Page 77 - UK ADR Aerodrome Regulations (Consolidated) October 2021

Part OPS - ANNEX IV - Operations Requirements - Aerodromes

(i) Rigid pavement: Code R;
(ii) Flexible pavement: Code F;
(2) Subgrade strength category:
(i) High strength: characterised by K = 150 MN/m3 and representing all K values
above 120 MN/m3 for rigid pavements, and by CBR = 15 and representing all
CBR values above 13 for flexible pavements — Code A;
(ii) Medium strength: characterised by K = 80 MN/m3 and representing a range
in K of 60 to 120 MN/m3 for rigid pavements, and by CBR = 10 and
representing a range in CBR of 8 to 13 for flexible pavements — Code B;
(iii) Low strength: characterised by K = 40 MN/m3 and representing a range in K
of 25 to 60 MN/m3 for rigid pavements, and by CBR = 6 and representing a
range in CBR of 4 to 8 for flexible pavements — Code C;
(iv) Ultra low strength: characterised by K = 20 MN/m3 and representing all K
values below 25 MN/m3 for rigid pavements, and by CBR = 3 and
representing all CBR values below 4 for flexible pavements — Code D;
(3) Maximum allowable tire pressure category:
(i) Unlimited: no pressure limit — Code W;
(ii) High: pressure limited to 1.75 MPa — Code X;
(iii) Medium: pressure limited to 1.25 MPa — Code Y;
(iv) Low: pressure limited to 0.50 MPa — Code Z;
(4) Evaluation method:
(i) Technical evaluation: representing a specific study of the pavement
characteristics and application of pavement behaviour technology — Code T;
(ii) Using aircraft experience: representing a knowledge of the specific type and
mass of aircraft satisfactorily being supported under regular use — Code U;
(d) The bearing strength of a pavement intended for aircraft of apron (ramp) mass equal to or
less than 5 700 kg, should be reported by reporting the following information:
(1) maximum allowable aircraft mass; and
(2) maximum allowable tire pressure.
PRE-FLIGHT ALTIMETER CHECK LOCATION
(a) One or more pre-flight altimeter check locations should be established.
(b) The elevation of a pre-flight altimeter check location should be given as the average
elevation, rounded to the nearest metre or foot, of the area on which it is located. The
elevation of any portion of a pre-flight altimeter check location should be within 3 m (10 ft)
of the average elevation for that location.
(c) Pre-flight check location could be located on an apron. Locating a pre-flight altimeter
check location on an apron enables an altimeter check to be made prior to obtaining taxi
clearance and eliminates the need for stopping for that purpose after leaving the apron.
Normally an entire apron could serve as a satisfactory altimeter check location.
DECLARED DISTANCES
(a) The following distances should be calculated to the nearest metre or foot for a runway
and reported to the aeronautical information services and Air Traffic Services:
(1) Take-off run available (TORA);
(2) Take-off distance available (TODA);
(3) Accelerate stop distance available (ASDA); and
(4) Landing distance available (LDA).
(b) The take-off run available (TORA), take-off distance available (TODA), accelerate stop
distance available (ASDA) and landing distance available (LDA) should be calculated
according to the following (all declared distances are illustrated for operations from left to
right):
(1) Where a runway is not provided with a stopway or a clearway and the threshold is
located at the extremity of the runway, the four declared distances should normally
be equal to the length of the runway
(2) When a runway is provided with a clearway (CWY), then the TODA will include the
length of clearway.
(3) Where a runway is provided with a stopway (SWY), then the ASDA will include the
length of stopway.
(4) Where a runway has a displaced threshold, then the LDA will be reduced by the
distance the threshold is displaced. A displaced threshold affects only the LDA for
approaches made to that threshold; all declared distances for operations in the
reciprocal direction are unaffected.
(5) Where a runway is provided with more than one of the clearway, stopway, or having
a displaced threshold, then more than one of the declared distances will be
modified. The modification will follow the same principle as in (1)-(4)
(c) The information on declared distances should be provided according to the following
table:
If a runway direction cannot be used for takeoff or landing, or both because it is
operationally forbidden, then this should be declared and the words ‘not usable’ or the
abbreviation ‘NU’ entered.
(d) When intersection take-offs are performed, the datum line from which the reduced
runway declared distances for take-off are determined, should be defined by the
28th October 2021 77 of 144