Runway Infrastructure Condition


The maintenance of airport infrastructure is critical to safe and efficient air cargo transport. The OKI region’s eight public airports have a combined 14 runways of various dimensions, pavement types and conditions. Every three years, Federal Aviation Administration (FAA) requires airports receiving federal funding to review and make needed improvements to every paved surface, including runways, taxiways, and gates or plane parking spots.

CVG Runway Reconstruction

In Fall 2021, CVG completed a $69-million, full reconstruction of Runway 9/27 that included new asphalt, concrete, and lighting updates. Seventy-five percent of the project was funded by FAA. Runway 9/27 is CVG’s longest and most utilized runway at 12,000 feet. Its east/west alignment is heavily used for nighttime operations by some of the largest and heaviest air cargo carriers. CVG’s next runway project will be Runway 18C/36C with its rehabilitation scheduled for 2023. (Source: Conrad, Debbie. (2021). Cincinnati/Northern Kentucky International Airport.)

Ground level view of cracked and worn Runway 9/27 pavement and paint-stripes before reconstruction.

Runway 9/27 Pre-Reconstruction Pavement Conditions
Source: Cincinnati/Northern Kentucky International Airport (CVG). (2021).

Ground level view of brand new paved and grooved Runway 9/27 after reconstruction. Two crisp, wide white-painted stripes edged in black fade into the distance.

Runway 9/27 Post-Reconstruction Pavement Conditions
Source: Cincinnati/Northern Kentucky International Airport (CVG). (2021).

Close view of an old, dimly lit runway light before 9/27 reconstruction

Runway 9/27 Pre-Reconstruction Runway Lighting
Source: Cincinnati/Northern Kentucky International Airport (CVG). (2021).

New LED runway 9/27 light and small, blue taxiway edge light. Both raised about two feet off the ground on yellow poles.

New Runway 9/27 LED and Taxiway Edge Lights
Source: Cincinnati/Northern Kentucky International Airport (CVG). (2021).

Pavement Classification Number (PCN)

The Pavement Classification Number (PCN) is a number that expresses the load-carrying capacity of a pavement for unrestricted operations. The PCN system uses a coded format to maximize the amount of information contained in a minimum number of characters and to facilitate computerization. The PCN for a pavement is reported as a five-part number where the following codes are ordered and separated by forward slashes.

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Numerical PCN value

The PCN numerical value indicates the load-carrying capacity of a pavement in terms of a standard single wheel load at a tire pressure of 181 psi (1.25 MPa). The PCN value should be reported in whole numbers, rounding off any fractional parts to the nearest whole number. For pavements of diverse strengths, the controlling PCN numerical value for the weakest segment of the pavement should normally be reported as the strength of the pavement. Engineering judgment may be required in that if the weakest segment is not in the most heavily used part of the runway, then another representative segment may be more appropriate to determine PCN.

Pavement type (F=Flexible or R=Rigid)

  • Flexible pavements support loads through bearing rather than flexural action. They comprise several layers of selected materials designed to gradually distribute loads from the surface to the layers beneath. The design ensures that load transmitted to each successive layer does not exceed the layer’s load-bearing capacity.
  • Rigid pavements employ a single structural layer, which is very stiff or rigid in nature, to support the pavement loads. The rigidity of the structural layer and resulting beam action enable rigid pavement to distribute loads over a large area of the subgrade. The load-carrying capacity of a rigid structure is highly dependent upon the strength of the structural layer, which relies on uniform support from the layers beneath.

Subgrade category (A, B, C, or D)

Rigid Pavement

Code Designation Subgrade Strength Category Subgrade Support k-Value pci (MN/m3) Represents pci (MN/m3)
A High 552.6 (150) k>442 (>120)
B Medium 294.7 (80) 221<k<442 (60<k<120)
C Low 147.4 (40) 92<k<221 (25<k<60)
D Ultra Low 73.7 (20) K<92 (<25)

Flexible Pavement

Code Designation Subgrade Strength Category Subgrade Support CBR-Value Represents
A High 15 CBR>13
B Medium 10 8<CBR<13
C Low 6 4<CBR<8
D Ultra Low 3 CBR<4


Allowable tire pressure (W, X, Y, or Z)

Code Category Tire Pressure Range
W High No pressure limit
X Medium Pressure limited to 218 psi (1.5 MPa)
Y Low Pressure limited to 145 psi (1.00 MPa)
Z Very Low Pressure limited to 73 psi (0.50 MPa)


Method used to determine the PCN

(T=Technical Evaluation Method or A=Aircraft Method)

Source: Federal Aviation Administration (FAA). (2011). Advisory Circular No: 150/5335-5B, Standardized Method of Reporting Airport Pavement Strength – PCN.

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