Date: 25 Jan 98 03:27:23 From: "David E. Pearce Jr." <email@example.com> Organization: Lockheed Martin References: 1
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Ken S wrote: > I was wondering if any one can help explain the FAA rational for deicing > aircraft. I have seen aircraft deiced when the outside air temp was -10c > and very light snow falling. Now I understand the Clean aircraft concept > yet it seems to me that this snow (maybe enough to leave a trace after > several hours) poses no threat to the aircraft. Yet because our ops > specs call for a "clean airplane" we must de-ice. Airline pilots are not test pilots. If specific icing conditions are not enveloped in testing, then a flight into those icing conditions are test flying. It is difficult to quantify snow and icing conditions on an aircraft, so instead they prep the aircraft to known conditions (ie deice it). Also, the aircraft surface could be above freezing and the snow falling could be melting and draining to a lower and colder part of the aircraft and freezing. The snow could melt on the top surface of the wing due to warm fuel and flow down to the leading edge, which being thin metal without fuel behind it is colder, and refreezing. Ice on the leading edge of a wing is not a good place to have it as it can upset the flow over the entire rest of the wing upper surface.