Archive for November, 2013


Wednesday, November 6th, 2013

IMG_3445The icing season is upon us, and every so often we are reminded that it can and does bring down not only the small, but larger aircraft as well. Cases in point: Air Florida Boeing 737—Washington, District of Columbia; American Eagle ATR 42—Roselawn, Indiana; Air France Airbus 330 (pitot system icing)—South Atlantic Ocean; Cirrus SR22—Norden, California (near Reno, Nevada); TBM 700—Morristown, New Jersey.

Out of the five listed, all but one, the SR22, were Flight-into-Known-Icing (FIKI) approved. The exact causal factors are different in each case, but the point is that super-cooled liquid droplets can be disastrous no matter what size aircraft. Unlike thunderstorms where life gets ugly immediately, icing problems come on gradually over the course of minutes. This usually gives the pilot warning that he or she is in an unfriendly part of the sky and it’s time to do something. Unlike severe turbulence, which dramatically shreds aircraft or flips the pilot over and lets him finish the deed, ice just chokes the lift out of the wings, the tail, and sometimes the engine. All those parts and pieces are needed to fly.

In the case of the TBM 700 over New Jersey, it was literally only a matter of a few minutes before the aircraft was ground bound. It’s the subject of the December AOPA Pilot “Landmark Accident” feature. So as you fly and train think about escape plans before getting into the clouds or freezing precipitation. Minutes matter. The Air Safety Institute has considerable educational resources available on the topic, including a recorded webinar on cold weather operations and this week’s webinar (recorded after Thursday) on Airframe Ice: Avoidance and Escape.

Our ability to predict ice is gradually getting better, but still isn’t nearly as precise as seeing convective weather via the derivative of heavy precipitation. I’ve made a career out of fussing at the FAA and NWS about greatly expanding the need for pireps so that airmets can be a little less broadly constructed. There are some systemic issues that include what to do with the pirep once the pilot provides it. Often, it cannot get into the system, or at least deeply enough, to change an airmet.

This is not easy stuff to resolve because just using cloud and cold temperatures to predict ice is a pretty blunt tool. Moisture content is key, and that can sometimes be hard to get at. Additionally, as we see with convection, the atmosphere is not universally cooperative or uniform in composition. For those of us in non-FIKI aircraft, AND for those of us flying the FIKI birds, give and get pireps. Treat ice with the same respect you reserve for sparking clouds.