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I've decided to create a new section on this web site to capture some of the great flying advice that streams through some of the e-mail lists that I follow. I'll update the Pearls of Wisdom as I come across them.

There was an interesting series of messages about flight in icing conditions on the RV-List recently which has a few good lessons. The following messages are posted with the permission of the original authors.

Read on for more.

From: "Jim ****"
To: "RV List" This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject: RV-List: When the vibration stops
Date: Sat, 29 Nov 2003 11:43:35 -0500

--> RV-List message posted by: "Jim ****"

Listers,
Just got in from Fort Worth via an all night stay at Terre Haute. I leftMt. Vernon (MVN) on the way to Warsaw in 2000 ft. ceilings and reported icefrom 4-6000 ft. I filed IFR at 3000 because that's as low as they would giveme, and climbing on top would have put me in ice for longer than I wanted tobe. Twelve miles north of Terre Haute my airspeed indicator went to zero. Itold Terra Haute I wanted to spend the night with them. I received radarvectors to HUF started to 1500 ft , made the turn south and the engine quitwhen I reduced power. I had carb heat on and throttle full open, I had tojockey the mixture at the full lean position. I pulsed the engine for eightmiles. These RVs take very little power to keep them afloat. Finally theengine would take a richer mixture and started running OK as I got to theairport. Made a good landing and approach thanked me for not making them doa lot of paperwork. My controller at Terre Haute talked to me continuallyand indicated places to sit down if I had too, he was a Godsend.

Chad Williams and the guys at the Flight Center put my RV4 in a heatedhanger to let the ice melt off last night.

Last night it dawned on me that a lot of you listers probably have thesame carb heat set-up that I do. You use a heat muff around the pipes to getcabin heat and carb heat. IF YOU GET CARB ICE, TURN THE CABIN HEAT OFF WHILEYOU'RE TRYING TO GET YOUR ENGINE TO RUN AGAIN. I didn't think of this untillast night in the motel room. ALSO, WHEN THEY SAY ICE, THEY MEAN ICE. Ididn't have pitot heat because I wasn't going to be foolish enough to fly inicing conditions, RIGHT!

Jim ****
Older and Wiser


From: "Doug Rozendaal"
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject: RV-List: Really long winded Icing dribble, was : When the vibration stops
Date: Sat, 29 Nov 2003 22:12:06 -0600

--> RV-List message posted by: "Doug Rozendaal"

> --> RV-List message posted by: Jerry Springer
>
> Now I can't let this go without asking why you would file
> and fly into KNOWN icing conditions? I know that you said
> the ice was from 4000-6000 ft and you filed for 3000 ft but
> still I would not have done that myself because no one can
> predict that closely at what level the ice well really
> start and stop. IMO
>

It has been a long weekend, and I seem to have nothing better to do so Iwill tackle this one.... I flew night freight in Twin Beeches and C-402spart-time for 10 years in Iowa and along the way, I got a little experiencewith ice.

Before we go any farther, flying IFR without pitot heat is a bad idea.(Sorry Jim, but that is the fact. I imagine you have already ordered aheated pitot tube. Sick engine + no airspeed = no fun.) Pitot heat is a NOGO item for IFR, in all but the low altitude summer time, and even then youcan have freezing temps at fairly low altitudes when convective activitygets rolling.

If you plan to fly IFR out here in the Midwest, you have to remember we onlyhave 2 WX briefings from FSS, when we call, we get a message that says, "ifit is between April 1 and November 1 press 1 for the summer briefing,otherwise press 2 for the winter briefing." The summer briefing says"afternoon thunderstorms with tops to FL 450, hail to 2", and wind gusts to50kts." The winter briefing says "Scattered snow showers with visibilityreduced to 1/2 mile and Moderate Mixed Ice in the clouds from the freezinglevel to FL180.

The only way to fly IFR out here in the winter is to "manage ice" Ice islike turbulence, there is almost always some, and it is usually not a bigdeal. Without knowing the WX pattern etc, I don't know what Jim's plan wasor should have been, but "plan" is the key word and with a "plan" usuallyyou can "manage" ice pretty effectively. Flying IFR in the winter up northis not for marginal instrument pilots. Flying and navigating needs to beeasy enough for the pilot to leave plenty of mental horsepower available forgathering weather information and planning.

Deicing equipment on light airplanes is highly overrated, the best friendyou can have in the ice is climb performance, and RVs have good climbperformance!

The whole icing syllabus can not be reduced to a post on this list, but hereare some points that might be useful for managing ice.

#1 Never fly in Freezing Rain.
#2 Have a Plan, and a plan B.
#3 Upon encountering Ice, take immediate action, in accordance with #2
#4 Never fly in Freezing Rain
#5 If the plan falls apart, implement Plan B and formulate Plan C. Repeat asnecessary.
#6 Pilots almost always stop flying before the airplane. NEVER QUIT FLYING!!! Most airplanes (fat wing, RV included) will fly with OBSCENE amounts of ice on them. NEVER QUIT FLYING!!!!
#7 Never fly in Freezing Rain.
#8 95% of all icing encounters are less than 3000 feet vertically.
#9 Upon encountering ice, the default reaction should be to climbimmediately. Descending is always an option, but if you descend and guessedwrong, climbing is no longer an option.
#10 Never Fly in Freezing Rain. This is the exception to #9 if youencounter freezing rain turn around, as quickly as you can.
#11 Do not let ATC fly your airplane. If you are on top and they want youto descend into the ice 40 miles from the airport, do not do it. Stay uphigh, then dive for the airport as late as possible. If you need to climb,ask once, and then insist on a climb even if it means you have to changeheading to clear traffic.
#12 You guessed it, Never Fly in Freezing Rain.

With these rules in mind, the "plan" might be, Get a briefing, If the topsare below 8000 feet, and the freezing level is 4000 feet. Plan A might belike Jim's try to stay below it. upon encountering the ice, Plan B isimmediately request an unrestricted climb to 8 or 9000 feet and use FULLpower. RV's climb well in cold weather and within 5 minutes you should beon top. Plan C then becomes turning around and beginning a decent to anearby airport for a straight in approach. Do not *censored* foot around with(unnecessary) procedure turns if you are accumulating ice at a rapid rate.If you are in radar coverage get vectors, if not they won't know you skippedthe PT anyway.

Now you are up on top at 9000 feet and the clouds are sneaking up beneathyou. Ask center for a pilot report or get on the flight watch, ask what isgoing on below. Remember that 95% thing, it came from a big study done bysome PHD types that I got as a reference for an icing article in IFRmagazine. You punch into the clouds, and if you start getting ice you maywant to climb to 10 or 11, or you may want to request 4 or 5 thousand. butonce you start the decent if you start picking up ice, you either have toclimb backup, or you are committed to descend till you get out of it, orpick a place to land if you can't get below it. (have a alternate in mindwhen you start the decent) 95% of the time you will be below it in 3000feet and you can continue to your destination.

In the briefing, planning and flying, try to visualize the weather system.Where the cold air and where the warm can be found. Either one is fine, itis the kinda cold air that causes the problems. Unless you are flyingparallel with the weather system, the altitudes on the top and bottom ofthese areas, will move up or down as you cross the fronts. So in theprevious example where the tops of the clouds, and ice, are rising, thechances are the base of the icing layer is rising as well and on a trip likethat you could cross the icing layer twice and never spend more than 10minutes total exposed to the ice. Unless you are in Freezing Rain, 10minutes of ice will seldom cause you any more trouble than a frozenwindshield. Something to consider if you are shooting a non-precisionapproach. If you can't see the runway, fly to the airport, and circlelooking out the side using a carrier type approach.

That is the short version.

Some quick war stories:

You may have determined by now that I have a healthy respect for freezingrain. I descended into freezing rain in a Cessna 402 at 3000 ft on an ILSwith the gear up planning to circle. I broke out of the clouds at 2000 feetwith full power, the gear was still up and the airplane was barely flyable,at DH I put the gear down. The windshield was covered so I kept thelocalizer centered till I saw the runway lights out the side window andsmashed it on to the runway. It was the closest I have ever been to buyingthe farm. I was in the clouds for less than a minute and had over 2" ofclear ice that ran back to the spar. NEVER QUIT FLYING the airplane. (youwonder why I fly warbirds on weekends instead of night freight?)

Another time, I was flying VFR underneath the clouds, at night, the ceilinggot below 1000 ft and I was 40 miles from my destination. I asked for myclearance (which I had briefed ATC would be my plan if the ceiling got toolow.) and climbed to 4000 ft. With only 40 miles to go, why climb higher,besides I had deice equipment. I climbed into a 30 kt headwind, and startedpicking up rime ice. I did not want to climb any higher, I only had 40 nmto go.... I thought I would just slug it out. I kept cycling the boots,and kept the wings clear, but every unprotected leading edge of anythingjust kept piling on ice, which reduced my groundspeed even further. I justkept adding power and when I started down the glideslope I was at 110 knotswith climb power. No options, no climb performance left, nothing, justshoot an approach and make it. No excuses. I was in the ice for over 30minutes including the approach maneuvering and it was too long. There was 3to 4 inches of mixed ice on the unprotected areas.

The more winters I flew the less ice I seemed to encounter, and the weathernever changed. I can honestly say there have been entire winters when Inever cycled the boots......

Sorry for the long post, but it really is the short version.

Tailwinds,

Doug Rozendaal


A few comments, based on a bunch of flying in icing conditions on Grumman Trackers doing maritime patrol, some icing flight testing, and a bit of civilian operational icing experience:

  1. Jim's original point about how the use the carb heat system is relevant. If you have a single heat muff that feeds both carb heat and cabin heat, you really should stop the cabin heat when you use carb heat.
  2. The weather forecasters don't have the tools to accurately forecast icing conditions, so they will cover their butt by making a blanket statement about possible icing conditions in cloud above the freezing level. Sometimes there is ice, but often there isn't. But, if you head into the clouds above the freezing level, you had better have a good escape plan in case you find ice.
  3. One thing I've learned from icing flight testing - in layer type cloud there is often a very thin layer of icing conditions about 50 ft below the top of the layer. This is even more pronounced in the top layer. So, don't linger around the top of the cloud layer.
  • I've done quite a few flights with large simulated ice shapes glued to the wing and tail leading edges. Most aircraft fly quite nicely with ice on the airframe, other than a drag increase and a significant loss in maximum lift. The maximum lift could easily decrease by 40%, which means about a 20% increase in stall speed.
  • Your prop will collect ice, which will greatly affect its efficiency, and cause a significant drop in available thrust. So, if you get in ice don't waste any time getting out, or your prop could become a baseball bat.
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