NTSB QUESTIONS

Yet the NTSB review completed just after the Idaho crash raised questions about the Cessna's icing safeguards. Among the concerns: The plane's boot de-icing system, which is not a "turn on and leave on'' system, forces pilots to constantly monitor accumulation.

Another problem: The plane's high wing makes it nearly impossible for a pilot to see whether ice is forming on the upper wing.

The plane's handbook tells pilots to wait until ¼- to ¾-inch of ice has accumulated before activating the de-ice boots. But that presents problems. Because of the extra workload during approach and landing, "the pilot may not be able to adequately monitor and evaluate the ice accumulation," said the Dec. 15, 2004, NTSB report to the FAA.

The safety board also questioned FAA oversight, saying its "surveillance practices may not be adequate'' to ensure operators avoid icing crashes.

Salmon Air's own safety manual warned, "The Cessna Caravan's weak point known throughout the industry is its ground icing and/or in-flight icing scenarios," files show.

Cessna said the planes are safe -- as long as pilots and carriers abide by procedures spelled out by the company.

"A lot of them are carriers who, because of their business, they are required to move freight and people at night with weather," said Dick Ziegler, a spokesman for Cessna Aircraft Company.

"If the operators of the airplane operate within the parameters of that pilot's operating handbook, the airworthiness directives that call for physical inspections . and basically don't fly your airplane in ice, that would go a long way toward reducing a number of accidents," he said.

But the NTSB had problems with the manufacturer's safety awareness caveats, saying the program "might not place sufficient emphasis on recognizing unacceptable ice accumulations." It concluded pilots may be unprepared for icing conditions.

After the string of fatal crashes and numerous warnings, the NTSB urged the FAA to ''expeditiously'' require more pilot training, develop strategies to avoid icing crashes, mandate more thorough checks of the plane's wings by pilots and operators for icing before flight -- and reexamine its own monitoring of the plane.

Then, in January, the NTSB went one step further: It issued an "urgent'' safety recommendation to the FAA to ban all operators of Cessna 208 series planes from flying in conditions "determined to be more than light icing."

CESSNA TRACK RECORD

In light of the recent actions, The Miami Herald asked the safety board whether it was reconsidering any of its probable cause findings in Cessna's crashes. The NTSB did not respond.

An investigation into a May 2001 crash raises questions about the plane's safety and the NTSB's conclusions.

A Cessna 208B owned by FedEx Corp. and operated by Corporate Air of Billings, Mont., crashed into mountains about three miles south of Steamboat Springs, Colo., killing the 44-year-old pilot.