Cold soaked wing

ctab5060X · April 25th, 2008, 23:19

During our discussion of winter ops and holdover tables this week during groundschool, several of us were wondering about a specific condition listed on the holdover tables, and we are still trying to get a satisfactory answer to the question.

Holdover Time Tables Winter 2007-2008

If you look at the charts for the holdover times, there is a column that is headed "Rain on Cold Soaked Wing**" In the notes portion of the table, it states "This column is for use at temperatures above 0 degrees Celsius (32 degrees Fahrenheit) only". Further investigation into the actual times allowed for the Rain on Cold Soaked Wing column on the reference card we were given this week shows holdover times ranging from 2 minutes with Type I to 5 to 15 minutes with Type IV (depending on manufacturer and concentration). FYI, I do know that the FAA tables range from

The question we had was that considering the limited amount of time allowed from the start of de-ice/anti-ice...what is the definition of a cold soaked wing when it is raining at temperatures just above freezing? Is there a certain time after arrival that the wing becomes cold soaked? Is it a certain temperature of the surface of the wing?

Any info would be appreciated...

ElyJs · April 26th, 2008, 01:18

If your lucky enough to get off before your holdover time after deice then it ain't that bad, but if its warmer than freezing do a quick check to make sure your clean (pretakeoff contam) and blast off.

ASpilot2be · April 26th, 2008, 04:04

What is a cold soaked wing?

calcapt · April 26th, 2008, 09:40

A wing becomes cold soaked when it has been flown on longer legs and the fuel temperatures become super cold. Generally anytime the fuel is below freezing and the fuel is in contact with the upper or lower wing surface, the wing is considered to be cold soaked. When an airplane arrives at it's destination and moisture (rain or humidity) comes in contact with this wing containing very cold fuel, the moisture will freeze in the form of frost or clear ice and adhere to the wing even though the outside temperatures are well above freezing. This can catch you by surprise the first time you see it. The wing is considered to be not cold soaked when the fuel contained in it reaches temperatures above freezing. If warmer fuel is added to the aircraft before the next leg, that will normally take care of the cold soaked issue; however, if you don't add fuel, it could take quite a bit of time to allow the fuel to warm. You may be able to deice and anti-ice the wing always referring to the cold soaked wing tables in your specific aircraft manual.

On the 737, it is not unusual to see the right wing with ice or frost and the left wing with none. Why? The 737 uses fuel from the left wing (#1 tank) to cool the hydraulics and therefore the fuel in that tank is warmer than the fuel in the right wing. Your specific aircraft might have something like this and understanding your systems can help solve these little mysteries from time to time.

ASpilot2be · April 27th, 2008, 00:59

Quote:

Originally Posted by calcapt

A wing becomes cold soaked when it has been flown on longer legs and the fuel temperatures become super cold. Generally anytime the fuel is below freezing and the fuel is in contact with the upper or lower wing surface, the wing is considered to be cold soaked. When an airplane arrives at it's destination and moisture (rain or humidity) comes in contact with this wing containing very cold fuel, the moisture will freeze in the form of frost or clear ice and adhere to the wing even though the outside temperatures are well above freezing. This can catch you by surprise the first time you see it. The wing is considered to be not cold soaked when the fuel contained in it reaches temperatures above freezing. If warmer fuel is added to the aircraft before the next leg, that will normally take care of the cold soaked issue; however, if you don't add fuel, it could take quite a bit of time to allow the fuel to warm. You may be able to deice and anti-ice the wing always referring to the cold soaked wing tables in your specific aircraft manual.

Thanks.

ctab5060X · April 27th, 2008, 08:58

Thanks calcapt.

April 26th, 2008, 01:18	#2
ElyJs Junior Member Join Date: Jul 2006 Location: Boulder, Colorado Posts: 270	Re: Cold soaked wing If your lucky enough to get off before your holdover time after deice then it ain't that bad, but if its warmer than freezing do a quick check to make sure your clean (pretakeoff contam) and blast off.

April 26th, 2008, 04:04	#3
ASpilot2be Old Skool Join Date: May 2005 Location: Paradise:) Posts: 4,427	Re: Cold soaked wing What is a cold soaked wing? __________________

April 26th, 2008, 09:40	#4
calcapt Senior Member Join Date: Feb 2007 Location: Houston Posts: 812	Re: Cold soaked wing A wing becomes cold soaked when it has been flown on longer legs and the fuel temperatures become super cold. Generally anytime the fuel is below freezing and the fuel is in contact with the upper or lower wing surface, the wing is considered to be cold soaked. When an airplane arrives at it's destination and moisture (rain or humidity) comes in contact with this wing containing very cold fuel, the moisture will freeze in the form of frost or clear ice and adhere to the wing even though the outside temperatures are well above freezing. This can catch you by surprise the first time you see it. The wing is considered to be not cold soaked when the fuel contained in it reaches temperatures above freezing. If warmer fuel is added to the aircraft before the next leg, that will normally take care of the cold soaked issue; however, if you don't add fuel, it could take quite a bit of time to allow the fuel to warm. You may be able to deice and anti-ice the wing always referring to the cold soaked wing tables in your specific aircraft manual. On the 737, it is not unusual to see the right wing with ice or frost and the left wing with none. Why? The 737 uses fuel from the left wing (#1 tank) to cool the hydraulics and therefore the fuel in that tank is warmer than the fuel in the right wing. Your specific aircraft might have something like this and understanding your systems can help solve these little mysteries from time to time. __________________

April 27th, 2008, 08:58	#6
ctab5060X Senior Member Join Date: May 2007 Location: Southaven, MS Posts: 505	Re: Cold soaked wing Thanks calcapt.

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April 25th, 2008, 23:19	#1
ctab5060X Senior Member Join Date: May 2007 Location: Southaven, MS Posts: 505	Cold soaked wing During our discussion of winter ops and holdover tables this week during groundschool, several of us were wondering about a specific condition listed on the holdover tables, and we are still trying to get a satisfactory answer to the question. Holdover Time Tables Winter 2007-2008 If you look at the charts for the holdover times, there is a column that is headed "Rain on Cold Soaked Wing**" In the notes portion of the table, it states "This column is for use at temperatures above 0 degrees Celsius (32 degrees Fahrenheit) only". Further investigation into the actual times allowed for the Rain on Cold Soaked Wing column on the reference card we were given this week shows holdover times ranging from 2 minutes with Type I to 5 to 15 minutes with Type IV (depending on manufacturer and concentration). FYI, I do know that the FAA tables range from The question we had was that considering the limited amount of time allowed from the start of de-ice/anti-ice...what is the definition of a cold soaked wing when it is raining at temperatures just above freezing? Is there a certain time after arrival that the wing becomes cold soaked? Is it a certain temperature of the surface of the wing? Any info would be appreciated...