What Role Did Ice Play in Continental Connection Crash?

Buffalo, NYAlthough the investigation into the plane crash of Continental Connection Flight 3407 is ongoing, speculation is still strong that icing may have played a role in the crash. While nothing can bring back the lives that were lost in the crash, a proper understanding of what caused the horrific plane accident can prevent similar crashes in the future.

A recording of air traffic controller conversations [as written up in the Buffalo News] with pilots that occurred just after the plane crash indicates that controllers were concerned about ice in the area and thought it may have been a factor in the plane crash.

"Delta 1998, you getting any icing where you're at?" was the question from a Buffalo air traffic controller, in the minutes following the Continental crash. The pilot's response was, "We picked it up on the way down. I don't think it's building any more here but about 6,500 [feet] down to 3,500 [feet] maybe."

Two other pilots also indicate they are picking up ice. "We're picking up rime ice here," says one pilot. "We've been picking up rime ice for the last 10 minutes or so," says another pilot.

Prior to the crash, the crew of Flight 3407 commented on significant ice buildup on the plane's wings, but it is not known how much ice constitutes "significant" buildup. According to an NTSB member, weather reports in the area indicated pilots had a visibility of 3 miles in snow and mist, making conditions suitable for icing.

As recently as December 2008, the National Transportation Safety Board released a safety alert, warning that as little as ¼ an inch of ice can be deadly. Even that small an amount of ice can change the handling of a plane, causing the NTSB to warn pilots against using autopilot in icing conditions. Use of autopilot may prevent a pilot from recognizing a change in the handling of the plane, making him less able to quickly respond to problems.

According to the NTSB, the pilots of Flight 3407 had their deicing system turned on but also had the plane on autopilot—meaning that they may not have noticed quickly enough that the plane's handling had changed. However, aviation experts say that it is not uncommon that pilots would use autopilot close to an airport when the crew is preparing for an "instruments approach." Use of the autopilot would reduce the pilots' workload—making the approach easier.

The question then becomes, when does the use of autopilot to lessen the pilots' work become a risk for the people on the plane?

Turboprop planes are at a higher risk of icing than jets mainly because they are flown more frequently at lower altitudes, which is where icing is most likely to happen. In-flight icing occurs while the plane flies through clouds made up of liquid water droplets, which can freeze when they impact the airplane. The ice builds up on the front surfaces of the plane, such as the front edge of the wings, nose and tail. The build-up of ice changes the surface of the wings and tail of the plane, changing the plane's aerodynamics. The change in aerodynamics means that a plane experiences more drag and less lift and can also increase the risk of aerodynamic stall.

Whether or not icing was the cause of the plane crash remains to be seen, with the NTSB investigation expected to take months to complete. Meanwhile, families who lost loved ones in the plane crash are left to grieve and wonder what could have caused Continental Connection Flight 3407 to fall out of the sky and take 50 lives in the process.