Can Pilot Isolate Hydraulic Leak In Flight???
Thread Starter
Joined: Jun 2005
Posts: 182
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From: USA
Can Pilot Isolate Hydraulic Leak In Flight???
Hi,
Many aircraft are fitted with hydraulic shutoff valves. They are used by maintenance crew when needed. In case of hydraulic leakage (inflight) can the crew isolate this leak using these shutoff valves, so the remaining hydraulic can be used for the rest of the flight? If yes can you give examples and post some procedures from the manual (commercial aircraft).
Thank you. Feedback appreciated
Best regards
Many aircraft are fitted with hydraulic shutoff valves. They are used by maintenance crew when needed. In case of hydraulic leakage (inflight) can the crew isolate this leak using these shutoff valves, so the remaining hydraulic can be used for the rest of the flight? If yes can you give examples and post some procedures from the manual (commercial aircraft).
Thank you. Feedback appreciated
Best regards
Joined: Dec 1998
Posts: 3,038
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From: .
A/C are also fitted with hydraulic fuses, which when a certain flow rate is sensed (i.e. a leak) the fuse will isolate that system to prevent further hydraulic lose.
There is a previous thread on here with a lot more detail, you'll have tyo search for it though.
There is a previous thread on here with a lot more detail, you'll have tyo search for it though.
Joined: Nov 2002
Posts: 53
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From: uk
hyd leaks
Thought i had already answered this..........seems i was wrong.
Further to the hyd fuses.....the shut off valves (SOV) are for Maintenance perposes only and are usually only accessable from the outside of the A/C.
Further to the hyd fuses.....the shut off valves (SOV) are for Maintenance perposes only and are usually only accessable from the outside of the A/C.
Joined: Mar 2000
Posts: 8,571
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From: Arizona USA
It is interesting to note that, among the first generation of wide body civil jet transport aircraft, only one type had hydraulic fusing installed as standard equipment...
The Lockheed TriStar.
The rest had hydraulic fusing added after incidents/accidents.
Just like the autopilots used with the big Lockheed tri-motor, it was built to a slightly higher standard.
Entering my 25th year of operating this very fine aircraft, and altho the fleet numbers are reducing, it is still appreciated by many.
The Lockheed TriStar.
The rest had hydraulic fusing added after incidents/accidents.
Just like the autopilots used with the big Lockheed tri-motor, it was built to a slightly higher standard.
Entering my 25th year of operating this very fine aircraft, and altho the fleet numbers are reducing, it is still appreciated by many.
Thread Starter
Joined: Jun 2005
Posts: 182
Likes: 2
From: USA
Hi,
Thank you for your posts.
I know that aircraft are fitted with hydraulic fuses.
The raison why I asked this question because these valves are accessible from the cockpit and I think there are not inhibited in flight. So I was wondering if there are used on flight also in case of hydraulic leakage (otherwise I tought it may be simple to don't add electric motors, wires, switches, ...to these valves since there are intended to be used only on the ground?). In addition other shutoff valves are actuated only manually and accessible only the ground (like 2 maintenance valves for the main landing gears and 6 shutoff valves for the rudder..... in B737), so it is obvious that these valves will be for ground use only. That`s why I was asking if there are any procedure from the flight manual (as evidence or fact). If there are no procedures, it mean they are used only on ground. Are such valves installed on other aircrafts?
It will very helpful if someone can post hydraulic loss procedure (at least for B737, other aircraft are very welcome also) to see if these shutoff might be used or not in flight in such abnormal flight condition.
Thank you.
Best regards.
Thank you for your posts.
I know that aircraft are fitted with hydraulic fuses.
The raison why I asked this question because these valves are accessible from the cockpit and I think there are not inhibited in flight. So I was wondering if there are used on flight also in case of hydraulic leakage (otherwise I tought it may be simple to don't add electric motors, wires, switches, ...to these valves since there are intended to be used only on the ground?). In addition other shutoff valves are actuated only manually and accessible only the ground (like 2 maintenance valves for the main landing gears and 6 shutoff valves for the rudder..... in B737), so it is obvious that these valves will be for ground use only. That`s why I was asking if there are any procedure from the flight manual (as evidence or fact). If there are no procedures, it mean they are used only on ground. Are such valves installed on other aircrafts?
It will very helpful if someone can post hydraulic loss procedure (at least for B737, other aircraft are very welcome also) to see if these shutoff might be used or not in flight in such abnormal flight condition.
Thank you.
Best regards.
Joined: Dec 2005
Posts: 13
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From: Earth
You could be right Dan, but when my airline thinks of retiring their TriStars, they back away slowly, as they are paid for...and making to darn much money
That's a laugh, Air Universal only owns two aircraft! If they were to retire their TriStars they'd be out of business!
Some airline!
Joined: Mar 2000
Posts: 8,571
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From: Arizona USA
Only two...?
Only two aircraft, total, you say, CMFlieger?
How about the two 747's in the fleet now, or the next two to be delivered in the next two weeks...or the two after that?
Seems you're slightly behind the times, old boy....
How about the two 747's in the fleet now, or the next two to be delivered in the next two weeks...or the two after that?
Seems you're slightly behind the times, old boy....
Joined: Mar 2000
Posts: 8,571
Likes: 3
From: Arizona USA
<<The raison why I asked this question because these valves are accessible from the cockpit and I think there are not inhibited in flight. So I was wondering if there are used on flight also in case of hydraulic leakage (otherwise I tought it may be simple to don't add electric motors, wires, switches...>>
Certainly a reasonable question, AeroTech, and for the Lockheed Tri-motor, both EDP pump supply and shutoff valves are available in flight to cater for the fluid loss situation.
Thus, hydraulic EDP's can be isolated if flight, and in addition, air turbine motors (ATM's) are available for alternate hydraulic system pressurisation, together with power transfer units (PTU's) to restore system pressure as well.
In one particularly serious situation on an SV aircraft, on which a tire/wheel rupture rendered three of four hydraulic systems without adequate system fluid, hydraulic fusing was able to retain enough fluid available to enable, in the one remaining system, a safe landing to be accomplished.
As the only remaining system was system 'D', the aircraft was landed by the First Officer, and this ain't easy.
This scenario was trained for at each PC, and it certainly proved its value.
Certainly one (of many reasons) to respect the abilities of the First Officer, to say the least....
I am sure that others can describe the various hydraulic system enhancements on more modern aircraft.
TriStar...an oldie, but a goody.
Certainly a reasonable question, AeroTech, and for the Lockheed Tri-motor, both EDP pump supply and shutoff valves are available in flight to cater for the fluid loss situation.
Thus, hydraulic EDP's can be isolated if flight, and in addition, air turbine motors (ATM's) are available for alternate hydraulic system pressurisation, together with power transfer units (PTU's) to restore system pressure as well.
In one particularly serious situation on an SV aircraft, on which a tire/wheel rupture rendered three of four hydraulic systems without adequate system fluid, hydraulic fusing was able to retain enough fluid available to enable, in the one remaining system, a safe landing to be accomplished.
As the only remaining system was system 'D', the aircraft was landed by the First Officer, and this ain't easy.
This scenario was trained for at each PC, and it certainly proved its value.
Certainly one (of many reasons) to respect the abilities of the First Officer, to say the least....
I am sure that others can describe the various hydraulic system enhancements on more modern aircraft.
TriStar...an oldie, but a goody.
