767ALLTHEWAY From United States of America, joined Nov 1999, 659 posts, RR: 0 Posted (15 years 1 month 2 weeks 4 days ago) and read 2129 times:
What are the parameters in the weather that requires and aircraft to be de-iced before departure? Does it have to do with how long the aircraft was staionary in winter precipitation? or are there other factors that affect when de-icing begins/stops?
Thanks in Advance,
"Courage is not the absence of fear, but rather the judgement that something else is more important than fear"
OPNLguy From , joined Dec 1969, posts, RR:
Reply 1, posted (15 years 1 month 2 weeks 3 days 23 hours ago) and read 2079 times:
1/ FARs prohibit takeoffs with snow ice adhering to the aircraft.
2/ Once an aircraft has been de-iced, the time interval before it must again be de-iced is based on many variables, such as:
* Type of precip falling (snow, ice pellets, freezing rain).
* Intensity of precip (light, moderate, heavy),
* Type of de-ice fluid (Type-1, -2, -3, -4),
All of these things (and others) affect the effectiveness of the de-icing fluid, since the precip (water) is diluting the fluid. This effective time of the fluid is called "holdover time" and it's really brief (2-3 minutes) in some freezing rain conditions, and much longer for dry snow conditions.
After USAir lost 405 at LGA back in 1992 (F-28 on takeoff, iced up) Faa held a major industry conference on de-icing, and lots of loopholes and gray areas were tightened up, and folks have a better understanding about the threat(s) if procedures are properly followed.
Kaitak From Ireland, joined Aug 1999, 13175 posts, RR: 33
Reply 4, posted (11 years 3 weeks 4 days 9 hours ago) and read 1984 times:
Just curious about de-icing (but you'll have guessed that already!).
At airports where there can be long queues and which are also susceptible to extreme cold - eg JFK, ORD, DTW, YYZ, how long before t/o can the aircraft be de-iced. It occurs to me that if it's de-iced at the gate, but is then in a 20+ aircraft queue, it might need more de-icing before it takes off - particularly if jet blast from aircraft in front affects surfaces such as leading edges, which have already been de-iced.
Dalmd88 From United States of America, joined Jul 2000, 2847 posts, RR: 13
Reply 5, posted (11 years 3 weeks 4 days 5 hours ago) and read 1954 times:
Most modern jets have heated leading edges so once they are de iced and the engines are started the leading edges stay clean. The tops of the wing and the control surfaces are the real problem while waitng on the ground. Some weather prone airports de ice near the end of the runway, so re applying isn't an issue. PIT I think was the first to use this system.
L-188 From United States of America, joined Jul 1999, 30265 posts, RR: 57
Reply 7, posted (11 years 3 weeks 4 days 3 hours ago) and read 1922 times:
"Type 4 is a fluid only applied to large aircraft."
I personally have put it on 25/35 series lears.
But getting back to the original subject. There is no set standard rule for de-icing. The rules will be laid out in the companies ops manuals, and that is a negotiated document with the FAA. There are certain things they like to see, but their hard and fast rule, is simply the airplane has to be clean. Unless noted in that ops-spec there is no limitation on how to do it.
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Smcmac32msn From United States of America, joined May 2004, 2211 posts, RR: 4
Reply 8, posted (11 years 3 weeks 4 days 3 hours ago) and read 1927 times:
It doesn't matter what size the plane is. Its the conditions that dictate the type, unless the deicing company does not have type IV. Type IV holds over longer than type I, thats why they did it with type IV.
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