Defining Freezing Rain FZRA

B767Driver said:
As a side note, a couple of years ago the FAA stopped endorsing the procedure of "polishing" frost on airplanes. Frost must be removed prior to flight. I know there are a lot of pilots out there unaware of this.
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Polishing frost? Would you mind elaborating? I think I know what you're referring to but still...
 
ZapBrannigan said:
Ok. So let's simplify. If you had an SOP that said, "Thou shalt not depart in FZRA" and you noticed it was raining with a temperature of -1C...

What would you do?

I get that most of you are suggesting a pre-takeoff contamination check and that is the only true determiner of airframe icing prior to departure. I guess I was just trying to figure out if there were any environmental conditions that could be used to make that determination earlier in the planning process and therefore allow for less impact to the passengers. (i/e allow them to stay at the office and keep working if we're going to delay, etc.)
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Zap, I think that you are still missing the true definition of freezing rain. It is not just rain falling with ambient temperatures <= 0C. casey explains it very well in the post above. You will know freezing rain because, by definition, it is freezing on contact when it strikes a solid surface. It doesn't really matter what the air temperature is on the surface, it only matters that the water is supercooled, which means that the temperature of the droplets is below freezing. The only reason that it is still in liquid form and hasn't turned into snow or hail is that the molecules haven't been disturbed from their liquid state by an outside influence (don't shoot me on that description - just trying to keep it simple!).

In your scenario you are not experiencing "freezing rain". You are experiencing rain, with a surface temperature low enough that the rain may freeze when the surroundings have cooled the water droplets to below 0C. Not the same thing as freezing rain. Your SOP does not apply.

That is not to say that you aren't correct in the decision to not-go, only that you technically can't use "freezing rain" as the reason.

:)
 
B767Driver said:
As a side note, a couple of years ago the FAA stopped endorsing the procedure of "polishing" frost on airplanes. Frost must be removed prior to flight. I know there are a lot of pilots out there unaware of this.
Click to expand...


135.227



(a) No pilot may take off an aircraft that has frost, ice, or snow adhering to any rotor blade, propeller, windshield, wing, stabilizing or control surface, to a powerplant installation, or to an airspeed, altimeter, rate of climb, or flight attitude instrument system, except under the following conditions:
(1) Takeoffs may be made with frost adhering to the wings, or stabilizing or control surfaces, if the frost has been polished to make it smooth.


121.629

a) No person may dispatch or release an aircraft, continue to operate an aircraft en route, or land an aircraft when in the opinion of the pilot in command or aircraft dispatcher (domestic and flag operations only), icing conditions are expected or met that might adversely affect the safety of the flight. (b) No person may take off an aircraft when frost, ice, or snow is adhering to the wings, control surfaces, propellers, engine inlets, or other critical surfaces of the aircraft or when the takeoff would not be in compliance with paragraph (c) of this section. Takeoffs with frost under the wing in the area of the fuel tanks may be authorized by the Administrator.




91.527 Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft


(a) No pilot may take off an airplane that has --
(1) Frost, snow, or ice adhering to any propeller, windshield, or powerplant installation or to an airspeed, altimeter, rate of climb, or flight attitude instrument system;
(2) Snow or ice adhering to the wings or stabilizing or control surfaces; or
(3) Any frost adhering to the wings or stabilizing or control surfaces, unless that frost has been polished to make it smooth.



Better let the FAA know that they don't endorse that practice anymore... :D

Under 91 and 135 polishing is still allowed, 121 is a no-go though unless the FAA/Operator is ok with the underwing/fuel tank frost exception.
 
FlySmiley said:
135.227



(a) No pilot may take off an aircraft that has frost, ice, or snow adhering to any rotor blade, propeller, windshield, wing, stabilizing or control surface, to a powerplant installation, or to an airspeed, altimeter, rate of climb, or flight attitude instrument system, except under the following conditions:
(1) Takeoffs may be made with frost adhering to the wings, or stabilizing or control surfaces, if the frost has been polished to make it smooth.


121.629

a) No person may dispatch or release an aircraft, continue to operate an aircraft en route, or land an aircraft when in the opinion of the pilot in command or aircraft dispatcher (domestic and flag operations only), icing conditions are expected or met that might adversely affect the safety of the flight. (b) No person may take off an aircraft when frost, ice, or snow is adhering to the wings, control surfaces, propellers, engine inlets, or other critical surfaces of the aircraft or when the takeoff would not be in compliance with paragraph (c) of this section. Takeoffs with frost under the wing in the area of the fuel tanks may be authorized by the Administrator.




91.527 Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft


(a) No pilot may take off an airplane that has --
(1) Frost, snow, or ice adhering to any propeller, windshield, or powerplant installation or to an airspeed, altimeter, rate of climb, or flight attitude instrument system;
(2) Snow or ice adhering to the wings or stabilizing or control surfaces; or
(3) Any frost adhering to the wings or stabilizing or control surfaces, unless that frost has been polished to make it smooth.



Better let the FAA know that they don't endorse that practice anymore... :D

Under 91 and 135 polishing is still allowed, 121 is a no-go though unless the FAA/Operator is ok with the underwing/fuel tank frost exception.
Click to expand...


The "no polish" policy is in the form of an AC I believe, when has the FAA ever been quick to update the FARs??

edit
here it is, not an AC but a SAFO
http://www.faa.gov/other_visit/avia...afety/safo/all_safos/media/2006/safo06002.pdf


Zap,

I think you are looking for a set in stone definition of FZRA and Casey, IMO gave the best one. Skin temp and such of the airplane may dictate icing accumulation but I don't think you can stretch that to make rain intor FZRA. All that being said, if you are not comfortable taking off with the conditions you described, you don't go. Explain your position to your partner and that is that.
 
FlySmiley said:
Better let the FAA know that they don't endorse that practice anymore... :D

Under 91 and 135 polishing is still allowed, 121 is a no-go though unless the FAA/Operator is ok with the underwing/fuel tank frost exception.
Click to expand...

It was issued under a SAFO a couple of years ago. Basically, it said that any "polishing" procedure must be in compliance with manufucturers guidelines.

To date...there's not a single manufacturer than issues POH guidelines for this procedure.


oops...Dugie beat me to it.
 
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