flying in arctic conditions

[ALASKA99762]

Could some of you guys who fly in the cold give us rookies some general advice on cold weather ops. I'm mostly concerned with taking real good care of the engine, although i'm sure there are a lot of other things to watch out for. We moved back to Fairbanks to escape the Nome wind and I sure would like to get some flying in before spring. It's finally above zero today!! Small pleasures.

[iowa]

mr alaska!
i'm curious about this also.
i know it averages about 32 here in
the middle of iowa,
so isn't much of a concern.
i remember i flew up to my brother's once
in tintah (90 mi south of fargo)
and it was -17F the morning i was to fly back.
we threw a big tarp over the cowling
and used a big space heater to warm things up.
like an idiot, i still had 100/50 wt oil in the engine!
i rember it started fine
but the oil pressure read quite high for most of the
3 hr trip back.
and then slowy came down to normal.
suppose i put 50 hours of wear on my engine
during that time?
iowa

[alaskan99669]

I use a Red Dragon heater to pre-heat my plane. When it's below zero out I have to run a rose bud over the propane tank to keep a good flame going and I also block half the air intake of the Red Dragon to slow the flow which increases the temperature of the air coming out the end. I have 110 volts nearby so I also throw heater in the cabin while I'm doing the pre-flight. I take my time removing the wing covers and do a thorough pre-flight with lots of warm-up breaks. 45 - 60 minutes later the engine is warm to the touch. I then put everything away while that heat soaks to the rest of the engine. Then I give it 3 strokes of prime and pull the prop through several times. Then 3 more primer strokes and it fires right up. I then plug in my 12 volt defroster and aim it at my side of the windscreen and it keeps the frost off while taxing. On the climb out the normal defroster takes over and the front seats stay fairly warm with my winter kit on, heater air scoop mod, and oil cooling blast tubes plugged off. This all worked good on a recent 311 mile cross-country to Fairbanks last week. It was -30 in Fairbanks.




Hey FUTR_ALASKAFLYR, recognize this?:

[futr_alaskaflyer]

Sure, can't you see me waving down there in the second photo?

Is that all the snow there is at the Talkeetna airport?!? It looks like September in the Otter photo.

Anyway, I have closed off my lower cowl intake as well as the intake for my oil cooler with my "winterization kit" i.e. white duct tape. I've left my upper/main cowl openings alone. In my recent trip from Edmonton to Fairbanks my oil temps showed 180 F with a OAT of -30 , to 205 degrees in an OAT of almost 30 (Fahrenheit.) My single probe CHT always stayed less than 300, and the EGT acted normally. Cabin heat was a little lukewarm at the coldest temps but toasty once the OAT climbed above -10 F or so.

I wear surplus winter weight military CWU-64/P flight coveralls, and air force mukluks so I don't mind so much.

I own a red dragon too and the one time I needed to use it this trip it worked fine, it was about -20 F at the time. 15 minutes of heat followed by about 30 minutes of rest with an insulated engine cover and the oil on the dipstick was noticeably warm as was the crankshaft coming out of the front of the case. The rest of the time I had a plug in available. I bought a little 120V 700 watt car accessory heater from Canadian Tire which I stuck up through the bottom cowl opening and plugged in over night. In the morning the engine was just as toasty as when I shut down the day before, with the insulated cowl cover on. I had a second little 1000w heater in the cabin which I plugged in about thirty minutes before departing (while I was preflighting, fueling etc.) directing warm air under the instrument panel to warm up the gyros and defrost the windshield. It also warmed the cabin up to tolerable, if not comfortable

[mit]

Sure, can't you see me waving down there in the second photo?

Is that all the snow there is at the Talkeetna airport?!? It looks like September in the Otter photo.

Anyway, I have closed off my lower cowl intake as well as the intake for my oil cooler with my "winterization kit" i.e. white duct tape. I've left my upper/main cowl openings alone. In my recent trip from Edmonton to Fairbanks my oil temps showed 180 F with a OAT of -30 , to 205 degrees in an OAT of almost 30 (Fahrenheit.) My single probe CHT always stayed less than 300, and the EGT acted normally. Cabin heat was a little lukewarm at the coldest temps but toasty once the OAT climbed above -10 F or so.

I wear surplus winter weight military CWU-64/P flight coveralls, and air force mukluks so I don't mind so much.

I own a red dragon too and the one time I needed to use it this trip it worked fine, it was about -20 F at the time. 15 minutes of heat followed by about 30 minutes of rest with an insulated engine cover and the oil on the dipstick was noticeably warm as was the crankshaft coming out of the front of the case. The rest of the time I had a plug in available. I bought a little 120V 700 watt car accessory heater from Canadian Tire which I stuck up through the bottom cowl opening and plugged in over night. In the morning the engine was just as toasty as when I shut down the day before, with the insulated cowl cover on. I had a second little 1000w heater in the cabin which I plugged in about thirty minutes before departing (while I was preflighting, fueling etc.) directing warm air under the instrument panel to warm up the gyros and defrost the windshield. It also warmed the cabin up to tolerable, if not comfortable

Richard

You didn't ask me but...... I would give it alot more time than that 45 min at 20 below! I have a Herman and would give it at least a full hour at -20.
with the electric heaters at the cabin about 4 to 6 hours. You don't ever hear about too much heat at -20 unless it is on fire

[auxtank]

It brings back memories to hear about flying in the very cold. Here's a story from a few years back:

Hours before sunrise on November 28, 1995, I left Haines, Alaska, intending to fly my ragwing 170 to Anchorage in one long day with a quick stop for fuel in Northway. A few months earlier, my wife had moved to Anchorage for a new job, and the purpose of the flight was to ferry Zero Two Victor to her new home at Merrill Field.

My flight planning had shown that, even with “severe clear” conditions over most of the state, flight hours would exceed daylight hours at this time of year. Because, I was completely unfamiliar with the Anchorage Bowl and its relatively complex airspace, I choose a predawn launch into mountainous but well-known surroundings over a pitch-dark arrival into Anchorage's unfamiliar sea of lights. However, I didn't make it past Northway that day for a number of reasons.

With Willy, my blue heeler, I arrived at the field about 6 AM that cold November morning eleven years ago. I thought about how it would get much colder when I climbed to cruising altitude and colder, still, as I flew north from the coast into the frigid continental air mass blanketing the state. I checked the outside-air temperature gauge and noted that the +5 degrees F it was reading was the warmest weather the plane, the dog, and I would see for awhile.

Power was not available at any of the tie downs at the Haines Airport, so I brought my 1000-watt Honda generator to the airfield that morning. About the size and weight of a full 5-gallon gas can, the unit is very compact, easy to start, and reliable. I had recently equipped my plane with a heating pad on the oil pan, and the generator has enough capacity to run the pad and a small electric heater, which I slide into the back of the lower cowl. Rather than pay extra for a tie down with power, I continued to use this system during Zero Two Victors two winters at Merrill field and still use it occasionally in Juneau, where I now reside.

I wrapped the cowl with the engine cover, started the generator, plugged in the heaters, did a good preflight, and loaded the plane. When the chores were done, Willy and I napped comfortably in the idling truck, giving the engine time to warm.

Prior to departure, I put on the arctic gear I had kept since working on the trans-Alaska pipeline nearly twenty years before: bunny boots, down pants, and a down parka. I also made sure I had my wool mittens with leather overmitts close at hand for the cruise portion of the flight.

My route of flight was “I follow roads” all the way, with the first leg of the flight following the Haines Highway north to Haines, Junction, Yukon and from there tracking the Alaska Highway to Northway.

Outside-air temperature at cruise altitude was –20 F for most of the flight. I had been told by a pilot from Fairbanks that in the interior I could expect temperatures on the ground to be colder than those at altitude, a phenomenon caused by the sinking of the heavy, cold air. He advised keeping my fuel stops as brief as possible in order to stay out of the extreme ground-hugging cold. My logbook shows 4.3 flight hours to Northway and includes the notation “ORT Clear –40.”

I can’t say that flight was the most fun I ever had with an airplane, but it certainly made an impression and taught me a few lessons.

Unfortunately, my stop in Northway took longer than the allotted half hour. After fueling the plane, I discovered that the grease in the tailwheel had solidified to the point that the tailwheel would not swivel at all. I spent four nights in Northway, but that’s another story.

Gordon Sandy

[GAHorn]

Wow! The frozen grease was not the cause of the 4 nite stay, however, was it?
What, if anything did you do about the tailwheel?
Do any of you AK folks use low-temp grease in wheel bearings, etc., as a precaution? (I'd think synthetic grease might be an answer?)

[auxtank]

George,

Since you asked...no, the frozen grease in the tailwheel was not the reason for the overlong stay...nor was my fondness for Northway in the winter. I’ll write more about the other problems. But, right now, I’m heading out to the airport to trouble shoot an inoperative strobe light. It’s an old Hoskins unit and is probably headed for the parts box.

Gordon Sandy

[cpolsley]

Auxtank

I would like to hear more about your trip as well and other cold weather experiences.

[hilltop170]

As far as the original question on this thread, as can be seen in the pictures in the posts above, winter can be the best time of the year to fly if the right precautions are taken.

First, maintain the airplane like your life depends on it, it does. A sprained ankle can be fatal on an emergency landing when the temps are 30 below. Any injury can be fatal, heck no injury at all can be fatal if the plane burns up with your survival gear in it. Make sure the plane is in good shape!

Covers are just about mandatory in winter. They will keep the plane airworthy when there is no hangar available, like when hunting or camping or going to the hot springs for a soak. They keep frost, snow, and ice off of the flight surfaces and windshield which can destroy lift if allowed to collect. Don't use them in a high wind unless they are spoiler covers with mesh fabric, they can flap and tear up parts of the plane plus not much is going to accumulate in a wind anyway.

Warming the engine properly IS mandatory. If the engine doesn't start when out in the bush, it's survival situation time again. An engine cover made for the plane that fits properly and closes tight enough to prevent drafts and an appropriate heater inside the cowl is just about the only way to preheat on your own. Coleman makes a little catalytic heater called "Sport Cat" which is about 5" in diameter and 6" tall which screws onto a 16oz. propane bottle and heats about 20 hours on one bottle. It fits safely into the cowl area without danger of catching anything on fire. It will not ignite a gasoline soaked piece of newspaper or melt scat hose or blister paint. If the engine is covered as soon as you land and you light the Sport Cat and get it inside before the engine cools down it will keep it warm at just about any temperature you're brave enough to fly in. My cut-off is 20 below.

Some folks like direct fired heaters like Red Dragons or weed burners. They heat fast and hot and are a huge fire hazard. They work but must be continuously monitored and the colder it is the less the propane will vaporize and the less heat they put out. You need to be patient and make sure the heating is not rushed like Corey mentioned above. Since they are a hot, fast heat it is easy to get the cylinders hot to the touch while the oil, crank, and core of the engine is still well below freezing. The oil needs to be above freezing before the engine is started and preferrably above 50F. Oil does not conduct heat very well and nowhere near as well as metal so it takes awhile longer to heat it up. The oil can be drained when you land and kept inside where it will stay warm all night. Even if it's put back into a cold engine it will flow much better.

Another problem with the direct fired heaters, including catalytic, is they put out huge amounts of water vapor. It's no problem if the temperature inside the cowl is above the dew point but if direct fired heat is put into a stone cold cowl the first thing that happens is the whole thing gets covered with frost. Then as it heats up above freezing lots of water is on everything and it stays there until it evaporates away. That is the main reason I like the catalytics because they never let the engine cool down and condense the water vapor.

For that same reason direct fired heaters should never be used to warm up the interior. It's almost impossible to keep the cabin warm overnight unless there is electricity available for an electric heater. If direct fired heat is ever applied inside a cold cabin once, you won't do it again. It makes such a dismal mess you will be convinced for life and all that condensation won't do your interior any good at all. Of course, I've never done it myself, I've only heard about it. Yeah, right.

The best heaters are the small electric 800watt or so car interior heaters. They will heat up a cold engine in 6 or 8 hours or keep a warm engine warm without being much of a burden to whatever they are plugged in to. One under the instrument panel helps out too if there is enough power available. Electricity is sometimes a scarce or intermittent commodity in the bush. Most folks shut down their generators at night so be prepared with "Plan B". The best part is they produce no water vapor and are very easy if electricity is available. I usually carry one with 150' of 12 gauge arctic grade extension cord. The insulation on the cheap cords will crack apart below zero and it's amazing how short 150' can be when you try to run the cord over to a plug. A light bulb can also be used but 100watts does not put out enough heat when the ambient is below zero.

The best winter operating practice is to put the plane in a heated hangar overnight before you fly it or at least a couple of times thru the winter to melt and dry out any ice, snow, or condensation that has accumulated inside the plane and in the fuel tanks. Blowing snow can put pounds of unknown weight into places on the plane where it shouldn't be, like control surfaces and the tail cone. More than one aileron has been ripped off of Cessnas in Alaska because of flutter caused by the unbalanced weight. Who knows how many other accidents have been caused by it.

I regularly get water out of the fuel tanks and gascolator on the 170 with its aluminum tanks even while keeping it in a heated hangar with the tanks full. I think they are condensation magnets. Ice crystals in the fuel can plug off the tank screens if allowed to accumulate. HEET can be used in the fuel to clear out the ice but it's not approved. An airplane that sits outside should always have the tanks topped off.

Also, since the days are so short in the winter, I usually try to plan on only making one-way flights if I'm actually going somewhere. Although I enjoy it, I try not to fly much after dark when it's really cold. If you have a problem the chances of being able to make a good emergency landing are not very good and your chances of survival go down very rapidly if you are injured. Skis are a good insurance policy which improve your chances of surviving a forced landing and they are great fun, but that's another story.

I really enjoy winter flying and look forward to it every year. The extra precautions are not a burden they are just part of the fun. It's all about attitude.

George, as far as grease is concerned, I use red Mobil Synthetic Lubricating Grease, MLITH SHC-220 in the tailwheel and main wheel bearings. It has great low and high temp properties, is very stabile, and is just about waterproof. An old Federal Fish and Wildlife pilot in Alaska told me about it. The feds used it in their amphibs as well.

Richard

[Roesbery]

The above is good advice. A couple other methods for when you are away from any services. Propane liquifies at - 40 F, you will not get any gas from it unless you warm it up, the hoses need to be artic grade or they will crack when you bend them. A small white gas catalitic heater will work down to -35 F, if used overnight with a good insulated engine cover, but you will get a lot of frost in the cabin. Another way is to carry three or four 4 inch joints of stove pipe and a adjustable elbow and a multi fuel backpack, or military type stove that will burn avegas ( should be in your survival kit anyway ). Should be large enough to hold several hours fuel set on high burn. Put the elbow over the stove with surport so that air can enter around the stove and the heat goes up the several joints of pipe to the cowling. feel the heat comming out the pipe with your hand and adjust it so that you don't burn or melt any parts. Control cables lined with plastic won't handle much heat. Take your time and when the prop will move freely the engine will start. I would usually let the engine run for awhile then shut it down and cover it up tight and let it sit for about 20 minutes, so the engine heat can spread around more. Load up the plane, then uncover wings and tail, stow the covers, then the engine cover last. start up and go.

[pdb]

it.

I regularly get water out of the fuel tanks and gascolator on the 170 with its aluminum tanks even while keeping it in a heated hangar with the tanks full. I think they are condensation magnets. Ice crystals in the fuel can plug off the tank screens if allowed to accumulate. HEET can be used in the fuel to clear out the ice but it's not approved. An airplane that sits outside should always have the tanks topped off.
ll.

Richard

Richard:

Be careful with Heet. One version, I think the common yellow container, contains methanol. The other, Iso-HEET, contains isopropanol.

The local Anchorage FSDO used to publish an Advisory Circular that specified that only ISOPROPYL could be used as an anti-icing agent for our engines and only in 50:1 mixtures. For 37 gal useable, that conveniently works out to 3 pints/wing tank.

I'll be damned if I can locate my copy of that AC but I did write down the specific kind of alcohol and the ratio to keep as a reference in the plane.

Other kinds of alcohol can cause problems for o-rings and other parts of the fuel system. I agree that keeping tanks topped is the best prevention but be especially careful the next time you push a super cold plane into a warm hangar. If there is any moisture in the air at all, the plane, and the voids in your tank will atttract the moisture and cause condensation.

[GAHorn]

I once made some pretty strong opinionated statements (I know. I know. Hard to believe, huh?) regarding the addition of alcohol to fuel intended for aviation use. I consider it very hazardous. Our aircraft type certificate prohibits it.
But the FAA did produce an AC some years ago recommending isopropyl (in 1% proportions) as an anti-icing additive. I don't know why they specified isopropyl, as methanol is used in many aircraft for fuel anti-icing, but ...isopropyl is what was specified.
I'd like to make certain that everyone recognizes this is NOT the rubbing alcohol you have in your bathroom (which is likely diluted with glycerin and water to a 70% mix.) Isopropyl can be purchased at many paint/harware stores, etc., but it is NOT necessarily the same as "Denatured Alcohol" either. (Be careful to read the container.)

100% Isopropyl can also be purchased at many aviation supply houses.

All alcohol is corrosive to aircraft fuel systems and will degrade any rubber components like gaskets, O-rings, etc. Don't be surprised if you later find yourself overhauling/rebuilding your carburetor, if you use it.

[pdb]

I'd like to make certain that everyone recognizes this is NOT the rubbing alcohol you have in your bathroom (which is likely diluted with glycerin and water to a 70% mix.) Isopropyl can be purchased at many paint/harware stores, etc., but it is NOT necessarily the same as "Denatured Alcohol" either. (Be careful to read the container.)

100% Isopropyl can also be purchased at many aviation supply houses.

All alcohol is corrosive to aircraft fuel systems and will degrade any rubber components like gaskets, O-rings, etc. Don't be surprised if you later find yourself overhauling/rebuilding your carburetor, if you use it.

George

Thanks for the follow up. As I was rummaging through my files I came across the Cessna Service Information Letter SE79-30 dtd 6/18/1979 which confirms your 100/1 ratio for isopropyl. I 'll go with Cessna over the FAA on this one. It also stresses the importance of completely mixing the isopropyl in the fuel, either by introducing it directly into fuel stream from the nozzle when fueling or by mixing the isopropyl in a separate container with 2-3 gallons of gas and then pouring that into the tanks.

In any case, any alcohol can't be doing the fuel system any good. The best method is the old standby of keeping the tanks full and the sumps well drained and using the isopropyl sparingly if at all.

By the way... the FAA also advises that it's ok to land Cub on a lake if you see moose tracks but that landing on sea ice near polar bear tracks is dangerous as a polar bear can (and do) spread their legs wide and cross ice on which a man will fall through. Is this the sort of arctic flying tips that the group finds helpful?

[hilltop170]

Pete and George-
I agree with you on not using HEET or any alcohol if you don't have to. If I recall properly, Cessna says don't use methanol because it might damage rubber fuel bladders as in the C-180/185 and other rubber parts in the fuel system. Alcohol also lowers the octane rating of the fuel but that's not a concern unless your engine requires 100 octane fuel. The yellow HEET bottles contain methanol. Do not use the yellow bottle HEET in an airplane.

Isopropyl alcohol is not supposed to damage the rubber components (as bad?). HEET in the red bottle contains isopropyl. The red bottle is the only type I would ever use and only if it is a last resort. If I'm caught outside with ice crystals in the tank and no hope of getting into a warm hangar, I'd use the red bottle HEET. I don't think a one time use will really hurt much but I wouldn't run a steady diet of it. In 37 gallons, 1% is 1-1/2 pint per tank, 3 pints total.

I really don't understand why I've been getting so much water out of the tanks unless it accumulated in the 6 months the plane was down for overhaul and the system was drained. I guess it just takes time and agitation to get it all out. At least it's clean looking water. I especially don't want to put any additives in the fuel to help dry it up during the break-in process and probably for at least the first 50 hours. In the mean time I'll keep the tanks full and see how it goes.