747-400 Insulation Valves
Thread Starter
Joined: Jul 2007
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From: USA
747-400 Insulation Valves
Need some info regarding the 744.
Are Left ISLN and R ISLN switches ever used or does the queen do this automatically. I recently read this was part of engine start procedure, turn left off for starting 3-4 and right off for starting 1-2. Never seen this under the engine start in a 744 checklist and never heard of them being used.
Some insight would be great!
Leo
Are Left ISLN and R ISLN switches ever used or does the queen do this automatically. I recently read this was part of engine start procedure, turn left off for starting 3-4 and right off for starting 1-2. Never seen this under the engine start in a 744 checklist and never heard of them being used.
Some insight would be great!
Leo
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From: USA
On the overhead of the 400 just under the pack switches to the left of pack 2 is the L ISLN isolation switch and to the right is the R ISLN switch. Thats what i mean. So what is their function? and are they really used during engine start and how?
Leo
Leo
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From: South of Watford
If there is LOW air pressure supplied by the APU or ground air sources,[for example at hot and high airfields such as Bogota or Mexico City], closing the offside ISLN valve can assist in maintaining air pressure for starting as there will be less opportunity for the air to leak away. (only one side of the air ducts will be perssurised) 
Last edited by Sir Richard; 15th October 2008 at 04:33. Reason: Additional Information
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From: UTC +8
Take this guy's B744 quiz: Boeing 747-400 Stuff - Flying the Boeing 747-400
Joined: Jun 2005
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From: AEP
The correct name is "wing isolation valve" -
There is a L and a R wing isolation valve.
Would be nice to call things by their right name...
xxx
Happy contrails
Also...
What is the "queen" in the original question...?
There is a L and a R wing isolation valve.
Would be nice to call things by their right name...
xxx
Happy contrails
Also...
What is the "queen" in the original question...?
Last edited by BelArgUSA; 15th October 2008 at 08:04.
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From: Korea
The isolation valve switches are used only it a bleed duct leak in L, C, or R duct occurs ( to isolate the leaking duct) or if a APU to pack take off has to be performed; the all 3 ducts are isolated, pack 1 and 3 off and pack 2 is supplied from the APU.
Source: Boeing QRH and OM vol.1, supplemaentary procedures.
P.S.: they are called "isolation valve switch" only, at least from Boeing, the manufacturer.
Cheers
Source: Boeing QRH and OM vol.1, supplemaentary procedures.
P.S.: they are called "isolation valve switch" only, at least from Boeing, the manufacturer.
Cheers
Joined: Jan 2008
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From: London
BelArgUSA - Wow Give the 16 year old kid a break..
And as the above poster stated if your operating outa somewhere like Quito, Bogota or very hot conditions you can perform a Pack to APU departure to give you a little extra margin, Packs 1 + 3 off and Isolation valves closed.
And as the above poster stated if your operating outa somewhere like Quito, Bogota or very hot conditions you can perform a Pack to APU departure to give you a little extra margin, Packs 1 + 3 off and Isolation valves closed.
Joined: Apr 2006
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From: EDDF
Hi you "insulation valve specialists" 
If a ground air start has to be performed because APU is INOP there is a nice "trick"
if you are in MEX or similar place where the air is thin and the GND air equipment is sometimes really weak the ducktpressure is too low. maybe only 9psi
Remember that the demandpumps 1 and 4 are running on bleed, so if you turn them off helps a lot. its like closing a big hole in the duckt...
etc. Starting engine 3 and switching Dem. Pum 1 off and R ISLN makes your ductpressure rise from 9 to 25
its not an official procedure but might make your day....
Lars
If a ground air start has to be performed because APU is INOP there is a nice "trick"
if you are in MEX or similar place where the air is thin and the GND air equipment is sometimes really weak the ducktpressure is too low. maybe only 9psi
Remember that the demandpumps 1 and 4 are running on bleed, so if you turn them off helps a lot. its like closing a big hole in the duckt...
etc. Starting engine 3 and switching Dem. Pum 1 off and R ISLN makes your ductpressure rise from 9 to 25
its not an official procedure but might make your day....
Lars
Last edited by warmkiter; 15th October 2008 at 13:24.
Thread Starter
Joined: Jul 2007
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From: USA
Thanks for the great answers guys! Makes perfect sence now.
BelArgUSA
No offense taken, i was simply convinced that the 747 would also be known as the "Queen" for those of you who are lucky enough to fly such a great plane
Cheers
BelArgUSA
No offense taken, i was simply convinced that the 747 would also be known as the "Queen" for those of you who are lucky enough to fly such a great plane
Cheers
Joined: Feb 2004
Posts: 1,410
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From: Australia
ducktpressure
Remember that the demandpumps 1 and 4 are running on bleed, so if you turn them off helps a lot. its like closing a big hole in the duckt...
etc. Starting engine 3 and switching Dem. Pum 1 off and R ISLN makes your ductpressure rise from 9 to 25
its not an official procedure but might make your day....
etc. Starting engine 3 and switching Dem. Pum 1 off and R ISLN makes your ductpressure rise from 9 to 25
its not an official procedure but might make your day....
Didn't realise these aircraft had such leaky ducts.
"Queen"... popularized by the Microsoft Flight Simulator community
Thread Starter
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From: USA
"Queen"... popularized by the Microsoft Flight Simulator community
Known as the "Queen of the Skies," the 747 has carried 3.6 billion people more than 35 billion nautical miles (64.8 billion km) -- equivalent to 74,000 round trips to the Moon -- since entering service in 1970.
Leo
Joined: Jul 2008
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From: CET
Additionally:
For ground air start : only PART of the supplementary RR procedures :
Left ISLN Valve ............................................................ .............. CLOSE
Close Left Isolation valve to reduce duct leakage.
Duct pressure ............................................................ .............. OBSERVE
Observe duct pressure is minimum of 30 PSI (less 1 PSI per 1,000
feet of pressure altitude).
Autostart Switch ............................................................ ....................OFF
Engine No. 3 ............................................................ ....................START
Accomplish manual engine start etc...
On 744 there's usually plenty of ductpressure hot and high, if the APU runs normally, eg LTX: elev 9,200' ISA +20, our regular stop.
ss
For ground air start : only PART of the supplementary RR procedures :
Left ISLN Valve ............................................................ .............. CLOSE
Close Left Isolation valve to reduce duct leakage.
Duct pressure ............................................................ .............. OBSERVE
Observe duct pressure is minimum of 30 PSI (less 1 PSI per 1,000
feet of pressure altitude).
Autostart Switch ............................................................ ....................OFF
Engine No. 3 ............................................................ ....................START
Accomplish manual engine start etc...
On 744 there's usually plenty of ductpressure hot and high, if the APU runs normally, eg LTX: elev 9,200' ISA +20, our regular stop.
ss
Joined: Apr 2006
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From: EDDF
to demandpumpers and groundairstarters and insulationswitchers
to strawberry boy and NSEU
to my favorite strawberry type
if the APU is delivering "plenty of ducktpressure" you dont have to perform a ground air start. its performed when the APU does´nt deliver pressure
to NSEU
as we know the Demand pumps are AUX/ AUTO for engine start. 1,2 and 3 are AUTO and 4 is AUX
you asked why do i run the Demandpumps.its MAGIC! because the selector is in AUTO. It stands for AUTOMATIC
.they run by them self. the conditions for demand pumps to jump in are
Respective Engine Driven Pump output pressure is low or respective Fuel Control Switch in CUTOFF
when hot and high and especially on ground air you are starting one engine at a time, its usually 2 or 3. ALL conditions are met for demand pump auto function. the number 1 demand pump runs magically by it self. this reduces "ductpressure"
unless you turn number 1 demand pump selector to OFF instead of AUTO.
try it next time. if the APU is running normally, maybe the rise in PSI is not so significant, but if you are on a cart you will see the difference.
dont know if the FS2000 support this feature for the simmers
happy enginestarts
Lars
to my favorite strawberry type
if the APU is delivering "plenty of ducktpressure" you dont have to perform a ground air start. its performed when the APU does´nt deliver pressure
to NSEU
as we know the Demand pumps are AUX/ AUTO for engine start. 1,2 and 3 are AUTO and 4 is AUX
you asked why do i run the Demandpumps.its MAGIC! because the selector is in AUTO. It stands for AUTOMATIC
.they run by them self. the conditions for demand pumps to jump in areRespective Engine Driven Pump output pressure is low or respective Fuel Control Switch in CUTOFF
when hot and high and especially on ground air you are starting one engine at a time, its usually 2 or 3. ALL conditions are met for demand pump auto function. the number 1 demand pump runs magically by it self. this reduces "ductpressure"
unless you turn number 1 demand pump selector to OFF instead of AUTO.
try it next time. if the APU is running normally, maybe the rise in PSI is not so significant, but if you are on a cart you will see the difference.
dont know if the FS2000 support this feature for the simmers
happy enginestarts
Lars
Joined: Jul 2008
Posts: 19
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From: CET
To w....r :
Quote : "to my favorite strawberry type
if the APU is delivering "plenty of ducktpressure" you dont have to perform a ground air start. its performed when the APU does´nt deliver pressure"
Never said groundair is to enhance ductpressure when APU in use, was the other bloke.
Secondly : check the spelling on my previous post and see where you go wrong...
Thirdly : B-HKD was only asking, when to twiddle with the knobs. Suggest you check who writes what...
ss
Quote : "to my favorite strawberry type
if the APU is delivering "plenty of ducktpressure" you dont have to perform a ground air start. its performed when the APU does´nt deliver pressure"
Never said groundair is to enhance ductpressure when APU in use, was the other bloke.
Secondly : check the spelling on my previous post and see where you go wrong...
Thirdly : B-HKD was only asking, when to twiddle with the knobs. Suggest you check who writes what...
ss
