MEL: avoid icing conditions?

[Typhoon1244]

Overheard a discussion on Delta radio a couple of days ago: a Delta flight had some sort of deferral that prevented them from flying in "icing conditions," and they were explaining to their dispatcher that they couldn't go into their destination because it was reporting 5 deg. C in rain. Obviously, the Delta pilots have the same definition of "icing conditions" that we do at ASA: 10 C or less with visible moisture. The dispatcher was arguing, though, because as far as he was concerned, "icing conditions" means that icing is occurring, i.e. has been reported.

I've done some unofficial asking around, and was surprised to discover that with respect to the MEL, the definition of "icing conditions" is not all that cut-and-dried. It seems to vary from company to company, and even from airplane to airplane. (Yes, I'll pursue it through my own chain of command as well.)

If I were in this Delta pilot's shoes, and if his dispatcher was correct, I'd have been in hot water because I've got a definition right in front of me that says 10 C or less, visible moisture.

Anyone else have any wisdom to share concerning this?

 

[Flechas]

Same here, 10 C or less and visible moisture, as far as being on the ground, cause it implies that you will be below 0 C at and above 5000 AGl.
Had that been my flight, I would not go either.

 

[jetexas]

At Eagle, icing conditions are defined as "10 C or less in visible moisture...rain, fog with vis less than a mile, snow, sleet, ice crystals". I'd go with what the company manual says, or whatever is most conservative.

 

[KeroseneSnorter]

Unless they have changed(Like maybe yesterday!), the FAA defines icing conditions as 10 and below vis moisture.


I would not have gone either based on the info you have provided. Of course a lot depends on the MEL and it's conditional requirements. That is probably what the dispatcher and pilot were arguing about. I have seen some of the MEL's that made the distinction between "known" icing and "forcast icing" or "icing conditions"

 

[Markm1811]

And we say............

10 degrees or less. visible moisture within the range of the field in question. We also have a 10 mins after take off or before landing that is in some MEL's.

Thats the red tail answer. FOM..

MidnightBrit..

 

[TurboS7]

You can beat that by flying at 330 knots wich will keep the ram temp up above 10C. The problem is that at some time you have to slow down so if you destination experiencing icing conditions then you just have to get the MEL fixed in order to go to that destination. Usually in an airline operation they can flow the "bad" airplanes to the warmer weather and the good ones to the icing weather. Most of the time the MEL items can be fixed pretty quickly as usually it is just a valve or whatever.

 

[atrdriver]

I have never had a dispatcher argue with me about flying into icing conditions with a MEL'd item. Have had a lot of other argurments, but not about that.

 

[avbug]

Icing ideally is five degrees to the plus through fifteen degrees to the minus.

Flight into known icing conditions means any conditions that are known to cause ice, or be conducive to icing...not just areas of forecast or reported ice.

 

[Ty Webb]

It would depend on whether they were talking about a MEL that applied to engine anti-icing, or wing de-icing.

It sounds like the Dispatcher was talking about airframe ice, versus engine anti-icing criteria.

If I had some sort of airframe de-ice MEL, I would be inclined to observe PIREPS, and be checking "representative surfaces" but if the MEL applied to engine anti-icing, then you would have less leeway, since your AOM and/or FOM probably defines when you must have the engine anti-ice on.

In our case, that would mean TAT less than +10C and in visible moisture, except in cruise and climb, when the SAT is less than -40C, whereas for airframe de-ice, it would be based on "representative surfaces" or the actual wings, if you can see them (you can in the 737, but not in the 717, at least not from the cockpit).

 

[atrdriver]

It would depend on whether they were talking about a MEL that applied to engine anti-icing, or wing de-icing.

When our MEL says ICE, it means ANY kind of ice. And our criteria for inflight icing conditions are 7 degrees TAT or below in any type of moisture. If our MEL says avoid icing conditions, that means no clouds with TAT below 7. Period.