ICAO Annex 14
ABBREVIATIONS AND SYMBOLS
ACN - Aircraft classification number

2.6 Strength of pavements

2.6.1 The bearing strength of a pavement shall be determined.

2.6.2 The bearing strength of a pavement intended for aircraft of apron (ramp) mass greater than 5700 kg shall be made available using the aircraft classification number — pavement classification number (ACN-PCN) method by reporting all of the following information:

a) the pavement classification number (PCN);

b) pavement type for ACN-PCN determination;

c) subgrade strength category;

d) maximum allowable tire pressure category or maximum allowable tire pressure value; and

e) evaluation method.

Note — If necessary, PCNs may be published to an accuracy of one-tenth of a whole number.

Important Note: This is the old version of the regulation, as of November 2024 ICAO fully implemented the change from ACN/PCN to ACR/PCR regarding pavement bearing strengths. However, ECQB January 2026 Update states that, as of end 2025 pavement strength in the EU Member States was still being determined using the ACN / PCN. that's why we still keep it in database. You can find new regulation below:

Annex 14 Vol I - Amendment 18 (Latest Version)
Definitions
Aircraft classification rating (ACR). A number expressing the relative effect of an aircraft on a pavement for a specified
standard subgrade category.
Note: The aircraft classification rating is calculated with respect to the centre of gravity (CG) position which yields the
critical loading on the critical gear. Normally the aftmost CG position appropriate to the maximum gross apron (ramp) mass
is used to calculate the ACR. In exceptional cases the forwardmost CG position may result in the nose gear loading being more
critical.

Pavement classification rating (PCR). A number expressing the bearing strength of a pavement.

2.6 Strength of pavements

2.6.1 The bearing strength of a pavement shall be determined.

2.6.2 The bearing strength of a pavement intended for aircraft of apron (ramp) mass greater than 5 700 kg shall be made
available using the aircraft classification rating-pavement classification rating (ACR-PCR) method by reporting all of the
following information:

a) pavement classification rating (PCR) and numerical value;

b) pavement type for ACR-PCR determination;

c) subgrade strength category;

d) maximum allowable tire pressure category or maximum allowable tire pressure value; and

e) evaluation method.

Note: Guidance on reporting and publishing of PCRs is contained in the Aerodrome Design Manual (Doc 9157, Part 3).