Firm News

Buffalo Flight 3407 All Over Again? Turboprop Icing Possible Cause for Montana Crash

Posted on Mar 25, 2009

"It's Buffalo all over again, or it could be," said John Goglia, a former member of the National Transportation Safety Board. "Icing, given those conditions, is certainly going to be high on the list of things to look at for the investigators." Yahoo News March 23, 2009.

Speculation over the crash of the single-engine turboprop Pilatus PC 12/45 aircraft, shifted to ice on the wings Monday after it became less likely that overloading was to blame.

While descending, the plane passed through a layer of air at about 1,500 feet that was conducive to icing because the temperatures were below freezing and the air "had 100 percent relative humidity or was saturated," according to AccuWeather.com.

Safety experts said similar icing condition existed when a Continental Connection Flight 3407's twin-engine turboprop crashed into a home near Buffalo Niagara International Airport last month.

Mark Rosenker, acting NTSB chairman, told reporters in Montana that investigators would look at icing on the wings as a factor. "We will be looking at everything as it relates to the weather," he told Yahoo News.

Jim Hall the Former National Transportation Safety Board (NTSB) chairman pointed out the similarities between the Butte, MT crash and a March 26, 2005 crash near Bellefonte, PA.

In both of those crashes the airplane involved was a Pilatus PC 12/45 and was on approach to an airport. In both cases there were reports of conditions conducive to icing at lower elevations. Also in both the Montana and the Pennsylvania tragedies, witness reported that the plane appeared to dive into the ground.

Hall also told Yahoo News, "I'm certain they are also going to look at the weather conditions at the time and the pilot's training," Hall said. He pointed to a recommendation on NTSB's "most wanted list" of safety improvements that FAA test the ability of turboprop planes to withstand a particular type of icing condition called "super cooled liquid drops" before certifying the aircraft design for flight. FAA officials have said they're working on that recommendation. "If you had some precipitation and the temperature was in the right range, that again is an area that investigators would look at," Hall said.

The PC 12/45 is certified for flight into known icing conditions, according to the manufacturers' Web site.

The Pilatus PC 12/45 in the Butte crash and the Bombardier Dash 8 involved in the Buffalo tragedy, like all turboprop planes, rely on deicing boots - strips of rubber-like material on the leading edge of the wings and the horizontal part of the tail - that inflate and contract to break up ice. That technology, which was introduced in the 1930's, isn't as effective at eliminating ice as the heated wings that jet airplanes use to eliminate icing form their wings.