Presented to: By: Venue: Date: Federal Aviation Administration COMFAA 3.0 Update Airport Pavement Working Group Gordon Hayhoe, ANG-E262 Sheraton Atlantic

Presented to:

By:

Venue:

Date:

Federal AviationAdministration

COMFAA 3.0 Update

Airport Pavement Working Group

Gordon Hayhoe, ANG-E262

Sheraton Atlantic City Convention Center

April 25, 2012

2Federal AviationAdministration

Airport Pavement Working Group – COMFAA 3.0April 25, 2012

COMFAA 3.0 Outline

• Brief PCN background.• Current AC and COMFAA.• Changed radius of relative

stiffness multiplier for rigid ACN.• Other possible changes to the

AC and COMFAA.



• The aircraft mfg. provides the ACN.

• In the US, the airport determines the PCN using FAA advisory circular guidance.



Technical Method for PCN

• Find the Maximum Allowable Gross Weight of the Critical Aircraft for it to be able to operate at the Existing Traffic Level on the Existing Pavement.

• The ACN of the Critical Aircraft at the Maximum Allowable Gross Weight is then the PCN of the pavement.



PCN Calculation for Large-Hub Airports with AC 150/5335-5A

• Airports with a large number of narrow-body aircraft (737, A320, etc.) and a relatively small number of wide-body aircraft (777, A360, 787, etc.) can:– Have one of the narrow bodies as the critical aircraft,

which will give a fairly low PCN.– Have one or more of the wide-bodies with ACN values at

operating weights much higher than the PCN determined by the narrow body critical aircraft.

• This will mean that wide body aircraft in the original design mix might not be eligible for operation under the ACN-PCN system.



The AC 150/5335-5B PCN Methodology

• The AC 150/5335-5A methodology finds the critical aircraft and then finds the ACN of that aircraft at the maximum allowable gross weight. That ACN is then the PCN.

• The -5B methodology is the same except that the ACN at maximum allowable gross weight is calculated for all of the aircraft in the mix.

• The largest ACN value is then selected as the PCN.

• There is a need for a way to eliminate “occasional or overload” aircraft from the mix.



AC 150/5335-5B



AC 150/5335-5B, Applicability



AC 150/5335-5B, Downloads

http://www.faa.gov/airports/resources/advisory_circulars/index.cfm/go/document.list



AC 150/5335-5B, Downloads

http://www.faa.gov/airports/resources/advisory_circulars/index.cfm/go/document.list



Current COMFAA 3.0



Current COMFAA – Aircraft Window



Current COMFAA – Details Window



Changes To Be Made to COMFAA

• The cutoff radius for rigid pavement ACN computation will be changed from 3.0 to 5.0 times the radius of relative stiffness.

• Values for only the applicable support strength will be included in Table 2. PCN Values in the Details Window.

• Total CDF will be added to Table 2. PCN Values in the Details Window.

• Output text files optional by user selection.• Updated Airbus aircraft library.



Rigid Cutoff = 3.0, C-17A



Rigid Cutoff = 5.0, C-17A



Updated COMFAA – Details Window



Updated Airbus Library



Possible Modification to AC 150/5335-5

• Expanded and more precise guidance on when low-traffic aircraft should be considered overload rather than part of the traffic mix.

• Contact Jeffrey Rapol for more information at [email protected]

Documents

Presented to: By: Venue: Date: Federal Aviation Administration COMFAA 3.0 Update Airport Pavement Working Group Gordon Hayhoe, ANG-E262 Sheraton Atlantic