Teach Me About Deicing

NealRomeoGolf

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What are the parameters where airlines deice? Precip? Temp?

And why do they have to run the engines up after doing a spray? Dry out the overspray?

And why does it take so long? Luckily I made my connecting flight.
 
I don't know how to summarize the deice procedures in a short message. It is complex and extensive. Regulations require us to maintain the clean aircraft concept. We can not takeoff with contamination adhering to the aircraft.

If there is no active icing conditions (snow, sleet, freezing rain, frost, etc.) occurring, it's pretty easy. Any contamination must be removed.

If there is ongoing active icing then we first have to clean the airplane and then provide protection which will prevent contaminates from adhering before takeoff. This is normally accomplished with two applications. The first is a deicing application which uses heated Type I fluid (usually pink in color). While this removes existing contamination, it does not provide significant protection from new contamination. The anti-ice application is a cold Type IV (Type II has been replaced) fluid (green). The Type IV fluid is a thick gel that remains on the airplane's surfaces and collects the falling precipitation, preventing it from reaching the airframe. During takeoff, the Type IV gel shears off the airplane taking the contamination with it.

Type I and IV fluids have holdover times. This is the time during which it can protect the aircraft under a specific set of conditions of temperature and type and intensity of precipitation. Type I has very short holdover times which generally do not allow enough time to finish deicing, taxi, and takeoff so a Type I then Type IV application is generally needed with active icing conditions.

After deicing/anti-icing, just before takeoff, a "nose check" is accomplished. We look for signs of contamination on the surfaces visible from the cockpit. If we are within our holdover time, and the "nose check" looks good, we can takeoff. If the holdover time expires, a "wing check" is required within 5 minutes of takeoff. This involves qualified ground personnel inspecting the wings for contamination or, more commonly, one of the pilots going back and inspecting the wings from the passenger cabin. If the "wing check" passes, you have five minutes to takeoff before another "wing check" is required. If the "wing check" fails, you have to go back to deice/anti-ice again.

There are conditions, such as freezing rain and heavy snow, where it is not possible to maintain a clean airplane long enough to takeoff.

The engine runup is because the engine inlets and engine pressure probes are deiced by bleed air. At ground-idle, the temperature and flow rate of the bleed air is insufficient so periodic engine runups are required to ensure the inlets and pressure probes are clear. It doesn't have anything to do with having been sprayed, other than both deicing/anti-icing and the engine runups are required during active icing conditions.

Much of the time it takes for deicing is waiting your turn. An airline schedule has a lot of flights departing within a short period of time and, when they all have to deice, the deicing process will be a bottleneck. If there is no wait for a deice team, the process will take around ten minutes, plus or minus, depending on the conditions and the size of the deice team (1 truck or multiple trucks).

At stations where they frequently have winter weather, the deice crews get pretty good as running the deice operation. At stations where they only deice a few times per year, it's going to take longer because training doesn't take the place of experience and currency.

Bottom line is that when deicing operations on in progress, flights will be delayed. With that in mind, I bid my January schedule to avoid winter to the extent possible. I have layovers in Sint Maarten, Aruba, Nassau, Ft. Myers, & Palm Beach.
 
I don't know how to summarize the deice procedures in a short message. It is complex and extensive. Regulations require us to maintain the clean aircraft concept. We can not takeoff with contamination adhering to the aircraft.

If there is no active icing conditions (snow, sleet, freezing rain, frost, etc.) occurring, it's pretty easy. Any contamination must be removed.

If there is ongoing active icing then we first have to clean the airplane and then provide protection which will prevent contaminates from adhering before takeoff. This is normally accomplished with two applications. The first is a deicing application which uses heated Type I fluid (usually pink in color). While this removes existing contamination, it does not provide significant protection from new contamination. The anti-ice application is a cold Type IV (Type II has been replaced) fluid (green). The Type IV fluid is a thick gel that remains on the airplane's surfaces and collects the falling precipitation, preventing it from reaching the airframe. During takeoff, the Type IV gel shears off the airplane taking the contamination with it.

Type I and IV fluids have holdover times. This is the time during which it can protect the aircraft under a specific set of conditions of temperature and type and intensity of precipitation. Type I has very short holdover times which generally do not allow enough time to finish deicing, taxi, and takeoff so a Type I then Type IV application is generally needed with active icing conditions.

After deicing/anti-icing, just before takeoff, a "nose check" is accomplished. We look for signs of contamination on the surfaces visible from the cockpit. If we are within our holdover time, and the "nose check" looks good, we can takeoff. If the holdover time expires, a "wing check" is required within 5 minutes of takeoff. This involves qualified ground personnel inspecting the wings for contamination or, more commonly, one of the pilots going back and inspecting the wings from the passenger cabin. If the "wing check" passes, you have five minutes to takeoff before another "wing check" is required. If the "wing check" fails, you have to go back to deice/anti-ice again.

There are conditions, such as freezing rain and heavy snow, where it is not possible to maintain a clean airplane long enough to takeoff.

The engine runup is because the engine inlets and engine pressure probes are deiced by bleed air. At ground-idle, the temperature and flow rate of the bleed air is insufficient so periodic engine runups are required to ensure the inlets and pressure probes are clear. It doesn't have anything to do with having been sprayed, other than both deicing/anti-icing and the engine runups are required during active icing conditions.

Much of the time it takes for deicing is waiting your turn. An airline schedule has a lot of flights departing within a short period of time and, when they all have to deice, the deicing process will be a bottleneck. If there is no wait for a deice team, the process will take around ten minutes, plus or minus, depending on the conditions and the size of the deice team (1 truck or multiple trucks).

At stations where they frequently have winter weather, the deice crews get pretty good as running the deice operation. At stations where they only deice a few times per year, it's going to take longer because training doesn't take the place of experience and currency.

Bottom line is that when deicing operations on in progress, flights will be delayed. With that in mind, I bid my January schedule to avoid winter to the extent possible. I have layovers in Sint Maarten, Aruba, Nassau, Ft. Myers, & Palm Beach.
That's an awesome explanation, thanks.

I've only experienced it once, and it was before I was a pilot. I do remember wondering why it took so long (one old truck at a small airport where they don't do it often) and why they sprayed the whole plane twice (it was sleeting at the time). Now I know :)
 
Agree, that's one of the best explanations I've read of anything.

They didn't always do all those steps in the late 80's, and I avoided connecting flights in snow areas in the winter to/from here. I remembered the coverage of the flight into the bridge in DC that happened in the early 80's. Then, more or less, a Fokker crashed taking off from LaGuardia in the 90s, and the procedures changed. In the 80's and 90's it snowed a lot more here.

I think there's only one de-ice setup at Albany. It's a small airport, and usually no delays, but there are if they have to de-ice. So the times that's happened, I'm thinking a) I'm going to be late and b) I'm going to get there just fine. The younger people probably don't remember the times when "It'll probably be OK" seemed to be the mantra. This is all me as a passenger. With the little planes I fly, I avoid anything related to ice as much as possible. And yeah, I'm a baby about ice.
 
What are the parameters where airlines deice? Precip? Temp?

And why do they have to run the engines up after doing a spray? Dry out the overspray?

And why does it take so long? Luckily I made my connecting flight.

We deice any time there is contamination adhering to the aircraft (from previous precipitation, frost, accumulation from a previous flight, or slush splashing onto it from the ground), or likely to adhere (precipitation actively falling and below 40°F). The latter also requires anti-icing so they have to spray the aircraft twice, once with deice fluid (called Type I) and again with anti-ice fluid (called Type IV).

My aircraft does not require a runup after deicing, however, it does require an ice protection test before departure in icing conditions. The test involves a runup in order to ensure adequate hot bleed air to the protected surfaces, but it may be done before or after deicing. Each aircraft type has its own procedures.

It takes time to get set up, for the deicing crew to spray the aircraft, spray it a second time if anti-ice (Type IV) is required, do a walkaround, communicate with the flight crew. Then we have a checklist to accomplish that requires waiting several minutes in between steps.

The time to wait in line and the time it takes for them to spray depends on how busy and adequately equipped and staffed the facility is and how fast or slow the person spraying is. I remember getting sprayed one morning by two trucks at once--one doing the left side and the other doing the right side. That was nice. Usually the process is about as fun as being stuck in a traffic jam on the interstate due to an accident.
 
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Med/big plane (A330) would get a small FLEET of trucks to deice at a properly equipped airport… an impressive ballet.
 
Only thing I can add is we do run-ups on the B777 and the A320 for ice-shedding and to minimize ice build up on non anti-iced surfaces like fan blades, not due to lack of bleed pressure at idle.
 
Same for the A330. It has sufficient bleed air at idle to anti ice the cowls. Fan blades however have no protection so the engines are periodically run up to shed the fan blade ice via centrifugal force. The time limits are set to prevent ice buildup on the fan from reaching a point where it can cause damage when shed.
 
Edmonton has a neat little setup, with indicator lights and digital signage for the pilots. Pull up when it’s your turn, get hosed down, next. They were running a couple at a time.
 
Can you go straight to Type IV? Say pulling it right out of the hangar?
 
Can you go straight to Type IV? Say pulling it right out of the hangar?

If you can do it before any precipitation hits the surface. The type 1 has a little anti ice value, and the type 4 was probably certified only after application of type 1. Remember that it has to shear off and I'm not sure what speed it needs. Maybe in excess of 80 knots. Different brands of type 4 have different holdover times.

If they anti ice our planes, in anticipation of frozen precipitation falling to sit over night, the type 4 has to be washed off with type 1 before the aircraft can depart.
 
If you can do it before any precipitation hits the surface. The type 1 has a little anti ice value, and the type 4 was probably certified only after application of type 1. Remember that it has to shear off and I'm not sure what speed it needs. Maybe in excess of 80 knots. Different brands of type 4 have different holdover times.

If they anti ice our planes, in anticipation of frozen precipitation falling to sit over night, the type 4 has to be washed off with type 1 before the aircraft can depart.
Type IV is designed to shear in the 100-110 kt range. I’ve watched the wing when riding in the back and you can see it suddenly liquify and run off. Kinda cool.
 
I don't know how to summarize the deice procedures in a short message. It is complex and extensive. Regulations require us to maintain the clean aircraft concept. We can not takeoff with contamination adhering to the aircraft.

If there is no active icing conditions (snow, sleet, freezing rain, frost, etc.) occurring, it's pretty easy. Any contamination must be removed.

If there is ongoing active icing then we first have to clean the airplane and then provide protection which will prevent contaminates from adhering before takeoff. This is normally accomplished with two applications. The first is a deicing application which uses heated Type I fluid (usually pink in color). While this removes existing contamination, it does not provide significant protection from new contamination. The anti-ice application is a cold Type IV (Type II has been replaced) fluid (green). The Type IV fluid is a thick gel that remains on the airplane's surfaces and collects the falling precipitation, preventing it from reaching the airframe. During takeoff, the Type IV gel shears off the airplane taking the contamination with it.

Type I and IV fluids have holdover times. This is the time during which it can protect the aircraft under a specific set of conditions of temperature and type and intensity of precipitation. Type I has very short holdover times which generally do not allow enough time to finish deicing, taxi, and takeoff so a Type I then Type IV application is generally needed with active icing conditions.

After deicing/anti-icing, just before takeoff, a "nose check" is accomplished. We look for signs of contamination on the surfaces visible from the cockpit. If we are within our holdover time, and the "nose check" looks good, we can takeoff. If the holdover time expires, a "wing check" is required within 5 minutes of takeoff. This involves qualified ground personnel inspecting the wings for contamination or, more commonly, one of the pilots going back and inspecting the wings from the passenger cabin. If the "wing check" passes, you have five minutes to takeoff before another "wing check" is required. If the "wing check" fails, you have to go back to deice/anti-ice again.

There are conditions, such as freezing rain and heavy snow, where it is not possible to maintain a clean airplane long enough to takeoff.

The engine runup is because the engine inlets and engine pressure probes are deiced by bleed air. At ground-idle, the temperature and flow rate of the bleed air is insufficient so periodic engine runups are required to ensure the inlets and pressure probes are clear. It doesn't have anything to do with having been sprayed, other than both deicing/anti-icing and the engine runups are required during active icing conditions.

Much of the time it takes for deicing is waiting your turn. An airline schedule has a lot of flights departing within a short period of time and, when they all have to deice, the deicing process will be a bottleneck. If there is no wait for a deice team, the process will take around ten minutes, plus or minus, depending on the conditions and the size of the deice team (1 truck or multiple trucks).

At stations where they frequently have winter weather, the deice crews get pretty good as running the deice operation. At stations where they only deice a few times per year, it's going to take longer because training doesn't take the place of experience and currency.

Bottom line is that when deicing operations on in progress, flights will be delayed. With that in mind, I bid my January schedule to avoid winter to the extent possible. I have layovers in Sint Maarten, Aruba, Nassau, Ft. Myers, & Palm Beach.
hope you don't have to deice at rsw, i don't think there is even a truck on the field. i had frost one morning in KGNV one morning and had to wait until the sun came up and melt it to leave.
 
Type IV is designed to shear in the 100-110 kt range. I’ve watched the wing when riding in the back and you can see it suddenly liquify and run off. Kinda cool.
when i was flying the ATR, we were still using type 2. the shear speed was right in the rotation range and it made for a real interesting pitch change right after the mains came off do to the shear.
 
hope you don't have to deice at rsw, i don't think there is even a truck on the field. i had frost one morning in KGNV one morning and had to wait until the sun came up and melt it to leave.
Our station info page for RSW doesn't mention deicing so I'm not sure if there's a truck or not. If they do, I doubt its used for much other than an occasional defrost in the mornings.
 
This is all you need to know...
IMG_9923.JPG

Good use of your PPL.
IMG_9921.JPG
 
Another issue that may/will affect the time it takes to deice is the required aircraft configuration for the de/anti-icing to take place. On something like the 777, depending on airport procedures, types of trucks, etc., you may have to shut down one or both engines (and/or APU) in order to get sprayed. Then, after it's complete, re-start, more checklists, etc. before you can get back on your way.
 
I don't know how to summarize the deice procedures in a short message. It is complex and extensive. Regulations require us to maintain the clean aircraft concept. We can not takeoff with contamination adhering to the aircraft.

If there is no active icing conditions (snow, sleet, freezing rain, frost, etc.) occurring, it's pretty easy. Any contamination must be removed.

If there is ongoing active icing then we first have to clean the airplane and then provide protection which will prevent contaminates from adhering before takeoff. This is normally accomplished with two applications. The first is a deicing application which uses heated Type I fluid (usually pink in color). While this removes existing contamination, it does not provide significant protection from new contamination. The anti-ice application is a cold Type IV (Type II has been replaced) fluid (green). The Type IV fluid is a thick gel that remains on the airplane's surfaces and collects the falling precipitation, preventing it from reaching the airframe. During takeoff, the Type IV gel shears off the airplane taking the contamination with it.

Type I and IV fluids have holdover times. This is the time during which it can protect the aircraft under a specific set of conditions of temperature and type and intensity of precipitation. Type I has very short holdover times which generally do not allow enough time to finish deicing, taxi, and takeoff so a Type I then Type IV application is generally needed with active icing conditions.

After deicing/anti-icing, just before takeoff, a "nose check" is accomplished. We look for signs of contamination on the surfaces visible from the cockpit. If we are within our holdover time, and the "nose check" looks good, we can takeoff. If the holdover time expires, a "wing check" is required within 5 minutes of takeoff. This involves qualified ground personnel inspecting the wings for contamination or, more commonly, one of the pilots going back and inspecting the wings from the passenger cabin. If the "wing check" passes, you have five minutes to takeoff before another "wing check" is required. If the "wing check" fails, you have to go back to deice/anti-ice again.

There are conditions, such as freezing rain and heavy snow, where it is not possible to maintain a clean airplane long enough to takeoff.

The engine runup is because the engine inlets and engine pressure probes are deiced by bleed air. At ground-idle, the temperature and flow rate of the bleed air is insufficient so periodic engine runups are required to ensure the inlets and pressure probes are clear. It doesn't have anything to do with having been sprayed, other than both deicing/anti-icing and the engine runups are required during active icing conditions.

Much of the time it takes for deicing is waiting your turn. An airline schedule has a lot of flights departing within a short period of time and, when they all have to deice, the deicing process will be a bottleneck. If there is no wait for a deice team, the process will take around ten minutes, plus or minus, depending on the conditions and the size of the deice team (1 truck or multiple trucks).

At stations where they frequently have winter weather, the deice crews get pretty good as running the deice operation. At stations where they only deice a few times per year, it's going to take longer because training doesn't take the place of experience and currency.

Bottom line is that when deicing operations on in progress, flights will be delayed. With that in mind, I bid my January schedule to avoid winter to the extent possible. I have layovers in Sint Maarten, Aruba, Nassau, Ft. Myers, & Palm Beach.

On top of all this you have to fly the airplane, wowzers, mind boggling, cheers.
 
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