ultrapig
Posts: 568
Joined: Fri Dec 12, 2003 11:38 pm

Cold Airport Operations

Fri Jan 27, 2006 4:38 am

I did a search and don't see an answer-if I've missed it let me know please


I see its 46 below in Fairbanks today


How does that affect oeprations- doesn't fuel start to gell? Can a piston engine start while cold at that temperature- How about a Jet engine?


I assume that the non engine parts of the plan have no problme with such a temperture because they operate in that temperature when cruising.
 
Grbld
Posts: 349
Joined: Tue Dec 06, 2005 9:25 pm

RE: Cold Airport Operations

Fri Jan 27, 2006 4:52 am

Ultrapig, there are other things to consider. For example, when the plane has a layover in those conditions, it may be procedure to have the batteries disconnected and the outflow valve manually closed.

Indeed, it's getting awfully close to jet fuel gelling temp, so it may be a wise idea to have some "warm" fuel added by the local fuellers when starting up.

Grbld
 
TimT
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RE: Cold Airport Operations

Fri Jan 27, 2006 6:41 am

When it's that cold, a piston engine should be warmed prior to a start attempt. In fact, it may not start, either due to not turning, or more likely the fuel won't vaporize. Even with fuel injection that sprays fuel in the cylinder it may not have enough vapor to fire. Add that to the fact the engine oil is really thick and will take some time to warm enough to provide lubrication, you get washed down cylinder walls and possibly fuel in the oil.

Jet fuel dosen't really need vapor to fire (burn) but it is atomized thru the nozzles. Rolls Royce MM spells out the temps for engine operation and requires preheat below a specific temp. And just above that temp the start sequence calls for the "rich" position on the fuel cutoff lever be used. I'n not sure about P&W's specs/limits for a cold start.

I think some of this was covered in another thread- you might get more info by doing a search for cold weather ops.
 
HiFi
Posts: 189
Joined: Fri Apr 29, 2005 5:36 am

RE: Cold Airport Operations

Sat Jan 28, 2006 2:03 am

This is valid for jet aircraft:

First, there's survivability at low temperatures... that's when an aircraft , de-energized, spends the night in a very cold place (not operating, just surviving), for example. Fuel and water reserves will probably have to be drained after landing. Then there are limits to what temperature components will endure in order to be able to start when required. If the limits are exceeded, additional proceedings will be necessary when starting up. If the temperature is within the aircraft's operational envelope, usually that's around -40º C on ground, you may re-fuel the aircraft and fly. If it's not, you don't fly.

If it's really cold (maybe around -50º C), operation is possible with a few tricks to keep components warmer... APU remains ON and the aircraft energized, for example... That will keep all the equipment inside the pressurized region in adequate conditions. Hydraulic pumps may require to be turned on and off from time to time... Engines too, in order to keep the fuel from getting too cold. Doors or access panels may need some hot air blowed.

In flight, operation might be extended to -55, -60 or even -70º C... In these conditions, the components are not always at the same temperature as external air due to Mach effect.. that's heating caused by friction. So there might be a note in the flight manual restricting operation to a determined Mach range if temperature is too low.

Lots of problems and solutions involved... and not only engines  Wink
no commercial potential
 
avioniker
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Joined: Tue Jan 01, 2002 5:38 am

RE: Cold Airport Operations

Sat Jan 28, 2006 2:18 am

On the couple of occasions I've had to RON in Fairbanks when it was that cold (the temperature actually went down as we descended from FL 370)
We kept the APU running overnight and hired a service to keep a pair of Hunter heaters blowing on the struts so they wouldn't collapse as the seals contracted in the cold.
Preheating the engines for an hour at -40 is more than just nice to have on a JT-9.
 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
Poitin
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RE: Cold Airport Operations

Sat Feb 04, 2006 3:10 am

Quoting TimT (Reply 2):
When it's that cold, a piston engine should be warmed prior to a start attempt. In fact, it may not start, either due to not turning, or more likely the fuel won't vaporize.

When I lived in Minneapolis, I thought nothing of going out to my C175 at -25 degree F, cranking it up and go flying. However, I had the battery in my house at night (to keep it warm) and the GO300 engine had the winter kit on it, including the oil dilution valve. What that did was pour av gas into the crankcase (about a quart as I remember) and dilute the oil so it was not so viscous. Normally, you put the gas in just after shutting down the engine from the previous flight, then crank the engine for a minute with the magneto off to mix it.

Below -25 degrees, we had to preheat the engine with a space heater.

As for the gas in the oil, it vaporised and went out the breather once the engine was warm. I have no idea if they do this any longer as this was 30 years ago.
Now so, have ye time fer a pint?
 
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Starlionblue
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RE: Cold Airport Operations

Sat Feb 04, 2006 7:05 am

And that's just planes.

Let's not forget the snowblowers, plougs, de-icing trucks, warm coats, boots and popsicle rampers you need.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
2H4
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RE: Cold Airport Operations

Sat Feb 04, 2006 7:16 am




Quoting Starlionblue (Reply 6):
Let's not forget the snowblowers, plougs, de-icing trucks, warm coats, boots and popsicle rampers you need.

A friend of mine flys King-Airs out of a private airport. To clear the snow from the runway, his company has a jet engine mounted on a trailer. They tow it behind a pick-up truck and aim the exhaust at the runway, clearing it with little effort and lots of kerosene.




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Starlionblue
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RE: Cold Airport Operations

Sat Feb 04, 2006 9:15 am

Quoting 2H4 (Reply 7):
A friend of mine flys King-Airs out of a private airport. To clear the snow from the runway, his company has a jet engine mounted on a trailer. They tow it behind a pick-up truck and aim the exhaust at the runway, clearing it with little effort and lots of kerosene.

LOL! That's such a typically American solution. Big grin
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
2H4
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Joined: Tue Oct 19, 2004 11:11 pm

RE: Cold Airport Operations

Sat Feb 04, 2006 9:22 am




Quoting Starlionblue (Reply 8):
LOL! That's such a typically American solution.

Indeed. The truck even has a gun rack.  sarcastic 



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