Aircraft Classification Number

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The aircraft classification number (ACN) is a number expressing the relative effect of an aircraft on therunway pavement for a specified standard subgrade category (ICAO).

The ACN is a single unique number expressing the relative effect of an aircraft on a pavement for aspecified subgrade strength specifying a particular pavement thickness. It consists of a number on acontinuous scale, ranging from 0 on the lower end and with no upper limit, that is computed between twopavement types (rigid or flexible), and the subgrade support strength category. ACN values for civil aircrafthave been published in ICAOs Aerodrome Design Manual and in FAA Circular 150/5335-5.

Using the ACN method, it is possible to express the effect of individual aircraft on different pavements by asingle unique number, which varies according to pavement type and subgrade strength, without specifying aparticular pavement thickness.

The ACN is twice the derived single-wheel load expressed in thousands of kilograms, with single-wheel tirepressure standardized at 1.25 megapascals (= 181 psi). Additionally, the derived single-wheel load is afunction of the sub-grade strength.

The ACN of an airplane is a function of not only its weight but also the design parameters of its landing gearsuch as the distances between the wheels of a multiple-wheel landing gear assembly.

The pavements strength is denoted by its pavement classification number (PCN).

The load exerted on a pavement by the landing gear of an airplane is denoted as its ACN, or airplaneclassification number. The ACN is not permitted to exceed the PCN of the runway to be used, in order toprolong pavement life and prevent possible pavement damage.

The ACN is defined for only four subgrade categories (high, medium, low, and ultra low).

1 The ACN-PCN method2 ACN reporting3 Subgrade support strength category

3.1 Flexible pavements3.2 Rigid pavements

4 Updates5 Aircraft ACN list

The ACN-PCN system of rating airport pavements is designated by the International Civil AviationOrganization (ICAO) as the only approved method for reporting strength.

The bearing strength of a pavement intended for aircraft of apron (ramp) mass greater than 5700 kg shall bemade available using the aircraft classification number pavement classification number ACN-PCNmethod (ICAO Annex 14, clause 2.6.2)

Aircraft classification number - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Aircraft_classification_number

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The ICAO system for civil airport pavements involves comparison of an airports pavement classificationnumber (PCN) with an aircraft classification number (ACN). According to this worldwide ICAO standard,aircraft can safely operate on a pavement if their ACN is less than or equal to the pavement load bearingcapacity or PCN. An aircraft having an ACN equal to or less than the PCN can operate without weightrestrictions on a pavement. The PCN is formally published in an Aeronautical Information Publication(AIP).

States are required to evaluate and publish the strength of airport pavements using ICAOs ACN-PCNsystem. The method concentrates on classifying the relative damage of aircraft. ICAO foresees that eachpavement authority will define a PCN by whatever means is considered suitable to indicate the support levelof a particular pavement such that all aircraft with a published ACN equal to or less than the reported PCNcan use that pavement safely, without load bearing failure or undue damage to the structure.

The ACN-PCN system provides a standardised international airplane/pavement rating system replacing thevarious S, T, TT, LCN, AUW, ISWL, etc., rating systems throughout the world. In 1981 ICAO promulgatedthe ACN-PCN method as the single universal system for determining the weight limitation of aircraftoperating on airport pavements by a procedure of comparing an airports PCN with an ACN. To avoidaccelerated deterioration and excessive maintenance costs and for the safeguarding of pavement integrityand assurance of optimum service life ICAO utilises the ACN /PCN load classification method for reportingpavement strength. According to this world-wide standard, aircraft can safely operate on a pavement if theirACN is less than or equal to the pavement load bearing capacity or PCN. An aircraft having an ACN equalto or less than the PCN can operate without weight restrictions on a pavement.

The ACN-PCN method is not a design or evaluation method, but purely a classification system.Unfortunately the fact that the method of calculating ACN utilises two common design and analysismethods (the CBR equation and Westergaard theories) has led a surprisingly large number of people toassume that it is a design and evaluation method. It is not uncommon for reference to be made to PCNscalculated by the ACN-PCN method. In fact the ICAO documentation makes it very clear that it is not adesign/evaluation method and that the PCN is simply the ACN of the most damaging aircraft that can usethe pavement on a regular basis (regular being defined by the operator).

The ACN-PCN method only deals with aircraft weighting in excess of 5,700 kg (12,566 lb) as the airportswith pavement for smaller size aircraft need only report the maximum allowable mass and the maximumallowable tire pressure if applicable.

The ACN/PCN system ensures that both aircraft and pavement can be utilised to their maximum extentwithout detrimental effects. According to the Design Manual the method is meant only for publication ofpavement strength data in the Aeronautical Information Publication (AIPs). It is not intended for design orevaluation of pavements, nor does it contemplate the use of a specific method by the airport authority eitherfor the design or evaluation of pavements. Although the Design Manual states that any method may be usedto determine the load rating of the pavements, it is obvious that the use of layered elastic method inconjunction with calibrated failure criteria is preferred

ACN values for selected aircraft have been calculated by the International Civil Aviation Organization(ICAO) using two computer programs, one for rigid pavements and the other for flexible pavements.

Manufacturers are required to calculate ACNs for new aircraft as they come into service and publish theresults in flight manuals. The tables give ACN values for two weights, one at the maximum total weightauthorized and the other at the operating weight when empty. If an aircraft is operating at an intermediateweight, the ACN value can be calculated by a linear variation between the limits. Extrapolation is notpermissible. ACN is calculated with respect to the center of gravity position, which yields the critical


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loading on the critical gear. Normally, the aftmost center of gravity, or CG position, appropriate to themaximum gross apron (ramp) mass, or ramp weight, is used to calculate the ACN. In exceptional cases, theforwardmost CG position may make the nose-landing gear loading more critical.

The ICAO "Aerodrome Design Manual Part 3 Appendix 2" contains computer programs (source code)for the calculation of ICAO ACN's for aircraft operation on both rigid and flexible pavements. The ICAOACN Fortran source code has been rewritten and recompiled by Transport Canada into two (2) executablestand-alone programs. The original input/output formats of the ICAO ACN programs were followed asclosely as possible. The internal program calculations and equations of the ICAO programs were alsofollowed and incorporated in the new .exe files. The result is the computation of aircraft ACN values thatare fully compatible with the ICAO ACN/PCN strength reporting system for airfield pavements. Theprograms are available at http://www.tc.gc.ca/CivilAviation/.../software.htm

The FAA also has a large amount of guidance material available on their website. Advisory Circular AC150/5335-5B provides further guidance on ACN and PCN calculations and the relationship between the twonumbers. The FAA also provides a more user friendly version of the ICAO computer programs, although itshould be noted that code has been translated from the original Fortran language to Visual Basic. The FAAsoftware is COMFAA and is available from their software download page at:http://www.airporttech.tc.faa.gov/naptf/download/index1.asp#soft

The ranges of subgrade strength covered by these standard subgrade categories (designated as A, B, C andD) are shown below.

Flexible pavements

The flexible pavements have four subgrade categories:

A. High Strength CBR 15 (All CBR above 13%).B. Medium Strength CBR 10 (For CBR between 8% to 13%).C. Low Strength CBR 6 (For. CBR between 4% to 8%).D. Ultra Low Strength CBR 3 (For CBR below 4%).

Rigid pavements

The rigid pavements have four subgrade categories:

A. High Strength Subgrade k = 150 MN/m3 (550 lb/in3) (All k values above 120 MN/m3).B. Medium Strength k = 80 MN/m3 (300 lb/in3) (For values between 60 to 120 MN/m3).C. Low Strength k = 40 MN/m3 (150 lb/in3) (For values between 25 to 60 MN/m3).D. Ultra Low Strength k = 20 MN/m3 (75 lb/in3) (All k values below 25 MN/m3).

As per October 2007, ICAO revised the alpha factor for four wheel undercarriages. Based on recent findingsof full scale pavement tests, ICAO agreed to the following revisions concerning the alpha factor values: a.change the alpha factor value for all four-wheels per main landing gear from the current 0.825 to 0.80; b.retain the alpha factor for six-wheels per main landing gear at 0.72; and c. change the alpha factors for othermain landing gears so that the ranking of the damaging effect remains consistent.


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Aircraft Classification Numbers (ACNs)

AircraftWeight

Maximum(kN)

TirePressure(MPa)

Flexible pavementsub-grades

CBR%

Rigid pavementsub-gradesk (MPa/m3)

High Medium Low Verylow High Medium LowUltralow

A B C D A B C D

15 10 6 3 150 80 40 20

A330-200(Configuration 1) 2,137 1.34 57 62 72 98 48 56 66 78

A330-200(Configuration 2) 2,264 1.42 62 67 78 106 53 61 73 85

A330-300(Configuration 1) 2,088 1.31 55 60 70 94 46 54 64 75

A330-300(Configuration 2) 2,137 1.33 57 61 71 96 47 55 65 77

A330-300(Configuration 3) 2,264 1.42 62 68 79 107 54 62 74 86

A380-800 (6 WheelMain Gear) 5,514 1.47 56 62 75 106 55 67 88 110

A380-800 (4 WheelWing Gear) 5,514 1.47 62 68 80 108 55 64 76 88

B737-800 777 1.47 44 46 51 56 51 53 55 57

B737-900 777 1.47 44 46 51 56 51 53 55 57

B737-BBJ 763 1.47 43 45 50 55 50 52 54 56

B747-400, 400F, 400M 3,905 1.38 53 59 73 94 53 62 74 85

B747-400D (Domestic) 2,729 1.04 36 39 47 65 30 36 43 51

B747-400ER 4,061 1.58 57 63 78 100 59 69 81 92

B747-SP 3,127 1.26 45 50 61 81 40 48 58 67

B777-300 2,945 1.48 53 59 72 100 54 68 88 108

B777-300ER 3,345 1.52 64 71 89 120 66 85 109 131

B787-8 2,240 1.57 60 66 81 106 61 71 84 96

BAC-111 Series 400 390 0.97 23 24 27 29 25 27 28 29

BAC-111 Series 475 440 0.57 23 28 29 32 26 28 29 31

BAC-111 Series 500 467 1.1 29 31 33 35 33 34 35 36

BAe-146-100 376 0.84 18 20 23 26 20 22 24 25

BAe-146-200 416 0.97 22 23 26 29 24 26 27 29

BAe-146-300 436 1.1 24 25 28 31 27 28 30 31

Bae-ATP 232 0.85 12 13 14 16 13 14 15 16

Beech 1900C, 1900D 76 0.67 3 4 4 5 4 4 5 5


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Beech 2000 Starship 65 0.54 2 3 4 4 3 4 4 4

Beech Jet 400, 400A 73 0.86 6 7 7 7 6 6 6 6

Beech King Air 100,200 Series 56 0.73 2 3 3 4 3 3 3 4

Beech King Air 300,300C, 350, 350C 67 0.73 3 3 4 4 4 4 4 4

Bombardier 415(Canadair CL-215, 415) 196 0.53 12 14 17 17 14 14 15 15

Bombardier BD-700,Global Express, XRS 437 1.15 26 28 31 32 30 31 32 33

Bombardier Challenger300 168 1.21 9 9 11 12 11 11 12 12

Bombardier Challenger800 237 1.12 13 14 16 17 16 16 17 18

Bombardier ChallengerCL 600, 601, 604 215 1.21 12 13 15 16 15 15 16 16

Bombardier CRJ100,CRJ200, CRJ440 237 1.12 13 14 16 17 16 16 17 18

Bombardier CRJ700Series 335 1.06 18 18 21 24 20 21 22 23

Bombardier CRJ900Series 377 1.06 21 21 24 27 23 24 26 27

Bombardier Dash 8Q100, Q200 Series 162 0.9 8 8 9 11 9 9 10 10

Bombardier Dash 8Q300 Series 192 0.67 8 9 11 13 10 11 11 12

Bombardier Dash 8Q400 287 0.67 14 16 18 20 16 17 18 19

Bombardier Global 391 1.15 23 24 27 29 26 27 28 29

C-123K Provider(Fairchild/Republic) 267 0.69 20 22 24 25 21 21 22 22

C-141B Starlifter(Lockheed) 1,553 1.31 52 60 73 88 51 61 70 78

C-17A (Globemaster III) 2,736 0.95 46 51 61 80 55 51 61 76

C-5 Galaxy (Lockheed) 3,723 0.77 31 33 40 51 28 31 37 45

Cessna 501 (Citation I Eagle) 56 0.69 4 5 5 5 4 5 5 5

Cessna 550 (Citation II) 64 0.69 5 5 6 6 5 5 5 5

Cessna 550 (CitationBravo) 67 0.69 5 6 6 6 5 5 6 6

Cessna 560 (Citation V,Ultra, Encore) 75 0.69 6 6 7 7 6 6 6 6


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Cessna 560 XL (CitationExcel) 90 1.48 9 9 9 9 9 9 9 9

Cessna 650 (Citation III,VI) 99 1.02 6 6 7 7 7 7 7 7

Cessna 650 (CitationVII) 104 1.16 6 7 7 8 7 8 8 8

Cessna 750 (Citation X) 160 1.16 10 11 12 12 12 12 13 13

CF-18 249 1.38 21 20 20 20 21 21 21 21

Convair 240 190 0.64 7 9 10 12 9 10 10 11

Convair 340, 440, 540 222 0.47 7 9 11 14 9 10 11 12

Convair 580 259 0.59 10 12 14 17 12 13 14 15

Convair 5800 280 0.59 11 13 15 19 13 14 16 17

Convair 600 210 0.73 9 10 11 14 10 11 12 13

Convair 640 245 0.52 8 11 12 15 10 12 13 14

Convair 880 860 1.03 27 31 36 44 26 31 36 40

Convair 990 1,135 1.28 40 46 53 64 40 47 54 60

Dassault Falcon 164 1.36 9 10 11 12 11 12 12 13

Dassault Falcon 2000EX 189 1.51 11 12 13 14 14 14 15 15

Dassault Falcon 10 84 0.93 5 5 6 6 6 6 6 6

Dassault Falcon 20 128 0.92 8 9 9 10 10 10 10 10

Dassault Falcon 50 173 0.93 9 10 12 13 11 12 12 13

Dassault Falcon 900 202 1.3 11 12 14 15 14 14 15 15

DC-10-10, 10CF, 15 2,037 1.34 57 62 74 101 49 58 69 80

DC-10-20, 20CF, 30CF,40CF 2,485 1.14 60 67 81 110 49 59 72 85

DC-10-30, 30ER, 40 2,593 1.22 59 65 79 107 50 59 72 84

DC-3 147 0.31 5 7 10 12 8 8 9 9

DC-4 335 0.53 12 15 17 21 14 16 17 19

DC-6, 6B 480 0.73 20 23 25 30 22 24 26 27

DC-7 (All Models) 640 0.89 34 36 42 46 37 40 42 44

DC-8-10, 20 Series 1,226 1.01 36 41 49 62 32 39 46 53

DC-8-43, 55, 61, 71 1,470 1.3 47 54 64 79 45 54 63 71

DC-8-61F, 63F 1,557 1.32 51 59 69 85 50 59 68 76

DC-8-62, 62F, 63, 72, 73 1,593 1.35 52 59 70 87 50 59 69 77

DC-9-10, 15 404 0.93 22 23 26 29 24 26 27 28

DC-9-21 445 1.02 25 26 30 32 28 29 31 32

DC-9-30, 32 485 1.05 27 29 33 35 30 32 34 35

DC-9-41, 50, 51 543 1.17 31 33 37 40 35 37 39 40


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DHC4 Caribou 130 0.28 2 3 5 7 4 4 5 6

DHC5 Buffalo 187 0.41 6 8 10 12 8 9 10 11

DHC6 Twin Otter Series300 56 0.26 2 2 3 5 3 3 3 4

DHC7 Dash 7 209 0.74 10 12 13 15 12 13 14 14

DHS-2 Conair Firecat 116 0.62 8 10 10 11 9 9 9 10

Dornier 228 Series 63 0.9 5 6 6 6 6 6 6 6

Dornier 328 Jet 155 1.13 8 8 10 11 10 10 10 11

Dornier 328-110(Turboprop) 138 0.8 7 7 8 10 8 8 9 9

Dornier SA227 (Metro,Merlin, Expediter) 74 0.73 3 4 4 5 4 5 5 5

Douglas A-26 Invader 120 0.48 7 8 10 11 8 8 9 9

Douglas B-26 Invader 156 0.48 9 11 13 14 10 11 11 12

Embraer 170, 175 368 1.04 20 21 24 26 22 24 25 26

Embraer 190, 195 481 1.1 28 30 33 35 31 33 35 36

Embraer EMB-110(Bandeirante) 59 0.62 4 5 5 5 5 5 5 5

Embraer EMB-120(Brasilia) Series 119 0.76 5 6 7 8 7 7 7 8

Embraer ERJ-145 Series 237 0.9 14 15 16 17 16 16 17 18

Fokker 100 452 0.94 25 27 31 33 28 30 31 33

Fokker 50 205 0.59 9 11 13 14 11 12 13 13

Fokker 60 226 0.62 10 13 14 16 13 14 14 15

Fokker 70 410 0.81 21 24 27 30 24 26 27 29

Fokker F27 Friendship 205 0.57 9 11 13 14 11 12 13 13

Fokker F28 Fellowship 325 0.53 14 17 20 23 16 18 20 21

Gulfstream G100(IAI-1125-Astra SPX) 111 0.86 6 6 7 8 7 7 7 8

Gulfstream G159 156 0.83 8 8 10 11 9 10 10 11

Gulfstream G200(IAI-1126-Galaxy) 159 0.86 9 10 11 12 10 11 11 12

Gulfstream II 294 1.04 17 18 20 22 20 21 21 22

Gulfstream III 312 1.21 19 20 22 23 22 23 23 24

Gulfstream IV 334 1.21 20 22 24 25 24 25 25 26

Gulfstream V 405 1.37 26 28 30 31 31 32 32 33

Hawker 1000 (BAe1000A) 138 0.83 8 8 9 10 9 9 10 10


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Hawker 400XP (BeechJet 400A) 73 0.86 6 7 7 7 6 6 6 6

Hawker 800, 800XP(HS-125-800, 800XP) 125 0.83 7 7 8 9 8 8 9 9

Hercules C-130, 082,182, 282, 382 778 0.67 29 34 37 43 33 36 39 42

Hercules L-100(Commercial) 693 0.74 27 30 33 38 30 33 35 38

HS/BAe 125 (All Seriesto 600) 112 0.83 6 6 7 8 7 7 8 8

HS/BAe 700 114 0.88 6 7 7 8 7 8 8 8

HS/BAe 748 227 0.51 9 11 14 16 11 12 13 14

Ilyushin IL-18 625 0.8 16 17 21 29 13 16 20 23

Ilyushin IL-62, 62M 1,648 1.65 52 58 68 83 51 59 68 77

Ilyushin IL-76T 1,677 0.64 24 27 34 45 29 33 30 34

Ilyushin IL-76TD 1,775 0.66 27 30 37 49 32 35 32 37

Ilyushin IL-86 2,054 0.88 34 36 43 61 26 31 38 46

Jetstream 31, 32 (BAe) 69 0.39 3 4 5 6 4 5 5 5

Jetstream 41 (BAe) 107 0.83 5 5 6 7 6 6 7 7

KC-10 (McDonnellDouglas) 2,593 1.22 59 65 79 107 50 59 72 84

KC-135 Stratotanker(Boeing) 1,342 1.38 38 41 49 64 35 40 48 55

L-1011-1 Tristar 1,913 1.35 52 56 66 90 45 52 62 72

L-1011-100, 200 Tristar 2,073 1.35 57 63 75 101 49 58 69 81

L-1011-250 Tristar 2,269 1.35 64 71 86 114 55 66 79 91

L-1011-500 Tristar 2,295 1.35 65 72 87 116 56 67 80 93

Learjet 24F(Bombardier) 62 0.79 3 3 4 4 4 4 4 4

Learjet 25D, 25F(Bombardier) 69 0.79 3 4 4 5 4 5 5 5

Learjet 25G(Bombardier) 75 0.79 4 4 5 5 5 5 5 5

Learjet 28, 29(Long-horn)(Bombardier)

69 0.79 3 4 4 5 4 5 5 5

Learjet 31A, 35A, 36A(Bombardier) 83 0.79 4 5 5 6 5 5 6 6

Learjet 40, 45, 45XR(Bombardier) 98 0.79 5 6 7 7 6 7 7 7


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Learjet 55B, 55C(Bombardier) 97 1.24 6 6 7 7 7 7 7 7

Learjet 60 (Bombardier) 106 1.48 6 7 7 8 8 8 8 8

Lockheed 188 Electra 503 0.95 27 29 33 36 30 32 34 36

MD-11 2,805 1.38 67 74 90 119 58 69 83 96

MD-81 628 1.14 36 38 43 46 41 43 45 46

MD-82 670 1.14 39 41 46 49 43 46 48 50

MD-83 716 1.14 42 45 50 53 47 50 52 54

MD-87 628 1.14 36 38 43 46 41 43 45 46

MD-88 670 1.14 39 41 46 50 44 46 48 50

MD-90-30 699 1.14 41 43 48 52 46 48 50 52

MD-90-30ER 739 1.14 44 47 52 55 49 51 54 56

MD-90-50, 55 772 1.14 46 50 54 57 52 54 57 58

P-3A/B/C Orion 623 1.31 38 41 44 47 44 46 48 49

Saab 2000 226 0.69 11 13 14 16 13 14 15 15

Saab 340 A, B 131 0.82 6 7 8 9 7 8 8 9

Sepecat Jaguar(Configuration 1) 154 0.58 7 9 10 11 9 10 10 11

Sepecat Jaguar(Configuration 2) 108 0.58 4 6 6 7 6 6 7 7

Shorts 330 102 0.55 6 8 9 9 7 8 8 8

Shorts 360 121 0.54 7 9 10 11 9 9 9 9

Shorts Sherpa 114 0.54 7 8 10 10 8 8 9 9

Shorts Skyvan 67 0.28 2 3 4 6 4 4 4 4

Swearingen SJ30-2 60 1.07 3 3 3 4 4 4 4 4

Transall C-160 500 0.38 8 10 13 18 10 10 10 13

Tupolev TU-134 463 0.59 10 12 15 20 9 11 14 16

Tupolev TU-154 961 0.93 19 22 28 37 18 24 30 36

Tupolev TU-204, 214,224, 234 1,096 1.38 31 33 40 53 29 34 40 46

VC10 Series 1,590 1.01 48 54 66 83 41 50 60 69

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Aircraft Classification Number