Page 24 - TNTMay18

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descending even at full power, crashed into a mountainside.
The only remaining option was to do exactly what we were taught NOT to do, which was fly on straight ahead, taking advantage of the tailwind to get us over the crest of the Cascades on over lower terrain as soon as possible. Looking out of the nearly iced-over side window, ice was rapidly accumulating on all parts of the airframe we can see, making proceeding on a very precarious and difficult choice to make.
You only have a neophyte experience once before you learn there are some very effective strategies that can be used to avoid this situation from ever presenting itself.
One of the most basic procedures is to make sure the airplane is well above the icing (that is on top of the clouds), before departing the safety of sea level terrain. To implement this procedure, on the first call to departure control once off BFI request vectors “for ice avoidance” that keep the airplane over or near Puget Sound until it is on top. Upon hearing that request, the controller would probably extend the departure
leg to the NW, and then clear the aircraft direct to back SEA then to the flight plan route. Most departure controllers in the Northwest understand the ice problem and are very cooperative in helping the pilot avoid it. The “ice avoidance” request, however, needs to originate with the pilot. Making such a request is the professional thing to do as it shows you are planning well ahead of the aircraft.
If ice is encountered that stops airplane from climbing while still over sea level terrain, you can always quite safely descend to nonfreezing conditions without hitting anything, and without even requesting much special handling from ATC. When flying near or over salt water on the West Coast, it is helpful to know that ocean temperatures from the Gulf of Alaska to Northern California rarely are colder than 45 degrees F. This “heat source” almost always produces ice-free air below 3,000 or 4,000 feet when over or near salt water, and the MEAs over that water are typically well within those altitudes.
The next question is given the conditions, what should your flight plan route actually be. Clearly the direct one chosen on the above flight was not wise.
The lowest mountain crossing MEA is 6,500 and involves using V2 from SEA to BEEZR intersection, and from there direct to Yakima (YKM), but it is slightly out of the way. An alternative would be to use V4 from SEA to YKM, which is direct but with an MEA of 10,000 feet. From YKM, V4 goes more or less direct to BOI with MEAs on the order of 9,000 feet. When it was new and the C414 airframe was ice free, the book says it could maintain 14,000 feet on one engine. But there are lot of “ifs” in there, so the best route would be the one with the lowest MEA, which is V2, SEA, BEEZR, YKM. The direct route at least from SEA to YKM would not be advisable as the MEAs and terrain are much higher.
So even with a route plan that takes the airplane over manageable single- engine MEAs you still really want to be above the cloud tops before proceeding eastbound. But sometimes, regardless of forecast, the cloud tops exceed the altitude capability of pressurized piston- powered airplanes. If this happens while still over sea level terrain, the flight to that point would had to have been pretty much ice-free in order for me to feel comfortable continuing eastbound and
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22 • TWIN & TURBINE
May 2018