COMFAA 3.0 Beta Administration Federal Aviation 3_0 Beta Brill.pdf · · 2011-09-09ICAO Aerodrome...

Presented to: VIII ALACPA Airport Pavement Seminar & VI FAA Airport Pavement WorkshopBuenos Aires, Argentina

By: David R. Brill, P.E., Ph.D.

Date: 2 September 2011

Federal AviationAdministrationCOMFAA 3.0 Beta

Demonstration and Hands-On Training

2Federal AviationAdministration

COMFAA 3.0 Beta Demonstration & Hands-On Training2 September 2011

Acknowledgments

• Gordon Hayhoe, Rodney Joel and Jeff Rapol, FAA.

• Ken DeBord and Mike Roginski, Boeing Commercial Airplane Co.



Outline

• Brief review of ACN/PCN system and ICAO definitions.

• FAA guidance on PCN calculation.

• Draft AC 150/5335-5B and computer programs (COMFAA 3.0 and new support program).

• Flexible example using COMFAA 3.0.

• Rigid example using COMFAA 3.0 for a large hub airport.

• Using COMFAA 3.0 additional features.



The ACN/PCN System - General

• Aircraft Classification Number (ACN) is specified as a standard by ICAO in Annex 14 to the Convention on International Civil Aviation.

– Aircraft manufacturers are required to publish properly computed ACN values for all of their aircraft.

• Pavement Classification Number (PCN) procedures are given in the ICAO Aerodrome Design Manual, Part 3, Pavements.

– The PCN procedures in the manual are for guidance only and a great deal of latitude is provided.

– Airport operators are responsible for determining and publishing PCN values for runways.



ICAO Documents Annex 14 to the Convention on International Civil Aviation

ICAO Aerodrome Design ManualPart 3 – Pavements



ACN/PCN System - Definitions

• ACN – A number expressing the relative effect of an aircraft on a pavement for a specified standard subgrade strength.

• PCN - A number expressing the bearing strength of a pavement for unrestricted operations.

• Therefore, if a particular aircraft at a given weight has an ACN less than, or equal to, the PCN of a particular pavement (ACN PCN), then no restrictions need to be placed on operation of that aircraft on that pavement.

• Special provisions for overload evaluation.



ACN Computation

• ACN is computed as the ratio of a computed (derived) single-wheel load to a reference single-wheel load.– Flexible: Based on the US Army Corps of Engineers ESWL

CBR method of design using alpha factors adopted by ICAO October 2007. Thickness is computed for 10,000 coverages.

– Rigid: PCA Westergaard interior stress method of design. Thickness is computed for 10,000 coverages.

• These are fixed, standard procedures. Other design procedures or traffic levels cannot be substituted.



Subgrade Strength for ACN Computation

• Flexible: The CBR of the subgrade soil.

• Rigid: The k-value at the top of the support, including all subbase layers. – It is not the same as the k-value of the subgrade

soil.



PCN Reporting Format

• PCN values are reported in a coded format using 5 parts separated by “/”

Sample 39/F/B/X/T

• Information includes:– Numerical PCN Value (39 in this example)

– Pavement Type (F = Flexible, R = Rigid)

– Subgrade Strength Category (A, B, C or D)

– Allowable Tire Pressure (X 1.5 MPa = 218 psi)

– PCN Evaluation Method (U = Using, T = Technical)



Proposed Change to ICAO PCN Tire Pressure Limits (Flexible Only)

Tire Pressure Category

Current ICAO Designations and Limits

Proposed ICAO Designations and Limits

W High: no pressure limit Unlimited

X Medium: pressure limited to 1.50 MPa (217.6 psi)

High: pressure limited to 1.75 MPa (253.8 psi)

Y Low: pressure limited to1.00 MPa (145.0 psi)

Medium: pressure limited to 1.25 MPa (181.3 psi)

Z Very low: pressure limited to 0.50 MPA (72.5 psi)

Low: pressure limited to0.50 MPA (72.5 psi)



PCN – Using Aircraft Method

• Find the ACN of all of the aircraft regularly using the pavement and pick the largest ACN to be the PCN of the pavement.

• But see page 3-27 of the ICAO manual:“Support of a particularly heavy load, but only rarely, does not necessarily establish a capability to support equivalent loads on a regular repetitive basis.”

Where is the line between “regular” and overload operation?



PCN – Technical Method

• The ICAO manual covers in detail a very broad range of methods, including:– Any rational design procedure developed specifically

for airport pavements but applied in reverse for pavement evaluation.

– Pavement surface deflection measured under the load from a representative aircraft.

– Non-destructive test results with backcalculation.

– Allows for design and evaluation procedures not in use when the manual was written.



FAA Guidance on PCN Calculation

• The FAA is responsible for certifying all commercial airports in the U.S. and is the organization generally responsible for complying with international agreements on aviation.

• Well defined procedures are therefore required for determining and publishing PCN values for runways at all commercial airports in the U.S.



AC 150/5335-5A (2006)Standardized Method of Reporting Airport Pavement Strength – PCN

• Complete rewrite of AC 150/5335-5.

• Standardized the procedures for computing and reporting PCN values for inclusion in the 5010 database.

• AC 150/5335-5A is based in large part on the procedures described in Boeing Report D6-82203 “Precise Methods for Estimating Pavement Classification Number,” 1998.

• D6-82203 is, in turn, based largely on recommendations contained in the ICAO Aerodrome Design Manual.



Draft Advisory Circular 150/5335-5B

• AC 150/5335-5A, PCN, to be replaced by AC 150/5335-5B.

• Draft AC was posted for comment October 2009.

• Comment period has ended.

• Copy of draft AC is included on the CD.



AC 150/5335-5B STANDARDIZED METHOD OF REPORTING AIRPORT PAVEMENT STRENGTH - PCN

• The Pavement Classification Number (PCN) field has been added to FAA Form 5010 and data collection is underway.

• During each airport inspection, the airport owner will be asked to provide runway PCN information.

• WHY? – With release of AC 150/5320-6E, the “design aircraft” concept

has been replaced.

– This means the Aircraft Gross Weight fields on the 5010 will no longer be used to describe load carrying capacity of runways.



AC 150/5335-5B …PCN

• The Master Record is required to be updated periodically.

• PCN is now mandatory and Gross Weight data will possibly be phased out with time.

Gross Weight data

may transition.

PCN data request now part of all airport inspections



Draft AC 150/5335-5B - Changes from AC 150/5335-5A

• The procedure for selecting the critical aircraft has been substantially revised.

• The procedure for computing equivalent departures has been replaced by a new procedure based on cumulative damage factor (CDF).

• Except for obtaining the structure and aircraft properties, the procedure has been completely automated in a revised version of the computer program COMFAA (COMFAA 3.0).

• A spreadsheet application has been developed to facilitate determining the evaluation thickness.



Draft AC 150/5335-5B

• The design procedures recommended in the new AC are:– CBR ESWL with the new alpha factors for flexible pavements.

– Edge stress Westergaard as implemented in AC 150/5320-6C and -6D.

– The PCA center stress method can also be selected in COMFAA 3.0.

• These were selected for backward compatibility with established methods and compatibility with the ACN computation procedure.



New PCN Methodology• The current methodology (-5A) 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 new methodology is the same except that the ACN at maximum allowable gross weight is calculated for all of the aircraft in the mix. The CDF procedure is used for equivalent coverages.

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

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



ACN-PCN – Technical Evaluation

7 Basic Steps to Determine Pavement Classification Number in AC 150/5335-6B:

1. Identify pavement features and properties.

2. Determine traffic mixture.

3. Convert traffic to equivalent traffic of “critical” aircraft.

4. Determine allowable operating weight of critical airplane.

5. Determine ACN of critical airplane at allowable weight.

6. Repeat with each airplane as the critical airplane.

7. Report PCN.



AC 150/5335-5B Computer Programs

• COMFAA 3.0 Program

• Support Spreadsheet for COMFAA (Excel)Input Support:

– Flexible Layer Equivalency Worksheet

– Rigid Pavement k-Value Worksheet

Output Support:

– Output Data Parsing

– Rigid and Flexible Chart Creation

– FAA Form 5010 Preparation



COMFAA Support Spreadsheet

Flexible Layer Equivalency

– The equivalent pavement has three layers:

• 5 in. P-401,

• 8 in. P-209,

• P-154.

– The spreadsheet determines the maximum thickness for the equivalent pavement based on the user-defined layer equivalency factors.



Fig. A2-2 Figs. A2-1, A2-2Flexible Pavement Convert Convert

Structure Items to P-209 to P-154

P-401 and/or P-403 1.6 2.0ENTER P-401 and/or P-403 6.0 in.

P-306 1.2 1.6 ENTER P-306 0.0 in.

P-304 1.2 1.6 ENTER P-304 0.0 in.

P-209 1.0 1.4 ENTER P-209 12.0 in.

P-208 and/or P-211 1.0 1.3ENTER P-208 and/or P-211 0.0 in.

P-301 n/a 1.0 ENTER P-301 0.0 in.

P-154 n/a 1.0 ENTER P-154 13.0 in.

Equivalent Thickness, in. 9.0

Existing Flexible

Pavement Layers

ENTER Subgrade CBR

Reference Guidance AC 150/5335-5B Appendix A-2Existing

Layer Thickness

1.41.51.6

1.81.92.0

1.21.31.4

1.31.41.5

1.61.71.8

1.61.71.8

1.01.11.2

1.21.31.4

1.31.41.5

COMFAA Support SpreadsheetFlexible Pavement Input

• ENTER (or confirm) layer equivalency factors.– Refer to Table A2-1.

• ENTER all existing pavement layers starting at the surface of the pavement.

• ENTER the subgrade CBR value.



P-401P-401

P-209

P-209

P-154

P-154

Subgrade CBR 9.0

Subgrade CBR 9.0

0

5

10

15

20

25

30

35

Existing Pavement Equivalent Pavement

Dep

th f

rom

Su

rfac

e, i

n.

COMFAA Support SpreadsheetFlexible Pavement Output

• The spreadsheet determines and consolidates COMFAA software input values and recommends three of five necessary PCN codes.

• The spreadsheet updates the graphical representation of the existing and equivalent pavement.

PAVEMENT TO BE EVALUATED IN COMFAA

COMFAA Evaluation Criteria

Evaluation thickness t = 33.8 in.

Evaluation CBR = 9.0

Recommended PCN Codes: F/B/W or Recommended PCN Codes: F/B/X



Using the COMFAA 3.0 Program



COMFAA Input



Aircraft Window – COMFAA Input



Main Window - COMFAA Input

Click “PCN Flexible Batch”

Click “CBR” – Enter 9.0 in the dialog box.

Enter the evaluation thickness = 33.8 in.



COMFAA Output

Click “Details” to view the detailed output.

Message “Flexible Computation Finished”



COMFAA Detailed Output Screen

Summary Aircraft Table with -6D Thickness

Requirements



COMFAA Output – Details (I)

• PCN based on using aircraft ACN can be reported as 54.

COMFAA generates an aircraft ACN table. CBR 9 indicates B subgrade designation.



COMFAA Output – Details (II)

CBR 9 indicates B subgrade designation.

COMFAA generates a table based on the CDF method. For each aircraft, allowable gross weight and corresponding PCN are identified.



COMFAA Output – Details (III)

• CDF method identifies (3) aircraft that contribute substantial structural damage based on pavement structure: 727-200, 747-400, and A300-B4.

• PCN based on technical CDF method can be reported as the highest PCN of these aircraft = 73.



COMFAA Detailed Output Screen

Copy and paste data into COMFAA support

spreadsheet.




Data Parse• Copy/Paste output

data into Cell B5

• Click “Create Flexible Pavement Charts”

• Airplanes are ordered by PCN number, with the aircraft at top giving the highest PCN when treated as critical.



COMFAA Support SpreadsheetFlexible Charts

Thickness Comparison

• Compare thickness and gross weights.

• When CDF thickness (yellow) is less than evaluation thickness (red), excess PCN is available.

AC 150/5335-5B Example

0 in.

5 in.

10 in.

15 in.

20 in.

25 in.

30 in.

35 in.Most Demanding Aircraft in Traffic Mix

Rig

id P

avem

ent

Thi

ckne

ss

0

200

400

600

800

1,000

1,200

Airp

lane

Gro

ss W

eigh

t, lb

s. (

thou

sand

s)

1. 6D thickness at traffic mixGW

25.7 25.7 25.5 27.5 28.8 23.1

2. CDF thickness at max.GW

33.2 31.4 31.9 29.5 29.3 27.5

3. Evaluation thickness fromequivalent pavement

33.8 33.8 33.8 33.8 33.8 33.8

4. Max.Allowable AircraftGW from CDF

378,158 365,739 646,354 443,728 992,902 253,830

5. Aircraft GW from trafficmix

370,000 330,000 600,000 370,000 820,000 185,000

767-200 ER

DC8-63 777-200 A300-B4 747-400 727-200

``̀



COMFAA Support SpreadsheetFlexible Charts

PCN Comparison

• PCN needed for using traffic is 54.

• PCN based on CDF analysis can be reported as high as 73.


4549

51 52 54

4847

57 57

68 7173

PCN= 0

PCN= 10

PCN= 20

PCN= 30

PCN= 40

PCN= 50

PCN= 60

PCN= 70

PCN= 80

PCN= 90 Most Demanding Aircraft in Traffic Mix

Sub

gra

de c

ode=

B a

t C

BR

= 9

.0,

t= 3

3.8

0

500

1,000

1,500

2,000

2,500

3,000

3,500

Ann

ual

Dep

artu

res

1. Aircraft ACN at traffic mixGW

45.2 48.8 51.3 52.4 53.9 48.2

2. Calculated PCN at CDFmax. GW

46.6 56.7 57.0 68.3 70.6 72.8

3. Annual Departures fromtraffic mix

2,000 800 300 1,500 3,000 400

767-200 ER

DC8-63 777-200 A300-B4 747-400 727-200



Technical Method Example – Case 1

• International hub airport.

• Rigid pavement.

• Large number of narrow-body, dual-wheel-gear aircraft.

• Example courtesy of Rodney Joel.



CASE 1

Traffic Data

AIRCRAFTACN gear

Operating Weight, lb

Gear Load. lbs.

Wheel Load, lbs.

Avg Annual Departures

Total Coverages

20 yrs

DC-9-30/40 D 109000 51775 25888 8 44

B717-200 D 122000 57950 28975 301 1701

A318-100 std D 124500 59138 29569 654 3593

A319-100 std D 142500 67688 33844 13,002 70663

A320-100 D 151000 71725 35863 15,280 79583

MD-80/83/88 D 161000 76475 38238 739 4322

MD-90 D 168500 80038 40019 213 1283

B727-200 basic D 185200 87970 43985 111 760

B737-700 D 188200 89395 44698 18,133 96709

B757-300 2D 271000 128725 32181 10,079 51555

DC-8-60/70 2D 358000 170050 42513 79 472

A300-b4 std 2D 365750 173731 43433 831 4579

B767-300 2D 413000 196175 49044 2,521 14006

DC-10 2D 458000 217550 54388 115 622

B787-8 2D 478000 227050 56763 32 169

A330-200 std 2D 509000 241775 60444 88 936

A340-300 std 2D 608000 243200 60800 179 1884

MD-11 2D 633000 245288 61322 44 240

B747-400 2D 877000 208288 52072 754 4358

A380 (2D) 2D 1235000 469300 117325 59 309

B777-200 base 3D 537000 255075 42513 1,095 5153



CASE 1

Existing Pavement Data

17″ PCC, R = 775 psi

8″ CTB

k-value = 160 psi/in

Effective k at top of base = 323 psi/in

The original design based on procedures in AC 150/5320-6D called for 16.3 inches of PCC. This value was rounded to 17.0 inches.



CASE 1 Pavement thickness requirements based on actual annual departures:

•FAA AC 150/5320-6D

•PCA method

• B737-700 appears to be the “design” airplane based on 5335-5A procedures.

• B737-700 is comprised of several D gear airplanes.

AIRCRAFTACN gear

Operating Weight (lb)

Annual Departures

-6D Edge Load Thickness (in)

PCA Design Thickness (in)

DC-9-30/40 D 109000 8 8.04 7.24

B717-200 D 122000 301 9.66 8.65

A318-100 std D 124500 654 9.23 8.18

A319-100 std D 142500 13,002 12.17 10.14

A320-100 D 151000 15,280 12.98 10.73

MD-80/83/88 D 161000 739 11.67 10.46

MD-90 D 168500 213 11.49 10.27

B727-200 basic D 185200 111 10.92 9.81

B737-700 D 188200 18,133 15.47 12.71

B757-300 2D 271000 10,079 10.85 10.31

DC-8-60/70 2D 358000 79 10.05 9.72

A300-b4 std 2D 365750 831 10.78 10.62

B767-300 2D 413000 2,521 11.62 11.26

DC-10 2D 458000 115 9.52 9.21

B787-8 2D 478000 32 10.57 10.1

A330-200 std 2D 509000 88 10.84 10.28

A340-300 std 2D 608000 179 10.99 10.45

MD-11 2D 633000 44 10.65 10.27

B747-400 2D 877000 754 11.17 11.07

A380 (2D) 2D 1235000 59 10.60 10.13

B777-200 base 3D 537000 1,095 8.85 9.46



CASE 1 – Current Procedure

• Following 5335-5A procedures the B737-700 would become the “Critical Aircraft” due to its individual pavement thickness requirement.

• This is true for either the 5320-6D procedure or the PCA center slab procedure.

• It was speculated that the B737 was artificially elevated as the design airplane due to high departure levels caused by lumping several D-gear airplanes into one.



CASE 1 AIRPLANEACN gear

Allowable Operating

Weight

Equiv.Annual

Departures5335-5A PCN/R/B

DC-9-30/40 D 148600 739535 45.4

A318-100 std D 181000 345027 46.1

B717-200 D 158900 386168 50.1

A319-100 std D 189250 168314 52.1

A320-100 D 189500 125753 55.2

B737-700 D 201400 45167 59.8

MD-80/83/88 D 184000 92089 60.1

MD-90 D 189100 74317 61.4

B727-200 basic D 222200 48463 65.7

B757-300 2D 385300 130968 68.7

A300-b4 std 2D 481000 32997 84.9

DC-8-60/70 2D 457500 36135 85.6

B767-300 2D 553000 20131 87.3

A330-200 std 2D 672000 9296 89.3

A340-300 std 2D 806000 10907 90.1

A380 (2D) 2D 1568000 20322 92.0

B747-400 2D 1148000 15972 92.8

DC-10 2D 653600 13572 93.0

B787-8 2D 608500 11612 96.4

MD-11 2D 820500 9462 100.6

B777-200 base 3D 920500 23190 115.2

• PCN values calculated by following the procedures in AC 150/5335-5A and assuming that each airplane is the “design airplane.”

• In this mix, the B737-700 is comprised of several D gear airplanes, some with lower operating weights.



CASE 1

ACN values for each airplane (from COMFAA)

Assuming the B737-700 as the design airplane per the procedures in 5335-5A

Calculated PCN 59.8/R/BPCN = (60/R/B)

Airp

lane

s ca

n op

erat

e w

ithou

t re

stric

tion

Wei

ght

Res

tric

tions

AIRPLANE

Gear type for

ACNOperating

WeightAirplane ACN/R/B

A318-100 std D 124500 29.5

DC-9-30/40 D 109000 31.3

B717-200 D 122000 36.5

A319-100 std D 142500 37.2

B757-300 2D 271000 41.4

A320-100 D 151000 42.2

B777-200 baseline 3D 537000 47.4

MD-80/83/88 D 161000 51.3

B727-200 basic D 185200 52.7

MD-90 D 168500 53.5

B737-700 D 188200 55.2

DC-10 2D 458000 56.4

A300-b4 std 2D 365750 57.3

B767-300 2D 413000 57.4

DC-8-60/70 2D 358000 60

A330-200 std 2D 509000 61.2

A340-300 std 2D 608000 61.4

B747-400 2D 877000 63

A380 (2D) 2D 1235000 65.8

B787-8 2D 478000 68.3

MD-11 2D 633000 69.6



Case 1 – New CDF PCN Procedure

• The procedure for finding equivalent coverages in AC 150/5335-5A is based on gear equivalency factors and the ratio of wheel loads.

• An alternative procedure based on cumulative damage factors (CDF) gave more consistent, and rational, results.

• The new procedure for finding equivalent coverages has been incorporated in the new AC 150/5335-5B.



COMFAA 3.0 – Case 1




Rigid Pavement k-Value

– Each subbase layer contributes to an improved subgrade support k-value.

– ENTER all existing pavement layers.

– ENTER the flexural strength of the concrete and the subgrade support k-value.

– The spreadsheet updates the graphical representation of the existing and equivalent pavement.



COMFAA 3.0 – Aircraft Window



COMFAA 3.0 – Case 1 ResultsSubgrade Category B



COMFAA 3.0 – Case 1 Results

Copy and Paste Data into Support Spreadsheet



COMFAA Support SpreadsheetCase 1

Data Parse• Copy/Paste output

data into Cell B5

• Click “Create Rigid Pavement Charts”

• Airplanes are ordered by PCN number, with the aircraft at top giving the highest PCN when treated as critical.

• Next, click Rigid Chart tab.



COMFAA Support SpreadsheetRigid Charts – Case 1

Thickness Comparison

• Compare thickness and gross weights.

• When CDF thickness (yellow) is less than evaluation thickness (red), excess PCN is available.


0 in.

2 in.

4 in.

6 in.

8 in.

10 in.

12 in.

14 in.

16 in.

18 in. Most Demanding Aircraft in Traffic Mix

Rig

id P

avem

ent

Th

ick

ness

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

Airp

lane

Gro

ss W

eig

ht,

lbs.

(th

ous

and

s)

1. 6D thickness at traffic mixGW

11.1 10.8 11.1 10.6 10.5 10.6

2. CDF thickness at max. GW 15.0 15.0 15.0 15.0 14.9 14.9

3. Evaluation thickness fromequivalent pavement

17.0 17.0 17.0 17.0 17.0 17.0

4. Max.Allowable Aircraft GWfrom CDF

1,076,982 657,683 785,764 1,558,981 590,004 792,982

5. Aircraft GW from traffic mix 877,000 509,000 608,000 1,235,000 478,000 633,000

B747-400A330-200

stdA340-300

stdA380-Wing

B787-8 (Preliminar

y)MD11

``




PCN Comparison

• 6 most demanding aircraft in mix.

• PCN needed for using traffic is 70.

• PCN based on CDF analysis can be reported as high as 96.

• Next, click on Form 5010 tab.


63 61 6166 68 70

85 87 8791 92

96

PCN= 0

PCN= 10

PCN= 20

PCN= 30

PCN= 40

PCN= 50

PCN= 60

PCN= 70

PCN= 80

PCN= 90

PCN= 100

PCN= 110 Most Demanding Aircraft in Traffic Mix

Sub

grad

e co

de=

B32

3.0,

t=

17.

0

0

100

200

300

400

500

600

700

800

Ann

ual D

epar

ture

s

1. Aircraft ACN at traffic mixGW

63.0 61.2 61.4 65.8 68.3 69.6

2. Calculated PCN at CDFmax. GW

84.6 86.6 87.0 91.2 92.2 95.8

3. Annual Departures fromtraffic mix

754 88 179 59 32 44

B747-400A330-200

stdA340-300

stdA380-Wing

B787-8 (Prelimina

ry)MD11




Form 5010 • Enter PCN Number.

• PCN can be reported as:

96/R/B/W/T

Project info

FLEXIBLE PAVEMENT MAXIMUM TIRE PRESSURE METHOD USED TO DETERMINE PCN

RIGID PAVEMENT AIRCRAFT GEAR TYPE IN TRAFFIC MIX

FAA Form 5010 Data Element

Gross Weight and PCN

#35 S 100#36 D 280

#37 DT 793#38 DDT#39 PCN 96 / R / B / W / T

96Enter PCN

S (single wheel gear)

D (dual wheel gear)

2D OR 3D (dual tandem OR triple tandem wheel gear)

W/B (tandem gear under wing AND tandem gear under body)

A Subgrade Category (CBR 15)

B Subgrade Category (CBR 10)

C Subgrade Category (CBR 6)

D Subgrade Category (CBR 3)

A Subgrade Category (k 552 pci)

B Subgrade Category (k 295 pci)

C Subgrade Category (k 147 pci)

D Subgrade Category (k 74 pci)

Using Aircraft

Technical

W Unlimited

X 218 psi

Y 145 psi

Z 73 psi



Case 1 – PCN ComparisonPCN calculated assuming each airplane is treated as the design airplane

0

20

40

60

80

100

120

0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000

Reported Operating Weight, lbs. (not the weight used for PCN calculation)

PC

N o

r A

CN

5335-5A PCN/R/B

5335-5B PCN/R/B

Airplane ACN/R/B

D Gears 2D Gears

A380B747

B777B757



COMFAA 3.0 – Options

• Batch– Runs all airplanes in

succession.

– Automatically invoked by PCN Flex and Rigid Batch function.

• Metric

• PCA Thick– Equivalent coverages

computed with the PCA interior stress design method.

• PCA GW– Maximum gross weight

computed with the PCA interior stress design method.



COMFAA 3.0 – Computational Modes

• ACN – Computes ACN at indicated gross weight & strength.

• PCN – Computes PCN using CDF-based procedure.

• Thickness – Computes by AC 150/5320-6D procedure.

• MGW – Computes maximum gross weight for airplane.

• Life – Computes coverages to failure for indicated thickness.

• Interior Stress

• Edge Stress



COMFAA 2.0 Will Continue to be Supported – Simpler and Old Alphas



More Information

• Contact Dr. Gordon Hayhoe– [email protected]

• FAA Airport Technology R&D Group– www.airporttech.tc.faa.gov

– Click on “Downloads” then “Pavements”



Questions?

COMFAA 3.0 Beta Administration Federal Aviation 3_0 Beta Brill.pdf · · 2011-09-09ICAO Aerodrome...

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