Page 282 - UK Air Operations Regulations 201121

Part CAT - ANNEX IV - Commercial Air Transport Operations

the cloud ceiling will be above 600 ft by day or 1 200 ft by night.
(b) Flight with helicopters to a helideck or elevated FATO shall only be operated when the
mean wind speed at the helideck or elevated FATO is reported to be less than 60 kt.
CAT.OP.MPA.250 Ice and other contaminants — ground procedures
(a) The operator shall establish procedures to be followed when ground de-icing and anti-icing
and related inspections of the aircraft are necessary to allow the safe operation of the
aircraft.
(b) The commander shall only commence take-off if the aircraft is clear of any deposit that
might adversely affect the performance or controllability of the aircraft, except as permitted
under (a) and in accordance with the AFM.
CAT.OP.MPA.250 GM1 Ice and other contaminants — ground procedures
TERMINOLOGY
Terms used in the context of de-icing/anti-icing have the meaning defined in the following
subparagraphs.
(a) ‘Anti-icing fluid’ includes, but is not limited to, the following:
(1) Type I fluid if heated to minimum 60°C at the nozzle;
(2) mixture of water and Type I fluid if heated to minimum 60°C at the nozzle;
(3) Type II fluid;
(4) mixture of water and Type II fluid;
(5) Type III fluid;
(6) mixture of water and Type III fluid;
(7) Type IV fluid;
(8) mixture of water and Type IV fluid.
On uncontaminated aircraft surfaces, Type II, III and IV antiicing fluids are normally applied
unheated.
(b) ‘Clear ice’: a coating of ice, generally clear and smooth, but with some air pockets. It forms
on exposed objects, the temperatures of which are at, below or slightly above the freezing
temperature, by the freezing of super-cooled drizzle, droplets or raindrops.
(c) Conditions conducive to aircraft icing on the ground (e.g. freezing fog, freezing
precipitation, frost, rain or high humidity (on cold soaked wings), snow or mixed rain and
snow).
(d) ‘Contamination’, in this context, is understood as being all forms of frozen or semi-frozen
moisture, such as frost, snow, slush or ice.
(e) ‘Contamination check’: a check of aircraft for contamination to establish the need for de-
icing.
(f) ‘De-icing fluid’: such fluid includes, but is not limited to, the following:
(1) heated water;
(2) Type I fluid;
(3) mixture of water and Type I fluid;
(4) Type II fluid;
(5) mixture of water and Type II fluid;
(6) Type III fluid;
(7) mixture of water and Type III fluid;
(8) Type IV fluid;
(9) mixture of water and Type IV fluid.
Deicing fluid is normally applied heated to ensure maximum efficiency.
(g) ‘De-icing/anti-icing’: this is the combination of de-icing and anti-icing performed in either
one or two steps.
(h) ‘Ground ice detection system (GIDS)’: system used during aircraft ground operations to
inform the personnel involved in the operation and/or the flight crew about the presence of
frost, ice, snow or slush on the aircraft surfaces.
(i) ‘Lowest operational use temperature (LOUT)’: the lowest temperature at which a fluid has
been tested and certified as acceptable in accordance with the appropriate aerodynamic
acceptance test whilst still maintaining a freezing point buffer of not less than:
(1) 10°C for a Type I de-icing/anti-icing fluid; or
(2) 7°C for Type II, III or IV de-icing/anti-icing fluids.
(j) ‘Post-treatment check’: an external check of the aircraft after de-icing and/or anti-icing
treatment accomplished from suitably elevated observation points (e.g. from the de-
icing/anti-icing equipment itself or other elevated equipment) to ensure that the aircraft is
free from any frost, ice, snow, or slush.
(k) ‘Pre-take-off check’: an assessment normally performed by the flight crew, to validate the
applied HoT.
(l) ‘Pre-take-off contamination check’: a check of the treated surfaces for contamination,
performed when the HoT has been exceeded or if any doubt exists regarding the continued
effectiveness of the applied anti-icing treatment. It is normally accomplished externally, just
before commencement of the take-off run.
ANTI-ICING CODES
(m) The following are examples of anti-icing codes:
(1) ‘Type I’ at (start time) — to be used if anti-icing treatment has been performed with a
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