- The PCN is to be based on the ACN values of the most damaging aircraft that can use the pavement on a regular basis (regular being defined by the operator),
- The PCN determination must consider the number of coverage’s during the pavement’s life.
Naturally, an analytical technical evaluation is preferred over empirical methods (i.e. CBR-method), revealing the true material strength using calibrated failure criteria for all pavement materials and subgrade. ICAO requires that the strength of pavements for aircraft with mass greater than 12,500 lb ( 5,700 kg) be made available using ACN-PCN method by reporting all of the following information:
- Pavement Classification Number
- Pavement type
- Subgrade strength category
- Maximum allowable tire pressure category or maximum allowable tire pressure value
- Evaluation method
|
PCN
Numeric Value |
Pavement Type |
Subgrade Strength
Category |
Allowable Tire Pressure |
Method of PCN
Determination |
| 31 |
R – Rigid
F – Flexible |
A – High
B – Medium
C – Low
D – Ultra low |
W – No limit
X – to 1,5 MPa (217 psi)
Y – to 1,0 MPa (145 psi)
Z – to 0,5 MPa (73 psi) |
T – Technical
U – Using aircraft |
Example of reporting PCN
A flexible pavement with a subgrade CBR of 7, a numeric value of 31 determined by a technical method, and having an allowable tire pressure of 1,6 MPa is reported as 31/F/C/W/T.
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