Freezing Rain

[AltFlaps]

Hi All,

Other than the normal in-flight and pre departure de-icing and holdover limits, do any of you have additional company restrictions on operating in Freezing Rain ?

If so, what aircraft types?

Thanks

AF

[rubik101]

If the flight conditions are such that you are experiencing anything more than light to moderate icing then you are flying outside the limitations of 'all' aircraft types.
If the freezing rain causes heavy ice then you had better turn around or get in out of the rain asap.

[AltFlaps]

Thanks Rubik,

But I'm trying to find out if any operators have specific limitations with regard to Freezing Rain ... I've heard that some airlines specifically prohibit operation in known freezing rain conditions

AF

[wacky]

Flybe forbid it, as did BAConnect etc beforehand. Company policy for all types.

Neither a take-off nor an approach and landing is to be carried out in actual freezing rain or freezing drizzle conditions. In practice this implies:
a. Before departure if the destination is actual, or forecast to have, freezing rain or freezing drizzle then two alternates must have landing minima and no freezing rain or freezing drizzle.
b. If, when airborne, the ATIS gives freezing rain or freezing drizzle then no
approach can be made to that airport until the condition has cleared.
c. A take-off is not permitted during reported freezing rain or freezing drizzle

[Admiral346]

A takeoff is simply not possible for anyone, because no holdovertimes exist for freezing rain (they do for FZDZ). You would have to depart with ice on your wings (most likely prohibited by your SOPs) or without a holdover time (against all SOPs known to me).

Nic

[Swedish Steve]

Other than the normal in-flight and pre departure de-icing and holdover limits

Have you looked at the deice hold over times? Even 100pc type 11 can give you as little as 5 mins holdover. This is counted from start of deicing. Can't be done safely.

[rubik101]

Alt Flaps, if you are looking for someone to post on here that they work for an airline which allows operation in freezing rain, forget it. It is not allowed, under any circumstances.
End of discussion.

[topjetboy]

Under Canadian regs, Type IV allows operation in -FZRA down to -10 with a holdover bracket of 10-20mins. Or, if it's warmer, as much as 40mins!
The FOM specifically allows us to plan to, and operate in -FZRA.
Unlucky Rubik.

[rubik101]

Thank goodness I don't fly to Canadian regs. What a bunch of tossers if they allow such lunacy. You will surely die if you try to fly in freezing rain, no question.
I say again: Just don't do it.

[Intruder]

There is a difference between LIGHT Freezing Rain and Freezing Rain. AFAIK, no operator allows attempted takeoff in Freezing Rain, for the reasons already stated above. However, some do allow takeoff in LIGHT Freezing Rain or Freezing Drizzle, if holdover times allow and visual inspection is successfully accomplished immediately prior to takeoff.

[just.n.av8r]

FAA holdover allowed for light freezing rain as well.

Stupid Yanks, between them and the Canucks it is a good thing they don't fly in much weather.

[secret agent 86]

Being ignorant of a topic is not a reason to call people tossers. The simple fact is that in the Great Lakes and Eastern Seaboard region of North America, freezing precipitation of some sort is a fact of life in winter and if all aviation were to shut down then chaos would ensue. By following established guidelines, operations in freezing precip can and is safely carried out.

[Pugilistic Animus]

Stupid Yanks, between them and the Canucks it is a good thing they don't fly in much weather.

yeah right

we are known have the world worst wx supercells, squall lines, tornadoes mesoscale convective TS, mountain wave activity, hurricanes, freezing precip., hail, as well as plenty of interesting terrain

[indiscipline_girl]

I lived and flew airplanes in alaska before. The single most hazardous weather event was freezing rain. Even just driving cars, I was stuck in traffic for 3 hours because the entire highway turned into an ice rink within minutes (near eagle river for those in the know).

Freezing rain is GOD's way of ruining your plans for the day.

[porch monkey]

I guess the sarcasm was lost on you P.A.?

[just.n.av8r]

P.A.,

Sorry my sarcasm wasn't clear.

BTW, worst freezin rain I ever experienced was in North Carolina, not Alaska.

[Pugilistic Animus]

Just.n.av8r

Worst freezing rain I ever experienced was in North Carolina, not Alaska.

RDU? usually a nice place
I'm an ass

I guess it's best to fly in the part of the US where the humuhumunukunukuapuaa go swimming by

[Mansfield]

More thoughts on freezing rain

I have been involved in the issues of inflight icing for a number of years, both as a USALPA representative and an independent consultant. In the course of that work, I developed an icing database from a review of all US icing accidents and reportable incidents from 1978 through 2006. The latest iteration of this work was a presentation to the SAE at Seville in September of 2007, and can be seen at this URL:

http://www.sae.org/events/icing/pres...07s30green.pdf

Unfortunately, this online PDF has some problems with some of the charts; I'd be glad to send a cleaner copy to anyone interested.

One outcome of the work was based on normalizing the frequency of surface precipitation reports with the events in the database. 32% of the events were associated with snow, and snow comprised 32% of the surface precipitation reports in the continental United States. However, 33% of the events were associated with either ZR or ZL, which comprised only 1.8% of the total surface precipitation reports.

The majority of this data involves non-transport certificated aircraft.

It would be a mistake to assume that snow is safer, as seen by the large number of icing events that take place in the presence of snow. While the snow itself does not generate an ice accretion, it is often mixed with supercooled liquid water, which does. But the high frequency of events associated with freezing precipitation, compared to it's relative low occurrence rate, is an indication of it's vicious nature in the world of aerodynamics.

Indeed, there are not as yet any certification criteria or standards for conditions known as Supercooled Large Droplets (SLD) which we define as droplets with a median diameter of more than 50 microns. Thus, no aircraft are equipped with ice protection systems that have been designed or certificated for these conditions. This is in stark contrast to the existing holdover tables, which do allow operation in light ZR and light to moderate ZL. The dichotomy has kept a number of people in the authorities very busy, and very frustrated, for several years now.

[just.n.av8r]

My airline's FAA approved specific limitation prohibits flight into greater than light freezing rain and they provide us with FAA approved holdover tables for light freezing rain.

From that information I imply that operations in light freezing rain are permitted with appropriate procedures and precautions.

[che ci dō che ci dō!]

"... certification standards provide protection for the majority of atmospheric conditions encountered, but not for freezing rain or freezing drizzle or for conditions with a mixture of supercooled droplets and snow or ice particles...."


does any of you know in which part of JAR 25 one can find the above mentioned limitation? I couldn't find it.

Thanks