Heat/Poor air quality on Ryanair planes.

Living Off The Splash

I have flown a number of times with Ryanair this year. I have noticed on their newer aircraft the thingy above your head to get "fresh" air is not as effective as those on the older aircraft.
Is there any reason why the pilot will not switch on the air con while the plane is waiting for take off? I have been told it will be switched on when "we are airborne". Not very nice sitting in a sweltering hot plane waiting for it's take off slot.

L1011

Fuel consumption basically

smurfjed

Total guess here, the airconditoning system gets air from 3 possible sources, an external ground truck, the aircraft APU and the aircraft engines. I doubt that there are many (if any) airconditioning trucks in Dublin, so the aircraft has to use its APU, this can be limited by the airlines desire to save fuel and the airports demands for limit use due to noise. So after engine start the airconditioning will use the air from the engines, unfortunately on the ground the APU rotates at a high constant speed and provides enough air for cooling, the engines do not.

So the crew wont have turned off the airconditioning, but they just don't have enough air from the engines to make it effective.

theyoungchap

Probably because air con is only effective with a closed system, i.e. not one with 2 doors open at either end?

billy few mates

smurfjed wrote: »

Total guess here, the airconditoning system gets air from 3 possible sources, an external ground truck, the aircraft APU and the aircraft engines. I doubt that there are many (if any) airconditioning trucks in Dublin, so the aircraft has to use its APU, this can be limited by the airlines desire to save fuel and the airports demands for limit use due to noise. So after engine start the airconditioning will use the air from the engines, unfortunately on the ground the APU rotates at a high constant speed and provides enough air for cooling, the engines do not.

So the crew wont have turned off the airconditioning, but they just don't have enough air from the engines to make it effective.

I think you lost it there at the end...

goingnowhere

Well if you have a

Long flight
Heavy plane
Warm conditions
Short runway

You can switch off the air conditioning packs until airborne to
1. Get more trust
2. Use a lower engine trust setting (derate)
3. Less noise due lower trust

APU is normally run on the ground to power the aircraft but ground power could be used instead, you can fly quite happily without one, so if the APU is bust you won't have a great AC experience on the ground unless the engines are running and even then the crew could elect for a packs off take off

duskyjoe

goingnowhere wrote: »

1. Get more trust

Apart from the spelling error your dead right - more thrust means more trust .

In Thrust we trust

smurfjed

Which part Billyfewmates?

Just looked it up and found this in the FCOM.

After engine start with the engines at ground idle, the pneumatic pressure
available to the bleed air system may not be sufficient to provide
adequate cooling during extended ground operations. Use of APU bleed
air instead of engine bleed air to supply the packs while on the ground
can significantly increase cabin cooling

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Ryanair have a general policy not to have the APU (little jet engine in the tail that provides aircon and electricity) running until time to push back from the stand.
However in the current hot conditions the Captain should have enough cop on to start it as soon as boarding begins as the cabin gets hot very quickly.

However, the APU could also be broken which unfortunately can happen. A pain in the arse for both the pilots and passengers!

billy few mates

smurfjed wrote: »

Which part Billyfewmates?

Just looked it up and found this in the FCOM.

After engine start with the engines at ground idle, the pneumatic pressure
available to the bleed air system may not be sufficient to provide
adequate cooling during extended ground operations. Use of APU bleed
air instead of engine bleed air to supply the packs while on the ground
can significantly increase cabin cooling

I don't think it's anything to do with the speed of the APU exactly, the FCOM says it may not be sufficient for extended ground operations but in practice the engine PRSOVs should regulate the bleed pressure to approx 40psi (the same as the APU and ground cart) which should be more than sufficient for the packs to operate correctly. Wear in an engine can reduce its efficiency and ability to deliver the correct bleed air pressure. Where this is the case, at low power settings the high stage valve is supposed to modulate open to augment the low stage compressor air flow to maintain adequate duct pressure for the pneumatic system to operate correctly. It's not unusual on these aircraft for the high stage valve to remain closed until you advance the power lever momentarily. In ground operations it may not always be possible to do this (if the aircraft is on a stand for example). Most aircraft would be well able to maintain sufficient bleed pressure with engines at idle for air conditioning but it's not necessarily a problem when they don't as the APU should comfortably be able to run both packs sufficiently.

McSween

I always felt Ryanair kept it turned off so passengers would be more inclined to buy drinks :-)

billy few mates

Also, the little vent 'thingy' overhead is called a gasper. On the ground with the air conditioning off the air is just being blown out for ventilation and airflow purposes but it won't deliver conditioned air until the air conditioning is switched on. That's why it's often felt as insufficient when you first get on and the cabin is hot but shortly afterwards you have to turn it off because it's freezing...

theyoungchap

I wonder would this thread have been started if it wasn't Ryanair......

dobman88

duskyjoe wrote: »

Apart from the spelling error your dead right - more thrust means more trust .

If you're going to correct a spelling mistake, at least make sure yours is right

bkehoe

billy few mates wrote: »

I think you lost it there at the end...

His last point is entirely correct. The bleed pressure provided by the engines at idle thrust is nowhere near what the APU provides. The packs will run but nowhere near as effectively as when thrust is applied to the engines or with APU bleed source.

About 35% N1 is required to deliver the same bleed pressure as the APU provides. Idle is ~20%.

billie1b

duskyjoe wrote: »

Apart from the spelling error YOUR dead right - more thrust means more trust .

Apart from your spelling/grammar YOU’RE dead right, more thrust gives you more trust

Irish Steve

OK, enough of the off topic sniping about grammar and spelling.

billie1b

Some people are way over sensitive....good God

AlekSmart

I think the OP is referring to the latest new additions to the FR 737 fleet,which have the revised interior,and suffer from a decidely less effective "gasper",as part of a somewhat less effictive PSU group.

To me it looks like a Boeing issue rather than an FR one,but I could be wrong

theyoungchap

AlekSmart wrote: »

I think the OP is referring to the latest new additions to the FR 737 fleet,which have the revised interior,and suffer from a decidely less effective "gasper",as part of a somewhat less effictive PSU group.

To me it looks like a Boeing issue rather than an FR one,but I could be wrong

Stop getting in the way of an anti Ryanair rant.....

smurfjed

These are for a Rolls Royce engine and a Honeywell APU.





ON ground the APU is delivering 34 PSI to the air conditioning packs, while the 2 engines can only supply 11 PSI. Cabin cooling will therefore suffer.

FionnK86

I used Ryanair from Dublin on Tuesday. There were 4 Ryanairs all in a row, with their asses faced out onto the 'island where the little Stobart ATR turbos sit, with plenty of morning handling traffic in between. No APU on (I believe due to exhaust from back blowing onto island but could be wrong. Aircraft was quite warm, and cabin crew did turn it down when I asked. Some pilots won't drop the air con. If you don't ask, you don't get i suppose.

Tenger

theyoungchap wrote: »

I wonder would this thread have been started if it wasn't Ryanair......

My guess it was started due to the OP being stuck on a Ryanair plane for 30-45 mins over the last week.



Last year I was stuck on an Aer Lingus A330 for approx 50 mins before pushback. (Offloading bags from missing passengers)
It was 26 degrees and the ground power was (I assume) providing just enough for essential system. The gaspers (never knew that was the term) were basically pointless as they was nothing coming out. Passengers were sweating and moaning all around me. I had lucky brought on a good half dozen bottles of water so I was keeping my kids cool with that.
After takeoff though it got cold very quickly as the 250+ fully open gaspers pumped A/C into the cabin.

trellheim

I remember being stuck in Johannesburg on an AF744 with a failed APU and ground trying to find a working cart , talk about sweatbox city , you never heard such cheering when the cart fired up

PS the gaspers on the new 738s are terrible

It was 26 degrees and the ground power was (I assume) providing just enough for essential system. The gaspers (never knew that was the term) were basically pointless as they was nothing coming out. Passengers were sweating and moaning all around me. I had lucky brought on a good half dozen bottles of water so I was keeping my kids cool with that.

I have always wondered - why don't the crew just open all the doors and get some air circulating while waiting ?

tu2j2

trellheim wrote: »

I have always wondered - why don't the crew just open all the doors and get some air circulating while waiting ?

Ironically because people are liable to walk out an open door and assume there's a steps there

Those new psu's are rubbish, the same air doesn't seem to flow from them, the rest of the system is essentially identical. Anything else about not having it on is company procedure.

Apu usage is kept to a minimum, ish.

billy few mates

smurfjed wrote: »

These are for a Rolls Royce engine and a Honeywell APU.





ON ground the APU is delivering 34 PSI to the air conditioning packs, while the 2 engines can only supply 11 PSI. Cabin cooling will therefore suffer.

I don’t think the difference is quite as extreme on the B737NG, 11psi at idle seems very low I’ve never actually seen one where the engines couldn’t run the packs as well as the APU could apart from the odd one where you had to nudge the power lever out of idle to kick open a sluggish high stage valve. Even the FCOM suggests the engines “may not” be sufficient for “extended” ground operations, nothing to suggest it shouldn’t work in normal circumstances...

kevinandrew

I've always found 737s in general to be very hot and stuffy, particularly upon boarding. Usually once in the air things start to cool down but it's still not great compared to some other aircraft. 

This morning I flew with Ryanair, it was already 25C by the time we boarded and the cabin was unbearable, it improved but nowhere near a comfortable level. A recent Wizz Air flight on an A321 was completely different, cool and fresh feeling cabin even before take off with plenty of air from the gaspers.  

I've often heard people complaining about transatlantic flights being too cold but I'd rather a cold cabin over a warm one any day!

vicwatson

Flew Ryanair recently and it was freezing onboard during flight. I asked the air steward to turn it off or reduce the cold, was grunted at and told someone else already asked and they were doing it, a simple “no problem” would have sufficed

Living Off The Splash

kevinandrew wrote: »

I've often heard people complaining about transatlantic flights being too cold but I'd rather a cold cabin over a warm one any day!

I asked one of the Ryanair crew could she do something about the heat on the plane. She didn't. I noticed her turning one of the large gaspers in the staff preparation area on herself to cool off.

It's the one thing I dread about flying. Being stuck on a hot stuffy plane.

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The 737 has a nightmare of an air-conditioning system. It's very sensitive and requires constant adjustment by the pilots (based on complaints from passengers and cabin crew).
Boeing could have saved the pilots a lot of heartache by putting the cabin temperature controller in the galleys!