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How Cold Is Too Cold?


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The January deep freeze has hit northern MB. I went to YQD to shovel out my Mooney and plug in for a couple of CASARA flights tomorrow (Sunday) starting at 7:30 a.m. local. I was supposed to fly to Swan River and pick up a load of navs and spotters and bring them to YQD where we would meet the Herc and do a couple of exercises in the area, and then fly them back home. The high today was -26C and the sock was straight out. The forecast low is for -32C tonight with a forecast high of -24C tomorrow afternoon. CASARA has a -25C limit on TRAINING missions, although the real search is PIC's discretion. I've lived in the area for 30 plus years and have seen my share of cold. If I recall, my coldest takeoff was at -32C last winter. Density altitude was somewhere around 5,000 below sea level. Pretty good performance!


My question is, what are your temperature limits for flying? Are they set by your company if you work for one, or set by the aircraft manufacturer, or set by your own common sense? Does single engine, twin or turbine make a difference? Input would be much appreciated.

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Guest graunch1

In Tuk-by-the-Sea a few eons ago we had a bottom end of -37C on the S76s due to that's the coldest it got when Sikirsky did the cold Wx trials. If I recall correctly the S61 operated until whatever.. I think we launched at -45.


The coldest flight I recall was a medivac from Faro,YT to Whitehorse in 74. the 206 was tented but the OAT was -70. When they arrived n Whitehorse the pilot complained that none of his radios worked.. :rolleyes:


We launched our L188 Electra from Whitehorse that same time at -63 over to Inuvik where the temp was a balmy -50.


1974 was a Cold winter. DnD came to YXY on a search with a Buffalo from Comox which after sitting outside overnight just crapped out. The 2nd Buff blew all the prop seals.


someone from TNTA found the missing a/c.


It took our fearless AF 3 weeks to get their a/c out of YXY and back to the wet coast. After the Wx warmed up they came up with a PR group and put on a SAR seminar. They were laughed out of town :down:

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Guest Airplay

The logical way to determine what your minimum "launch" temperature is as follows:


a) Check out the type certificate for your airplane. It may state things like minimum oil temperature for a start and minimum operating temperature. Many small airplanes like the Mooney 20 series don't list a minimum operating temperature.


B) Check the flight manual (AFM) or pilots operating manual (POH). If the TCDS doesn't state temperature minimums, you may find it there. You may also find cold weather operating procedures or suggestions.


c) If there is no stated temperature limitation, for the airframe, look for one for the engine. Engines have their own type certificate. Again though, many GA engines don't state min starting/oil temps.


d) Do a similar assessment for the critical and essential equipment. For example if you are flying IFR, you may want to determine if you can keep the neccessary avionics and other electrical gear like fuel pumps going. Many GA avionics are rated for -20. If it's in the cokpit, a pre-warm would suffice because I doubt you'll launch if you can't expect to get the cockpit above -20 in flight. There are of course remote electronics that may not be installed in the cockpit to consider.


e) If you are satisfied that everything will work at the launch temperture, then just consider the economics and safety aspects. Working a piston engine at extreme tempertures will lower its life and increase your operating costs no matter how you look at it. Launching a SAR or Medevac mission at extreme temperatures won't help anyone if you add another aircraft to look for, or finish the job on the patient that mother nature couldn't.


Considering all that, personally, I wouldn't launch my own non-commercial piston airplane below -25C. If it was commercial, and it was a twin, I'd bend that back to about -33-ish. And only with a good thorough pre-heat. Of course when you are talking turbine, most of that changes.


You might also want to research any cold weather kits such as the air dam available for some cessna air inlets. it decreases the area to restrict cooling air. You don't want to try to design one yourself....theres alot to consider.


And...one thing that many pilots don't consider when they launch in the extreme cold is altimeter cold weather correction. You can have an altimeter error of over 1000 feet (altimeter reads high) at 5000 feet ASL when its -40C. Check the AIP for the corrections.

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We used to operate the G1, F-27 and the HS25. -40 was about the lowest you wanted to see, particularly with the F-27 because of the pneumatic system.

I've flown the Beaver at -40. It had warmed up from the -46 it was when I started preheat. Don't get a lot of hot air outta the smokestack heater at that temp. We had one Beaver with a Southwind heater in the camera hatch. Sheer luxury. B)

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When going from Little Moosepoop to Greater Moosepoop it is A/C limits - but - dropping guys off in the field with a helicopter or Skiplane what are they going to do all day at 45 below but stand around a fire going " F--- It's cold ".

Actually flew an Otter all winter in Jimmy's Lagoon with no heater from Jan to May 74 - Gawd I remember it well. We rigged a very illegal piece of scat hose from the carb heat box to the cockpit to defrost the windshield and provide some warmth for the 5 gals of oil we carried in the cockpit. The adventures of the young and stupid.

Actually one of the greatest considerations is how you dress. I have seen people jump off a 737 and be perfectly willing to leap into a 206 for a 100 mile flight wearing a trench coat, street shoes and leather gloves - no hat. At minus 35 no less!!

A very wise man told me never to go bush flying unless you and your passengers are dressed to stand around looking dumb for 24 hours in what they are wearing.

Even a 20 minute stop to check a chip light will put the badly dressed in danger and what happens if the **** thing won't start or the chip has a part number. These thing always happen 30 minutes before dark just as the other helicopter at camp goes U/S and the crew opens some antifreeze.

I have refused to carry badly dressed customers and nearly got fired for it once - a company president with common sense saved my butt and fired a missle at the marketing dept. that caused multiple casualties - the customer's safety dept. got involved and severely reamed the passenger involved. - see there is a God!

Common sense and airmanship should dictate limits.

It plummeted to + 19 C here in the gulf last night and I am thinking of wearing a jacket for our evening walk. Have fun guys.

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The chip light thing happened to me in a Hughes 500, one day in January 88 or 89.


It was a dark and stormy night B) , and I was trying to get home in some marginal wx. My four pax were executives of a large mining firm, two from Canada and two from England. As with most geologists, they were very well prepared as were the machine and I. We were about a half hour back from base, getting dark, and the ENG CHIP light came on. Two choices - pressing on meant crossing a large lake in very light snow, stopping to check the light meant staying the night in the boonies. I chose the latter, even though a glance at the OAT showed -29ºC.


I called dispatch on the HF and told them where we were, and that we'd be spending the night, then landed and checked the chip detector. Sure enough, it was fuzz. By that time it was well and truly dark, and I dispatched my well-dressed pax to fetch some firewood. We started a fire and set up the "5-man emergency shelter" (yeah, right), opened the survival kit and made tea. We spent the evening by the fire, drinking tea and dining on the contents of the survival kit.


Bed time proved to be fun, as my four large pax crammed into the 5-man tent. I slept in the aircraft, starting it every hour or so to keep both of us warm.


The next morning we packed up and headed home. The two guys from England had never really had an experience like that before, and thought it was a big adventure. Before flying home, they paid a visit to an art gallery in Corner Brook and each bought a painting of Newfoundland winter scenes.


I have often though of that story when flying in the cold. Had these guys not been prepared, it would have been a very uncomfortable night for all of us. On top of that, it may have pressured me to push the dark with a chip light because I knew they weren't prepared.


So, after such a long, drawn-out story - how cold it too cold? As long as you're prepared for the worse, I guess whatever the limits of the aircraft and its equipment are.


Certain jobs require you to take serious risks with the cold - like the North Warning System work in the Arctic. For a couple months ij the winter, it's dark, -40º or worse, and there is NOTHING to burn or use for shelter anywhere. The nearest thing to come get you is a thousand miles away. Spending a few days in that would probably not be pleasant.

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Guest graunch1

The lack of proper Arctic wear came to a climax back in 75 when PAnArctic Oils from YYC dropped an Electra through the ice just short of the runway at Rae Point NWT in the middle or an winter's night. There were only 2 survivors by time they were rescued a couple hours later. No One on the aircraft were dressed for the weather - just wearing light coats,shoes etc. (after all it is only a short run into the camp from the a/c)

As a result the oil companies intstuted strict dress cdes fro anyone heading north from Sept 1 until May 1. It was tough climbing onhte boeing in YYC when it was +25c but quite nice when it was -3million on the shores of the Beufort :rolleyes:


I always beleived that it is easier to take clothes off than to wish you had more to put on.

Of course the biggest concern was making it back from the Kopper King to the Chalet in YXY wearing jeans and a light jacket in a truck that often quit :P

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My personal opinion for piston flying is -25, maaaaaayyybe -30 at the absolute lowest. Our ho's fly colder than that, but for recreational type flying, why risk blowing jugs? Where I used to teach at CYBW we'd often get the chinooks that didn't quite touch down. So it's much warmer at 6000', then have at er... Just remember to cool your engine down gradually. An inch a minute, or if you really want to baby it, 2 inches a minute will save you some grief.


Our PT6's are limited by oil temp for start, and by OAT for the fuel heat as was mentioned. We always carry plugs, little buddy's, de ice fluid, etc... Oh and I alway dress as though I were going to be walking home... :) cj

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