luv2flypilot
Well Known Member
An interesting question came up in a conversation between pilots today. Is a heated pitot required for IFR flight? Excuse my ignorance of knowledge on this subject since I do not have my IFR ticket.
Van's Air Force
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Does IFR Flight Require Heated Pitot?
- Thread starter luv2flypilot
- Start date
sglynn
Well Known Member
nope
Nope, not required, but think about it. If you are in the clouds even in summer freezing level is probably not higher than 9k so chances are your pitot will freeze and you'll lose your speed, maybe altimeter to. Even Piper Cherokees come with a heated pitot. Unless you are hard over on never poking holes in the clouds, get a heated pitot. have fun
Nope, not required, but think about it. If you are in the clouds even in summer freezing level is probably not higher than 9k so chances are your pitot will freeze and you'll lose your speed, maybe altimeter to. Even Piper Cherokees come with a heated pitot. Unless you are hard over on never poking holes in the clouds, get a heated pitot. have fun
Kevin Horton
Well Known Member
It depends on where you are flying. If you stay in the US, there is no regulatory requirement for a heated pitot to fly IFR. If you fly in Canada, there is a requirement for "a means of preventing malfunction caused by icing for each airspeed indicating system" and "an alternative source of static pressure for the altimeter, airspeed indicator and vertical speed indicator". These requirements are applicable to all aircraft flying in Canada, even if the aircraft is foreign registered.
But, the laws of physics are the same whether you are flying in Canada, or in the US. A heated pitot system is a very good idea if you will be flying IFR above the freezing level.
RV10inOz
Well Known Member
I am 99.9% sure it is required downunder also.
If its IFR in my opinion it has to have it regardless of whether you think you will ever need it, coz one day you will!
DB
PS Just checked CAO20.18 and for private ops its not LAW, but it would be stupid not to. For any Charter or RPT it is naturally enough!
Is your life worth another $200 or so?
If its IFR in my opinion it has to have it regardless of whether you think you will ever need it, coz one day you will!
DB
PS Just checked CAO20.18 and for private ops its not LAW, but it would be stupid not to. For any Charter or RPT it is naturally enough!
Is your life worth another $200 or so?
Must have or want......
Not required but....
I have a different point of view.
Years ago when heated pitot's were invented, we didn't have GPS. A heated pitot was the only way you could get your speed back. Now, you can tell you groundspeed (not airspeed) and altititude even if both the pitot and static are frozen over.
Not required but....
I have a different point of view.
Years ago when heated pitot's were invented, we didn't have GPS. A heated pitot was the only way you could get your speed back. Now, you can tell you groundspeed (not airspeed) and altititude even if both the pitot and static are frozen over.
Kevin Horton
Well Known Member
What ground speed does your aircraft stall at?
the_other_dougreeves
Well Known Member
While GPS GS isn't the same as IAS, it is helpful. With respect to the wind, you do know what the winds are forecast to be, right? You did get this on your preflight, right? Ok, let's say that the winds are supposed to be about 15 kt from the north and I'm heading NW. My headwind is about sqrt(2)/2 or 0.7 of the wind, so call it 10 kt. Add 10kt to GS to get a rough approximation of IAS. I certainly wouldn't use it to get close to the stall, particularly if icing is suspected. However, it should be enough to keep you around Va, which is where I think I'd want to be if things started to go wrong.
I fly a glider that has a pitot / total energy probe that is notorious for getting twisted out of true when slipped. This happened during a 200 ft rope break last weekend. I freaked out a little as the ASI was low during the 45 deg turn, but the nose was well below the horizon and the sound was right, so I trusted that I had enough speed. I realized that the ASI was off when we floated a long way during the landing (more than just the downwind effect). Got out and sure enough, there it was, twisted at about 20 degrees from true. We hadn't reset it after slipping in on the previous landing; dumb.
Anyway, the point is that loosing the ASI shouldn't doom you to crashing. There are other clues to your relative airspeed - sound, control feel, GPS groundspeed, combination of power level and pitch, etc. Use all the information that is available to you and fly the airplane. The airplane doesn't know it's lost the ASI. Kind of reminds me of the Roadrunner cartoon gag where Wylie E. Coyote runs off the cliff chasing the roadrunner and doesn't start falling until he realizes he's gone over the edge.
TODR
PS - as for the stall speed in groundspeed, I've practiced slow flight where I was slow enough (35 kt IAS) and the wind strong enough that we were basically stationary over the ground. Kinda like an AN-2
I fly a glider that has a pitot / total energy probe that is notorious for getting twisted out of true when slipped. This happened during a 200 ft rope break last weekend. I freaked out a little as the ASI was low during the 45 deg turn, but the nose was well below the horizon and the sound was right, so I trusted that I had enough speed. I realized that the ASI was off when we floated a long way during the landing (more than just the downwind effect). Got out and sure enough, there it was, twisted at about 20 degrees from true. We hadn't reset it after slipping in on the previous landing; dumb.
Anyway, the point is that loosing the ASI shouldn't doom you to crashing. There are other clues to your relative airspeed - sound, control feel, GPS groundspeed, combination of power level and pitch, etc. Use all the information that is available to you and fly the airplane. The airplane doesn't know it's lost the ASI. Kind of reminds me of the Roadrunner cartoon gag where Wylie E. Coyote runs off the cliff chasing the roadrunner and doesn't start falling until he realizes he's gone over the edge.
TODR
PS - as for the stall speed in groundspeed, I've practiced slow flight where I was slow enough (35 kt IAS) and the wind strong enough that we were basically stationary over the ground. Kinda like an AN-2
Kevin Horton
Well Known Member
Excellent question. I intend to fly IFR, so it is a question that is dear to my heart. I will make ever attempt to avoid ice, but there are no guarantees once you go into cloud. If you get unlucky, some day you will pickup some ice that you cannot get rid of.
I eventually intend to answer this question by conducting a test program with a small amount of simulated ice on the wing and tail leading edges. The testing will use 40 grit sand paper on the leading edges to simulate a small amount of ice. There will be a build-up in the span wise extent of the simulated ice, to reduce the risk. For the first flight, the simulated ice will only cover a small portion of the inboard leading edges of the wing and HS, and a small portion of the bottom of the VS leading edge. If the handling is acceptable, the next flight will extend the simulated ice a bit further along the wing and tail leading edges. Eventually, the simulated ice will cover the whole span of the leading edges.
I'd rather find out the performance and handling effects of ice on the aircraft on my own terms, using an incremental build up in good weather, rather than have the flight test forced on me in IFR, with the whole span iced up for the first test point.
A quick, non-contributing story:
I remember many years ago my father was flying into North Platte NE to pick me and a couple of friends up. In the short decent through the mush he picked up heavy unreported icing. He landed his 340A covered with all manner of ice - even with de-icing equipment. It was a scary deal to be sure. Both engines were wailing WOT on short final, just to keep the thing from dropping right out of the sky. I'll guarantee you he has no recollection of the airspeed at touchdown. It was high. We spent the night in NP and thawed the 340 in a heated hangar. The only thing that got him down safe was a few thousand hours of experience.
ff
I remember many years ago my father was flying into North Platte NE to pick me and a couple of friends up. In the short decent through the mush he picked up heavy unreported icing. He landed his 340A covered with all manner of ice - even with de-icing equipment. It was a scary deal to be sure. Both engines were wailing WOT on short final, just to keep the thing from dropping right out of the sky. I'll guarantee you he has no recollection of the airspeed at touchdown. It was high. We spent the night in NP and thawed the 340 in a heated hangar. The only thing that got him down safe was a few thousand hours of experience.
ff
terrykohler
Well Known Member
Kevin:
I'm not sure that trying to simulate ice build-up with sandpaper is going to tell you anything useful. Ice can accumulate as rime, clear, or mixed and will adhere to surfaces in almost limitless ways depending upon moisture content, type of ice, temperature, skin surface temperature, aircraft attitude, etc. At the same time, we haven't even taken into account the element of weight and weight distribution.
If you're really intent on learning about airframe icing, do it in an aircraft certified for known ice. Even then, it's important you know OAT and lapse rate, bases and tops, and are operating with an escape plan. Certainly, if you intend to fly IFR in Canada, you're eventually going to encounter ice. Some good reading on the topic as well as actual experience with a qualified pilot and aircraft will serve you well.
Terry, CFI
RV9A N323TP
I'm not sure that trying to simulate ice build-up with sandpaper is going to tell you anything useful. Ice can accumulate as rime, clear, or mixed and will adhere to surfaces in almost limitless ways depending upon moisture content, type of ice, temperature, skin surface temperature, aircraft attitude, etc. At the same time, we haven't even taken into account the element of weight and weight distribution.
If you're really intent on learning about airframe icing, do it in an aircraft certified for known ice. Even then, it's important you know OAT and lapse rate, bases and tops, and are operating with an escape plan. Certainly, if you intend to fly IFR in Canada, you're eventually going to encounter ice. Some good reading on the topic as well as actual experience with a qualified pilot and aircraft will serve you well.
Terry, CFI
RV9A N323TP
Lycosaurus
Well Known Member
Kevin Horton
Well Known Member
I appreciate and understand your concern. But, I've got hundreds of hours flying in actual icing conditions. I've done flight testing with simulated ice shapes on several types of aircraft, and I've done flight testing in natural icing conditions on several types of aircraft.
40 grit sandpaper has been found to be a pretty good simulation of the worst case roughness from a short duration icing encounter. And, strangely enough, on the ice shapes flight test programs that I have participated in, the effect on stall speed from a narrow strip of 40 grit sandpaper was more significant than even some very ugly doubled horned ice shapes. In other words, the first bit of ice accretion gave the worst effect. If you then picked up some more ice things actually seemed to get better.
I'm not suggesting that anyone else should do this. This is not a good thing to do unless you have a very good idea of what you are doing. And even then, there are definitely risks. But, I'd rather face those risks on my own terms, rather than someday end up with ice on the aircraft in cloud, and have that be the first chance I have to learn the effect on my RV.
Kevin Horton
Well Known Member
Thanks for that reference. Very useful and interesting. It certainly calls into question my belief, based on my experience with larger aircraft, that 40 grit sand paper was a suitable means to simulate the initial ice buildup on our aircraft. The report does give the reduction in lift at the stall, which is a useful reference. The testing was on the NACA 23012 airfoil, which is in the same family as the airfoil on the short wing RVs. The testing simulated an aircraft that had pneumatic deice boots, and they looked at the effect of the ice that would build up on the leading edge between cycles of the boots, and at the effect of the small amount of ice that remained on the leading edge after the boots were cycled.
The stall speed in the worst cases they evaluated would increase by about 60%. I.e., if your stall speed without ice was 58 mph (Van's number for the RV-8 at gross weight), it would increase to about 93 mph with the worst case condition tested in this report. That is quite sobering. I was expecting about a 40% increase in stall speed, not 60%.
terrykohler
Well Known Member
Kevin:
Sorry. Didn't know your background/knowledge base re. A/C icing. Every once in a while, I run across posts where I think, "you shouldn't be doing that". Just trying to keep everyone flying safe without first asking, "what are your qualifications". For many pilots, FAA-H-8083-15A contains a good deal of useful information about icing. Your sandpaper "technique" is interesting (I learned something new), and the tech report a real eye-opener. While not a test pilot, I have flow for many years around the midwest in KI equipped aircraft. My advice to anyone flying instruments, particularly in our part of the hemisphere, is; continue to get up to date weather info, expect the unexpected, know your personal and equipment limitations, have an out, and communicate and act soon. Oh yeah, and re. the original questions posed, have a heated pitot.
Fly Safe,
Terry, CFI
RV9A N323TP
Sorry. Didn't know your background/knowledge base re. A/C icing. Every once in a while, I run across posts where I think, "you shouldn't be doing that". Just trying to keep everyone flying safe without first asking, "what are your qualifications". For many pilots, FAA-H-8083-15A contains a good deal of useful information about icing. Your sandpaper "technique" is interesting (I learned something new), and the tech report a real eye-opener. While not a test pilot, I have flow for many years around the midwest in KI equipped aircraft. My advice to anyone flying instruments, particularly in our part of the hemisphere, is; continue to get up to date weather info, expect the unexpected, know your personal and equipment limitations, have an out, and communicate and act soon. Oh yeah, and re. the original questions posed, have a heated pitot.
Fly Safe,
Terry, CFI
RV9A N323TP
