Ryanair single pack operations?
Thread Starter
Joined: Jul 2003
Posts: 8
Likes: 1
From: U.K.
Ryanair single pack operations?
On a recent flight with Ryanair, I noticed that the entire flight was done with one Pack switched off until descent, at which point both packs were operating. I guess there is a fuel savings in operating in this fashion. I was wondering if it is normal for Ryanair to fly with just one pack whenever operationally practical to capitalize on the fuel savings, or would this have been a one-of for some other reason?
Joined: Oct 2001
Posts: 3,832
Likes: 115
From: UK
Since you know that the flight was conducted with one pack switched off until the descent, then you must have been on the flight deck!
So why did you not ask the operating crew for the answer?
For what it is worth, flying from UK to LAX on the DC-10 with one pack switched off used to save around 2000 lbs of fuel.
So why did you not ask the operating crew for the answer?
For what it is worth, flying from UK to LAX on the DC-10 with one pack switched off used to save around 2000 lbs of fuel.
Joined: Mar 2000
Posts: 21
Likes: 0
From: south of BEXAL
I don’t know if the 737 has flight level restriction for a one pack operation, should there be one, it would be a waste of time and effort.
If you noticed a change of air flow noise at the start of descent it would have been the change of bleed valves from low pressure to high pressure valves at the selection of idle thrust.
If you noticed a change of air flow noise at the start of descent it would have been the change of bleed valves from low pressure to high pressure valves at the selection of idle thrust.
FAO Danny
Joined: May 2000
Posts: 214
Likes: 0
From: UK
On the ground the NG is supposed to have 2 packs running for air con. Switching one off (the other remaining in AUTO) increases APU fuel burn from about 220lb/hr to 270lb/hr (approx figures) and increases APU EGT by about 100deg. due to the remaining pack reverting to high flow.
Since switching a pack off in flight will cause the remaining pack to go to high flow too, and following the logic demonstrated by the APU, I'd guess that the engines wil use more fuel too to power one pack rather than 2.
The only sensible reason I can imagine for operating a single pack is a failure in the other.
The FL250 restriction is in the MEL, but not the QRH or Part B limitations, so descending following an inflight pack failure is a matter of airmanship rather than procedure.
(Edited for bad typing!)
Since switching a pack off in flight will cause the remaining pack to go to high flow too, and following the logic demonstrated by the APU, I'd guess that the engines wil use more fuel too to power one pack rather than 2.
The only sensible reason I can imagine for operating a single pack is a failure in the other.
The FL250 restriction is in the MEL, but not the QRH or Part B limitations, so descending following an inflight pack failure is a matter of airmanship rather than procedure.
(Edited for bad typing!)
Last edited by Whippersnapper; 28th July 2004 at 09:15.
Joined: Apr 2002
Posts: 1,052
Likes: 8
From: Put out to graze
If the MEL gives a restriction of FL250 it is not an airmanship consideration but a mandatory Operational Procedure.
Ain't no choice in the matter!
Its a consideration relating to the ROD achieved following a failure of the remaining pack. Airbus I seem to remember is FL310.
Ain't no choice in the matter!
Its a consideration relating to the ROD achieved following a failure of the remaining pack. Airbus I seem to remember is FL310.
Joined: May 2000
Posts: 1,021
Likes: 2
From: Glorious West Sussex
er...
Only if you depart with one pack inop. If one pack fails in flight the MEL does not apply.
TP
If the MEL gives a restriction of FL250 it is not an airmanship consideration but a mandatory Operational Procedure.
TP
Joined: Oct 2003
Posts: 51
Likes: 0
From: Europe...the country?
Doubt you were in the flight deck cause you don´t work for FR. With that in mind, just out of curiosity, what exactly does a single pack operation feel like sitting in the back?
I´m assuming you were in a -200 and are therefore mistaking the gasper fan for a pack. Most -200 operators turn it off climbing FL100 and on again at FL100 in the descent.
I´m assuming you were in a -200 and are therefore mistaking the gasper fan for a pack. Most -200 operators turn it off climbing FL100 and on again at FL100 in the descent.
Last edited by Rocco in Budapest; 27th July 2004 at 20:39.
Joined: Apr 2002
Posts: 1,052
Likes: 8
From: Put out to graze
TYRO,
the previous postings referred to an operation where single pack was used as a normal, continuous procedure.
Besides which, dont you think it would be prudent to observe such limitations should a pack fail in flight?? They are there for a reason!
the previous postings referred to an operation where single pack was used as a normal, continuous procedure.
Besides which, dont you think it would be prudent to observe such limitations should a pack fail in flight?? They are there for a reason!
Joined: Jan 1999
Aviation Qualifications: ATPL
Posts: 601
Likes: 13
From: Brisbane
Tyres,
There are a whole raft of reasons why you wouldn't necessarily descend to FL250 after a pack failure enroute.
The MEL restriction is a "boots and braces" method of ensuring that the aircraft is operated conservatively with a pack U/S it does not require the descent of the aeroplane if a pack fails in flight
Descent would, or should, certainly be part of the decision making considerations, but a decision not to descend should not be universally condemned as "bad airmanship"
The "airmanship" chestnut is interesting because what I consider to be good airmanship is entirely different to the next bloke - and so on..
There are a whole raft of reasons why you wouldn't necessarily descend to FL250 after a pack failure enroute.
The MEL restriction is a "boots and braces" method of ensuring that the aircraft is operated conservatively with a pack U/S it does not require the descent of the aeroplane if a pack fails in flight
Descent would, or should, certainly be part of the decision making considerations, but a decision not to descend should not be universally condemned as "bad airmanship"
The "airmanship" chestnut is interesting because what I consider to be good airmanship is entirely different to the next bloke - and so on..
Joined: Oct 2000
Posts: 114
Likes: 0
From: Crufts
I'm probably going to look stupid for this, (no change there, then!) but...
What were you doing in the flight deck, since you must have been there to notice the pack situation? The only people who should be on a flight deck are operating crew members: If you were operating, how come you don't already know the answer, or couldn't ask?
Apologies if I'm missing the obvious here after getting back from a night PMI -I've tried applying gin to my logic, but it hasn't helped as much as I'd hoped!
What were you doing in the flight deck, since you must have been there to notice the pack situation? The only people who should be on a flight deck are operating crew members: If you were operating, how come you don't already know the answer, or couldn't ask?
Apologies if I'm missing the obvious here after getting back from a night PMI -I've tried applying gin to my logic, but it hasn't helped as much as I'd hoped!
Thread Starter
Joined: Jul 2003
Posts: 8
Likes: 1
From: U.K.
I’m sorry that some of you felt defensive of the original question, with the need to respond with an attacking accusation of how I could be sitting somewhere where I could have known the condition of the packs (i.e. cockpit). I understand why as an employee you would be sensitive to the trend of condemning Ryanair’s style, and that was not my intent.
I believe I can conclude that the answer to my question is: there could be a variety of reasons that single pack operations could occur, and that it is not a company policy to operate in a single pack configuration as a method of cost savings.
Thank you to all who added other insight into this thread.
I believe I can conclude that the answer to my question is: there could be a variety of reasons that single pack operations could occur, and that it is not a company policy to operate in a single pack configuration as a method of cost savings.
Thank you to all who added other insight into this thread.
Joined: Apr 2002
Posts: 386
Likes: 0
From: UK
What nonsense you are talking TogaLock. Most guys are not getting defensive on this trading about FR "secrets", they are asking you how you noticed that they had single pack operations!
So I'll ask again, for whatever reason HOW did you notice "single" pack operations on the FR flight you were on.
BTW on the 737 NG if you are @ FL400 and you get 1 pack trip off and unable to reconnect you WILL need to descent, cos 1 pack can't cope to maintain the pressure differential.
So I'll ask again, for whatever reason HOW did you notice "single" pack operations on the FR flight you were on.
BTW on the 737 NG if you are @ FL400 and you get 1 pack trip off and unable to reconnect you WILL need to descent, cos 1 pack can't cope to maintain the pressure differential.
