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Are RV’s particularly dangerous in ice?

DylanRush

Active Member
I’m instrument rated and I own a -6A and a partnership in a 172, both equipped for instrument flying. I will never fly either into known icing conditions, but I’ve heard that the 172 is going to handle ice better that the RV, and that you probably don’t want to spend too much time in the RV in the soup. I’ve had light ice in the 172 and didn’t consider it an emergency but it was something to be avoided and remedied. What about my RV? Is light ice an emergency? Does anyone have experience in how it performs? I assume the usual rules apply (descend and land fast, avoid flaps, get out of moisture)
 
Just me

If I was to encounter ‘light’ icing, i would rather be in an RV than a 172. The stall speed is lower compared to cruise, and the RV has more climb capability. If ice is forcing a descent, its seems the RV’s better climb ability just makes one go a little farther before the crash.
 
Any time, in any airplane that’s not icing approved that you encounter icing, it is an urgent situation, requiring immediate action to get out of the icing conditions.

I truly hope that there are not many of us that can say they know about how the RV handles in icing.
 
I’d be concerned about the integrity of the alternate air / carb heat system in many RV’s more than the airfoil. That said, ice scares me enough that a chance of an encounter keeps me on the ground.
 
YES

RVs are very dangerous in icing conditions. Comparing a 172 to an RV in icing conditions is a matter of how far the nervous chills run down my spine. On a scale of 1-10, the 172 is a 9.9 and the RV is a 9.8.

Airborne icing takes down small, and not so small aircraft that are certified for flight into known icing conditions. The turbine powered Cessna Caravan comes to mind as well as an ATR-72 accident from 1994.

Without a full compliment of deicing equipment, stay far from icing conditions. Even if it's tucked into an expensive hangar far from home. Icing has killed pilots of far more capable aircraft than an RV. Even in an aircraft with a full compliment of capable and certified deicing equipment the goal is to minimize exposure as it's still dangerous.
 
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I’m instrument rated and I own a -6A and a partnership in a 172, both equipped for instrument flying. I will never fly either into known icing conditions, but I’ve heard that the 172 is going to handle ice better that the RV, and that you probably don’t want to spend too much time in the RV in the soup. I’ve had light ice in the 172 and didn’t consider it an emergency but it was something to be avoided and remedied. What about my RV? Is light ice an emergency? Does anyone have experience in how it performs? I assume the usual rules apply (descend and land fast, avoid flaps, get out of moisture)

I have a 6A with an O360 A1A. Standard airbox and carb heat.

I would strongly advise you to closely look at the carb heat mechanism and repair/rebuild as they can be faulty, nearly faulty, inoperative, etc.

Many here have posted what steps to take to beef it up.

I had an occasion in real imc to use carb heat which worked well but subsequently stuck in carb heat mode which is not optimal.

It has been fixed but was rather inconvenient at the time.

Having said that I also had an airbox carb heat issue in a 172 which resulted in an aborted flight plan and return to base. Poor power generation which was subsequently traced to the air box. This was in an older rental 172.

neither of those incidents are likely relevant to your question other than to make sure whatever plane you're flying is working properly...
 
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The first indication of ice for me was when the front of the canopy frosted over. Most RV's I've seen, including my own, don't have enough defrost capability to counter this. You'll definitely want to know that you can safely get below the freezing level with room for the ice to come off in order to land.

I fly a 7A, and I've wondered more about the horizontal stabilizer than the wing. The wing seems to handle a light trace of ice fairly well - but I can't say that the tail is really visible and the thin cross section of the HS would have me believe that it will collect its fair share of ice.

I have yet to come up with a good heated alternate air solution, so problems with the induction system seem like they would also be an issue.

The bottom line for me, there are too many risk factors that I can't control to make RV flight in icing conditions something I'd want to try on any kind of regular basis. In the great lakes area, you don't have to go far to find ice - it often finds you. Given the choice of taking a challenging IFR trip where icing might be encountered - Cherokee or RV - I have to say the Cherokee would be my choice.

Dan
 
My name is Brad, and I've flown my -6A into (unknown) icing conditions.

34330309763_a54807080c_c.jpg

Light icing accumulation on the wing (from a different trip than described below)

Coming back from a trip down south several years ago, descending through a layer at about 9,000 to my fuel stop in Sullivan, MO I accumulated what looked like perhaps 3/8" or 1/2" of rime ice on the leading edges of the wing, among other areas. Twisting around, I could see there was a good bit of ice on the horizontal as well, along with some buildup on the windshield.

But I broke out around 9000", the temperature on the ground was reported to be in the 60's, and it was clear below. I had my test cards on my iPad, so I cancelled IFR and re-ran my stall tests.

What I found was the the stall speed increased by approximately 4 knots - not really a big deal. But the nature of the stall changed; it felt more like "tipping over" with a definite nose-down tendency vs. just mushing forward - classic symptom of a tailplane stall. Dropped some flaps and tried it again, same thing only more pronounced.

Kept the descent going and shed all the ice by about 6000' or so.

Lessons learned:
1) The 23000 series airfoil on the airplane didn't seem to be as affected by *this specific instance* of ice buildup as I would have thought. I figured the stall speed would be more dramatically impacted.
2) Climb rate was subjectively only marginally affected; I didn't measure it but had no issues climbing from 7500' to 8500' with the extra load.
3) AoA was not helpful in predicting the stall. I speculate this is because it was a tailplane stall, not a stall of the wing which the AoA indicator is associated with.
4) Flaps had a noticeable impact on the abruptness of the stall, again I speculate because it was a tailplane stall vs. wing.

I had considered the possibility of icing, and mitigated that risk by having an out (warm temperatures on the ground, ceiling well above the freezing level, etc.). Additionally, I engaged pitot heat before entering the undercast to prevent ice buildup vs. waiting until I suspected a problem.

I've encountered light or more severe levels of ice several other times - and have promptly exited icing conditions by climbing, turning, or otherwise leaving ASAP. Controllers have always been very accommodating once they hear the word "ice". Don't be afraid to ask for a change when seeing ice start to accumulate, and don't be afraid to *tell* them what you are doing if they can't/won't help. A non-event in something with turbines and bleed-air anti ice could be catastrophic in a piston single.

I think of it like this: Winning a fight with icing conditions is like winning a gunfight - the only sure fire approach is to be somewhere else.
 
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....I’ve had light ice in the 172 and didn’t consider it an emergency but it was something to be avoided and remedied. .....

You answered you own question.

In my experience, if you fly IFR, you're going to end up in in some IMC. When I've been in IMC in my RV-7A, my best tool to indicate potential ice is the OAT reading when in visible moisture (clouds and/or precip). Most high performance airplanes I've flown consider that icing conditions prevail when the OAT is +5C(41F) or less. At that point, I'll go full carb heat and be alert for any IAS abnormalities. If I had pitot heat, I'd also turn it on at that point.

If you have white painted wings, it's very, very difficult to see any ice buildup on them. The controllers will help remedy the situation, but it's up to you to be aware and initiate the action.

In my latest occurrence, I was VFR when I entered a snow squall at about +2C. Within a couple of minutes, the IAS started jumping from normal cruise to "0" and back as the big wet snowflakes started plugging up the pitot tube since I don't have pitot heat. I was on autopilot and at one point, the IAS pegged out at "0" long enough for the ESP system on the Garmin autopilot to sense a "too low" airspeed and it initiated a 1500 fpm descent. Up to that point, the ground speed hadn't wavered. The descent was more an annoyance than anything so the I clicked the autopilot off and hand flew with the IAS pegged at "0" while I sorted out my options. I flew out of the the squall and landed without incidence.

A few observations:
An OAT gage is your best friend. Pitot heat would be a close second. The high performance airplanes always fly with pitot and static heats on. Know your situation. Know your equipment. Communicate with ATC as necessary. They will help. Don't panic. It's not an emergency, but could be if you let it get to that point.
 
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The conditions for icing are very predictable, if there is visible moisture and the temperature is near or below 0C, ice can form. It's easy to anticipate and avoid this scenario!
 
I've had my 9A in ice three times, unintentionally. First time was at 17,000' coming home from Reno and I was in the very top of a layer and picked up some light rime. I requested FL190 to climb out of it, and ATC granted that, it sublimed off in a few minutes and was a non-event - but only because I had enough performance to climb out of it even at that altitude, and I knew I was right there at the tops. That was actually the first time my airplane took me into the flight levels and Class A airspace, was kinda cool except for the reason I did it.

Second time was a LOT more scary - I was flying below an undercast doing some ground scouting, temp was just below freezing and I wandered up into the bottom of the undercast while turning over some interesting stuff on the ground. I was in it less than 20 seconds, going immediately onto the gauges and in a slight descent to get back clear, and I picked up between 1/8" and 1/4" of clear ice just that fast. It was fairly obvious looking at the wings, and there was zero accumulation below the layer - but in that layer it was accumulating FAST. I headed to the house, parked in the hangar and called it a good lesson learned about supercooled droplets.

Third time was shooting approaches in actual IMC in Midland, with a strong temperature inversion. I was on my second approach for the ILS at KMAF at around 4500 when I noticed a fair bit of ice accumulating on the windshield and wing leading edge. I cancelled the approach and requested 7000, above the inversion layer, to let it melt off.

Ice is not something to play with - it will kill you dead - stay out of it when you can, and get out of it when you can't.
 
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How Much Ice?

We have an RV-6. It can handle 60 lbs. of ice, max, if it’s in the baggage compartment. Comparing how much ice any given RV can handle compared to a 172 is not much different from asking if a fire is worse in one than the other. Very, very few light singles can handle much of any ice.
 
Respectfully, but after 18 years of flying ATRs-777s out of Newark throughout New England and points beyond, phraseology like this sends a chill up my spine.
I’ve had light ice in the 172 and didn’t consider it an emergency...

Since you cannot see the top of the wing, how did you know how bad the icing was?


The conditions for icing are very predictable, if there is visible moisture and the temperature is near or below 0C, ice can form. It's easy to anticipate and avoid this scenario!

Ice can form on an aircraft when the SAT is above 0°C if the aircraft surface is below freezing. This situation can occur when the aircraft descends from subfreezing temperatures. It can also occur on areas where the local temperature is reduced to below freezing due to local flow acceleration.
-NASA



Please, please, PLEASE, everyone, go watch this right now: https://aircrafticing.grc.nasa.gov/1_1_2_2.html

Icing is not something to mess around with in a light aircraft.
 
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Respectfully, but after 18 years of flying ATRs-777s out of Newark throughout New England and points beyond, phraseology like this sends a chill up my spine.

Phraseology is important. The AIM has specific descriptions of what "trace", "light", "moderate", mean with respect to icing and it has nothing to do with how much ice has accumulated. Rather, it has everything to do with the time required to accumulate ice.

I feel like what many call "light ice" would in fact be moderate or worse. AIM 7-1-21 (link) defines "light" ice as an accumulation rate of .25" - 1.0" per hour. Many times when I've heard people described picking up "light ice" they said it happened in a few minutes; a .25" accumulation of ice in five minutes would equate to three inches per hour. According to the AIM definition, that's on the borderline between moderate and severe.

I would categorize my encounter described above as moderate, based on that metric, and that's what I told the controller. Phraseology is important part of communications with ATC, and words like "moderate" or "severe" convey a very different description of the situation than does "trace" or "light".

This is also where the difference between aircraft becomes important. Something moving at 300 kts will have more ram rise and slipstream effects to prevent/remove ice than with something moving at 150 kts, regardless of any anti-icing systems present on the aircraft. The former might see "light" icing as a result, while the latter might see "moderate" or "severe" while flying through the exact same conditions.
 
I encountered ice 3 times , actually maybe more than that , but these three cases were serious ,
RV’s will do better than any other aircraft , in my opinion ,
1st time over Nova Scotia, late may , heading to france , @10k feet , decending lower solved the problem .
Second time was severe icing , over Pittsburg , late November , heading to Utah , we were cruising @ 8k , descended through a layer of about 2000 feet ( about two minutes total time inside the soup , we accumulated 1/8th” , lost pitot , lost outside reference ( the canopy froze as well ) , but the frightening thing was a stuck elevator , you’d have to shake it really well several times to free it .
The 3rd time , over New Hampshire , heading to Bar harbor Maine , @ 9000 feet , we were flying over cloud tops , temperature was around -30C , there was no reason for ice to be there , we also had a stuck elevator due to ice , a few shakes solved the problem ,
In all cases , flight characteristics remained similar to no icing conditions , I couldn’t tell about airspeed since we lost pitot but i am sure we lost a couple of knots.
All the above was flight into UNKNOWN UNFORCAST ice.

Some pictures :




 
Anytime you pick up ice in a plane that isn’t certified for known icing, it’s an emergency! I used to fly a 675hp Caravan, fully protected with boots and a hot plate, and if you get into ice, it degrades the performance so much! The indicated airspeed without ice would hang around 160 knots, and with ice would fall to about 140 knots. The ice boots would be less effective at the lower speed, and it would only crack and chip away at the leading edge. Asking for a block altitude, I could dive it down close to redline, blow the boots and it would shed the ice really well, then zoom back to the original altitude with the extra energy and a clean wing. You have to get out of it. As for a Cessna 172, even with 180 HP, it is not powerful enough to deal with ice. Those pictures above are really only trace to light ice. Moderate to severe ice is much thicker, accumulates very quick and will easily take down a GA airplane without protection, eventually taking down a GA plane with protection if you sit in it long enough. I’d say that if you are thinking that you got away with ice once or twice, and that you know how to handle it, you are being dangerous. Look at that Cessna 210 crash in Lubbock a few weeks ago. Most people would say the 210 has good power, but not with a load of ice..
 
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If you'll allow a Lancair guy to make a comment, the factory came out with a Service Bulletin to open the gap to 1/4" between the elevator horns and the horizontal stabilizer. Apparently that's an area which can freeze over in icing conditions.
 
Those pictures above are really only trace to light ice.

As I mentioned above, "trace" and "light" have very specific definitions in the AIM 7-1-21. If that was accumulated in the span of just a few minutes, it very likely would meet a definition of "moderate" or perhaps even "severe".

Words mean things, and characterizing that as "trace" ice to a controller wouldn't convey nearly the same sense of urgency as "moderate" or "severe" would. And urgency in such a case is of paramount importance as you point out...
 
Definitions

The definitions are also relative to the capability of the aircraft's de/anti-icing systems.

In an aircraft with no ice protection systems, I'd argue that there is no light, or moderate icing since it is all beyond the capability of the non-existent ice protection equipment. Trace ice would exist since it the definition doesn't depend upon or necessitate the use of ice protection equipment. So in an RV, the options for icing conditions are none, trace or severe. With experience, the line between trace and severe icing is very fine and hard to detect until it's obviously more than trace. With aircraft certified for known icing, the line between moderate and severe is the same, it's all okay until the escape plan is in full motion. Escape plan being idle descent or max power climb at the aircraft's minimum icing airspeed.

I'm going to second what Steve Crewdog said above, and expand slightly. +5*c and below in visible moisture is no place for an aircraft not certified for known icing conditions. At +5*c and below, an RV is a VFR only aircraft.
 
Anytime you pick up ice in a plane that isn’t certified for known icing, it’s an emergency! I used to fly a 675hp Caravan, fully protected with boots and a hot plate, and if you get into ice, it degrades the performance so much! The indicated airspeed without ice would hang around 160 knots, and with ice would fall to about 140 knots. The ice boots would be less effective at the lower speed, and it would only crack and chip away at the leading edge. Asking for a block altitude, I could dive it down close to redline, blow the boots and it would shed the ice really well, then zoom back to the original altitude with the extra energy and a clean wing. You have to get out of it. As for a Cessna 172, even with 180 HP, it is not powerful enough to deal with ice. Those pictures above are really only trace to light ice. Moderate to severe ice is much thicker, accumulates very quick and will easily take down a GA airplane without protection, eventually taking down a GA plane with protection if you sit in it long enough. I’d say that if you are thinking that you got away with ice once or twice, and that you know how to handle it, you are being dangerous. Look at that Cessna 210 crash in Lubbock a few weeks ago. Most people would say the 210 has good power, but not with a load of ice..
HI Tom ,
I appreciate your input ,
in fact , the total time spend in the soup in any of the occasions i mentioned above was less than 2 minutes , but that didn't prevent a pitot tube icing and a blocked elevator ,
I honestly did not think I was getting away with it , I would never fly into known ice , othwerise this would be normalization of hazardous behavior ,
I have been thinking about using some kind of electrically heated tape (with adhesive ) to protect the leading edges , as an experimental hot wing anti ice system ,
This past summer, I flew with another guy to Cold foot from Fairbanks ,
we encountered ice on the way back @9000 feet , the aircraft was a Piper chieftain , was nicely equipped and had Deice boots , the PIC didn't seem to be concerned at all !
 
Trend

One trend I'm noticing in this thread is a comparison of those who have flown aircraft certified for known ice compared to those who have not.

Posters who have flown aircraft certified for known icing are quite nervous with this thread and are posting serious warnings. Those without any experience in known icing certified aircraft seem to be downplaying the hazard.

I suspect this difference is simply from a lack of experience with icing conditions. With experience, we have seen how a "thin layer at 8000ft" can surprise a pilot and cause problems.

Once I did an approach and missed approach in a DH8 where total time in icing conditions was 7 minutes with all the ice protection systems running on the highest settings. During the missed approach, the aircraft was barely climbing at normal climb power and airspeed, maybe 300fpm. That's 7 minutes where enough ice was packed onto the plane that it struggled to climb with two turbine engines and the full deal of ice protection systems. I opened the taps and unleased all 4000hp and that resulted in about 1000fpm climb. Yes the DHC8 weighs a lot, but it's got a similar power to weight ratio of a 200hp RV7 or 8 and the DHC8 is generally considered underpowered in it's category. In my situation, anything without ice protection systems would be in a descent at full power, if not out of control. The ice also formed in the classic rime style. What might have been 1" thick was about 1.5" wide. So the 1/4" post and 1/8" antennas were now about 1.5" wide, triangle shaped and very jagged into the airflow creating huge amounts of drag.

Please don't tempt fate and go into a cloud when it's near freezing or below. One might get away with it 1 time or 100 times, but eventually luck will run out. I want to see all my fellow VAFers continue to fly another day.

It's also important to share stories about getting caught off guard. Nobody else can learn from our mistakes if we hide them. By sharing the scary stories, maybe 5 other pilots will avoid the same issue. Might even save someone's life.
 
One trend I'm noticing in this thread is a comparison of those who have flown aircraft certified for known ice compared to those who have not.

Posters who have flown aircraft certified for known icing are quite nervous with this thread and are posting serious warnings. Those without any experience in known icing certified aircraft seem to be downplaying the hazard.

There's a lot more options available in turbine powered aircraft, for sure - some obvious and some not so much. My ice story in turbine aircraft was a duct failure, with the QRH requiring that anti-ice be turned off. Happened shortly after takeoff in 1/4sm, 100' vv, SN/BLSN conditions out of KATW. We declared, then accelerated to Vmo - 335 knots - until clear of icing conditions. THAT kept most of the ice from building; prior to accelerating, it was visibly growing on the windshield wipers.

Hard to accelerate that much in an RV.
 
Really surprised myself with an ice encounter, no forecast ice and clouds/visible moisture were low-mid 40’s. Cruised well over the layer of clouds in the low teens and essentially cold soaked the airplane, when I hit the clouds on the descent the airplane instantly iced over the windscreen and was building pretty quickly on the leading edges. I increased the rate of descent knowing the bases were a couple thousand below and warmer. The ice started melting off before I exited the cloud bases and only lasted about a minute, more than enough time to get my attention.
 
Really surprised myself with an ice encounter, no forecast ice and clouds/visible moisture were low-mid 40’s. Cruised well over the layer of clouds in the low teens and essentially cold soaked the airplane, when I hit the clouds on the descent the airplane instantly iced over the windscreen and was building pretty quickly on the leading edges. I increased the rate of descent knowing the bases were a couple thousand below and warmer. The ice started melting off before I exited the cloud bases and only lasted about a minute, more than enough time to get my attention.

The ice is usually (but certainly not *always*) located right at the top of a cloud layer, and there is often a slight but noticeable drop in OAT when descending into the layer as well. Good call on increasing the descent rate...
 
I have been thinking about using some kind of electrically heated tape (with adhesive ) to protect the leading edges , as an experimental hot wing anti ice system
With the utmost respect, testing an ice protection system can be extremely risky - you'd be jumping into a potentially (probably, really) critical flight condition just to see if the tape works. This is an area best left to professional test pilots and engineers.

Besides, electrical anti-ice requires huge amounts of current - lots more than our alternators are capable of producing.

Dave
 
With the utmost respect, testing an ice protection system can be extremely risky - you'd be jumping into a potentially (probably, really) critical flight condition just to see if the tape works. This is an area best left to professional test pilots and engineers.

Besides, electrical anti-ice requires huge amounts of current - lots more than our alternators are capable of producing.

Dave

Hello Dave ,
I agree on not testing equipment in icy condition , as it is very hazardous ,
The platform must have dual alternators and dual batteries , the system isn't designed for FIKI , but as an out should an icing condition arise during a flight ,
I am talking to two suppliers , one here in the states , extremely expensive , but has a certified aviation product , the other is in China , Home Depot pricing
 
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