AIRPORT PLANNING MANUAL 7.9. ACN-PCNSYSTEM-FLEXIBLEANDRIGIDPAVEMENTS The ACN/PCN system as referenced in Amendment 35 to ICAO Annex 14, “Aerodromes”, provides a standardized international aircraft/pavement rating system. The PCN is an index rating of the mass that according to evaluation can be borne by the pavement when applied by a standard single wheel. The ACN is established for the particular pavement type and subgrade category of the rated pavement, as well as for the particular aircraft mass and characteristics. An aircraft shall have an ACN equal to or less than the PCN to operate without restriction on the pavement. The method of pavement evaluation is left up to the airport, and the results of such evaluation are presented as follows: Table 7.1 - Pavement Evaluation PAVEMENT SUBGRADECATEGORY TIRE PRESSURE CATEGORY METHOD TYPE R–Rigid A–High W–NoLimit T – Technical F – Flexible B–Medium X–to1.5 Mpa (217 psi) U–Using aircraft C–Low Y–to1.0 Mpa (145 psi) D–Ultra Low Z – to 0.5 Mpa (73 psi) Report example: PCN 80/R/B/X/T, where: 80 = PCN R=PavementType: Rigid B=Subgrade Category: Medium X=Tire Pressure Category: Medium (limited to 1.5 Mpa) T=Evaluation Method: Technical The flexible pavements have four subgrade categories: A. High Strength - CBR 15. B. Medium Strength - CBR 10. C. Low Strength - CBR 6. D. Ultra Low Strength - CBR 3. The rigid pavements have four subgrade categories: 3 3 A. High Strength - Subgrade k = 150 MN/m (550 lb/in ). 3 3 B. Medium Strength - k = 80 MN/m (300 lb/in ). 3 3 C. Low Strength - k = 40 MN/m (150 lb/in ). 3 3 D. Ultra Low Strength - k = 20 MN/m (75 lb/in ). EFFECTIVITY: ALL Section 7 Page 7-19 Dec08/03 b-apm1346