Getting to Grips with Aircraft Performance

3.4.4. RUNWAY CONDITIONS 3.4.5. AIRCRAFT CONFIGURATION 4. DISPATCH REQUIREMENTS 4.1.1. RLD DRY RUNWAYS 118 3.4. EXTERNAL PARAMETERS INFLUENCE 119 119 119 119 120 120 121 4.1. REQUIRED LANDING DISTANCE (RLD) 121 121 4.1.2. RLD WET RUNWAYS 121 4.1.3. RLD CONTAMINATED RUNWAYS 122 4.1.4. RLD WITH AUTOMATIC LANDING (DRY) 122 4.2. GO-AROUND REQUIREMENTS 123 4.2.1. NORMAL APPROACH 123 4.2.2. CAT II OR CAT III APPROACH 123 4.3. CONCLUSION 123 5. IN-FLIGHT REQUIREMENTS 124 5.1. IN-FLIGHT FAILURE 124 5.2. OVERWEIGHT LANDING REQUIREMENTS 124 5.3. FUEL JETTISONING CONDITIONS 125 F. CRUISE 4 127 1. GENERAL 1.1. INTRODUCTION 127 127 1.2. SPECIFIC RANGE 127 2. SPEED OPTIMIZATION 128 2.1. ALL ENGINE OPERATING CRUISE SPEEDS 2.1.1. MAXIMUM RANGE MACH NUMBER (MMR) 2.1.2. LONG-RANGE CRUISE MACH NUMBER (MLRC) 2.1.3. ECONOMIC MACH NUMBER (MECON) 2.1.4. CONSTANT MACH NUMBER 128 128 130 131 133 AIRBUS Getting to Grips with Aircraft Performance TABLE OF CONTENTS 3. ALTITUDE OPTIMIZATION 3.1. OPTIMUM CRUISE ALTITUDE 133 133 3.1.1. AT A CONSTANT MACH NUMBER 133 3.1.2. WIND INFLUENCE 135 3.2. MAXIMUM CRUISE ALTITUDE 138 3.2.1. LIMIT MACH NUMBER AT CONSTANT ALTITUDE 138 3.2.2. MAXIMUM CRUISE ALTITUDE 138 3.3. EN ROUTE MANEUVER LIMITS 141 3.3.1. LIFT RANGE 141 3.3.2. OPERATING MANEUVER LIMITATIONS 142 3.4. CRUISE OPTIMIZATION: STEP CLIMB 147 147 4. FCOM CRUISE TABLE G. CLIMB 1. FLIGHT MECHANICS 1.1. DEFINITIONS 1.2. CLIMB EQUATIONS 1.2.1. CLIMB GRADIENT (Y) 1.2.2. RATE OF CLIMB (RC) 1.2.3. SPEED POLAR 149 149 149 149 150 151 151 1.3. INFLUENCING PARAMETERS 152 1.3.1. ALTITUDE EFFECT 152 1.3.2. TEMPERATURE EFFECT 153 1.3.3. WEIGHT EFFECT 153 1.3.4. WIND EFFECT 153 2. CLIMB IN OPERATION 2.1. CLIMB MANAGEMENT 2.1.1. THRUST SETTING 2.1.2. ENERGY SHARING 154 154 154 154 2.1.3. CLIMB CEILING 155 2.2. CLIMB SPEEDS 155 2.2.1. CLIMB AT GIVEN IAS/MACH LAW 155 2.2.2. CLIMB AT MAXIMUM GRADIENT 156 2.2.3. CLIMB AT MAXIMUM RATE 156 2.2.4. CLIMB AT MINIMUM COST 2.3. FCOM CLIMB TABLE 2.4. CABIN CLIMB H. DESCENT / HOLDING 1. FLIGHT MECHANICS 156 157 158 1.1. DEFINITIONS 1.2. DESCENT EQUATIONS 1.2.1. DESCENT GRADIENT (Y) 1.2.2. RATE OF DESCENT (RD) 1.2.3. SPEED POLAR 1.3. INFLUENCING PARAMETERS 1.3.1. ALTITUDE EFFECT 1.3.2. TEMPERATURE EFFECT 1.3.3. WEIGHT EFFECT 1.3.4. WIND EFFECT AIRBUS 159 159 159 159 159 160 161 161 161 162 162 163 LO 5 TABLE OF CONTENTS 2. DESCENT IN OPERATION 2.1. THRUST SETTING 2.2. DESCENT SPEEDS 2.2.1. DESCENT AT GIVEN MACH/IAS LAW 2.2.2. DESCENT at Minimum GRADIENT (DRIFT DOWN) 2.2.3. DESCENT AT MINIMUM RATE 2.2.4. DESCENT AT MINIMUM COST 2.2.5. EMERGENCY DESCENT 2.3. FCOM DESCENT TABLE 2.4. CABIN DESCENT 3. HOLDING 3.1. HOLDING SPEED 3.2. HOLDING IN OPERATION I. FUEL PLANNING AND MANAGEMENT 1. JAR - FUEL PLANNING AND MANAGEMENT 1.1. FUEL POLICY Getting to Grips with Aircraft Performance 164 164 164 164 165 165 165 166 166 167 168 168 169 171 171 171 1.1.1. STANDARD FLIGHT PLANNING 171 1.1.2. ISOLATED AIRPORT PROCEDURE 175 1.1.3. UNREQUIRED DESTINATION ALTERNATE AIRPORT 175 1.1.4. DECISION POINT PROCEDURE 175 1.1.5. PRE-DETERMINED POINT PROCEDURE 177 1.1.6. ETOPS PROCEDURE 177 1.2. FUEL MANAGEMENT 179 1.2.1. MINIMUM FUEL AT LANDING AIRPORT 179 1.2.2. MINIMUM FUEL AT DESTINATION AIRPORT 2. FAR FUEL PLANNING AND MANAGEMENT - 2.1. DIFFERENT TYPES OF OPERATIONS 2.2. FUEL POLICY 2.2.1. DOMESTIC OPERATIONS 179 181 181 182 182 2.2.2. FLAG AND SUPPLEMENTAL OPERATIONS 184 2.2.3. ISOLATED AIRPORT PROCEDURE 186 2.2.4. UNREQUIRED DESTINATION ALTERNATE AIRPORT 186 2.2.5. REDISPATCH PROCEDURE 187 2.2.6. ETOPS PROCEDURE 188 2.2. FUEL MANAGEMENT 188 2.2.1 MINIMUM Fuel at LANDING AIRPORT 188 J. APPENDIX 1. APPENDIX 1 : ALTIMETRY - TEMPERATURE EFFECT 2. APPENDIX 2 : TAKEOFF OPTIMIZATION PRINCIPLE 2.1. TAKEOFF CONFIGURATION 2.2. AIR CONDITIONING 2.3. TAKEOFF SPEED OPTIMIZATION 2.3.1. SPEED RATIOS: V₁/VR AND V2/VS 2.3.2. V1/VR RATIO INFLUENCE 2.3.3. V2/Vs RATIO INFLUENCE 2.4. RESULT OF THE OPTIMIZATION PROCESS 2.4.1. MAXIMUM TAKEOFF WEIGHT CO 6 AIRBUS 189 189 192 192 193 193 193 194 197 199 199 Getting to Grips with Aircraft Performance TABLE OF CONTENTS 2.4.2. TAKEOFF SPEEDS 200 2.4.3. LIMITATION CODES 200 2.4.4. RTOW CHART INFORMATION 202 3. APPENDIX 3 : TAKEOFF PERFORMANCE SOFTWARE 203 3.1. P.E.P FOR WINDOWS 203 3.1.1. WHAT IS P.E.P. ? 203 3.1.2. TLO MODULE 204 3.2. LESS PAPER COCKPIT (LPC) 205 4. APPENDIX 4: ABBREVIATIONS 206 7 AIRBUS Getting to Grips with Aircraft Performance INTRODUCTION 1. INTRODUCTION The safety of air transportation is a joint effort, regulated by the State on one hand, and practiced by the manufacturers, airlines and Air Traffic Controllers (ATC), on the other hand. The State is responsible for the supervision of civil aviation, to ensure that a high safety standard is maintained throughout the industry, and its primary means of enforcement is via the establishment and administration of written regulations. The control process encompasses a fixed set of rules to secure that all aircraft respect a minimum level of performance, which thereby leads to the definition of limitations. The "State administration" generally implies the civil aviation authority, which corresponds to the aircraft's country of registration. In the United States, for example, this role is devoted to the Federal Aviation Administration (FAA), whereas in France, it is the "Direction Générale de l'Aviation Civile" (DGAC). Every country has its own regulations, but the international aspect of air transportation takes into account the worldwide application of common rules. The International Civil Aviation Organization (ICAO) was therefore created in 1948, to provide a supranational council, to assist in defining the international minimum recommended standards. The Chicago Convention was signed on December 7, 1944, and has become the legal foundation for civil aviation worldwide. Although it is customary for each country to adopt the main airworthiness standards defined in conjunction with aircraft manufacturers (USA, Europe, Canada, etc.), every country has its own set of operational regulations. For instance, some countries (mainly European) have adopted JAR-OPS 1, while some others follow the US FAR 121. The "field of limitations" is therefore dependent upon an amalgamation of the following two realms: • • Airworthiness: Involving the aircraft's design (limitations, performance data etc....), in relation to JAR 25 or FAR 25. Operations: Involving the technical operating rules (takeoff and landing limitations, fuel planning, etc...), in relation to JAR-OPS 1 or FAR 121. Both airworthiness and operational regulations exist for all aircraft types. This brochure addresses "large aircraft", which means aircraft with a maximum takeoff weight exceeding 5,700 kg. Airbus performance documentation is clearly divided into the two above-mentioned categories: Airworthiness and Operations. Airworthiness: The Airplane Flight Manual (AFM) is associated to the airworthiness certificate and contains certified performance data in compliance with JAR/FAR25. AIRBUS 9 INTRODUCTION Getting to Grips with Aircraft Performance • Operations: The Flight Crew Operating Manual (FCOM) can be viewed as the AOM (aircraft-related portion of the Operations Manual), which contains all the necessary limitations, procedures and performance data for aircraft operation. The following table (Table 1) illustrates the large aircraft regulatory basis: Airworthiness ICAO Annex 8 to the Chicago Convention Annex 6 Operating Rules to the Chicago Convention EUROPE (JAA) USA (FAA) JAR¹ 25 FAR² part 25 JAR-OPS1 FAR part 121 Table 1: Large Aircraft Requirements All aircraft of the Airbus family are JAR 25 and/or FAR 25 certified. On the other hand, compliance with the operating rules remains under the airline's responsibility. This brochure is designed to address three different aspects of aircraft performance: • The physical aspect : This brochure provides reminders on flight mechanics, aerodynamics, altimetry, influence of external parameters on aircraft performance, flight optimization concepts... The regulatory aspect Description of the main JAR and FAR certification and operating rules, leading to the establishment of limitations. For a clear understanding, regulatory articles are quoted to assist in clarifying a given subject. In such cases, the text is written in italics and the article references are clearly indicated to the reader. • The operational aspect : Description of operational methods, aircraft computer logics, operational procedures, pilot's actions... 1 JAR: The Joint Airworthiness Requirements are under the European authority called the Joint Aviation Authority (JAA). FAR: The Federal Aviation Regulations are under the US authority called the Federal Aviation Administration (FAA). 10 AIRBUS Getting to Grips with Aircraft Performance GENERAL A. GENERAL 1. THE INTERNATIONAL STANDARD ATMOSPHERE (ISA) 1.1. Standard Atmosphere Modeling The atmosphere is a gaseous envelope surrounding the earth. Its characteristics are different throughout the world. For this reason, it is necessary to adopt an average set of conditions called the International Standard Atmosphere (ISA). 1.1.1. Temperature Modeling The following diagram (Figure A1) illustrates the temperature variations in the standard atmosphere: Altitude (ft) (km) STRATOSPHERE 40000 12 TROPOPAUSE subsonic jet 36089 ft transport 35000 10 cruise level 30000 8 25000 TROPOSPHERE 20000 6 15000 4 10000 2 5000 -56.5°C 15°C Sea level -60 -40 -20 0 20 40 60 Temperature (°C) Figure A1: ISA temperature The international reference is based on a sea-level temperature of 15°C at a pressure of 1013.25 hPa¹. The standard density of the air at sea level is 1.225 kg/m³. 1 1013.25 hPa is equal to 29.92 in Hg, ‘hPa' meaning hecto Pascal and 'in Hg' inches of mercury. I AIRBUS 11