Sunday, February 15, 2009

Could Ice have brought down Flight 3407?

UPDATE 02/15/09: It is rather disturbing to learn that the pilots decided to continue flying on auto-pilot even as they discussed the icing issues they were having. That model of Bombardier aircraft had a very sophisticated de-icing system installed.

The exact cause of last night's tragic crash of Continental Connection Flight 3407 from Newark, N.J.will not be known for some time. The National Transportation Safety Board is always very thorough with investigations. It is important, however, to review a widely known hazard to flight safety: ice.

New York from Newark 08876

The facts that are known at this time hint at several possible scenarios. The plane was flying at a low altitude of perhaps 2,500 feet above the ground level (AGL). It was flying in a snowstorm. The pilots of other aircraft flying in the same region at approximately the same time reported ice accumulation on their wings.

The Bombardier Q400 aircraft involved in the accident was a turbo-prop or propeller-driven aircraft. It is a very advanced model but, like all aircraft, still very susceptible to weather and pilot error, the two major causes of most accidents.

A recent (January, 2009) article on a website called "America's Flyways" provides significant details about the impact ice has on an aircraft in flight. I remember my flight school instructors telling me in no uncertain terms how accumulating ice reduces the ability of an aircraft's wings to provide lift. The ice actually changes the shape of the wing, in addition to adding considerable weight. Ice has long been proven to have a very great impact on aircraft propellers. Even though planes are equipped with various types of de-icing systems, there is always the threat of the ice striking the various surfaces of the plane as it is removed by these systems during flight.

Here are two outlines of the de-icing systems installed on the Q-400:
  • The Ice Detection System (IDS) assists in determining ice build-up and sends this information to the pilots in the flight compartment so that they can take the appropriate action.
  • The Pneumatic De-ice System (used in this airplane) removes ice accumulated on the leading edges of the wings, horizontal and vertical stabilizers, and the inlet lip of the engine nacelles.
  • The leading edges of the propeller blades are electrically de-iced.
  • The Anti-icing Systems are thermal, using electrical heating elements to prevent ice formation.
The Ice and Rain Protection System (IRPS) have these sub-systems:
  1. Air Intake De-icing
  2. Pitot and Static Anti-Icing System
  3. Windshield and Windows Ice and Rain Protection
  4. Propellers Ice Protection
  5. Ice Detection System
  6. Airframe De-icing Systems

Annapolis Ice Storm 70358

As I stated in my opening paragraph, it is important to let the NTSB investigators do their job. But it never hurts to remind pilots to be more cautious when flying into winter storms.


America's Flyways article
New York Times article
Washington Post article #1
Washington Post article #2

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