(review © 2002 Louise Parsons)
"Icing for General Aviation Pilots"
In preparation for showing this video that I obtained from NASA, this has been written by me for our local Corvallis Chapter of Oregon Pilots Association and the Oregon Pines Chapter of the Ninety-Nines.
""Icing for General Aviation Pilots" (Go to this link for information on how to obtain this video) 2002 Video NTSC 55 minutes GRC-382, produced by NASA Glenn Research Center, in conjunction with the FAA and the Air Safety Foundation of the AOPA. Note: Since I obtained this video, it is now available on DVD. It is ideal for group presentations or for individual study.

"Bonanza Seven Zero Kilo, Say souls on board."
The Bonanza is in serious trouble. Thus the video "Aircraft Icing for General Aviation Pilots" opens with an encounter with heavy icing by an IFR student and instructor. As they contact ATC, they have already lost 45 knots of airspeed and are unable to climb to an assigned minimum altitude. As you move to the edge of your seat, they ask for vectors to the ILS to the nearest airport. But there on edge you will stay for a while, not knowing the outcome of this encounter until the end of the video.

This video is produced jointly by NASA (Glenn Research Center), the FAA, and the AOPA Air Safety Foundation. In spite of some graphic manipulations to take advantage of research aircraft icing images, it is very realistic and "hands-on". After the suspenseful opening flight, there follows a very educational video session on all aspects of icing. Two pilots, Rona and Greg, are followed from pre-flight through all phases of their respective flights. Neither of them are participants in the above opening scenario, but they have interesting encounters with icing conditions of their own. Rona pilots a twin Seneca with de-icing boots, while Greg pilots a single engine Saratoga without any de-icing equipment. For both flights, several alternative scenarios are presented. You will follow these pilots from preflight briefing and weather evaluations through to final approach and landing.

Unlike airline pilots, private pilots must often make go/no-go decisions based on their own direct evaluations of the information available. We do not have the crew or technical staff to consult, but we do have numerous benefits of briefing tools. We use these tools to assess our risk of encountering ice. Know where your ceilings and tops are, obtain the freezing levels, any PIREPS, SIGMETS, or other information such as the presence of a front. The pilots in this video both ask --and answer well! -- the critical question, "Do you have any outs if ice is encountered?" Do you always have room and fuel to divert? Does your MEA give you room to descend? Can you climb? Have you reviewed your POH with regard to all cold-weather operations? GA aircraft tend to fly at altitudes that are conducive to icing conditions. Since icing is associated with dynamic weather conditions such as fronts, the window for decision-making can become suddenly narrowed. For instance, heavy icing conditions upon approach could preclude the option of a missed approach. If you are carrying ice to the point of degraded control, your only choice might be controlled descent rather than a stall or loss of control.

But there is much in this video to help us to avoid ever getting boxed-into such a drastic situation. We are reminded of a recent change in FAA rules that make flight into predicted, as well as known icing conditions without adequate equipment illegal. If you are on a decision edge where "everything would have to go just right" to complete the flight, it is better to choose another option. De-icing equipment is a possible out, but never to be used "as a tool of complacency". On the NASA research website, you can find photos of ice accumulation on surfaces not protected, as well as ice so severe that boots fail to keep up with it. You will learn how ice accumulation effects all of the aerodynamic forces and properties. It increases drag, increases stall speed, and increases fuel burn, while decreasing both lift and airspeed.

Greg starts out on his flight. Through careful monitoring he discovers an OAT lower than predicted and light accumulation of ice. Realizing that a front has arrived ahead of prediction, he wastes no time in dealing with the conditions. He contacts ATC and asks for a lower altitude. When ATC delays his request because of traffic, he stresses that he needs an immediate descent and will take any heading. In a differing situation, Rona also spots some light ice. She calls Center and asks where the tops are. The information that she receives allows her to elect to climb, with ATC cooperation of course. Under some circumstances, climbing can offer advantages such as more altitude to recover from "control anomalies". A climb may be the most direct path for avoidance. This must be a careful decision, however, since the region near cloud tops may contain the most severe icing conditions. In yet another scenario, Greg discovers worsening conditions and contacts Flight Watch. Their help, as well as that of ATC, allows him to execute a successful diversion. Under heavy icing circumstances, priority handling by ATC in response to declaring an emergency is a legitimate out. It is better to answer a few questions and possibly eat some humble pie –and surely it tastes better than mud.

The most severe and the most sudden icing conditions come from little nasties known as SLD's --supercooled large droplets. These can rapidly accrete on all surfaces of an aircraft. The Pacific Northwest is a region where SLD's can be expected. Atmospheric scientists are making remarkable progress with the prediction of conditions that produce SLD's, but it is still realistic to review all your options in case the unexpected happens. Watching this video will give you many tips for avoiding ice. But equally important, it provides many tips for getting out of ice encounters safely. I will share with you but a few from the video: Ice on approach is especially challenging, but a number of strategies are well-depicted in this video. Hand-fly, rather than use an autopilot, which can mask control degradations. Stay on top as long as practical to lighten any possible ice load. Try to use an ILS approach, or a localizer back-course if need be. This can help you to stay stable during pitch and roll upsets. If you suspect or know you are carrying ice, keep your speed up. Consider a no-flap or low-flap landing, since you likely have no way of knowing how much ice you are carrying on your horizontal stabilizer. Too much flap increases your chance of a tail stall, whose recovery can be difficult. Remember that the effects of ice will increase as your speed decreases anyway. If it is thick, your stall warning device may not work either, so you will want to do all that you can to avoid a stall, such as avoiding steep turns or abrupt maneuvers. The video also recommends delaying gear extension until you have the runway "made" ie..well in sight.

What happens to Bonanza Seven Zero Kilo? Watch this video to find out! In this review I have only touched the surface content-wise. I only have one small criticism of this video. It would have been nice to go into a bit more detail about synoptic conditions that lead to icing. Even a little more about cloud physics and accretion of ice would take a lot of the mystique out of it. For group presentations, it would be nice to augment it with a short presentation by a local weather guru, such as someone from a FSS. The video is positive and pro-active in its whole approach. In my opinion, it is one of the best flying videos that I have seen recently. Though there is suspense and some eery drama, the purpose is not to have us lock the hangar or shelve the approach plates for the winter in order to avoid ice. On the other hand, you may think to yourself, "Oh well, I only fly VFR anyway, so I don't expose myself to risks of icing". VFR pilots learn basics about instrument flying to be prepared for unplanned cloud encounters. Thus we all need the basic tools to deal with aircraft icing that might come along for the ride in any encounter with clouds and low temperatures. A large portion of fatal ice-related accidents "happen" to highly experienced pilots. There are none among us from low-timer to old-timer who would not stand to benefit from the current body of knowledge of aircraft icing. Well before the advent of flight, biologist Louis Pasteur said it best, "Chance favors the prepared."

Weather Conditions that Favor Icing in the Pacific Northwest

From information provided by McMinville FSS and several webpages, here is a brief summary to help with general awareness and understanding. It is not all-inclusive. Always get a real weather briefing!

We look at air masses on a weather map and tend to think of them as being symmetrical or even flat. Remember that these maps are simplified. The reality is more dynamic and complex than the maps can show. Supercooled liquid droplets suggest changes in weather. The very concept of water being supercooled implies a condition of change. This is why it is important to monitor and stay informed of weather changes. SLD's can form in an inversion associated with an advancing warm front. This happens frequently enough here to be a good cue to look out for ice. Cumuliform clouds embedded in stratus, low temperature-dewpoint spreads, and of course temperatures near freezing --all are important cues.

But we can also get SLD's with an advancing Pacific cold front. The cold front may push relatively warm air ahead of it. We get freezing rain when precipitation from a warmer layer falls into cooler air in the valleys. VFR flight in winter also demands watchfulness under these conditions, which may be partially clear and showery, and have alluring visibility. Over the valleys VFR pilots sometimes think nothing of flying right through light squalls and rain. And often as not, this is ok. Just be sure to watch your OAT and make sure that the squall is just plain RAIN and not the freezing rain that produces clear ice. Also be aware that wind shear conditions can accompany the squalls. Clear ice accumulates very rapidly on aircraft. Icing can also occur with orographic lifting. This can be quite localized. Here in the Pacific Northwest we usually think of orographic effects in association with the High Cascades, but cooling and icing conditions can occur over the lower Western Cascades or even locally over the foothills. Consult flight watch or McMinville FSS. Staying upwind of the lifting and cooling air mass may be a good strategy.

The Pacific Northwest is similar to the Great Lakes region in that we have a ready and abundant supply of moisture and ever-changing winter patterns of air flow. However, we are lucky that overall our winters are mild. Thus there are plenty of stable days with higher freezing levels. So, if conditions seem iffy, you can truly tell yourself that "Tomorrow is another day".