How would you interpret this warning?

Question

"WARNING: Severe icing may result from environmental conditions outside of those for which the airplane is certificated. Flight in freezing rain, freezing drizzle, or mixed icing conditions (supercooled liquid water and ice crystals) may result in ice build-up on protected surfaces exceeding the capability of the ice protection system, or may result in ice forming aft of the protected surfaces. This ice may not be shed using the ice protection system and may seriously degrade the performance and controllability of the airplane."

You're preparing to depart and the ATIS is broadcasting "light freezing rain". Do you go? (Assume you have no additional guidance in your OPSPECS or company manuals).

Answer 1

It sounds like a no go given that warning without any other kind of guidance (manuals or opspecs).

Our company manuals allow takeoffs in LIGHT freezing rain if it is not mixed with other precipitation types and we are within the published holdover times.  This usually means two step deicing/anti-icing (type I and type IV) and praying that the are no departure delays.  If there is light freezing rain at the surface, there is warmer (above freezing) air aloft.  That's the rationale behind allowing takeoffs.  Ice pellets at the surface are a different story.

But given the warning that you gave coupled with no additional company guidance, I'd say you made the right move.  Does your company have an internal safety reporting system and/or manual revision request forms?  I would fill out one (or both) of those forms.  If there is a difference between airplane manuals, manufacturer recommendations, company guidance (or lack of), and management expectations, there is a real problem there that needs to be addressed by the higher-ups.

Sorry to hear that you took a hit for doing the right thing.  Really frustrating...

Answer 2

Despite being cleared, I would request to to have the control surfaces de-iced prior to taking off just to be on the safe side,

Answer 3

There are so many considerations that it would be dumb to second guess you, as PIC, in this particular case.

However, you should always use more than just what the AFM says when making your Go-No-Go:

What were other pilots reporting about conditions after departure? PIREPS?

Was Ice forming on the aircraft while sitting on the ramp?

Do you have experience / training on flying in severe icing conditions?

Ask your Chief Pilot if he would have your Ops manual specifically order pilots to Take-Off into "light freezing rain".  He probably won’t for the same reason the OEM does not: If anything goes wrong then it’s THEIR fault!

Answer 4

A regional jet? If I was with an airline, I would radio the airline for advice and they'll probably say "GO"

I think I would go, light freezing rain is relatively local phenomenon from where I come from. (Montreal, Quebec, Canada) We get it all the time and the Air Canada jazz CRJs and Dash-8s are still flying.

Answer 5

Well, NO!  I'd rather be on the ground wishing I was in the air than in the air wishing I was on the ground.

Answer 6

I think you made the right choice Jim.

Definately no argument on my end.

Answer 7

Another question is where is the tops of the clouds, the area of icing?

The warning is definalty a cover all, but if the light FZRA is a local phenomomen, then the hold over time for type 4 would clearly be more than enough to prevent icing until you get on top of the clouds, or away from the icing.

The aircraft is equipped with a deice system, so flight into know icing is not prohibitted, What other deice systems are on the a/c, prop,engine inlet heat?  In the real world, their is a gray area sometimes, and operting in this is how you pay the morgage.. not saying its always the right decesion..

Answer 8

Before I read the additional info, Jim, I knew you were talking about deice boots. When I was flying with boots I found that if you didn't shed the ice at just the right time you could actually make things worse. You had to have enough ice on the wing so that it would break up sufficiently. Blow the boots to soon and you'd have a spider web. Too late and it was building up aft of the boot. As I remember you would ideally let about a half inch of ice build up before you'd hit the deice switch.

I think the warning is a cover your butt from the manufacturer. Unless there is a prohibition somewhere else in the AFM I don't see why you can't go. But then again, I'm a guy who doesn't have to fly with deice boots anymore.

Answer 9

There is a saying in the aviation industry, " Take-off is OPTIONAL, landing is MANDATORY"...so its a 'No',  in case of the above warning, as the ice will not shed using ice protection system. Further to this, the engine performance will be low.

Answer 10

Since the warning does not specify the degree of freezing rain (light, moderate, heavy), then I would interpret that as meaning ANY freezing rain. I don't depart. Also,

Dispatch has no say in my decision, other than to provide suggestions.

Answer 11

You have two factors in play, 1.  the warning.  Which says basically, "Don't fly in freezing rain."  2. Freezing rain.

Therefore:  Don't fly.

Answer 12

Freezing rain will adhere to the other surfaces of the aircraft that aren't protected by de-ice/anti ice systems.  

But if you have de-ice and anti-icing fluid sprayed on your aircraft and you takeoff before your holdover time is up, you should be able to takeoff and the the aircraft systems should be able to keep up (you said light freezing rain).

Other considerations would be the condition of the runway and crosswinds affecting aircraft control on the ground and balanced field performance.

Also the efficiency of the boots comes into play.  If the boots are old and patched they might not shed ice as easily.  Also applying a compound like Goodrich's ICE-X greatly improves the boot's performance.

Answer 13

light freezing rain can add weight to a/c --your a pilot--cant it disturb the flow of air over the wings thereby decreasing lift? cant it also freeze and lock the controls.

Answer 14

Congratulations on your first command decision Jim! Sounds as though you made the best decision. It's never easy but always remember it may mean your a** later, but it's better than your neck, and those of the pax counting on your sound judgment. You might take some guidance from some of your senior commanders with regard to their experiences in the specific aircraft operated. But management will always push their agenda since they are safe on the ground. Bottom line take a delay and you are an a****** for a week, crash an aircraft and you will never work as a pilot or maybe never forgive yourself or do anything for that matter ever again.