch (as installed) ......................................... As required
WINDOW HEAT switches ............................................................ .....OFF
WING and ENGINE ANTI–ICE switches ................................................OFF
ELECTRIC HYDRAULIC PUMP switches ............................................... OFF
CAUTION: To avoid unwanted control column movement during
gusty tailwind conditions, leave the B electric
hydraulic pump switch ON until completing the
Secure procedure.
RECIRCULATION FAN switches ........................................................AUTO
Air conditioning PACK switches.................................................As required
APU fuel flow is reduced with both pack switches off.
ISOLATION VALVE switch – OPEN
Engine BLEED air switches ............................................................ .....ON
APU BLEED air switch...................................................... ................ OFF
Exterior lights ............................................................ ..........As required
AUTO BRAKE select switch ............................................................ .. OFF
Flight deck lights ............................................................ .......As desired
SPEED BRAKE lever ............................................................ DOWN detent
Parking brake ............................................................ ....................SET
It is not necessary to release the parking brake after the chocks are in
position, unless the captain is of the opinion that the brakes are
unusually hot, then only for 5 to 10 seconds and reset the parking
brake. Inform engineering/services if hot brakes are suspected.
Cabin door ............................................................ .....................Unlock
The PF calls “SHUTDOWN CHECKLIST.”
The PM accomplishes the SHUTDOWN checklist.
CAUTION: To avoid the possibility of shoulder harness buckles
snapping back and pulling or damaging circuit
breakers, hold both straps before releasing and then
allow straps to retract slowly to the stowed position.
IRS mode selectors................................................... ...................................OFF
CAB/UTIL, IFE
GALLEY POWER switches (as installed) ................................... As required
EMERGENCY EXIT lights switch ........................................................OFF
Air conditioning PACK switches ........................................................OFF
Trim air switch ............................................................ .................OFF
APU switch/GROUND POWER switch..................................................OFF
If APU was operating:
Delay approximately 2 minutes after the APU GEN OFF BUS
light extinguishes before placing the BATTERY switch OFF.
BATTERY switch ............................................................ ..............OFF
The PF calls “SECURE CHECKLIST.”
The PM accomplishes the SECURE checklist.
End of discussion, or is it?
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
Main, not center. Is this poster referring to the main fuel pump? If so, why the main and not the centre?
Thread Starter
Joined: Oct 1999
Posts: 61
Likes: 0
From: europe
we are looking at revising our flight procedures and I just was interrested to know what the standard procedures are from other airlines who also operate 757/767.. and of course 737s.
thks for your replies- keep em coming!
thks for your replies- keep em coming!