It was a Cessna Caravan 208B cargo plane that spiraled out of control early yesterday morning (06 Oct 05) and crashed on the CN train tracks behind the Masonic Temple at Confusion Corner. The lone pilot, Nancy Chase-Allan, 49, was killed in the incident.

Radio communication between the pilot and air traffic controllers indicate the plane had become iced up in the moments before the crash.

There were 26 icing-related incidents involving Cessna Caravans between 1987 and 2003 in the United States. A Transport Canada spokeswoman said there have been six such incidents in Canada in the last 10 years.

Earlier this year, the Federal Aviation Administration in the United States issued an

airworthiness directive instructing all pilots flying Cessna Caravan aircraft they must now make a “hands-on” check of the wing before take-off when icing is possible. The directive is typically issued from the country that certifies the plane, but once issued, is adopted by international agreement by other countries. As a result, Canadian pilots are also bound by the new rule.

Prior to the directive, pilots needed only to visually check for icing on the plane’s wings prior to take-off.

As of March, 29, pilots must now run their hands along the wing edge and surface as well as along the tail and propeller blades. Those checks must be done when temperatures fall below 5 C and there is visible moisture.

Investigators are not yet sure whether Chase-Allan conducted such an inspection before take off. Dan Boettcher, a spokesman for Morningstar Air Express, which operates the plane, said yesterday he did not believe Chase-Allan put the plane through a complete de-icing prior to leaving Winnipeg.

“From what I’ve heard, she did not de-ice the plane prior to take-off.”

A paper-thin layer of frost can cause a plane to lose lift. The speed a plane must maintain to avoid stalling is 35 per cent higher with frost than without.

When a plane stalls, its engines continue to run, but there isn’t enough airflow over the wing to generate the lift needed to keep the plane flying.

The plane drops and the pilot loses the ability to navigate it.

Canadian regulations prohibit pilots from taking off with any ice, frost or snow on critical surfaces such as wings. It is up to the pilot or maintenance crew to determine if de-icing fluid should be sprayed on the wings and propellers.Transport Canada spokeswoman Lucie Vignola said yesterday there have been a handful of icing incidents involving Cessna Caravans in Canada in the last decade. She said Canada has implemented the new airworthiness directive from the FAA.

There are 54 Cessna Caravans in operation in Canada.

Last year, the National Transportation Safety Board in the United States issued an alert to all pilots, warning them the ice crystals as tiny as grains of salt scattered on a wing can be dangerous. Citing 26 U.S. crashes which resulted in 36 deaths, the NTSB in the states said they caused concern about “a possible systemic problem with the airplane’s design or operation.”

An American lawsuit is still pending in which the plaintiffs claim Cessna knew of a defect that made their

 Caravans especially vulnerable to ice. The claim has not yet been heard in court.

Additional safety directives pertaining to the Cessna Caravan are in the planning stages in the United States and may be implemented in the coming months. The new directive may compel the installation of de-icing boots on all Cessna Caravan landing gear.

According to international agreement, Canada would adopt the new rules if they are passed by the FAA.