A Chilling Encounter With Ice

Linda M. Dowdy

The following article was originally published in the January 1994 issue of Aviation Safety. For the non-pilot, the aviation terms are linked directly into a glossary.

"The ice built at a terrifying rate, and all my training told me to get it on the ground ASAP."

I read the recent article on coping with ice with interest ("Beyond the Basics of Icing," Nov. 15). Ice is one thing about which we pilots should be extremely cautious. The best defense against it is the simplistic one: don't get into it. Ice is a fact of life during our Minnesota winters, however; and, sometimes, this can lead to a dangerous mental combination of complacency and familiarity.

We emerge from our instrument training vowing never to get caught in an icing situation. But the real world has an insidious way of compromising these shiny new intentions, and in a short time we can find ourselves caught in a truly horrific situation.

Two years ago, my father and I were flying back to Minnesota from Fort Worth. The entire Midwest corridor was caught in a massive storm, with a large low pressure area camped over the Nebraska-Iowa area. After numerous discussions with Flight Service, I decided I could avoid the storm by tiptoeing up the western side of it and then turning east to Minneapolis when past the low pressure area. That would prove to be a major mistake.

The plan seemed to work at first. Over Oklahoma we encountered light icing. I climbed to 9,000 feet, but still was not free of it. With an elderly passenger aboard, I was reluctant to go any higher in an unpressurized plane, so I sought warmer air below. It worked, and we were soon ice-free.

The journey north remained uneventful until it was time to turn east towards Minneapolis. The cloud deck below began to slope upwards. Soon those innocent-looking tops reached our flight path.

Before long the OAT probe had collected a sheath of white rime ice, and I could see the dreaded signs of it on the leading edges of the wings. Based on my earlier experience, I again sought to escape the ice at a lower altitude. But the freezing level was now at ground level. Mistake number two: I did not turn around and go back to clear air.

The ice built at a terrifying rate, and all my training told me to get it on the ground ASAP. Grabbing my chart, I picked out the nearest ILS symbol, which happened to be pointing at the Yankton, S.D. airport. I advised Minneapolis Center that I was icing badly and requested immediate diversion to Yankton.

Mistake number three: in my haste to find an airport and get the plane down, I did not take the time to check on what facilities the airport had and what type of approach would be needed. Yankton turned out to be an uncontrolled field with no radar coverage. This necessitated flying the full approach in an ice-laden plane. At decision height I looked up, praying for any sign of a runway. I was greeted by blowing snow in dim twilight and a hill to my left. The runway could have been beneath me, and I would not have seen it.

Due to my low altitude, I could not communicate with Center, so ATC had asked another pilot to go into a hold far above me in order to relay communications. Center asked if I could manage to climb back up to 5,000 feet and then fly to Sioux Falls.

Somehow, with a lot of luck and a few prayers, I coaxed the ice-burdened plane into a climb, and we struggled up to 5,000 feet. Sioux Falls was an impossible 84 miles away.

Running at 25-square, we crept toward Sioux Falls at a true airspeed of 110 knots. This in a plane that trues out at 155 knots! During the trip, chunks of ice were flung off the prop and were banging into the fuselage with such force that I was convinced the plane was breaking up.

As Sioux Falls Approach started to vector us on to the ILS approach, I discovered that attempting to change direction by use of the ailerons resulted in no response at all for several seconds, followed by a heart-stopping drop of the "down" wing. This happened twice, and it dawned on me that I was probably periously close to a stall-spin accident. Thereafter all turns were done with rudder only.

At the outer marker, I barely touched the throttle, and the plane started a descent. Because of the aileron experience, I used no flaps, not wanting to take any chance of disturbing the wing configuration.

It was not until Sioux Falls Tower asked me to advise runway in sight that I made the final horrific discovery: I had absolutely no forward visibility. The windshield was a solid sheet of ice. I remembered making landings under the hood during instrument training, so I knew that if I flew the needles with absolute precision, the plane would land on the runway.

During the last few seconds in the air, a power reduction produced a "bucking" effect, so I quickly brought power back up. When the plane actually touched down, there was an alarming lack of directional control, as if a tire had blown. Such was not the case, however, and apparently it was caused by ice buildup on the tires.

I survived the trip, but the experience forever changed my outlook on ice. I relate this experience to the readers of Aviation Safety in order to share the awfulness of a close encounter with ice. In addition I offer the following general observations:

1. First and foremost, if you encounter ice, get out of it! If this means turning around and flying back, then do so.
2. Don't go around the northwest edge of a low pressure winter winter storm. The moist air will have circled counter-clockwise into the cold air on the north side of the low, making the northwest edge the worst possible choice of routes.
3. Don't hesitate to advise ATC that you are in trouble. It is scary when ATC has you squawk 7700 and starts asking how many souls are on board. But if you don't tell them you are in trouble, they can't help you.
4. Remember where the freezing level is. If it is on the ground, you won't be able to find warmer air by descending.
5. Take a few moments to study an approach before committing to it and giving up precious altitude. If you can't land, you may not be able to climb back up again to try somewhere else.
6. Don't forget pitot heat, alternate air, and defroster.
7. Don't change wing configuration with either flaps or ailerons. Make only gentle turns by use of the rudder.