1Page 1Geometric Specifications of AirfieldsAmedeo R. OdoniMassachusetts Institute of Technology1.231J/16.781J/ESD.224J Airport Systems 1.231J/16.781J/ESD.224J Airport Systems ––Fall 2007Fall 2007Page 2Airport Design SpecificationsAirport Design Specifications The two most-commonly used sources of geometric specifications for airfield design are:1. ICAO Annex 14 (“Aerodromes”) and associated supplements and manuals2. FAA Advisory Circular 150/5300-13 (“Airport Design”)http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/MainFrame?OpenFrameSet FAA updates of specifications are usually developed earlier than updates to ICAO Annex 14 (e.g., Group VI standards)Reference: de Neufville and Odoni, Ch. 9, Secs. 2-3, 5-92Page 3Classification (FAA)Classification (FAA)Aircraft Approach Category A: Speed < 91 knots B: [ 91 - 121) knots C: [ 121 - 141) knots D: [ 141 - 166) knots E: Speed 166+ knots Airplane Design Group I: Wing < 49 ft (15 m) II: [ 49 - 79) ft (15-24 m) III: [ 79 - 118) ft (24-36 m) IV: [ 118 - 171) ft (36-52 m) V: [ 171 - 214) ft (52-65 m) VI: [ 214 - 262) ft (65-80 m)Page 4Airport Reference Codes (ICAO)Airport Reference Codes (ICAO)Code # Reference field length Code letterWing span Main gear wheel span 1 Up to 800 m A Up to 15 m Up to 4.5 m 2 800-1200 m B 15 – 24 m 4.5 – 6 m 3 1200-1800 m C 24 – 36 m 6 – 9 m 4 1800 m + D 36 – 52 m 9 – 14 m E 52 – 65 m 9 –14 m F 65 – 80 m 14 –16 m3Page 5Remarks re ICAO and FAA Airport Reference CodesRemarks re ICAO and FAA Airport Reference CodesPractically all major commercial airports belong to the ICAO Code #4 classMain gear wheel span (ICAO) is “dominated” by wing spanICAO Code Letters A-F wing spans correspond exactly to FAA Airplane Design Groups I-VI wing spansMost geometric specifications for airports are determined by the wing span of the most demanding aircraftPage 6●787-8●●A350-800A350-9004Page 7A380 vs. B747A380 vs. B747(72.2 m)(79.8 m)(24.1 m)(64.4 m)(70.6 m)(19.4 m)(560 tons)(396 tons)Page 8Runway Separations (FAA)*Runway Separations (FAA)*AIRPLANE DESIGN GROUPRunwayCenterlineTo…I II III IV V VINON-PRECISION INSTRUMENT AND VISUALHold Line250 ft75 m250 ft75 m250 ft75 m250 ft75 m250 ft75 m250 ft75 mTaxiwayCenterline300 ft90 m300 ft90 m400 ft120 m400 ft120 m400/450/500120/135/150600 ft180 mParkingArea400 ft120 m400 ft120 m500 ft150 m500 ft150 m500 ft150 m500 ft150 mPRECISION INSTRUMENTHold Line250 ft75 m250 ft75 m250 ft75 m250 ft75 m280 ft85 m325 ft98 mTaxiwayCenterline400 ft120 m400 ft120 m400 ft120 m400 ft120 m400/450/500120/135/150600 ft180 mParkingArea500 ft150 m500 ft150 m500 ft150 m500 ft150 m500 ft150 m500 ft150 m*For aircraft approach Cat. C and D5Page 9Airfield CapacityAmedeo R. OdoniMassachusetts Institute of Technology1.231J/16.781J/ESD.224J Airport Systems 1.231J/16.781J/ESD.224J Airport Systems ––Fall 2007Fall 2007Page 10Airfield Capacity: IAirfield Capacity: IObjective– To summarize fundamental concepts re. airfield capacityTopics– Definitions of capacity– Factors affecting capacity– Separation requirements– A simple model for a single runway– Capacity envelopes and capacity coverage chartReference: Chapter 106Page 11Capacity MeasuresCapacity Measures Maximum-Throughput Rate• Average number of demands a server can process per unit of time when always busy–μ= maximum throughput rate– E(t) = expected service time Level of Service (LOS) related capacity• Number of demands processed per unit of time while meeting some pre-specified LOS standards (must knowμto compute)E(t)1 =μPage 12Definitions: Runway Capacity*Definitions: Runway Capacity*Maximum Throughput (or Saturation) CapacityThe expected (“average”) number of runway operations (takeoffs and landings) that can be performed in one hour without violating ATC rules, assuming continuous aircraft demand.Declared CapacityThe capacity per hour used in specifying the number of slots available for schedule coordination purposes; used extensively outside US; no standard method for its determination; no generally accepted LOS; typically set to about 85-90% of saturation capacity; may be affected by apron capacity and terminal capacity* These definitions can be applied to a single runway or to the entire complex of runways at an airport.7Page 13LOSLOS--Related Capacity Definitions (Less Common)Related Capacity Definitions (Less Common)Practical Hourly CapacityThe average number of operations that can be performed in one hour on a runway (or, more generally, a system of active runways) with an average delay per operation of 4 minutes.Sustained CapacityThe average number of operations per hour that can be “sustained” for periods of several hours; vaguely-defined, typically workload-related.Page 14Factors Affecting CapacityFactors Affecting CapacityNumber and layout of active runways Separation requirements (longitudinal, lateral)Weather (ceiling, visibility)Wind (direction, strength)Mix of aircraftMix and sequencing of operations (landings, takeoffs, mixed)Quality and performance of ATM system (including human factor -- pilots and controllers)Runway exit locationsNoise considerations8Page 15NConfiguration 22L/27 - 22R/22LSource: Idris (2000)Page 16Role of ATC Separation RequirementsRole of ATC Separation Requirements Runway (and airfield) capacities are constrained by ATC separation requirements Typically aircraft are separated into a small number (3 or 4) of classes Example: FAA classification– Heavy (H): 255000 lbs < MTOW– Large (L): 41000 lbs < MTOW < 255000 lbs – Small (S): MTOW < 41000 lbs Required separations (in time or in distance) are then specified for every possible pair of aircraft classes and operation types (landing or takeoff) Example: “arrival of H followed by arrival of S”9Page 17IFR Separation Requirements: Single Runway (USA)IFR Separation Requirements: Single Runway (USA)2.5 (or 3)2.5 (or 3)2.5 (or 3)S3/4*2.5 (or 3)2.5 (or 3)L544B7575/6*54HSL or B757HArrival-Arrival:(1) Airborne separations on final approach (nmi):Trailing aircraftLeading aircraft(2) Leading aircraft must be clear of the runway before trailing aircraft touches down* Applies when leading aircraft is at threshold of runwayPage 18IFR Separation Requirements: Single Runway (USA) [2]IFR Separation Requirements: Single Runway (USA)