Single Engine Flying into Known Icing conditions

By:       Norm Goyer

A reader, recalling that I was from New England, recently wrote and asked what I thought about knowingly flying into icing conditions with a single engine aircraft. I do have some very firm rules regarding any airplane and icing. Icing on a Pepperidge Farm coconut cream cake is great, icing on the wings of my aircraft I avoid at all costs, if I can help it. I have even fought snow and ice in the High Desert, as well as the great North East. Several times, while flying our Seneca over the San Bernardino Mountains at 10,000 feet to LAX, I experienced ice forming on the leading edge of the wings. I knew it was temporary because as soon as I was clear of 13,000 foot mountains and their lower passes I headed down to the much warmer air over the Los Angeles Basin. The ice melted and disappeared.

The TKS system pumps ethylene glycol out of tiny weep holes in panels on the leading edge of the wing, tail, props and windscreen. It is a well proven procedure.

My rules for flying into known icing conditions are very simple: DON’T DO IT! My favorite weather forecaster is a small sky blue card with a hole punched into the middle. You hold the card up to the sky and look through the hole. If the sky matches the color of the sky, go fly.  If not, you have some hard decisions to make. You then have to check the weather between your departure point and your destination, very carefully. If you might encounter IFR conditions, you have to check to make sure that you are you legal for IFR flight, and your aircraft and its instruments, currently certified for IFR flight.  If any doubts occur, take your car, take a train, take a bus, stay home until there are better conditions. Delaying a flight is a minor inconvenience, flying into a rock inside a cloud is a major inconvenience. If you are carrying any passengers, remember that you are responsible for their well being. Of course you can fly solo and do some real stupid tricks, and maybe get away with your carelessness, but taking another soul along with you is irresponsible.

Airliners are cleared of snow via high pressure hose guns. This procedure is best used just prior to take off.

Our reader was curious about methods of getting rid of ice while flying. Some older aircraft may have inflatable rubber boots on the leading edge of the wings, horizontal tail and even the props. One newer method has a reservoir of ethylene glycol which is pumped through tiny holes. This distributes the de-icing fluid over the wings and tail keeping ice from forming. It also aids in melting/dislodging the ice that has already formed. Of course stopping the ice before it forms is the smart way to go.

The most promising total deicing systems in our opinion is the TKS.  Tiny laser drilled holes in a titanium overlay containing the weeping plate and fluid holder. This unit is either built into or added onto the leading edge of the wing, plus the leading edge of the horizontal stabilizer and vertical stabilizer. You can also opt for perforated rings on the prop hub and a plate below the windscreen which can be activated from a control panel in the cockpit. Currently there are several single engine aircraft, including the A-36 Bonanza, that have been certified. Other popular aircraft are currently going through the process. The only moving part in the system is a two-stage pump. For certification of an aircraft for flying into known icing conditions, the system must contain two pumps. For non-certified systems there is one pump. The TKS system operates at various levels of pumping power, to prevent ice from forming, the pump puts out less pressure, to remove existing ice, the pump is run at a higher speed. The system causes the to run from the weeping panels back over the wing and then even blankets the tail surfaces with after wash. The system is very lightweight, has a capacity of approximately 5 to 8 hours of flight time depending on the intensity of the ice.

The downside of the TKS system is its relatively high cost, depending on the protection of the aircraft involved. The system has been tested and certified. It has been found to be very reliable. On the positive side, a pilot can preflight the system on the ground before departing and once airborne it can be checked again before entering the icing conditions. I would still not fly into known icing conditions, but this system could save your butt if you did encounter ice.

I was driving home yesterday, on Interstate 5,  in the SoCal mountains, over the Grapevine, when the windshield of my Buick started to ice over, I said to my brother Dick, “Sure glad I am in a car and not flying in this crud.”

Dick, also a pilot, answered very simply, ” Amen.”

For more information regarding the TKS system contact: Aerospace Systems and Technologies Website: www.weeping

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  1. Chuckl says:

    I’ve been flying for about 43 years now and I’ve owned and flown a Cessna 421B for the last ten. Even with a very capable twin certified for flight into known icing conditions, it’s something I avoid whenever possible. Sure, sometimes you might absolutely have to fly or, frequently, you’ll get caught in icing that wasn’t in the forecast. But I learned from the loss of a lot of good, pilot friends; “If you fly on a crappy day, they bury you on a sunny day.” There is almost no flight that can’t be postponed for a day or two while waiting for better weather.