Good Day,
I don't operate in COLD WX a lot, so got limited experience...
Referring to the HOT with Rain on a Cold Soaked Wing and the limited time it offers. Any info is appreciated.
2 x questions:
1) If you DE-ICE a cold soaked wing with Type I... followed by Anti- Ice Type II/IV, and you have moderate rain, do you still have a cold soaked wing, meaning you have to refer to the very limited HOT as mentioned above.
2) What is the definition of a cold soaked wing please? Can't seem to find it written in any manual...I have my ow definition, but looking for one in the manuals.
Is that correct of am I misunderstanding this....
Somehow it makes sense that you've cleaned the wing, heated it up with heated fluid, so the surface temp is OK, but you might still have Sub zero fuel in the tank, touching either the bottom, and more than often the top wing.
Thank you.
Regards
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- GalaxyFlyer
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Re: Cold Soaked Wing
Here’s NASA’s definition
Cold-soak Effect: The wings of aircraft are said to be “cold-soaked” when they contain very cold fuel as a result of having just landed after a flight at high altitude or from having been re-fuelled with very cold fuel. Whenever precipitation falls on a cold-soaked aircraft when on the ground, clear icing may occur. Even in ambient temperatures between -2°C and +15°C, ice or frost can form in the presence of visible moisture or high humidity if the aircraft structure remains at 0°C or below. Clear ice is very difficult to be detected visually and may break loose during or after takeoff. The following factors contribute to cold-soaking: temperature and quantity of fuel in fuel cells, type and location of fuel cells, length of time at high altitude flights, temperature of re-fuelled fuel and time since re-fuelling.
Cold Soaking Ice can form even when the outside air temperature (OAT) is well above 0°C (32°F). An aircraft equipped with wing fuel tanks may have fuel that is at a sufficiently low temperature such that it lowers the wing skin temperature to below the freezing point of water. If an aircraft has been at a high altitude, where cold temperature prevails, for a period of time, the aircrafts’ major structural components such as the wing, tail and fuselage will assume the lower temperature, which will often be below the freezing point. This phenomenon is known as cold soaking. While on the ground, the cold soaked aircraft will cause ice to form when liquid water, either as condensation from the atmosphere or as rain, comes in contact with critical surfaces.
From here,https://aircrafticing.grc.nasa.gov/documents/AircraftIcing_Glossary.pdf
Think of it as freezing rain, liquid rain falls onto cold surface, splatters and freezes.
GF
Cold-soak Effect: The wings of aircraft are said to be “cold-soaked” when they contain very cold fuel as a result of having just landed after a flight at high altitude or from having been re-fuelled with very cold fuel. Whenever precipitation falls on a cold-soaked aircraft when on the ground, clear icing may occur. Even in ambient temperatures between -2°C and +15°C, ice or frost can form in the presence of visible moisture or high humidity if the aircraft structure remains at 0°C or below. Clear ice is very difficult to be detected visually and may break loose during or after takeoff. The following factors contribute to cold-soaking: temperature and quantity of fuel in fuel cells, type and location of fuel cells, length of time at high altitude flights, temperature of re-fuelled fuel and time since re-fuelling.
Cold Soaking Ice can form even when the outside air temperature (OAT) is well above 0°C (32°F). An aircraft equipped with wing fuel tanks may have fuel that is at a sufficiently low temperature such that it lowers the wing skin temperature to below the freezing point of water. If an aircraft has been at a high altitude, where cold temperature prevails, for a period of time, the aircrafts’ major structural components such as the wing, tail and fuselage will assume the lower temperature, which will often be below the freezing point. This phenomenon is known as cold soaking. While on the ground, the cold soaked aircraft will cause ice to form when liquid water, either as condensation from the atmosphere or as rain, comes in contact with critical surfaces.
From here,https://aircrafticing.grc.nasa.gov/documents/AircraftIcing_Glossary.pdf
Think of it as freezing rain, liquid rain falls onto cold surface, splatters and freezes.
GF
Re: Cold Soaked Wing
Thank GF,
Now if you DE ICED the wing...will the COLD SOAK still be valid, as the wing surface is heated, but the cold still fuel, followed by Anti Icing en then moderate rain falls...DO you have to follow the RAIN ON A COLD SOAKED WING table?
Regards
Now if you DE ICED the wing...will the COLD SOAK still be valid, as the wing surface is heated, but the cold still fuel, followed by Anti Icing en then moderate rain falls...DO you have to follow the RAIN ON A COLD SOAKED WING table?
Regards
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- GalaxyFlyer
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Re: Cold Soaked Wing
I don’t think you can credit the de-icing as a warmed wing, if cold fuel is still indicated.
GF
GF
Re: Cold Soaked Wing
Cold soak also has an effect on the dimensions of a wing and it's components. On a test flight, we flew a 747-400 from PAE to GGW (about 1,000 miles) with #4 engine intensionally not running to cold soak the wing in the vicinity of where the pylon attaches. after landing at GGW we removed an upper wing access panel and took measurements between the fuel line and structure.
Re: Cold Soaked Wing
On moderate rain on cold soaked wings you don't have Holdover time. Only on light rain conditions you will have Holdover time. The wings temp will still be bellow 0 after DE/ANTI icing but they will be protected from refreezing untill the aircraft will be airborne in a specified time frame given by HOT Time Tables.
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