Pardon if this sounds dumb but can hoar frost form on a moving object? Particularly an aircraft in flight?
When it comes to hoar frost, is having a small amount ok for Toff or is it zero tolerance?
Hoar Frost
Moderators: sky's the limit, sepia, Sulako, Right Seat Captain, lilfssister, North Shore
Re: Hoar Frost
For practical purposes GA aircraft will not accumulate frost in flight. They could, however, accumulate impact ice, but you'd have to be flying in icing conditions for that to happen.
Regulations make no allowance for pilots to knowingly takeoff with any adhering frost/ice or snow to critical surfaces (airfoils). Some airfoils are critically sensitive, others less so, but you have no way of being certain which are which, so regulation does not allow you to make decisions in that regard.
Regulations make no allowance for pilots to knowingly takeoff with any adhering frost/ice or snow to critical surfaces (airfoils). Some airfoils are critically sensitive, others less so, but you have no way of being certain which are which, so regulation does not allow you to make decisions in that regard.
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youhavecontrol
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Re: Hoar Frost
In my experience, I have never seen frost forming during flight. Frost can, and often does, begin forming on a clean wing the moment you take the aircraft outside of your hangar, during sunrise/sunset, or shortly after you land.
As PilotDAR said, TC makes no exception for any contamination on a critical surface. They call it the Clean Aircraft Concept.
As PilotDAR said, TC makes no exception for any contamination on a critical surface. They call it the Clean Aircraft Concept.
"I found that Right Rudder you kept asking for."
Re: Hoar Frost
The CARs have an exemption to the clean aircraft concept for frost as follows:
602.11 (1) In this section, critical surfaces means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surface of an aircraft and, in the case of an aircraft that has rear-mounted engines, includes the upper surface of its fuselage.
(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(3) Notwithstanding subsection (2), a person may conduct a take-off in an aircraft that has frost adhering to the underside of its wings that is caused by cold-soaked fuel, if the take-off is conducted in accordance with the aircraft manufacturer’s instructions for take-off under those conditions.
602.11 (1) In this section, critical surfaces means the wings, control surfaces, rotors, propellers, horizontal stabilizers, vertical stabilizers or any other stabilizing surface of an aircraft and, in the case of an aircraft that has rear-mounted engines, includes the upper surface of its fuselage.
(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.
(3) Notwithstanding subsection (2), a person may conduct a take-off in an aircraft that has frost adhering to the underside of its wings that is caused by cold-soaked fuel, if the take-off is conducted in accordance with the aircraft manufacturer’s instructions for take-off under those conditions.
Re: Hoar Frost
There's one in every crowd 
I've had airplanes form frost when they get pulled out of the hanger below -20 early in the morning. Also had it form almost instantly after landing at night below -20. First time I had this happen, I hot unloaded a friend (pilot) at night it was around -22, took off flew back to my home airport. I did not even see light layer of frost until I climbed out myself and saw his hand prints!! That was probably a close one I care not to repeat.
I've had airplanes form frost when they get pulled out of the hanger below -20 early in the morning. Also had it form almost instantly after landing at night below -20. First time I had this happen, I hot unloaded a friend (pilot) at night it was around -22, took off flew back to my home airport. I did not even see light layer of frost until I climbed out myself and saw his hand prints!! That was probably a close one I care not to repeat.
"Carelessness and overconfidence are more dangerous than deliberately accepted risk." -Wilbur Wright
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Schooner69A
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Re: Hoar Frost
Back in the day, there were times when your helicopter would spend a winter's night outside and collect hoar frost in the process. The blade outer covering was quite susceptible to damage, so care had to be taken in removing the contaminant.
Usually, not all could be removed. However, the helicopter would be started up and the engine and RRPM slowly increased watching for any roughness. After a period of running at full power in flat pitch, the collective would be slowly raised to bring the machine into the hover; again watching for any roughness.
A period of this and a careful departure could be entertained; all the while watching for anything untoward.
That's one of the luxuries of rotary wing over fixed wing: you normally know whether or not you're going to get airborne before you reach a 100 knots in a mad dash down the runway...
Usually, not all could be removed. However, the helicopter would be started up and the engine and RRPM slowly increased watching for any roughness. After a period of running at full power in flat pitch, the collective would be slowly raised to bring the machine into the hover; again watching for any roughness.
A period of this and a careful departure could be entertained; all the while watching for anything untoward.
That's one of the luxuries of rotary wing over fixed wing: you normally know whether or not you're going to get airborne before you reach a 100 knots in a mad dash down the runway...
