Grbld From Netherlands, joined Dec 2005, 353 posts, RR: 3
Reply 1, posted (8 years 7 months 1 week 3 days 10 hours ago) and read 2173 times:
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.
TimT From United States of America, joined Jun 2001, 168 posts, RR: 0
Reply 2, posted (8 years 7 months 1 week 3 days 8 hours ago) and read 2144 times:
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 From Brazil, joined Apr 2005, 192 posts, RR: 0
Reply 3, posted (8 years 7 months 1 week 2 days 13 hours ago) and read 2072 times:
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
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 4, posted (8 years 7 months 1 week 2 days 13 hours ago) and read 2067 times:
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.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
Poitin From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 7 months 2 days 12 hours ago) and read 1939 times:
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.
2H4 From United States of America, joined Oct 2004, 8955 posts, RR: 60
Reply 7, posted (8 years 7 months 2 days 8 hours ago) and read 1892 times:
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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.
Starlionblue From Greenland, joined Feb 2004, 17035 posts, RR: 67
Reply 8, posted (8 years 7 months 2 days 6 hours ago) and read 1863 times:
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.
"There are no stupid questions, but there are a lot of inquisitive idiots."