Page 50 - Volume 16 Number 5

ON FINAL by David MillerIt’s Just a Trace of IceIhave decided that there is no such thing as a trace of ice. Oh, I learned all the definitions over the years, light – moderate- severe. I memorized them all. But my actual experience is that ANY ice is a bad thing. What got me thinking about this was the recent fatal accident involving a TBM departing TEB a few months ago. Although no conclusion has been reached in this accident investigation, audio tapes from aircraft in the same area tell the story of severe icing and immediate requests for higher altitudes even from air carriers.Ice is bad.Sometimes it’s our own fault. Years ago, the crew of a 727 departing Buffalo learned the hard way. Climbing through 16,000 feet, the overspeed warning sounded, followed by the stick shaker and stall warning. The aircraft descended out of control, taking with it the three crew members. The pitot heat was never turned on. Sometimes it’s not our fault. Severe pitot icing is believed to be a possible cause of the problems that led to the tragic crash of Air France 447.My personal experience goes like this.We departed KADS (Addison, Texas) on a warm July morning in 2007. I was new to the Citation Mustang with probably 50 hours in type. A few showers hovered around the Standard Instrument Departure path. Climbing through FL270 we entered the clouds. Prior to entering the moisture, I turned on the engine anti-ice. No visible airframe icing could be seen. A few minutes later, I noticed a less than normal climb rate. The Mustang has a wonderful FADEC controlled power management system that I had set in the CLIMB detent. But today, the computer had reduced the power setting to something less than CLIMB. We weren’t developing climb power. What was happening was that the T2 engine probe was accumulating ice in greater amounts than it was capable of melting. A dome of ice was covering the probe, reducing the airflow into the probe, and causing the computer to think that the engine was overheating. To protect the engine, the FADEC system automatically reduced the power on both engines. Not something you expect to see when trying to climb over weather. This phenomenon occurred once again that summer but never since.Between 2004 and 2006, there was a rash of un-commanded in-flight engine shut downs in JT15D powered airplanes flying in high altitude environments. Investigators attributed the incidents to highWith 5,000-plus hours in his logbook, David Miller has been flying for business and pleasure for more than 40 years. Having owned and flown a variety aircraft types, from turboprops to midsize jets, Miller, along with his wife Patty, now own and fly a Citation Mustang. You can contact David at davidmiller1@ sbcglobal.net.altitude ice crystals. Why did this engine design, which had been flying for many years with a long history of successful operation, have a problem with ice between 2004 and 2006?Was it just bad luck?I think Mother Nature today is producing more and different kinds of ice than our engineers, statisticians, and bureaucrats have planned for. Is it global warming? Maybe. But in this case, I don’t really care. What I do know is that I want FIRE breathing out of the tubes and vents of my airplane when I launch into cold, wet skies. As pilots, we should not have to wonder if our systems are up to the job if it’s cold outside.My guess is that current anti-icing and de-icing systems meet the “letter” of the standards in the airplanes we fly.Perhaps it’s time for the FAA to review the icing certification standards themselves.Some good things are happening. NASA announced last August their “High Ice Water Content Flight Campaign.” They are leasing a Gulfstream II for 200 hours of flight testing to define new parameters for developing and certifying aircraft engines, air data systems, weather radar systems, and forecasting tools to help pilots avoid potentially hazardous icing conditions.It’s about time. Fly Safe.48 • TWIN & TURBINE MAY 2012