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#1
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As we were flying over to Newton, IA today, we started discussing icing and
snow -- something that we must constantly worry about in these parts for at least the next 4 months. As we were talking, we heard a "Flight for Life" 'copter on Unicom, which got us to wondering how it is that these guys seem to fly in ANY weather. Which got us to wondering further: How do helicopters handle ice? Are the main rotor blades heated? Does the centrifugal force on those huge blades prevent ice build up? What about the rest of the fuselage? How do they de-ice themselves? Thanks! -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
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#2
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Well, I can tell you that helis are not free from ice worry. I know
Apaches have heaters in their blades allowing them to de-ice. Sadly, they can not use them because it causes problems with blade delamination. Which really means the cure is worse than ice. Hehe. Go figure. For $24Mil per Longbow, surely you didn't really expect an all weather bird! ![]() Long story short, if they fly in icing weather, I imagine are they have some form of heating in their blades. |
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#3
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Jay Honeck wrote:
As we were flying over to Newton, IA today, we started discussing icing and snow -- something that we must constantly worry about in these parts for at least the next 4 months. As we were talking, we heard a "Flight for Life" 'copter on Unicom, which got us to wondering how it is that these guys seem to fly in ANY weather. Which got us to wondering further: How do helicopters handle ice? Are the main rotor blades heated? Does the centrifugal force on those huge blades prevent ice build up? What about the rest of the fuselage? How do they de-ice themselves? Thanks! Jumping in here - Having worked for a medevac operator where most of the helicopters were VFR only, my guess is this - they don't fly in IMC, let alone IMC with the possibility of icing. I asked our helicopter pilots and mechanics about this time after time, and their reply was always the same - "Flying in the clouds, running into ice, and shooting approaches are dangerous. I can't believe you do it in an airplane." I'm sure there's more to it, but I never got a good answer. |
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#4
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Having worked for a medevac operator where most of the helicopters were
VFR only, my guess is this - they don't fly in IMC, let alone IMC with the possibility of icing. Of course, what's their definition of "IMC"? Don't helicopters have a lower threshold for IMC than we fixed wing folks? -- Jay Honeck Iowa City, IA Pathfinder N56993 www.AlexisParkInn.com "Your Aviation Destination" |
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#5
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Don't helicopters have a lower threshold for IMC than we fixed wing folks?
It's a lower VFR ceiling and visibility limit, about half of what the rest of us are held to. I guess we could call it an IMC threshold. Helicopters can move forward slowly when the viz is bad, and thereby avoid the cumulogranite. But IMC and ice are two different hazards. I have heard of a helicopter that runs hot bleed air through the rotors to deice them. I don't know if that also applies to the tail rotor, or if it might be electrically heated like a prop. Dan |
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#6
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We can request "special VFR" that'll even allow for near "no vis" opt
IIRC. |
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#7
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"Flyingmonk" wrote in message
oups.com... We can request "special VFR" that'll even allow for near "no vis" opt IIRC. Special VFR still requires a minimum of 1 mile visibility. |
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#8
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Yes, IIRC, "special VFR"
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#9
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Yes, IIRC, "special VFR"
It's not SVFR. Note the (c) and (d) paragraphs in our Canadian Law: 602.115 Minimum Visual Meteorological Conditions for VFR Flight in Uncontrolled Airspace 602.115 No person shall operate an aircraft in VFR flight within uncontrolled airspace unless (a) the aircraft is operated with visual reference to the surface; (b) where the aircraft is operated at or above 1,000 feet AGL (i) during the day, flight visibility is not less than one mile, (ii) during the night, flight visibility is not less than three miles, and (iii) in either case, the distance of the aircraft from cloud is not less than 500 feet vertically and 2,000 feet horizontally; (c) where the aircraft is not a helicopter and is operated at less than 1,000 feet AGL (i) during the day, flight visibility is not less than two miles, except if otherwise authorized in an air operator certificate or a private operator certificate, (ii) during the night, flight visibility is not less than three miles, and (iii) in either case, the aircraft is operated clear of cloud; and (d) where the aircraft is a helicopter and is operated at less than 1,000 feet AGL (i) during the day, flight visibility is not less than one mile, except if otherwise authorized in an air operator certificate or a flight training unit operator certificate - helicopter, (ii) during the night, flight visibility is not less than three miles, and (iii) in either case, the aircraft is operated clear of cloud. Dan |
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#10
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"Jay Honeck" wrote in message
news:XNvjf.611926$xm3.441724@attbi_s21... Having worked for a medevac operator where most of the helicopters were VFR only, my guess is this - they don't fly in IMC, let alone IMC with the possibility of icing. Of course, what's their definition of "IMC"? Don't helicopters have a lower threshold for IMC than we fixed wing folks? Yes. See FAR 91.155 and 91.157. For all practical purposes, helicopters can fly in arbitrarily low visibility. 91.155 grants them this right in Class G airspace, and 91.157 grants them this right elsewhere (with a Special VFR clearance). Since a pilot can get a Special VFR clearance pretty much anywhere that there *isn't* Class G airspace near the surface (generally below 700 or 1200 feet, depending), this means that as long as the helicopter pilot can see well enough to avoid obstacles, the visibility is defined as being sufficient, no matter how low it actually is. Pete |
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