Analysis of Air Transportation Systems The Aircraft and the System Dr. Antonio A. Trani Associate Professor of Civil and Environmental Engineering Virginia Polytechnic Institute and State University Falls Church, Virginia June 9-12, 2003 NEXTOR - National Center of Excellence for Aviation Research 1
Material Presented in this Section The aircraft and the airport Aircraft classifications Aircraft characteristics and their relation to airport planning New large capacity aircraft (NLA) impacts NEXTOR - National Center of Excellence for Aviation Research 2
Purpose of the Discussion Introduces the reader to various types of aircraft and their classifications Importance of aircraft classifications in airport engineering design Discussion on possible impacts of Very Large Capacity Aircraft (VLCA, NLA, etc.) Preliminary issues on geometric design (apron standards) and terminal design NEXTOR - National Center of Excellence for Aviation Research 3
Relevance of Aircraft Characteristics Aircraft classifications are useful in airport engineering work (including terminal gate sizing, apron and taxiway planning, etc.) Most of the airport design standards are intimately related to aircraft size (i.e., wingspan, aircraft length, aircraft wheelbase, aircraft seating capacity, etc.) Airport fleet compositions vary over time and thus is imperative that we learn how to forecast expected vehicle sizes over long periods of time NEXTOR - National Center of Excellence for Aviation Research 4
Aircraft Classifications Aircraft are generally classified according to three important criteria in airport engineering: Geometric design characteristics (Aerodrome code in ICAO parlance) Air Traffic Control operational characteristics (approach speed criteria) Wake vortex generation characteristics Other relevant classifications are related to the type of operation (short, medium, long-haul; wide, narrow-body, and commuter, etc.) NEXTOR - National Center of Excellence for Aviation Research 5
Geometric Design Classification (ICAO) ICAO Aerodrome Reference Code Used in Airport Geometric Design. Design Group Wingspan (m) Outer Main Landing Gear Width (m) Example Aircraft A < 15 < 4.5 All single engine aircraft, Some business jets B 15 to < 24 4.5 to < 6 Commuter aircraft, large business jets (EMB-120, Saab 2000, Saab 340, etc.) C 24 to < 36 6 to < 9 Medium-range transports (B727, B737, MD-80, A320) D 36 to < 52 9 to < 14 Heavy transports (B757, B767, A300) E 52 to < 65 9 to < 14 Heavy transport aircraft (Boeing 747, L-1011, MD-11, DC-10) NEXTOR - National Center of Excellence for Aviation Research 6
Geometric Design Classification (FAA in US) FAA Aircraft Design Group Classification Used in Airport Geometric Design. Design Group Wingspan (ft) Example Aircraft I < 49 Cessna 152-210, Beechcraft A36 II 49-78 Saab 2000, EMB-120, Saab 340, Canadair RJ-100 III 79-117 Boeing 737, MD-80, Airbus A-320 IV 118-170 Boeing 757, Boeing 767, Airbus A-300 V 171-213 Boeing 747, Boeing 777, MD-11, Airbus A- 340 VI 214-262 A3XX-200 or VLCA (planned) NEXTOR - National Center of Excellence for Aviation Research 7
ATC Operational Classification (US) Airport Terminal Area Procedures Aircraft Classification (FAA Scheme). Group a. At maximum takeoff gross mass. Approach Speed (knots) a Example Aircraft A < 91 All single engine aircraft, Beechcraft Baron 58, B 91-120 Business jets and commuter aircraft (Beech 1900, Saab 2000, Saab 340, Embraer 120, Canadair RJ, etc.) C 121-140 Medium and Short Range Transports (Boeing 727, B737, MD-80, A320, F100, B757, etc.) D 141-165 Heavy transports (Boeing 747, L-1011, MD-11, DC-10, A340, A300) E > 166 BAC Concorde and military aircraft NEXTOR - National Center of Excellence for Aviation Research 8
Wake Vortex Aircraft Classification Final Approach Aircraft Wake Vortex Classification. Group Takeoff Gross Weight (lb) Example Aircraft Small < 41,000 All single engine aircraft, light twins, most business jets and commuter aircraft Large 41,000-255,000 Large turboprop commuters, short and medium range transport aircraft (MD- 80, B737, B727, A320, F100, etc.) Heavy > 255,000 Boeing 757 a, Boeing 747, Douglas DC-10, MD-11, Airbus A-300, Airbus A-340, Lockheed L-1011 a. For purposes of terminal airspace separation procedures, the Boeing 757 is now classified by FAA in a category by itself. However, when considering the Boeing 757 separation criteria (close to the Heavy category) and considering the percent of Boeing 757 in the U.S. fleet, the use of three categories does provide very similar results for most airport capacity analyes. NEXTOR - National Center of Excellence for Aviation Research 9
IATA Aircraft Classification IATA Aircraft Size Classification Scheme. Category Number of Seats Example Aircraft 0 < 50 Embraer 120, Saab 340 1 50-124 Fokker 100, Boeing 717 2 125-179 Boeing B727-200, Airbus A321 3 180-249 Boeing 767-200, Airbus A300-600 4 250-349 Airbus A340-300, Boeing 777-200 5 350-499 Boeing 747-400 6 > 500 Boeing 747-400 high density seating Used in the forecast of aircraft movements at an airport based on the IATA forecast methodology. NEXTOR - National Center of Excellence for Aviation Research 10
Aircraft Classification According to their Intended Use A more general aircraft classification based on the aircraft use General aviation aircraft (GA) Corporate aircraft (CA) Commuter aircraft (COM) Transport aircraft (TA) Short-range Medium-range Long-range NEXTOR - National Center of Excellence for Aviation Research 11
General Aviation (GA) Typically these aircraft can have one (single engine) or two engines (twin engine). Their maximum gross weight usually is always below 14,000 lb. Single-Engine GA Twin-Engine GA Cessna 172 (Skyhawk) Beechcraft 58TC (Baron) Beechcraft A36 (Bonanza) Cessna 421C (Golden Eagle) NEXTOR - National Center of Excellence for Aviation Research 12
Corporate Aircraft (CA) Typically these aircraft can have one or two turboprop driven or jet engines (sometimes three). Maximum gross mass is up to 40,910 kg (90,000 lb) Raytheon-Beechcraft King Air B300 Cessna Citation II Gulfstream G-V NEXTOR - National Center of Excellence for Aviation Research 13
Commuter Aircraft (COM) Usually twin engine aircraft with a few exceptions such as the DeHavilland DHC-7 which has four engines. Their maximum gross mass is below 31,818 kg (70,000 lb) Fairchild Swearinger Metro 23 Bombardier DHC-8 Saab 340B Embraer 145 NEXTOR - National Center of Excellence for Aviation Research 14
Short-Range Transports (SR-TA) Certified under FAR/JAR 25. Their maximum gross mass usually is below 68,182 kg (150,000 lb). Fokker F100 Airbus A-320 Boeing 737-300 McDonnell- Douglas MD 82 NEXTOR - National Center of Excellence for Aviation Research 15
Medium-Range Transports (MR-TA) These are transport aircraft employed to fly routes of less than 3,000 nm (typical).their maximum gross mass usually is usually below 159,090 kg (350,000 lb) Boeing B727-200 Boeing 757-200 Airbus A300-600R NEXTOR - National Center of Excellence for Aviation Research 16
Long-Range Transports (LR-TA) These are transport aircraft employed to fly routes of less than 3,000 nm (typical).their maximum gross mass usually is above 159,090 kg (350,000 lb) Airbus A340-200 Boeing 777-200 Boeing 747-400 NEXTOR - National Center of Excellence for Aviation Research 17
Future Aircraft Issues The fleet composition at many airports is changing rapidly and airport terminals will have to adapt Surge of commuter aircraft use for point-to-point services Possible introduction of Very Large Capacity Aircraft (VLCA) NEXTOR - National Center of Excellence for Aviation Research 18
VLCA Aircraft Discussion Large capacity aircraft requirements Discussion of future high-capacity airport requirements Airside infrastructure impacts Airside capacity impacts Landside impacts Pavement design considerations Noise considerations Systems approach NEXTOR - National Center of Excellence for Aviation Research 19
VLCA Design Trade-off Methodology Aircraft designed purely on aerodynamic principles would be costly to the airport operator yet have low DOC Aircraft heavily constrained by current airport design standards might not be very efficient to operate Adaptations of aircraft to fit airports can be costly Some impact on aerodynamic performance Weight considerations (i.e., landing gear design) A balance should be achieved NEXTOR - National Center of Excellence for Aviation Research 20
VLCA Impact Framework (I) Aircraft Design Module Mission Profile Definition Range, Speed, Payload Takeoff Roll, Gate Comp. Takeoff Weight Requirement VLCA Physical Dimensions Aircraft Wingspan Aircraft Length Airport Geometric Design Runway and Taxiway Geometric Modeling Gate Compatibility Modeling New Geometric Design Criteria Aircraft Separation Analysis Aircraft Wake Vortex Model Aircraft Separation Standards Airside Capacity Analysis Runway, Taxiway and Gate Capacity Analysis New Capacity Figures of Merit Passenger Demand Flows Airport Landside Capacity Terminal Design Modeling Landside Simulations New Terminal Design Guidelines Landing Gear Configurations Landing Gear Configuration Strut Configurations Wheel Track, Wheel Length Pavement Design Analysis Flexible and Rigid Pavements Identify Areas of Further Research NEXTOR - National Center of Excellence for Aviation Research 21
VLCA Impact Methodology (II) Passenger Demand Flows Airport Landside Capacity Terminal Design Modeling Landside Simulations New Terminal Design Guidelines Landing Gear Configurations Landing Gear Configuration Strut Configurations Wheel Track, Wheel Length Pavement Design Analysis Flexible and Rigid Pavements Identify Areas of Further Research Thrust and EPNL/SEL Landing Gear Configuration Landing Analysis Takeoff Analysis VLCA Noise Model Noise Modeling of VLCA Operations (Ldn contours) Comparison with Current Limits VLCA Economic Impact Trade-off Model User Cost Impacts Community Impacts NEXTOR - National Center of Excellence for Aviation Research 22
VLCA Specifications (Typical) Parameter Boeing 747-500X VLCA (A380) Range (km) 13,000 13,000 Runway Length (m) 3,000 3,000 Payload (kn) 800 1,200 Passengers 500 630-650 Max.TOW (kn) 4,200 5,400 Wingspan (m) 75 80-85 Length (m) 74-76 76-85 NEXTOR - National Center of Excellence for Aviation Research 23
VLCA Schematic VLCA aircraft will have wingspans around 15-25% larger than current transports Four 315 kn Turbofan Engines MTOW = S = 700 m 2 5,400 kn AR = 9.5 Payload = 650 passengers Design Range = 13,000 km. 9-11 o 12 o 81-87 78.57 81.5 m. m NEXTOR - National Center of Excellence for Aviation Research 24
VLCA Schematic (II) Structural weight penalties of folding wings are likely to be unacceptable to most airlines The empennage height could be a problem for existing hangars at some airport facilities VLCA Boein g 7 47-400 24.87 m 14 o 75.67 m NEXTOR - National Center of Excellence for Aviation Research 25
Airbus A380 - First in a Family of VLCA Source: Airbus NEXTOR - National Center of Excellence for Aviation Research 26
Development of Subsonic Transport Wings The graphic below offers some idea on the development of transport wings over three decades 11.0 Long Range Aircraft Data Wing Aspect Ratio 10.0 9.0 8.0 7.0 A330/340 A310-300 B777-A B767-200 B767-300 L1011-500 B747-400 DC-8-63 IL-86 DC-8-50 A300-B4 DC-10-30 B707-320 DC-10-10 L1011-200 B747-300 B707-121 B747-100 B747-200 VLCA Aircraft 6.0 1940.0 1960.0 1980.0 2000.0 2020.0 Year in Revenue Service NEXTOR - National Center of Excellence for Aviation Research 27
VLCA Design Trade-off Studies Future VLCA would weight 5,400 kn for a 13,000 km design range mission Aircraft Maximum Takeoff Weight (kn) 7000 6500 6000 5500 5000 4500 VLCA Wing Aspect Ratio AR = 9.0 AR = 9.5 AR =10.0 5,400 KN 4000 B747-400 MTOW 3500 5000 5500 6000 6500 7000 7500 8000 (9,260) (10,186) (11,112) (12,038) (12,965) (13,890) (14,816) Design Range (Nautical Miles and Kilometers) NEXTOR - National Center of Excellence for Aviation Research 28
VLCA Design Trade-off Studies (II) It is possible that aircraft designers in the near future will exceed the FAA design group VI limits VLCA Aircraft Wingspan (Meters) 90 85 81.5 80 75 70 VLCA Wing Aspect Ratio AR =9.0 AR = 9.5 AR =10.0 FAA Design Group VI Limit 65 5000 5500 6000 6500 7000 7500 8000 (9,260) (10,186) (11,112) (12,038) (12,965) (13,890) (14,816) Design Range (Nautical Miles and Kilometers) NEXTOR - National Center of Excellence for Aviation Research 29
VLCA Impacts on Airside Infrastructure Increase taxiway dimensional standards for design group VI to avoid possible foreign object damage to VLCA engines (increase taxiway and shoulder widths to 35 m and 15 m, respectively) 61 m 31 m VLCA on DG VI Runway VLCA on DG VI Taxiway NEXTOR - National Center of Excellence for Aviation Research 30
Runway-Taxiway Separation Criteria Increase the minimum runway to taxiway separation criteria to 228 m (750 ft.). This should increase the use of high-speed exits 230 m 183 m NEXTOR - National Center of Excellence for Aviation Research 31
HS Runway Exits for VLCA Larger transition radii (due to large aircraft yaw inertia) Linear taper turnoff width from 61 m to 40 m (metric stations 250 to 650) Latera l Distan ce (m) 100 75 50 25 HS Exit 35 m/s design speed Boeing 727-200 Boeing 747-200 VLCA Aircraft 0 0 100 200 300 400 500 Downrange Distance (m) NEXTOR - National Center of Excellence for Aviation Research 32
Minimum Fillet Radius (m) VLCA Taxiway Fillet Radius Requirements The fillet radius design standards for design group VI should suffice for VLCA aircraft 31.00 30.00 29.00 28.00 27.00 26.00 FAA Design Group VI VLCA Design Region 25.00 27.00 28.00 29.00 30.00 31.00 32.00 33.00 34.00 Distance Distance from from Main Main Undercarriage to Cockpit to (m) (m.) Undercarriage Width (m.) Uw = 13.5 Uw = 15.0 Uw = 16.5 NEXTOR - National Center of Excellence for Aviation Research 33
Taxiway Length of Fillet Requirements VLCA length of fillet requirements will probably be satisfied using current geometric design criteria Fillet Length (m) 80.00 70.00 60.00 50.00 40.00 30.00 FAA Design Group VI VLCA Design Region 20.00 27.00 28.00 29.00 30.00 31.00 32.00 33.00 34.00 Distance Distance from from Main Main Undercarriage to Cockpit to (m) (m.) Undercarriage Width (m.) Uw = 13.5 Uw = 15.0 Uw = 16.5 NEXTOR - National Center of Excellence for Aviation Research 34
Impacts to Aircraft Separation Critical to estimate safe aircraft separation criteria Induced rolling acceleration principle ( quotient) Tangential speed matching method Derived formulation (using quotient principle) δ ij K 4 δ ij = Max L 1 + L 2 W i, K 1 + K W 2 i + K 3 { W j } is the separation distance between aircraft i and j in km,, and are regression constants found to be 6.1000, 0.00378, -0.24593 and 0.44145, respectively and are 4.7000 and 0.00172 and have been derived using empirical roll control flight simulation data K 1 K 2 K 3 K 4 L 1 L 2 p p NEXTOR - National Center of Excellence for Aviation Research 35
Aircraft Separation (km.) Aircraft Separation Analysis Recommended in-trail separation criteria for approaching aircraft using the P quotient criteria 24.0 20.0 16.0 12.0 8.0 Small (Learjet 23) Medium (DC9) Large (B757) Heavy (747) VLCA 4.0 0.0 750.0 1500.0 2250.0 3000.0 3750.0 4500.0 5250.0 Leading Aircraft Weight (kn) NEXTOR - National Center of Excellence for Aviation Research 36
Wake Vortex Tangential Speed Estimation Predicted tangential speeds of wake vortex using Robinson and Larson semi-empirical vortex model Tangential Speed (m/s) 7 6 5 4 3 2 1 Vortex Cores Clean aircraft Speed = 160 knots Sea Level ISA 14 km behind aircraft VLCA (4,400 KN) Lockheed C5A (2,060 KN) 0 20 30 40 50 60 70 80 9 Lateral Distance from Center of Fuselage (m.) NEXTOR - National Center of Excellence for Aviation Research 37
Aircraft Separation Analysis (cont.) In-trail separation criteria for approaching aircraft using the tangential speed matching method Miminum In-trail Separation (km) 16 14 12 10 IMC Conditions Trailing Aircraft Small MTOW < 267 kn Medium 267 KN < MTOW < 1,336 kn Heavy MTOW > 1,336 kn 8 3500 4000 4500 5000 5500 6000 6500 Maximum Takeoff Weight (kn) 5500 6000 6500 7000 7500 8000 (10,186) (11,112) (12,038) (13,000) (13,890) (14,816) VLCA Design Range (Nautical Miles and Kilometers) NEXTOR - National Center of Excellence for Aviation Research 38
Runway Saturation Capacity Impacts Small to moderate saturation capacity changes 60 50 40 Percent VLCA 0% 10% Parallel Runway Configuration IMC Weather Conditions (aircraft/hr) 30 20 20% Independent Parallel Approaches 10 0 0 25 50 75 100 Departure Saturation Capacity (aircraft/hr) NEXTOR - National Center of Excellence for Aviation Research 39
Airport Terminal Impacts (Landside) VLCA will certainly impact the way passengers are processed at the terminal in various areas: Gate interface (dual-level boarding gates) Service areas (ticket counters, security counters, immigration cheking areas, corridors, etc.) Apron area parking requirements NEXTOR - National Center of Excellence for Aviation Research 40
Airport Landside Effects Use of simulation models to estimate landside LOS 5 VLCA Aircraft (or 7 Boeing 747-400 ) Terminal 490 m. count Heavy Acft Gate VLCA Deplaning Model Heavy Acft Gate ReadMe Heavy Acft Gate Heavy Acft Gate Heavy Acft Gate a Entrance to Landside facilities Immigration Baggage Claim CUSTOMS Customs 0 F L W a? b select Transfer Passengers are seperated here c Circulation Exit 0 # Transfer Passengers Count Exit 33 # Passengers exiting from the Terminal Arriving Aircraft Gates NEXTOR - National Center of Excellence for Aviation Research 41
Sample Landside Simulation Results Analysis using the Airport Terminal Simulation Model 30 immigration counters Normal service times (µ=1.0 and σ=0.25 minutes) Total No. Passengers at Immigration Counters 500 400 300 200 100 7 Boeing 747-400 at 85% Load 5 VLCA at 85% Load 0 0 30 60 90 120 150 Time (minutes) NEXTOR - National Center of Excellence for Aviation Research 42
Airport Gate Interface Challenges VLCA aircraft could employ dual-level boarding gates to provide acceptable enplanement performance Terminal VLCA Dual-level Boarding Gates Boei ng 747-40 0 24.87 m 14 o 75.67 m Terminal VLCA Dual-level Boarding Gates Boei ng 747-40 0 24.87 m 14 o 75.67 m NEXTOR - National Center of Excellence for Aviation Research 43
Noise Impacts High by-pass ratio turbofan engines with maximum takeoff thrust of 315-350 kn will be necessary to power VLCA aircraft The engine size will probably be determined by takeoff run and engine-out climb requirements Sound Exposure Level (dba) 125 100 75 50 100.00 1000.00 Slant Slant Range Distance (m) (m) 10000.00 VLCA Thrust Rating (kn) 44.55 103.20 115.43 174.35 229.31 246.98 311.76 315.60 NEXTOR - National Center of Excellence for Aviation Research 44
DNL Takeoff Contours Larger engines coupled with smaller initial climb rate capability (compared to twin and three-engine aircraft) could result in expanded noise contours at most airports L dn = 55 Profiles MD-11(GE) Profile VLCA Profile Runway 0 2000 4000 6000 8000 10000 Scale in met ers NEXTOR - National Center of Excellence for Aviation Research 45
Pavement Design Impacts Multiple triple-in-tandem landing gear configurations are likely to be used for VLCA applications 180 Pavement Thickness (cm) 160 140 120 100 80 60 40 20 DC9-50 B727-200 VLCA B747-400 1 2 4 6 8 10 20 30 40 CBR Value Subgrade Strength, CBR Landing Gear Configuration Quadruple + Triple-in-Tandem NEXTOR - National Center of Excellence for Aviation Research 46
Administration & Sales Cost Systems Engineering Model Depreciation Ground Equipment Aircraft Life Cycle IOC Property and Equipment Cost Servicing Flight OPS Annual IOC ~ Fleet Purchases Fleet Size Fleet Additions Fleet Retirement Depreciation Cost Maintenance Cost Average Utilization Aircraft Life Cycle DOC Insurance Cost Annual DOC Annual Fuel Consumption Flight Operations Cost Crew Expenses Fuel Oil Costs Fuel Unit Cost Average Utilization NEXTOR - National Center of Excellence for Aviation Research 47
Sample Application of the Model Desired Range in Km. and (n.m.) Aspect Ratio Cruise Mach Number VLCA Capacity (pass.) MTOW kn (lbs) Wingspan (m.) Airfield Pavement Section Improvement 10,186 (5,500) 9.5 0.85 650 3,830 (860,000) 70 12,965 (7,000) 9.5 0.85 650 5,385 (1,210,000) 82 0 0 0 13,890 (7,500) 9.5 0.85 650 6,100 (1,370,000) 87 Noise Mitigation 5,000,000 7,872,000 10,000,000 Runway Improvement 19,250,000 19,250,000 24,319,277 Taxiway Improvement 13,663,234 13,663,237 15,413,237 90 Degree Exit Improv. 276,343 384,694 386,622 Runway Blast Pad Area Improvement 1,200,000 1,200,000 1,589,673 Terminal Apron Area Improvement 0 77,685 113,207 Land Acquisition Cost 63,869 229,328 297,101 NEXTOR - National Center of Excellence for Aviation Research 48
Desired Range in Km. and (n.m.) Aspect Ratio Cruise Mach Number VLCA Capacity (pass.) MTOW kn (lbs) Wingspan (m.) 10,186 (5,500) 9.5 0.85 650 3,830 (860,000) 70 12,965 (7,000) 9.5 0.85 650 5,385 (1,210,000) 82 13,890 (7,500) 9.5 0.85 650 6,100 (1,370,000) 87 Airfield Geometric Infrastructure Improvement Cost 39,017,641 48,299,715 59,736,701 Terminal Curb Frontage Improvement Cost 45,900 45,900 45,900 Parking Garage Improvement Cost 2,653,750 2,653,750 2,653,750 Landside Improvement Cost 2,699,650 2,699,650 2,699,650 International Terminal Infrastructure Improvement Cost 77,523,165 77,523,165 77,523,165 Total Airport Infrastructure Improvement Cost 124,240,456 136,394,530 149,959,516 NEXTOR - National Center of Excellence for Aviation Research 49
Summary An integrated life-cycle approach is needed to estimate the impacts of VLCA aircraft High-capacity aircraft operating at high-capacity airports will require some changes to current design standards Some of the design standards for airside infrastructure should be revised to plan ahead for strategic VLCA aircraft The effect of reduced airside capacity will not yield reduced passenger demand flow rates at airport terminals NEXTOR - National Center of Excellence for Aviation Research 50
High capacity airports could benefit from lower flight frequencies resulting from VLCA operations if the passenger demand flows are the same NEXTOR - National Center of Excellence for Aviation Research 51