ADR.OPS.C.011 Overload operations

CRITERIA FOR OVERLOAD OPERATIONS

(a)For those operations in which the magnitude of overload and/or the frequency of use do not justify a detailed analysis, the aerodrome operator should use the following criteria, in order not to adversely affect the pavement:

(1)for flexible pavements, occasional movements by aircraft with ACN not exceeding 10 % above the reported PCN should not adversely affect the pavement;

(2)for rigid or composite pavements, in which a rigid pavement layer provides a primary element of the structure, occasional movements by aircraft with ACN not exceeding 5 % above the reported PCN should not adversely affect the pavement;

(3)if the pavement structure is unknown, the 5 % limitation should apply; and

(4)the annual number of overload movements should not exceed approximately 5 % of the total annual aircraft movements.

(b)The aerodrome operator should not permit overload operations on pavements exhibiting signs of distress or failure. Furthermore, overload operations should be avoided during any periods of thaw following frost penetration, or when the strength of the pavement or its subgrade could be weakened by water. Where overload operations are conducted, the aerodrome operator should review the relevant pavement condition regularly, and should review the criteria for overload operations periodically, since repetition of overloads can cause severe shortening of pavement life or require major rehabilitation of pavement.

GENERAL Overloading of pavements can result from loads too large, from substantially increased application rate, or from both. Loads larger than the defined (design or evaluation) load shorten the design life, whilst smaller loads extend it. With the exception of massive overloading, pavements in their structural behaviour are not subject to a particular limiting load above which they suddenly or catastrophically fail. The behaviour is such that a pavement can sustain a definable load for an expected number of repetitions during its design life. As a result, occasional minor overloading is acceptable, when expedient, with only limited loss of pavement life expectancy and relatively small acceleration of pavement deterioration.