De-icing

[Maxxed out]

Just wondering how WestJetters decide when to use type 4. I was in Yul a few days back and we went to the pad for a spray and got type 1 and 4. A WestJet airplane was in the bay beside us and they took only type 1 after being questionned repeatedly by Aeromag.(not that Aeromag questionning means anything)

Out of curiousity I checked our charts, it was 1sm snow daylight hours. Which makes it light snow, type 1 gives you a holdover of 6-11 minutes from start of spray. Type 4 gives you 30 minutes minimum. 6 minutes from beginning of spray doesn't seem like much time to get airborne, and with the snow and blowing snow that day I think the fluid would have failed pretty quick. Maybe you have different charts but why would you not get type 4 on a day like that??

[Bugz]

I can't comment on that situation, but I've also seen the exact opposite. Clear blue sunny day in YYZ and saw the EMB beside us taking 1 & 4...wtf!

[Maxxed out]

I would rather err on the side of safety...

[Rotten Apple #1]

I saw Mexicana take type 4 wings, tail, and full fuselage in YUL last year. Tis a shame it wasn't St Paddy's day.

To answer the question, we use the charts.

[Ryan Coke2]

To further answer, have you heard of dan-ice? A system which takes more variables into consideration based on actual conditions to give a 'suggested' hold over time. It is advisory info only though.

Either way, what really matters is that the wing is clean before the power goes up for TO. Everything (including the regular charts, as rudimentary and extremely conservative as they usually are) is really just informational, all that matters in the end is that the wing is clean when you power up.

Believe me, if in doubt, I always go conservative course of action. But if you can safely go without 4, that is acceptable, right?

I have de-iced when no one around me is, and I haven't when most people are (though I triple check to see if I am missing anything). We all have to do what we think is right in our situation, even if it isn't what everyone else is doing (with a strong lean to being conservative, of course).

[twinpratts]

I agree with ryan... not taking the type 4 means you're gambling that you won't have to come back to the CDF, but there's always a chance you might have to turn back before takeoff.
The other thing is if it;s really cold, and the falling precip is dry snow, it may not be adhering... hence no spray.
Fly Safe.

[jjj]

Yes you are taking a gamble when one chooses to not take type IV when there is precip falling. It's a choice that we must make as mangers. Why not take an extra 5000 pounds of fuel every leg? - because if every pilot did that the costs would far outweigh the benefit. You make a choice based on the tables, your experience, how long ground says it'll take to get airborne after leaving the bay and the advice of your wingman etc.

[Four1oh]

And if we exceed a holdover time, do we not have the power to make our own judgment call by doing a pre-takeoff inspection? Perhaps this crew figured the ETD was close enough not to gamble the type IV? I don't know, wasn't there, but I did depart in -17 and BS without spraying the other day since the snow was only blowing across my wing, and ICEMAN inspected and agreed... We took off right behind a plane with type 5 goop all over his wing... not my problem, my plane was taken care of, maybe his situation was different from mine. Who am I to second guess the captain in front of me? Isn't he a professional as well?

[Maxxed out]

It just seems like going without type 4 on a day like that just means a mandatory inspection before take-off (because the 6 minutes would be up) and a probable return to the CDF, as type 1 is quit useless as a anti-ice... I agree that they would have been better off not to spray at all. Thats what I wanted to do, as the snow was all blowing off, but I got outranked, and I won't argue with someone that they are being "too cautious". I just hope that cost didn't win over safety.

[Four1oh]

To add to my last post, if my plane had been de-iced earlier in the day there would have been some 'leftovers' sticking to the wing and the snow would have stuck then. Bottom line. Worry about your own fucking airplane, and hope the guys making the 'big bucks' next door know what they're doing too.

[mulligan]

I got a great way to save money!! Took type 1 and 4 today and went YYZ-YOW. ATC slowed us to about 250kts all the way. That new green stuff is so sticky there was lots of it still on the wings. So I figger that if we just flew slow enough (200kts?) then one shot of type 4 could last all day...4 or 5 legs maybe!!:-) (how do you work those smilie things anyway?)

[twinpratts]

[rigpiggy]

As far as I know Westjet, hasn't crashed an A/C due to lack of deicing. Put that in yer hat.

[invertedattitude]

Unless things have changed, Type IV is not supposed to be put on the fuselage under any circumstances.

I'll add one thing to this conversation, take it for what it's worth.

Too many pilots flying transport category aircraft do not have a proper understanding of de-icing/anti-icing fluids uses and effects.

After more than once having a crew ask for Type I/IV because of "Anticipated icing after departure" it cemented my belief that crews are either not being trained uniformly, or not at all. I'm not speaking just of WestJet of course, in my previous experience WestJet crews were generally over-cautious in most circumstances, but applied the fluids under the correct circumstances.

An experienced de-ice team knows far more about fluid application than most crews do.

[. .]

WestJet also has approval to take off with spoiler frost. So despite seeing them depart with contaminated wings it's legal for them. Do any other Canadian 737 operators have the same privilege?

[mulligan]

What!? You're kidding right? Spoiler frost? I'd always wondered about that. I'm on the bus and I can't see why Airbus won't coat the spoilers with the same material (laminate?) that is on the rest of the wing. Lots of times we are spraying just for frosty spoiler panels while the rest of the wing is clean. Seems like something the airlines should be lobbying for.
So is it true, can you guys take off with frosty spoilers?

[. .]

Mulligan: It is true. The provision was originally requested by Southwest from Boeing. Apparently having to just spray the spoiler panels on their short turns was messing up their schedule and costing them lots of cash. So Boeing did flight testing with contaminated spoiler panels and submitted the data to the FAA. The FAA gave approval for takeoff with contaminated spoiler panels to Southwest. Transport Canada as they often do, just rubber stamped the US approval. Shortly after TC rubber stamped the approval the FAA realized they'd opened Pandora's box. It's hard to preach about a clean wing and then have exceptions. The FAA then rescinded the contaminated panel approval. Transport Canada has yet to revoke the provision though.

[FICU]

What about frosted ailerons... is that also included in the waiver?

I have hardly seen an occasion when the just the spoilers are covered in frost and the ailerons aren't.

[. .]

FICU: I believe the exemption was only for spoilers. Does anyone know if WJ is the only company in Canada able to use this policy, or does Sunwing, CanJet, etc have it too?

[daveg]

Not sure where you get this "frosty spoiler" thing from but you're wrong. We have an area on the wing outlined by a black line that as long as there is frost less than 1/16th of an inch thick (think fuel frost) we have an exemption as long as:

*the extent of the frost is similar on both wings
*the frost is on or between the black lines defining the permissible cold-soaked fuel area with no icd or frost on the leading edges or control surfaces (spoilers)

*the ambient temperature is above freezing
*no precip falling or vis less than 1 mile



........we have no exemption for frosty spoilers.

[FICU]

What area of the wing is outlined?

I had a co-worker mention that they departed on a WJ flight with frost on the spoilers and ailerons but the rest of the wing was clean... that's why I asked for clarification.

We spray if there is frost on the spoilers, the only exception being Boeing stated, is cold soaking on the underside of the wing.

[daveg]

http://www.youtube.com/watch?v=4X5bPZcf ... re=related


Have a look here... as you can see the spoilers are not part of the outlined area. Basically it's just above the fuel tank. Just about half way down the wing.

[FICU]

Thanks... nice exemption! That would save a lot of spraying due to cold soaking.

[daveg]

No prob. If there was frost on the spoilers and ailerons then they should have de-iced.

[. .]

It was awhile ago when I heard about this so I just did a bit of digging.

http://www.smartcockpit.com/data/pdfs/p ... _Frost.pdf

This pretty clearly lays it out.