To add to 'it.pilot's' query and to explain a little more of the 'problem' to 'Ice-bore', with reference to the 737 NG the 'frost' occurs due to fuel cold soak during prolonged cruise in cold upper temperatures. The 'thin wing' then allows the cold fuel to cool the wing surface, and cause condensation (obviously humidity related). If the fuel temperature in the wing is below zero, this dew can/will then freeze to produce a thin 'frost'. The thermal capacity of the cold fuel prevents the wing from warming up in line with the rest of the aircraft, even in OATs of 14-15 degrees C or more. I have had the problem at 20 deg C.
It affects ONLY the wing - the rest of the structure (no fuel contained therein - eg
other areas, e.g. where the L/G and engine(s) are attached to the wing, contain large amounts of metal which may have remained below 0 deg. C )
is not affected. They normally 'warm-up' on a t/round. If I elect to de-ice in these conditions I will de-ice only the wing upper surface. The addition of 'warm' fuel in an uplift [beware it is 'warm' - I have like a previous poster, seen sub-zero fuel loaded (in Krakow)] will, providing there is sufficient uplift, raise the tank fuel temperature to above zero. The 'frost' will melt, leaving 'dew'. In the OATs we are looking at (10 deg C plus), there is NO WAY the 'dew' will refreeze and it will obviously disappear during take-off and flight.
The upper surface is the problem - lower surface ice is allowed in controlled conditions. If you have arrived in Egypt in summer and ask to be de-iced, it proves a little difficult.
This is, IMO, a reasonable attempt (with testing) to review the age-old philosophy of a 'clean upper wing.
I have not looked in detail at the Boeing lnk above, but I'm pretty sure there is no 'condition' that de-icing is not available? I cannot see why people are getting so 'heated'
about this - if Boeing have tested it, the 'frost' is withing the defined area and is the 'correct' type PLUS it does not affect the handling/performance any more than a coating of de-icer, what is the issue?