How cold is to cold?

[gravedigger]

Light twin piston, 18000' and air temp -40. Do you attempt it or stay on the ground? I kept put...........................

[ArcticKat]

I'd think that would be a wise choice. Although the engines may be able to remain sufficiently warm, the rubber hoses may become more brittle and rupture.

[mbav8r]

What??? Never heard of such a thing, I used to take a C414 to FL270-FL310 all winter long, never had a problem. -40C ambient on the ground was cut off. The only concern I would have is draining water from the tanks.

[Hedley]

air temp -40. Do you attempt it or stay on the ground?

Depends how much I get paid to fly. Note that
when you start operating piston aircraft at low temps,
you run the risk of congealing oil in the cooler if it
drops below the rated pour point temperature of your oil.

Do you know the rated pour point temp of your oil?
Where is the cooler located? The C310 is bad for this -
the cooler is mounted right in the nacelle air intake.

IIRC they had a problem with this on a recent episode
of Ice Pilots - one of the engines had a very high oil temp,
and they didn't understand why. The reason why is that
oil stopped circulating through the cooler because the oil
congealed in the cooler and blocked it at the very low temps.


Also, are you sure that you will not have a problem with the
crankcase breather tube plugging up? Water is a byproduct
of combustion, and in very low temps, it can freeze and plug
up the breather tube outlet. The problem is that when this
happens, the pressure in the crankcase created by the ring
blowby will blow the front crank seal, which will blow all the
oil out of the engine. This is not good.

A friend of mine had the bottom 3 or 4 inches of his breather
tube plug up solid with ice this winter in cold temps. I had to
dig it out with my jackknife. Fortunately he had two tiny holes
drilled further up where it was warmer, to act as an emergency
vent.

The above are just two of the tiny details you need to be very
familiar with, to avoid nasty problems in cold wx, like these guys
did on their North Atlantic crossing in a Baron:

[CJ3PILOT]

Edmonton Wednesday morning -40 on the ramp..

[kilpicki]

I lived in the North and we ran pistons generally all winter. Engine baffles to restrict the frontal inlet and notch the breather inside the cowl, a notch about 1/3 the diameter of the breather tube. On the 310 we had homemade adjustable/rotary baffles in front of the oil cooler, closed for take off and you could pull/push a bowden cable to open/adjust the opening. worked very well.

[oldtimer]

Early Cessna 180/182 airplanes had same problem as the C310 with the congealing oil cooler that was solved with a non congealing oil cooler. Frozen crankcase beathers problems were partially solved with a winter kit that drills holes in the tube in a warm section of the cowl and wrapping tubes with insulation. Also, what is the airplane like to fly if the heater quits,(AND IT WILL). I suppose it can be done if proper preparations are made and procedures are followed. Having said that, what does the Airplane Flight Manual say about cold weather operations?
Remember the AFM is the Bible, everything else is just hearsay.

[bush pilot]

Hedley,

I do believe that it was the oil pressure that was climbing up as a block in the cooler does not allow any movement in oil hence High pressure, as a result you will get higher oil temp but the pressure is the problem. The solution could very, it depends on the circumstances of weather (ceiling) and location of oil cooler. We would typically bring the power settings up slightly and commence a climb increasing the temp of the engine and reducing the airflow to the cooler allowing it to warm up and unblock itself however if you are .. running like i was (still -40C) the few times it happened or you are not travelling a great distance (you don't need to climb that much and risk blocking the cooler on descent with reduced power settings) you could simply decrease the power settings and get an incresed angle of attack and once again reduce the amount of cold air hitting your oil cooler. It takes a bit of time for this option but it still works. The most important part is reducing the ram air from getting to the oil cooler.

Bush

[ogc]

Early Cessna 180/182 airplanes had same problem as the C310 with the congealing oil cooler that was solved with a non congealing oil cooler. Frozen crankcase beathers problems were partially solved with a winter kit that drills holes in the tube in a warm section of the cowl and wrapping tubes with insulation. Also, what is the airplane like to fly if the heater quits,(AND IT WILL). I suppose it can be done if proper preparations are made and procedures are followed. Having said that, what does the Airplane Flight Manual say about cold weather operations?
Remember the AFM is the Bible, everything else is just hearsay.

Yeah heaters in Piston aircraft suck...

I had a nose bomb quit on me in -20, I cannot imagine what it would have been like at -40...

It really brought home the point that you need to dress for the conditions, no matter what.

[MUSKEG]

Being young and inexperienced I took a Navajo with both front and rear heat into a very cold and wintery night. Five minutes after T/O front one goes. Carry on I'm told, you've got two so who cares right. It was only a 2 hour flight. I was wearing felt packs and insulated coverals but by the time I landed I had no sensation of feeling in my feet, when I complained about no heater (again) I was told that next time just put it on Auto Pilot and go to the back to warm up. Not a word of this made up.

[Hedley]

reducing the ram air from getting to the oil cooler

You could solve that problem by installing an aluminum plate in front of the cooler to block off (eg) half the air flow, when the temps drop below -20C.

The elegant way to do this would be to install a restrictor plate that covered the entire face, with a couple large holes drilled.

However, with no paperwork on this, if you get caught, you are sure to be punished because you are an Evil Man and will be sent straight to Hell to warm up.

PS Tell Mikey the crazy f_cks from Smiths Falls say "hi"

[bush pilot]

We had the restrictor plates yet they still congealed on the mother $%#$#&% cold days

[JMACK]

Being young and inexperienced I took a Navajo with both front and rear heat into a very cold and wintery night. Five minutes after T/O front one goes. Carry on I'm told, you've got two so who cares right. It was only a 2 hour flight. I was wearing felt packs and insulated coverals but by the time I landed I had no sensation of feeling in my feet, when I complained about no heater (again) I was told that next time just put it on Auto Pilot and go to the back to warm up. Not a word of this made up.

Wow PA31 flash back I flew Camaro trim from Windsor/Detroit to the GM factory in Montreal. Thank goodness we mostly ran 2 crew and would go put our feet on the heater outlet on the way home not possible loaded with trim though, so very cold. Always got pizza delivered to the FBO in YUL good times! Wouldn't trade one of those frozen minutes, love the Chieftain.

Dress warm boys and girls....Jim

[robertsailor1]

In the good old days cold winter flying was as normal as a walk in the park. We built restrictive covers for the engines and the oil coolers were restricted as well. Used to have a little system on my 180 that before shutdown I'd engage a selector which added fuel to the oil which would thin it down like water. Often on the real cold nights we'd remove the battery and keep it warm. When you fired it up the next morning you had to wait for the fuel/oil mixture to burn off the fuel in it which didn't take long.
Urban candy bum flyers talking about getting cold...I flew an open cock pit Stearman from Winnipeg to Edmonton in January..that was cold, real cold.

[International Harvester]

-54C, South Pole station in a Basler, turns carharts to plastic.

[Nark]

My final leg of my last flight in the mighty 'ho, the janitrol went out. Luckily it was only -20 outside.
I watched the oil temp and pressures like a hawk to see if the oil would congeal, however it never did.

It's incredibly funny that the amazingly high tech airplane I fly now, can't handle the temps that the mighty 'ho did. Example: the entire anti/de-ice system is automatic. It's min operating temp is -40. My last company, -45 or -50 was the cut-off for the 'ho (depending on the dispatcher...)

[kilpicki]

ah yes the cold, when your propane wont flow it's minus 40. you get into your Chev truck and the seat tells you when it's minus 40 because your head or parka touches the ceiling of the cab whereas it doesn't when its only minus 30 and the seat is pliable

reminsing from the sand box where its plus 40 as a rule

[Heliian]

Winter kits are available for a wide variety of a/c now as STC's so no cardboard and duct tape req'd. Each a/c will have temp limits for types of oil and those should be followed. Currently the a/c i'm on right now has an ambiant limit of -40 with the oil type, if we switched oils, we could go down to -54 deg C but that's too cold anyways and when the temp gets above 0 deg C you have to switch back. Most A/C have the oil temps and type limits written somewhere, whether it's the AFM or the MM. Doing some research on the type of a/c you fly would probably answer the question of how cold is too cold. Shock cooling is also bad.

For those cold days in the cockpit, pack some of those disposeable hand and foot warmer packs, they work like a charm. And dress for the weather outside, just like mom used to teach, always in layers. I get a good laugh at the guys wearing their captains shirts and loafers, trying to do a walkaround in -20 with 15kt winds, they sure look cool though.

[fish4life]

My final leg of my last flight in the mighty 'ho, the janitrol went out. Luckily it was only -20 outside.
I watched the oil temp and pressures like a hawk to see if the oil would congeal, however it never did.

It's incredibly funny that the amazingly high tech airplane I fly now, can't handle the temps that the mighty 'ho did. Example: the entire anti/de-ice system is automatic. It's min operating temp is -40. My last company, -45 or -50 was the cut-off for the 'ho (depending on the dispatcher...)

ya but when would you ever need to use the de-icing equipment if its below -40?

[Nark]

More appropriately I should have stated anti-ice system.

I'm still fascinated by it.
On the nose, there are two sensors that vibrate, when ice accumulates on it, it changes the frequency they vibrate. which sends a signal to the MAU (computer) and tells the anti-ice systems to turn on. This system is inhibited during the climb to 1700'agl, or 2 min which ever comes first. Unless we program the FMS otherwise before takeoff.
Also if it kicks on, it will increase the minimum N1 idle needed for bleed air.
It will also turn itself off if it doesn't detect ice for 5 minutes, however the min ice N1 stays, despite being +40 at the destination.


My point about -40, was the multi million dollar airplane is a sitting duck at -41 when the clapped out Navajo was still making money carrying frozen diapers and chips.