ACN/PCN PROGRAM for Windows™

Dynatest International

WinPCN has been upgraded and is now an optional module to Elmod5. WinPCN is no longer available as a stand-alone program.

WinPCN is a Windows based programme that uses the data files from Dynatest FWD/HWD equipment to calculate ACN/PCN values based on the methods used by ICAO.
The programme includes a database of over one hundred and twenty-five aircraft with ICAO ACN values.

Calculation of ACN/PCN values Users have the ability to modify the parameters of analysis, input the number of operations for the aircraft, and store and print the resultant analysis.
Output from the program includes screen review of the data, printed hard copy of the analysis parameters and results, and graphic display data.

Output files to database to enable importation to a variety of database and spreadsheet programs. The results from the programme are lists of ACN/PCN values reported from each test point. Additionally the ACN/PCN program can calculate a PCN value based on aircraft ACN values and subgrade CBR values as described in FAA Circular 150/5335 –5. The programme supports both ICAO and FAA standards.

The ACN/PCN MethodThe ACN/PCN Method

The ACN/PCN method was developed by ICAO and is described in "Aerodrome Design Manual", Part 3, Pavements, Second Edition, International Civil

Aviation Organization, 1983. The name "ACN/PCN" is derived from the classification of aircraft according to their Aircraft Classification Number (ACN), and pavements according to their Pavement Classification Number (PCN).

According to the Design Manual the ACN/PCN method is meant only for publication of pavement strength data in the Aeronautical Information Publication (AIPs).

It is not intended for design or evaluation of pavements, nor does it contemplate the use of a specific method by the airport authority either for the design or evaluation of pavements The basic principles of the ACN/PCN method may be explained through the following quotations from the manual:

"The method makes use of a mathematically derived single wheel load to define the landing gear/pavement interaction. This is done by equation, the thickness given by the mathematical model for an aircraft landing gear to the thickness for a single wheel load at a standard tire pressure of 125MPa (180 psi)".

Two mathematical models are used in the ACN/PCN method: the Westergaard solution for a loaded elastic plate on a Winkler foundation (interior load case) for rigid pavements, and the Boussinesq solution for stresses and displacements in a homogeneous isotropic elastic half-space under surface loading for flexible pavements".

"The ACN of an aircraft is numerically defined as two times the derived wheel load, where the derived single wheel load is expressed in thousand of kilograms".

Although the Design manual states that any method may be used to determine the load rating of the pavements, using criteria different from those used in deriving the ACN values will introduce an inconsistency, because it may change the relative effect of different aircraft and thus their relative ACN values. A PCN value derived using a certain type of aircraft may not be valid for other aircraft types. For thick pavements the differences will usually be reasonably small.

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