NEWS
In one of the worst air disasters in the history of the US, a Bombardier Q400 commuter aircraft of Continental Airlines crashed into a house at 10 pm on February 12 while approaching to land at the Buffalo-Niagara airport in New York State and exploded into a deadly fireball, killing around 50 people. It was not immediately known as to why the flight from Newark, New Jersey to Buffalo suddenly fell out the skies with no warning. At the time of the crash, the area had been experiencing fog, wind and snow. Although the weather conditions were common in New York this time of year, experts say it only takes a small amount of ice buildup to impact aerodynamics.

VIEWS
The Continental’s Q400 crash was not only unfortunate, it also ended the longest stretch in aviation history without a single airline fatality in the US. While the US National Transportation Safety Board (NTSB) will no doubt thoroughly investigate the accident, certain premises could be made. The good news is that both the Black Boxes—the Cockpit Voice Recorder and the Flight Data Recorders—have been recovered.

So what could have gone wrong with Continental Flight 3407 on that fateful night? First, the aircraft. The Dash 8 Q400 is a twin-engine turboprop medium capacity commuter airliner and, according to its manufacturer, Bombardier, it is the world’s most technologically advanced turboprop. There are 30 airlines around the world which are operating 220 of these planes with 127 more on order. The aircraft in question with registration N200WQ was less than a year old with no past history of any major malfunction. The weather was anything but benign that night, with poor visibility and snowfall. It may be recalled that the northern US has been experiencing a spate of snow storms right through the winter. It is quite possible that the crew experienced severe icing conditions in flight after take-off. This fact has been corroborated from the pilots’ conversation with the air traffic controllers. Even though the plane’s deicing system had been switched on 11 minutes into the flight, the crew had noticed considerable accumulation of snow on the wind-shield and the wings indicating that the de-icing system was unable to fully cope with the severity of the icing problem.

Ice accretion is a serious emergency in an aircraft as too much of it leads to increase in all-up weight with the resultant increase in the stalling speed of the aircraft. It also deteriorates the aerodynamic qualities of the lift and control surfaces. All these coupled with asymmetric ice accretion—a highly probable occurrence—can create a very dangerous situation for the aircraft. The most prudent course of action recommended in such cases is to take over control of the aircraft manually and vacate the snow-affected airspace immediately. In this case, while the crew showed concern over the snowy conditions and asked controllers for changes in altitudes, the auto-pilot was reportedly kept engaged till the last moments. Coupled with auto-trim, modern day auto-pilots are designed to fly the aircraft automatically in all phases of flight but within predetermined parameters. If the aircraft departs from any of the configurations, the auto-pilot would disengage automatically. Is that what happened?