Cabin temperatures.
 

I've made many long distance flights over the years and it always occurred to me that during overnight sectors the temperature in the cabin always seemed to rise when we, the passengers, were expected (required?) to go to sleep. Of course everyone's comfortable temperature is going to be different to everyone else, but when I was flying with others the general opinion among the group was that the temperature was too high to sleep with any comfort. Yes, I did occasionally ask the cabin crew to see if the temperature could be lowered and sometimes it was, sometimes it wasn't.

It occurred to me over the years that maybe this practice was only common in the economy sections of the aircraft where the larger number of passengers might cause more work for the cabin crew and hence a rise in cabin temperature might cause quite a few to be artificially 'heat sedated' and not cause too much further work for a few hours.

As the years have rolled by and finances have improved, I've spent recent years flying in flat bed class. To my personal disappointment I have found the practice still appears to happen there too. I have asked for the temperature to be reduced once we have been packed off to bed and I'd like to think the cabin crews have acted on my requests - to some extent anyway.

On my last trip it was so hot I even had to strip off my Virgin pyjamas and sleep only in my underpants because the cabin was so hot. I was not alone in my observation from asking around. (I did loosely place the blanket across me to limit the visual distress to my fellow passengers!).

So I guess my question is: Is there any sort of official or unofficial policy on cabin temperatures during overnight flying sectors. Or is it down to the individual cabin crew members?

I think the reason is simple. The cabin crew is sitting in the galleys, close to the doors. On most airplanes this is the coldest place, some are really cold.
Thence they perceive the cabin to be cool and adjust to higher temperatures.
When you walk thru the aile you will notice the temperature does change a lot with every step you walk.

What safelife said. BUT........

We all perceive temperature differently. What is hot for one person can be cool for another. In offices I've sometimes found people complaining they are cold when I'm OK.

If you went through a plane and asked everyone about the temperature I reckon you'd get a wide range of answers from "freezing" to "roasting". Whilst the answers might be related to where the passenger is seated that would not be the only criteria affecting the answers.

These are fair enough answers. The point I was hoping to make was that when we board the aircraft, eat our meals etc etc the temperature seems to be ok (to me). It is only when we have been packed off to sleep that I notice the rise in temperature. Generally I am not the only one.

So, I can see that the temperature throughout the cabin may vary depending on where an individual may be seated and of course their own personal view of what is a comfortable temperature or not. But given that the aircraft is an insulated and isolated cylinder, I might have presumed that once the overall cabin temperature was 'set' it would stay reasonably constant even if different zones of the aircraft are at different temperatures. I think safelife's suggested answer is likely to be correct. But I would be interested in any responses from cabin crew. (i'm assuming safe life isn't).

I suspect there's a fair chance safelife may well be crew. Certainly what he/she describes (door areas on some types being arctic cold) is a common observation and may well be one explanation for what you experienced.

However aside from the cabin crew winding the zone temperature up ( which does sometimes happen) the air conditioning systems themselves on some types aren't really that sophisticated and you can get considerable differences within a zone.

In that particular case I wonder if there had been a partial system failure - there's always the chance that due to some defect a particular zone's temperature may become very difficult or impossible to control with any finesse, e.g. if it's own "mixer valve(s)" fail. On many of the Boeing's there's often the ability to override the whole system from the Flight deck and run everything in a degraded mode but it's bit of black art and very difficult if not impossible to get every zone running at an ideal temperature .

If you are sat in the centre seats in the cabin then it can feel quite warm, if you are in a window seat it can be a lot cooler due to the proximity to the aircraft skin and the outside world (the sidewall panels can get quite cold after 'cold soaking' for several hours plus)
Back in the old days when perhaps more "analogue" and "artful" skills were required to operate an airliner and Flight engineers were part of the team the cabin crew would often come up and ask the FE to drop the zone temps at night after the meal service. The thinking behind this was that it would encourage the pax to sleep and they wouldn't keep pestering the galley slaves for drinks all night. This however just made it very cold for some of the pax so the FE I knew turned the temp down for 5 mins then turned it back up again! Also the flightdeck on the 747 classic could get quite nippy on a long night sector, even with the temp selected up, and "frost" would form on the uninsulated windowframes around the two windshields!

There also seems to be cultural differences as well. On most Asian carriers the cabin tends to be much cooler than on Western carriers.

There seems to have been a move away from individual air jets in recent years, which is a shame as the combination of a warmish cabin & cool jet meant that an individual could, to some extent, adjust their own temperature - and different people prefer different temperatures.

I guess that the reason is financial but if I was a boss concerned with passenger comfort I would insist on individual air jets on any new aircraft.

I have frequently been asked by cc on night flights to turn up the temp to "make the pax sleep" to give then a quiet trip home.

In my experience, cabin temp is controlled from the flight deck not by the cabin crew.

Must depend what you fly, I've experienced both methods....

On the 747 classic the individual zone temps were indeed controlled from the FEs station on the Flight Deck..

On the two more recent Boeing widebodies I've flown (744/777) whilst there's a master temp controller on the flight deck which sets a reference or mean temperature for the whole system the individual zones are controlled around that reference temperature (within a certain tolerance ) by the cabin crew, either from the Senior Cabin Crew Members station, and/or from individual zone temperature controllers at certain doors.

In normal Ops we set the Flight Deck master controller to a suitable position during the pre-flight and almost certainly ( as in over 90% of sectors) won't have to touch it again during the sector, leaving the Cabin Crew to control their own zones. If there are real problems getting a particular zone cooled we might lower the system "mean" temp on the Flight Deck master control, and in extremis if the individual zone controls fail we're then back to trying to run the system from the flight deck controls, but most of the time the zone temps are controlled by the cabin crew.

Hope that helps.

An article from the LA Times from 1994 about the practice of "coshing passengers" I seem to recall a similar article in the Sunday Times but have yet to find it. Snooze Control : Some Airlines Raise Temperature to Lull Passengers - latimes

In response to the article it might be deliberate "coshing" but OTOH it's worth being aware that on at least one type mentioned the AC system, as installed, will automatically slightly increase cabin temperatures during the early part of the cruise in order to compensate for the reduction passenger activity (it would wash that increase out on the descent). It is possible that not all the temperature increases claimed in the article were demanded by the crew.

Personally I've never been approached by cabin crew to crank system temperatures up to get passengers to sleep, but then again from the flight deck display I will admit to have occasionally seen some zone temperatures set to suspiciously high values by other crew members.

I thought the research evidence was that people slept better when the temp went down a couple of degrees? Need to keep the feet warm, but that's easily done.

I understand about the difficulty of controlling the different zones, and different personal thermostats (I was brought up in England, pre-North Sea Gas, my wife in Australia), but it's possible that if FAs are asking for the temps to go up to quieten us down, they're actually going the wrong way.