De-icing procedures

[matblack]

I understand the reasons why some professionals would like these forums restricted but as a frequent flyer (and mech. engineer) I read these forums in order to make informed decisions when making my travel arrangements. One area that has always concerned me is winter travel. Over the past few years I have noticed some differences between airlines with regards to de-icing. With BA I've experienced de-icing on every occasion when I've been the first flight out on a frozen morning (including sometimes being de-iced up to 3 times because of delays taxying and holding (20 minutes max between de-ice and take-off the pilot told us)). I took an early morning flight out of Kastrup with white frost clearly visible on the leading edge and upper wing surface of a Maersk 737 and yet no de-ice whereas other airlines were de-icing. It was also dark when the FO did his walk around. After many trips (even in Summer) on SAS MD-82/3 I asked why someone puts a ladder up to the wing and climbs up? To check for ice was the answer, even in warmer weather due to cold soak of the fuel. Do all MD 82/83 operators have the same purpose designed ladders and conduct the same checks at all of the airports they visit? Apparrently it all relates to an accident caused by ice breaking off the wings and damaging both engines simultaneously. A Ryanair departure from Torp, FO went outside and looked from the top of the steps for a visual of the wing upper surface and we duly de-iced even though the aircraft had only arrived 45 minutes previously with no precipitation. From the overwing seat though you could see frozen droplets on the leading edge. Sorry for the verbose lead up to my question which is "do airlines have SOP's regarding de-icing or do they leave the decision up to the pilots whilst adding some extra commercial pressures?". Is a pilot who is into his "discretion" hours going to wait for a de-ice if he has to make it back to his base airport which closes at 10.30pm which he might just make if he departs immediately and gets a break with ATC?

[Intruder]

There are airline SOPs as well as government regulations on deicing. In summary, no pilot can legally take off with ANY snow or ice adhering to the wings. The only contamination allowed is frost less than 1/8" thick on the underside of the wing, where supercooled fuel in the tanks causes frost to condense on the wings.

[BOAC]

For Intruder and matblack - the 737(NG) has an approved process where dispatch with 'cold fuel-frost' on the upper surface is allowable (within certain parameters).

[The Bartender]

Eventually, the "cold corner" was fixed by adding a Heater Blanket over that upper wing surface.

Not true AFAIK, as the brilliant Heater Blanket melted the clear-ice, wich subsequently froze again as it left the heated area, on the flaps...

I know SAS had these blankets installed on some aircrafts, but after the above was discovered, they were all disconnected.

I actually figured this was another failed "SAS-special" (like the MD-90 with ballast-bags instead of forward airstairs), because i've never seen other operators MD's with these blankets... :bored:

[Noak]

Before every departure one of the pilots or trained ground staff perform a contamination check from an elevated position to check that the aircraft is free from contamination (as mentioned earlier we may have some frost - up to 3 mm - on the lower wing surface within the wing tank areas. Also a thin layer of frost on the upper part of the fuselage is permitted).
The SAS MD-80's do have the inboard wing heater system in operational use. The system is installed to remove/prevent clear ice formation on the inboard end of the main wing tank upper surface ("cold corner").
Under certain conditions (i.e. the wing heaters are u/s and the outside temperature are below a certain value etc.) a clear ice check may be required. This check is a hands-on check.

[The Bartender]

The SAS MD-80's do have the inboard wing heater system in operational use.

Ok... The instructor said otherwise the last times i've attended the SAS de-icing courses, but it doesn't really matter..

[plain-plane]

Well this whole subject is fairly well regulated. And all the pilot has to do is follow the company SOP, which will insure that (s)he follows the letter of the law.
Most pilots go; if in doubt, your are not in doubt, you de-ice.
The pilots who operate more in icing conditions, will have more experience in with this subject and will on fewer occasions be in doubt, leading to maybe not de-icing an that occasion. Hence you can have two crews where one decides to deice and the other will not.

PS: when it comes to non environmental icing NEI, a low of factors comes into play, the A/C next to you might need to deice, but the A/C you are on might not, and so on