How Much Ice, How Much Trouble?

[201er]

For those of you with "a friend who's been in icing" in a Mooney, can you share how much ice accumulated in about how much time, the conditions, and how much of an effect it had on performance? As it increases, what do you notice in terms of speed, pitch, handling, etc? What amounts of ice are imperceptible (performance wise) and what amounts are deadly?

 

On the flipside, in below freezing temps but clear of clouds, how long does it take for the ice to break or sublimate off?

[Marauder]

Mike to you think any of us are going to declare that we have flown in icing conditions on a public forum? I have no idea what you are talking about. It's illegal to fly in icing conditions!

[Danb]

No clue. Just say no

[RocketAviator]

del

[Hank]

Asking how fast ice accumulates is like asking how fast rain falls or how quickly snow accumulates on the ground.

One winter day in college in southern Alabama, I walked to class in the morning rain and the bank said 32F. Nothing but wet. Two hours later walking home (10 minutes each way), still at 32F by the bank, my umbrella iced over solidly enough I had to shake it clear before it would close up. Two hours after that the mall lost power.

Don't tempt fate trying to fly in ice, it's too variable and unpredictable!

[tomn]

Inadvertent ice is the problem. I've run into it on occasions when it was not "known" - it was known after telling ATC about it. I've never stayed in it long enough to really see how the performance changes - not a good place to hang around to see what happens.

I did have an intersting thing happen flying through a cloud that ended up having heavy snow inside. The power dropped gradually and the plane began to slow. I knew it would be only a few minutes before popping out the other side so it was not an big issue. My guess is that the air filter became blocked by the snow since it picked back up after exiting the cloud. Isn't weather great!

Tom

[BorealOne]

I fly a FIKI Ovation, and can say that it's not possible to talk about 'how fast things get icy' without reference to specific conditions. I've flown through a lot of ice, and can only say that it's really variable. Sometimes it's just a little clear ice on the headlight lens, other times i've had ice coming off the wings in sheets that seem to form as fast as they are shed. Not anywhere you want to be without FIKI capability, and even then, you want to get out of it quickly.

[mulro767]

Icing can be more than just performance degradation and unsafe changes to aerodynamics. While on approach last winter through an 800' layer in unforecasted icing conditions, I picked up enough rime ice to cover my windshield. I had the defroster on but it didn't seem to help. So breaking out at 1500' AFE, I cancelled IFR and circled for ten minutes while the defroster opened up a 10" clearing. On the ground the leading edges showed just a trace of ice. And I noticed no performance changes. It got my attention and raised my ceiling minimums during winter ops.

[bnicolette]

Yeah the defroster is not very effective against ice.  When It's cold out I started run it full bore on the window and run the roof vents to keep it comfortable with the cooler air.  I have had a trace on the airplane before and the window gets frosted over really quick.  Since then I haven't had anything stick to the airplane to see if turning the defroster on early does any good but I am assuming it will do little if any good.

 

Mike what your asking is literally impossible to answer.  I have to assume with the thin wing we have that flying characteristics will degrade rapidly but I haven't been on that ride, nor do I want to be.

[201er]

Brett, I know you've never flown into known icing. But if you did... how much ice would you expect would cause a problem?

 

Let's see if this makes it easier for experienced pilots to answer based on encounters that may have happened to a friend:

 

1) How much ice to make climb impossible? (what model)

2) How much ice requires full power to maintain altitude?

3) How much ice raises stall speed by 10knots? 20? 30?

4) How much ice stalls the tail?

[N201MKTurbo]

When I was younger and the laws were more lax I would routinely fly in icing conditions until I got ice. That was the law back then. It wasn't known icing until you found it or somebody made a pilot report about it on the same route and altitude you were at.

I never got iced up enough to cause a handling problem. I did land a few times looking out the storm window because the windshield was iced over. The defroster doesn't do much. If you are lucky it will clear a 1/2 inch strip of the windshield.

I have had about an inch of rime and the plane flew just fine. I never got the horn formation always just a smooth buildup.

If you can get into the sunshine the ice will sublimate. Depending on the temperature and humidity it will go faster or slower, but I seem to remember it would lose about 1/2 inch an hour.

I was once flying in Wyoming on an IFR flight plan in clear air at 9000 feet OAT was -5C. There was a small very black cloud in front of me. I thought I would see how much ice there was in it. I was in that cloud for about 20 seconds and picked up over an inch if ice. It changed my attitude about icing.

When you decend into warmer air, sometimes all the ice will shed from one wing and not the other. This will cause a bit of a sudden rolling moment, but nothing that you cannot deal with.

[N201MKTurbo]

Mike to you think any of us are going to declare that we have flown in icing conditions on a public forum? I have no idea what you are talking about. It's illegal to fly in icing conditions!

My lawyer says that nothing you say on a public forum can be used against you in court. But it may get the attention of the powers that be to find some evidence they can use in court.

[Piloto]

My experience with ice on Mooneys has been positive in the sense that it will not drop out of the sky but it looses speed. With one inch on the leading edge I have seen 15kts drop in speed. The glareshield vents when air is set to full heat may clear a 3 inch area. You have to lower your head to see thru. Make sure the glareshield hoses are connected, they tend to disconnect. Ice on the prop will shake the plane giving you the impression of a stall and if the pitot heat is off you will get the gear alarm and make you think you are in a stall because the airspeed is close to zero. So make sure pitot heat is on and the ram air is closed. Best is to avoid icing conditions, but if you encounter them don't panic.

 

José  

[BorealOne]

My lawyer says that nothing you say on a public forum can be used against you in court. But it may get the attention of the powers that be to find some evidence they can use in court.

 

Say again? Online statements are not privileged, and are routinely used as evidence. There's a growing industry for validating and authenticating web content - obtaining admissible evidence from a public forum is as easy as entering the URL...

 

http://www.globalcolleague.com/WebSeal

[Jerry 5TJ]

At 10,000 feet with about 1/4 inch of rime a "C" won't climb at ~110 mph IAS, 2700 rpm and WOT. So I hear.

[DanM20C]

Icing can be more than just performance degradation and unsafe changes to aerodynamics. While on approach last winter through an 800' layer in unforecasted icing conditions, I picked up enough rime ice to cover my windshield. I had the defroster on but it didn't seem to help. So breaking out at 1500' AFE, I cancelled IFR and circled for ten minutes while the defroster opened up a 10" clearing. On the ground the leading edges showed just a trace of ice. And I noticed no performance changes. It got my attention and raised my ceiling minimums during winter ops.

This happened to me a few weeks ago. It was at night, my defroster cleared a spot the size of a silver dollar for me to look through.

When you guys are talking about an inch of ice, is this like an old fishing tale? I have inadvertently picked up ice many times, the worst being around 5/16". That knocked 15kts off my cruise speed. I don't think my c could stay in the air with an inch of ice. Granted you long bodied guys have a lot more HP.

[rocketman]

Forget about public disclosure and fearing FAA. Icing is a serious threat and if we can't discuss what we as Mooney pilots have experienced, than the past will be repeated.

 

I flew from Kentucky to Sun-N-Fun maybe 15 years ago IFR over the Smokey Mountains. No known icing forecasted in my 201 without de-icing equiptment. Over the mountains, the worst fear in my entire 28 years of flight hit me. I was in severe icing conditions very quickly, maybe 30 seconds, 8,000 feet and loosing speed very fast. Could not hold altitude and the mountains was a few thousand feet below me. ATC said I had to maintain altitude but I couldn't. I prayed! Even cycled the prop to shed the ice on the prop. Scared the S#$% out of me! And pleaded to find out my quickest escape. They told me South was the fastest route and so I continued heading towards FLorida. Within 10 minutes as best as I can recall, I got out of IFR conditions and proceeded to the air show sublimating my near death leading edge water crystals over the Georgia landscape. 

 

DON't FLY IN IFR CONDITIONS IN VISIBLE MOISTURE! If you do, have an escape, like lower altitudes with higher temperatures below you and before you land. Go through narrow bands of clouds and don't stay long in solid IFR conditions. ICING IS SERIOUS! And if you're not FIKI, don't temp it. Trust me.

 

IMO, the laminar flow Mooney wing attracts ice better than any other GA plane. Your a target, don't venture into enemy territory.

[Shadrach]

See attached pics as an example of what a Mooney will fly with. IIRC, according to the PIC this airplane was not loosing altitude at this level of accumulation, speed was degrading though.  Must have had some big brass ones to get these shots..."Oh look honey, there's an inch of rime on the leading edge, get my camera"). This is not me nor my plane.  I forget who posted them where and when, but I thought I'd save them for just this type of discussion.

 

I have had very few icing experiences. The worst was encountering freezing rain in a 172 while flying below the cloud deck VFR. It built up fast (maybe a 1/3" in about five minutes and also blocked all view out of the windshield. Luckily I was only about 10 miles from my destination when it happened.  My dad who is also a pilot came out to help me tie down. When he saw the clear ice melting off the wings of the C172 I was renting, he just about throttled me (I was 26 at the time so it was wore of a tongue lashing). Bad judgement but a good learning experience.

[Shadrach]

IMO, the laminar flow Mooney wing attracts ice better than any other GA plane. Your a target, don't venture into enemy territory.

 

 

 

What makes you say that?  I'm trying to figure out why a smooth low drag wing would "attract ice better". I can see how performance would degrade more for a given amount of ice, but not why it would pick up ice at a greater rate.

[N201MKTurbo]

The ice pictures above was caused by large super cooled water droplets. My ice experience is almost exclusively over the rocky mountains where the moisture content is usually much lower. Most of the time you get small droplet icing which tends to build up as a smooth coating and does not  build up the structure ahead of the wing illustrated above.

 

The pictures above are scary.....

[N201MKTurbo]

 

 

What makes you say that?  I'm trying to figure out why a smooth low drag wing would "attract ice better". I can see how performance would degrade more for a given amount of ice, but not why it would pick up ice at a greater rate.

 

 

Icing forms faster on smaller radius objects, so the Mooney wing will build up ice faster then a Cessna wing.

 

My personal opinion is that if a Cessna and a Mooney were flying in formation in icing conditions the Cessna would fall out of the sky first.

[bnicolette]

Brett, I know you've never flown into known icing. But if you did... how much ice would you expect would cause a problem?

 

Let's see if this makes it easier for experienced pilots to answer based on encounters that may have happened to a friend:

 

1) How much ice to make climb impossible? (what model)

2) How much ice requires full power to maintain altitude?

3) How much ice raises stall speed by 10knots? 20? 30?

4) How much ice stalls the tail?

 

Mike I'm sorry I can't respond to the above because I, nor "a friend", have ever experienced it.  Sorry I can't help.  The only thing I've ever had on the Mooney was a trace/coating of rime ice from climbing up through a known layer where there was clear on top.

 

The ice on the wings pictured above is real scary, to me.  It doesn't mention what altitude it was at but I would imagine even at lower altitudes it was becoming difficult to maintain altitude and climbing was probably out of the question.

 

Your question about the tail is more than likely going to bite you when flaps are entered into the equation.  If you've ever been accumulating ice and it's still there for landing, really think about whether you really need flaps for landing, or if you do want them, get ready to switch those puppies back in the up position if anything strange is felt.

[jlunseth]

So this friend of mine was coming back to Minnesota from Memphis, descending from the flight levels.  It was summer, but a layer built up that would be encountered in the descent and it was wet clouds.  He tells me the freezing level was about 8,000 and the cloud tops were about 14k.  No ice was forecast but sure enough when he entered the layer it started to build up.  Often most of the ice is encountered in the tops.  The windshield glazed over and mixed ice came back along the wing from the leading edge about an inch and a half.  Being in a high speed descent (with pitot and prop heat on, in still air), he was not concerned and sure enough, as soon as the temps got above freezing it all departed the aircraft quickly.  There was some warm rain and that helped.

 

Still in a descent, at an indicated airspeed in the 150-160 range, the stall alert went off.  Couldn't be, he thought, there is no ice on the wings and I am way over stall.  He even turned around to see if there was still ice on the horizontal stabilizer causing a tail stall, but no ice there either.  After eliminating all the possibilities whatever remains must be true.  It had to be a stall warning failure, perhaps caused by the rain being driven into the switch in the wing.  He disabled the stall alert (there is a switch) but although the aural alert will stop, the button in the middle of the panel will continue to flash, so he completed his trip flying an ILS to near minimums with that alert flashing.  Uneventful landing.

 

The A&P determined that indeed, the switch had gotten water in it and was in "constant on" mode.  The pilot felt that perhaps it was the great flight instructor in the sky tapping him on the shoulder and saying, "don't do that again."  So the pilot got the point and is in the market for a deiced aircraft.

 

The End.

[Hank]

Icing forms faster on smaller radius objects, so the Mooney wing will build up ice faster then a Cessna wing.

 

My personal opinion is that if a Cessna and a Mooney were flying in formation in icing conditions the Cessna would fall out of the sky first.

 

I have always heard that ice forms first and faster on smaller radii, which means our tails will ice up before it shows on the wing. A tail stall is not an attractive scenario. I was taught during initial PPL training to land with no flaps if I happen to accumulate any ice. That means somewhere with a longer, unobstructed runway and not at KHTW.

 

Which plane would have the most ice or the worst performance is not something I can address, nor would I care to find out first-hand. Reading the NTSB reports is bad enough. I have avoided icing so far by:

1. Driving to my destination at Christmas over the Appalachians [the last time we parked on the interstate for 2 hours while salt trucks drove up and down the Saluda Grade at the NC/VA line after freezing rain had moved through--so I made the right call].
2. Taking wide detours coming home instead of direct [the last time I went west from KFAY, past CLT and GSP, crossed the mountains, went north over Knoxville to LEX then headed east to get home, 4.4 hours instead of 2-2.2 direct through forecast icing areas]
3. Stayed an extra night and flew home the next day, with OATs near 40º and a close eye peeled anyway.

Old and bold and all that . . .

[RJBrown]

My experience out west has shown that the greatest ally is power to Climb above ice. Never flown with TKS. Comparison is between a J and a Rocket with a hot prop. At 1500 per climb you are not in ice very long. I preferred to stay above ice as long as possible descending only when at the destination and doing so quickly. Many flights in the Rocket were trace only where a J with limited climb would have been dangerous. The Rocket could always pick an ice free altitude, somewhere between 0 and 24,000 is an ice free zone.. The J was more or less stuck below 12. Climb above 12 in a J can be lost to winds or ice pretty easily. With 14,000' mountains and 16,600' MEAs a normally aspirated plane must remain clear of clouds. I remember one flight long ago in a 182 where I rode a mountain wave up to 20,000' coming across the front range. I was barely on top of the clouds. Wings were Ice free but got some on the wheel pants. Center gave my a block of airspace to play in. Very accommodating about ice. Inadvertent ice is not something they bust you for. It is something they want to help you out of. Don't be dumb about ice speak up if it is an issue.