De Icing Policy
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De Icing Policy
I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.
Re: De Icing Policy
The A320 in question probably had frost adhering to its critical surfaces. Deicing fluid is only effective before takeoff. During the takeoff run, the fluid is sheared from any surface it is on. In flight icing can only be treated with an aircrafts on board systems such as: Compressor bleed air heated leading edges, pneumatic rubber boots, heated prop etc.. The frost on the aircraft wing probably happened around sunrise, as this is the coldest time during the day.
Re: De Icing Policy
The "small square device attached to the center post " is a checklist
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Re: De Icing Policy
It is also possible that frost formed after landing, on portions of the wing that contained fuel that was cooled to well below the freezing point (as a result of the prior flight). I remember an Air Canada A320 needing de-ice spray in San Francisco one clear (but humid) summer evening when the OAT was about 15 for exactly that reason. The airport authority advised that it would take at least 4 hours to get a truck out to the plane. The Captain (a friend of mine) went outside, found a push broom and a ladder, and cleaned all the frost off himself. We then departed about 45 minutes behind schedule.darbel wrote:The frost on the aircraft wing probably happened around sunrise, as this is the coldest time during the day.
Michael
Re: De Icing Policy
So your basing everything on what you saw? Did you climb up and perform a tactile inspection? Just because it's 3 degrees and no frost on the ground doesn't mean there's none on aircraft that's been sitting outside all night.Cobra64 wrote:I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.
Re: De Icing Policy
I think Cobra was asking a genuine question and was not questioning the crew's decision.whiteguy wrote:So your basing everything on what you saw? Did you climb up and perform a tactile inspection? Just because it's 3 degrees and no frost on the ground doesn't mean there's none on aircraft that's been sitting outside all night.Cobra64 wrote:I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.
- iwannasoar
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Re: De Icing Policy
hey Whiteguy.............Relax , try to make friends not foes!whiteguy wrote:So your basing everything on what you saw? Did you climb up and perform a tactile inspection? Just because it's 3 degrees and no frost on the ground doesn't mean there's none on aircraft that's been sitting outside all night.Cobra64 wrote:I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.

- flying4dollars
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Re: De Icing Policy
whiteguy wrote:So your basing everything on what you saw? Did you climb up and perform a tactile inspection? Just because it's 3 degrees and no frost on the ground doesn't mean there's none on aircraft that's been sitting outside all night.Cobra64 wrote:I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Oh and one other thing. When standing on the bridge I watched the flight crew doing something to a small square device attached to the center post on the window, above the mode control panel. What was this?
Thanks.
I think that's why he's asking. I didn't see him questioning the crews decision. Relax.
Re: De Icing Policy
Sorry folks, didn't mean to come across so harsh. That was not my intent, apologies!
Re: De Icing Policy
If the airport is large enough, head out around sunrise and you may see them pre-spraying type 1 for frost before anybody shows up on the gate.Cobra64 wrote:I just recently started working on the ramp with AC and am confused about something. This morning it was beautiful, about 3 degrees not a cloud in the sky. I'm talking perfectly clear. There was no frost or moisture on the ground. And yet, when a 320 was leaving it got the e spray. I'm wondering what the SOP is for this, because as far as I can see from a bit of research, icing should only be a concern when it is below zero and there is clouds.
Thanks.
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Re: De Icing Policy
Cobra,
The airplane may have come in on an allnighter-the fuel in the tanks can be extremely cold.
Depending on the temp/dew point spread, frost can then occur at temps you would't expect it to.
The frost on the underside of the wing is allowable to an 1/8th of an inch-but none can be on the topside.
Cheers
The airplane may have come in on an allnighter-the fuel in the tanks can be extremely cold.
Depending on the temp/dew point spread, frost can then occur at temps you would't expect it to.
The frost on the underside of the wing is allowable to an 1/8th of an inch-but none can be on the topside.
Cheers
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Re: De Icing Policy
As examples, fuel stored in the ground can be cold, so that can make the wings colder than the air. Aircraft can arrive with cold fuel if the flight has been in a -60C (or so) temp for a few hours, say YYZ-YQR vs YWG-YQR. The previous flight could arrive with a condition require a deice prior to departure for the next flight. There are various materials that appear more susceptible to frost. It appears that some parts of the 320 particularly fit that description. The 320 types do seem to head to the deice bay more often than a lot of aircraft.
In my experience, different companies have more "latitude" in their policy... or pressure to save time and money at the potential expense of safely? At AC, at least, most of the deice policy is pretty cut-n-dried with very few options in the deice decision algorithm, especially since the political bureaucracy is involved.
The pendulum has swung a considerable distance since Dryden. Maybe working to the lowest common denominator is the only way to go. The pressure to push-on has pretty much been removed with a more or less hard and fast policy. I don't believe that much has changed in remote areas that were really the problem of the past, so likely a "Dryden" in some spot like that could happen again anyway.
Just my opinion. CR
In my experience, different companies have more "latitude" in their policy... or pressure to save time and money at the potential expense of safely? At AC, at least, most of the deice policy is pretty cut-n-dried with very few options in the deice decision algorithm, especially since the political bureaucracy is involved.
The pendulum has swung a considerable distance since Dryden. Maybe working to the lowest common denominator is the only way to go. The pressure to push-on has pretty much been removed with a more or less hard and fast policy. I don't believe that much has changed in remote areas that were really the problem of the past, so likely a "Dryden" in some spot like that could happen again anyway.
Just my opinion. CR