Helicopter Pilot Heat Stress

[cupajo]

We are trying to formulate some guidelines for our pilots when operating on very hot or very humid days, re: hydration, fatigue, effects of heat stress on cognitive skill levels etc. I know there has been some work done by the military for fighters but is there any helo research? Do other operators have heat policies? Do pilots feel heat stressed on 35+ degree C days? I think this is an issue that is being overlooked but as usual we just get in and do it but man is hot!! in the glasshouse some days!
Thanks for your thoughts,
Cuppa Joe

[oldbeefer]

I think the major factor is aclimatisation - when I have been on examining visits to heli units in the Middle and Far East for two week stints, I found it very difficult to cope with the feelings of fatique. After a month into a 6 month stint in Belize (+35 and vicious humidity) I realized that those feelings had gone. Apart from that, sleeping in A/C accom helps the body's core temperature to keep low(ish) and loads of water - if you don't need a pee every couple of hours, you're not drinking enough!

[BRASSEMUP]

Hi,
I found that operating in Hot climates did fatigue crews a lot quicker. Plenty of fluids were a norm and at least a week of acclimatisation with very little flying. I have had instances where I couldn’t see the instruments on start up because the sweat was pouring down my face, but once the fan got going it made it a lot more pleasant. I also wore a fridge suit a few times (like a set of thermals that has vein’s of ice water pumped around it). And the dog’s bo**ox it was aswell. But a rule of thumb was add 5 to 10 degrees to the outside temp then another 5 degrees for the temp inside your helmet and that was the conditions on start up!!!!! One word HOT.:uhoh:

[nimby]

FYI, there's a whole bunch of research done by IAM in the early 90s. Unfortunately not (apparently) in public domain.

Seems daft there's no formal guidance (e.g. H&SE), given the habit of bolting a greenhouse to the front of the airframe, then dressing in overalls before sitting in the sun.

In unpublished work:{, IAM found mid-summer Germany was enough to terminally fry the pilot:\ in less than 2 hours for some workloads, even after acclimatisation:cool:. Best answer was the liquid cooled (15 deg) suit, with an attached cooling skull cap worn under the helmet:sad:, which also supresses sweat. Pipes, plumbing, escape and cooler weight were all reasons why this isn't done now. That and looking a prat queueing at ATC with that lot on.

Perhaps an opening sunroof would help, given the big cooling fan on top (Brylcreme might be needed:)).

Nimby

[ShyTorque]

Crews were getting very fatigued in Belize in the early 1980s; I took part in an RAF heli pilot heat stress survey. I flew with a medic in the left seat; he took my temperature every 10 minutes and before and after every landing.

The looks on some soldiers faces, as they spotted the thermometer in my mouth while they filed past the cockpit to emplane, was a real picture :suspect: :eek:

The outcome was that I was operating with a body temperature of well over 100 degrees F. It was urgently recommended that the aircraft (Pumas) were fitted with a fan of some sort in the cockpit. Of course, this was regarded with the normal level of priority given to the well-being of helicopter crews........... i.e. none, at least nothing had changed by the time I became a civvie some 14 years later.

I wonder if Puma helicopters, over 25 years later, have been improved in this respect, given the location of their present deployments?

[Thud_and_Blunder]

For some reason a techie brought a min-max thermometer along on one of our border detachments in Oman in the early 80s. Popped it under my (green) flying helmet on the seat of my Huey after landing and left it there for an hour late one morning. Around midday I went back to check - it had reached 88 deg Celsius.

Once I'd seen some Oz troops using Camelbaks in the late 90s I bought one and kept it strapped to the back of my 212 seat in Borneo. Our doc said that if you feel thirsty you are already 5% dehydrated. Just make sure you train your bladder to last as long as the a/c fuel tank does - see Oldbeefers comments earlier :ok:

[nimby]

Shy,

Just think yourself lucky you weren't on one of my trials. I tend to insist on a proper core temp reading (and it doesn't come from the mouth!)

Nimby

[ShyTorque]

Not In My Back Y..passage!

Let me guess... Navy, eh :rolleyes:

:E

[Makiwa]

:mad::{:ugh::}:yuk::ok::p:ugh::}

[Lord Mount]

Makiwa,
You are the one who needs to get real!
The conditions in which you operate will affect the way you operate.
If you don't care about the service or safety you give to your employer or passengers then carry on with the macho bravado bulls**t.

Those professional pilots who do have an interest in flying as safely and efficiently as possible will be very interested in this valid thread.

Wind your neck in and keep you infantile comments to yourself.


LM

[Codger]

There was a study done in the late 80s on fixed wing drivers. I believe that it was undertaken on the behalf of an insurance company. All that I recall was that there was an optimum core temperature range and that even for someone that was supposedly well adjusted to one extreme or the other, the performance levels were measurably diminished. I only recall this because I believed that after having operated for some time in ambient temps of 35-45C that I was just as proficient as at 25C. I was wrong. Problem solving and reaction times were measured. I would guess that having your head cooking inside a brain bucket in a greenhouse wouldn’t make things any better. I took to wearing a cotton baseball cap with a wet sponge beneath it and keeping as many of the vents pointed at me as possible.

[hihover]

Ouch, somebody seems to have touched a raw nerve! Maybe a large Cognac will help.

Cupajo,

There have been some surveys done on this but all solutions that involve technology are very expensive and in the civilian world, usually prohibitively expensive.

I operated in Kuwait for several years where the summer temperatures got to 50 deg C on a regular basis. It was a dry heat and not as tiring as hot and humid, nonetheless, very hot. Unless absolutely essential, I stopped the pilots flying in temperatures above 45 deg C. Aircraft were kept inside until the last possible moment to minimise the time sitting on the ramp getting heatsoaked. Pilots spent the minimum amount of time outside before getting airborne. Two pilots at those temps, both rested and watered. Lots of water on board in case of a breakdown. All fairly common sense stuff that I am sure you know.

I now operate in Florida where the temperatures are lower but humidity is high and the discomfort is pretty much the same as in the Middle East. I now have my own operation and cannot justify high cost solutions, therefore, I have to apply all the common sense I can in order to minimise fatigue. Not always easy but that's why I love being a helicopter pilot.

I guess it comes down to how much you are prepared to spend and, of course, the aircraft you fly and the function you perform in your operation. There are some very good and light air conditioners available, otherwise, I'm afraid it really just comes down to awareness and there are several good points made on this thread already.

[Arm out the window]

I remember being told by some RAN guys about a helicopter heat stress trial they'd taken part in, about mid-eighties as I recall.
The thermometers were in fact rectal - not a pleasant thought, but I'm sure they did it for their country and the expansion of scientific knowledge (not to mention the expansion of bodily orifices... :eek:)

[Makiwa]

:}:mad::confused::ugh::{:ok::O:D:yuk::zzz::zzz::zzz:

[cupajo]

Thank you all for your thoughts,
I have been sent some interesting stuff, it seams the Australian Navy and the Royal Air Force Sea King guys have done some work that suggests a caution when operating above 37.5 C, it suggests restrictions on ground idle time and also recomends extended recovery periods between flights.(up to 2 hours in some cases) It also defines an extreme danger period above 45 C ambient where all but non essential flights be avoided (I know which flights my boss thinks are essential - you guessed it!) Other research also shows that aclimitization is very important as is dehydration, physiological studies show it is difficult for a person sweating profusely to rehydrate during the period of sweating - so drink before and after the flight. Heat stress appears to effect different people in different ways, quite clearly some "cope" better than others. The research and anecdotal evidence does suggest a reduction in skills at higher temps and an increase in fatigue related to the lenth of time exposed (this more how it effects me personally, I don't feel particually stressed during the hot flight but am more knackered at the end of the day) I think that if there is a factor (that can be mitigated) that can adversley effect our performance (and therefore our obligations to passengers and crew) then as professionals we should at least consider it. It may be as simple as a water cooler in the crew rest area or a complex risk matrix that cancels flights above a certain temp, I thinks its probably somewhere in between, thanks again for the responses, I appreciate it,
Joe.

[ShyTorque]

Makiwa, A question - How do you know how stressed folk are?

As far as being rude is concerned, I suggest you read both your posts again; it's not surprising that some folk take exception and retaliate.

Despite that, I'm sure your 120 hard men colleagues find you a pleasure to work with.

Meanwhile, I'm going for a lie down - it's a little warm this morning and I hate it when I perspire. :p

[spinwing]

Hey Makiwa,

Now I know why "Ridgebacks" are so popular ....:E:E:E

Cheers mate ...see you soon ... U got any RUM left? :ok:

[Whirlygig]

Makiwa, well good for you!


I have never felt as "stressed"

Actually, how would you know? That's the trouble with stress; it can be quite insidious. Maybe your reaction to the "softies" here is a result of the stress under which you are placed and no doubt your blood pressure is fluctuating.


I am not alone in my ability to handle the conditions

Again, how would you know - perhaps you are being a little subjective? And not a little aggressive. Maybe you can't handle it and an inability to cope with the stress is manifesting itself in this agression. Care to revisit your HPL studies?

Cheers

Whirls

[spinwing]

Whirls ....

I do know in fact that Makiwa does know what he is talking about .... the fact is we do operate in rather uncomfortable conditions during a middle eastern summer .... however we ARE used to it and are conditioned ... which is a very different situation to those who might not be!

I also think Makiwa might just be having a not too subtle "dig" at those he might percieve to be whingeing about the "tough" conditions that they have chosen to work in.

His final words "Hydrate or Die" ... so very true!

Cheers :}

[ShyTorque]

An important point is that once you are acclimatised it's not such a big problem; It's certainly a different ball game when you aren't.

I took it that the original question reflected this problem, presumably for inexperienced pilots perhaps meeting the conditions for possibly the first time.
As part of a deployable military oufit in the late 70s and 80s, we used to go from three months at 95 -100F and 95-100% humidity in Central America to well below freezing in the Central European winter, so we had quite a lot of acclimatisation to do.

I personally always find a hot climate takes longer to get used to. Sometimes in the Far East, the S-76's "Windscreen Hot" (overheat) captions were on as soon as we switched on the aircraft battery; it's been a while since I worked out there but I think they come on at +50C.

Yes, even "soft" pilots acclimatise, but everyone is different. We routinely wore Nomex flying suits, roll-neck long sleeved shirts, long socks, boots, gloves, helmets and underarm deodorant.. On the less hot days we used to wear a Nomex jacket too. :rolleyes:

To acclimatise more quickly, my advice is to stay out of over-airconditioned rooms, if possible. Just try to stay in the shade with a breeze going. Keep hydrated by steadily sipping water, not gulping it down - an over-full bladder only adds to the discomfort. I used to run about 15-20 miles a week in my far east days, so I certainly got used to the climate. Air-con is nice to sleep in, but it's also noisy. I preferred to sleep under a ceiling fan (she was nice, that See Ling Fan).

[Lord Mount]

Dear Makiwa,

How refreshing it is to see that you can construct a cogent, clear, intelligent and gramatically correct discourse, instead of just insulting your fellow pilots.

I don't think the previous posters were complaining about working in uncomfortable conditions. I saw the thread as being a genuine discussion about whether certain conditions could lead to any degredation of decision making ability and consequent detrimental effect on safety.

All you could do was call your peers "pussies" and insinuate that they were in some way not macho enough to be in charge of a helicopter.

Your second post, however, had some valid points about your flying experience in differing conditions and your belief that it didn't affect your abilities.

Is it not better to enter into reasonable and polite discussion rather than flame and insult people who are trying to make the envioronment in which we operate safer?

Rant over.

LM

[RVDT]

Air Con - ON, Check

[Makiwa]

:}:bored::confused::\:mad::ugh::{:yuk::*:zzz::zzz::zzz::{

[Lord Mount]

Big hugs all round.

[hihover]

Don't be hugging me pal, I'm still sweating from all this talk of rectal thermometers.

[Gordy]

Just to throw this out there....This was todays "six minute" discussion, I know it relates to firefighters but worth reading all the same:

Six Minutes For Safety (http://www.nifc.gov/sixminutes/dsp_discussion.php?id=68)

HYDRATION
Studies conducted on wildland firefighters indicate that fire suppression activities generate about 7.5 kilocalories of heat each minute worked, or 450 kilocalories for each hour. Additional heat (about 180 kilocalories per hour) comes from the environment and the fire. The total heat load amounts to 580 kilocalories per hour (400 + 180 = 580). Complete evaporation of 1 liter of sweat removes 580 kilocalories of heat. In order to maintain a healthy body temperature, the firefighter needs to evaporate about 1 liter (slightly more than 1 quart) of sweat during each hour of work.
Maintaining body fluids is essential for sweating. You must hydrate before, during, and after work.
Before work you should take extra fluids to prepare for the heat. Drink 1 or 2 cups of water, juice, or a sport drink before work. Avoid excess caffeine; it hastens fluid loss in the urine.
While working drink at least 1 quart of fluid per hour. Drink as much as you can during the lunch break. Water is your greatest need during work in the heat.
Providing a portion of fluid replacement with a carbohydrate/electrolyte sport beverage will help you retain fluids and maintain energy and electrolyte levels.
After work it is important to continue drinking to replace fluid losses. Thirst always underestimates fluid needs, so you should drink more than you think you need.
Rehydration is enhanced when fluids contain sodium and potassium, or when foods with these electrolytes are consumed along with the fluid.
Unacclimatized workers lose more salt in the heat so they need to pay particular attention to salt replacement. Don’t overdo salt intake; too much salt impairs temperature regulation. Excessive salt can cause stomach distress, fatigue, and other problems.
Make potassium-rich foods like bananas and citrus fruits a regular part of your diet, and drink lots of lemonade, orange juice, or tomato juice.
Limit the amount of caffeine drinks such as coffee and colas because caffeine increases fluid loss. Avoid alcoholic drinks. They also cause dehydration.
You can assess your hydration by observing the volume, color, and concentration of your urine. Low volumes of dark, concentrated urine, or painful urination indicate a serious need for rehydration. Other signs of dehydration include a rapid heart rate, weakness, excessive fatigue, and dizziness.
Rapid loss of several pounds of body weight is a certain sign of dehydration. Rehydrate before returning to work; continuing to work in a dehydrated state can lead to serious consequences, including heat stroke, muscle breakdown, and kidney failure.

This one is good too (http://www.nifc.gov/sixminutes/dsp_discussion.php?id=67)

Edited to add additional link

[spinwing]

Gordy ...


An EXCELLENT and informative post .... thanks

:D

[ShyTorque]

But it's only for softies. ;)

[Sgtfrog]

Nice one Shytorque:ok: where can I get a "ceiling" fan?:E

[jayteeto]

I am not a big fan of aircon, it stops true acclimatisation. In Belize we were just sensible, however you felt tired once you passed 6 hours flying time in that humidity. I found that with aircon off, physical exercise (running) and plenty of fluids, you could acclimatise reasonably well.
For those more outspoken people on Pprune, you have the luxury of acclimatisation on your side. If you are operating a few weeks on/off in the middle east, you can struggle. Don't knock the surveys, because of them, we have cooled suits, better materials made available and employers who are forced to supply drinks and breaks. Today in Liverpool it is only +21 and 68% humidity outside, the cockpit is a bit worse. I actually felt really uncomfortable on my last flight, I am not a wimp or whinging by saying that, just stating a fact!!
It could be that I am fat I suppose :)

[MSP Aviation]

I know that there are cooling suits made for racing drivers to be worn under their nomex suits. I believe that they are not prohibitively expensive, as many amateurs buy them, and they are not affiliated with aviation. Check these guys out: http://www.fastraceproducts.com/page/fastraceproducts/CTGY/coolsuit

[psyan]

Interesting thread, amusing as well. I knew I was suffering from the effect of heat the other day simply because I noticed that I had a considerable lack of interest in what I was doing. Upon landing some time later for a coffee, I felt unusually tired. Unusual in the sense that there was no real reason for me being so. I slept well the night before and had not done very much up to this point. So I determined it was the heat [pretty unusual in these climes I know] since I dress for flight pretty much like an onion, I simply peeled a layer or two off, had some lunch and Bob's yer uncle......

I think most people can tell/feel the effects incipient as they are and as in my case, it is only complacence about the potential that gets you there in the first place. But I am in the UK so perhaps I can be forgiven for retaining my crap weather operating mode.


Best Wishes

[Pekka]

In Norway it is quite common to haw 12 C one day, and to days later the temperature is 35 C (and remember, up hear the sun those not go down in June and July), so how in the hell are you going to acclimatize when the whether is shifting so often? One day I am frizzing my ass off, and den I am sweating like a piggy!!!

And by the way, Makiwa, you are an arrogant Mother F….

[Makiwa]

:{:}:bored::confused::\:mad::ugh::=:yuk::mad::8

[500e]

sgtfrog
I thought that is what we flywould be real worried if the big fan quits :suspect:

There appears to be a lot of testosterone flying as well, don't think that keeps you cool.
It would be real nice to keep the posts non personal.

[Morty]

Could there be that the heat is making you aggressive, so that in fact you really are affected?
It seems to me that you are condescending towards other contributors in this forum.:=
Let there instead be a sharing of experience in a grown up way, so others can enjoy taking part in this disscussion.
I agree with pekka that you are a bit arrogant.:ugh: