The dangers of ice

Last night’s crash of flight 3407 from Newark, NJ to Buffalo, NY, killing the flight crew, all of the passengers, and a victim on the ground, shows that in addition to being dangerous to ground traffic, ice can be extremely dangerous to today’s aircraft.

By the time that the flight crew realized that there was significant ice buildup on the aircraft during final approach to the Buffalo airport, it was too late.

Ice is one of the hidden dangers to airplanes and airliners of all shapes and sizes.

It’s unwanted dead weight that can disrupt the flow of smooth air over the wings, and if severe enough, can also disable certain control surfaces like the ailerons and elevators.  For some aircraft, the ice can build inside of the carburetor and greatly limit the amount of air going into the engine.

As it’s stated in the news article, the flight crew was heard discussing the significant amount of ice buildup on the windshield and leading edge of the wings.  After that, it was all over.  One of the witnesses on the ground claimed to hear the engine sputtering moments before impact.

It’s fairly easy to guess what most likely happened to the aircraft during its last few moments of the commuter flight.

As it was descending through the snowstorm, ice was rapidly developing on the aircraft, adding the extra weight and interfering with the airflow over the wing.  The crew noticed that the ice was spreading across the nose of the aircraft as they descended.  And of course, if there was ice there, then there was ice buildup on other parts including the wing and horizontal stabilizer on the tail of the aircraft.

The flight crew then most likely noticed that the aircraft was unable to maintain altitude once it reached its assigned altitude for that part of the approach.  They probably added full power to try to recover, but the ice was also interfering with the engines and they couldn’t reach maximum power.  The ice was building up faster than ever as it was moving near its final approach speed and significant weight was added to the front nose.  The elevator was most likely partially disabled by ice, and because of the weight of the ice up front and disruption of smooth airflow over the wing, the wing stalled, aircraft pitched over, and the crew was unable to recover in time.  Because of the flight crew realizing the significant ice buildup too late and too low to the ground, they were basically out of options for those last few seconds of flight as the aircraft fell two thousand feet and exploded into a house.

The interesting catch to the story is that there’s no mention as to whether or not the aircraft’s anti-icing system was operational or not.

Most aircraft have anti-icing systems such as carburetor heat, which removes ice built up in the carburetor, or bleeding hot air from the engines to areas of the airplane such as the leading edge of the wing.  Some aircraft have electrical heating devices to melt away ice, while others have thousands of tiny holes on the leading edge of the wing which release a special anti-icing fluid to prevent the development of ice.

It’ll be interesting to see the final report and see if the flight crew had activated any of the deicing systems on the aircraft.

It’s a very tragic story, especially when compared to the spectacular landing in the Hudson River that happened just a few weeks ago.  In that example, the entire flight crew and all of the passengers survived the emergency crash landing, which was a very rare event.