"During takeoff and climb-out, your aircraft is at a low altitude, high angle of attack, near maximum thrust, and at high drag with gear and flaps/slats out. This challenges, but is well within, your clean aircraft’s flight envelope. Adding even a thin layer of frost, particularly at the wing leading edge, can push you closer to the edge of the envelope.
For too many pilots, contamination has pushed them over the edge."
NTSB ALERT As a result of the Montrose, CO accident, this Operational Alert from the NTSB was issued.
Operational Alert: NTSB Advisory - December 29, 2004 ALERT TO PILOTS: WING UPPER SURFACE ICE ACCUMULATION
Partial text:
As a result of its ongoing investigation of the Nov. 28, 2004 fatal takeoff accident involving a Challenger 604 in Montrose, Colo., the NTSB on December 29 issued a special alert involving the detection and effects of ice accumulation on the wing. “It has become apparent that many pilots do not recognize that minute amounts of ice adhering to a wing can result in severe control penalties,” the Safety Board said. …
NTSB
recommends "touching" the upper
wing surface. (tactile
inspections)
The Safety Board notes that there are circumstances in which upper wing surface ice accumulation can be difficult to perceive visually. For example, depending on the airplane’s design (size, high wing, low wing, etc.) and the environmental and lighting conditions (wet wings, dark night, dim lights, etc.) it may be difficult for a pilot to see ice on the upper wing surface from the ground or through the cockpit or other windows. Further, frost, snow, and rime ice can be very difficult to detect on a white upper wing surface and clear ice can be difficult to detect on an upper wing surface of any color. However, it is critically important to ensure, by any means necessary, that the upper wing surface is clear of contamination before takeoff. That is why the Safety Board recently issued Safety Recommendation A-04-66, urging pilots to conduct visual and tactile inspections of airplane wing upper surfaces.
The bottom line is that pilots should be aware that no amount of snow, ice or frost accumulation on the wing upper surface can be considered safe for takeoff. However, history has shown that with a careful and thorough preflight inspection, including tactile inspections and proper and liberal use of deicing processes and techniques, airplanes can be operated safely in spite of the adversities encountered during winter months.…
11 Surface Contamination
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