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TAKEOFF PERFORMANCE

TAKEOFF PERFORMANCE. TAKEOFF CONSIDERATIONS. Factors to Consider: Aircraft Gross Weight Available Engine Thrust Field Elevation Pressure Altitude Temperature Winds Runway Length Runway Slope Runway Condition Terrain & Obstacles MEL/CDLs Icing. Improving Performance:

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TAKEOFF PERFORMANCE

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  1. TAKEOFF PERFORMANCE

  2. TAKEOFF CONSIDERATIONS Factors to Consider: • Aircraft Gross Weight • Available Engine Thrust • Field Elevation • Pressure Altitude • Temperature • Winds • Runway Length • Runway Slope • Runway Condition • Terrain & Obstacles • MEL/CDLs • Icing Improving Performance: • Engine Bleeds Closed. • Static vs. Flex Takeoff. • Flap Configuration(Less flaps = longer takeoff roll but better climb performance).

  3. TAKEOFF SPEEDS V1 (Takeoff Decision Speed) • V1 is selected so that if an engine failure is recognized: 1) at or above this speed, the takeoff may be continued with one engine inoperative, or 2) at or prior to this speed a stop maybe initiated and completed within the runway remaining. • The stopping distance is based on retarding the thrust levers to idle, maximum braking on a dry runway, and full spoiler extension. • The effect of reverse thrust is not included in the computation.

  4. TAKEOFF SPEEDS VR (Rotation Speed) • The speed at which the pilot begins to rotate the aircraft to the takeoff attitude. The rate of rotation may vary but rotation at the optimum rate will result in a minimum liftoff speed (Vlof). • This optimum rotation rate will result in attaining V2 speed at 35 feet at the end of the runway with one engine inoperative, or attaining the V2 speed at 35 feet over the runway with 15% of the runway remaining from that point with all engines operating.

  5. TAKEOFF SPEEDS VLOF (Lift-off Speed) • The speed at which the aircraft first becomes airborne. * Takeoff speeds vary with aircraft weight, aircraft configuration (flaps, bleeds, anti-ice, anti-skid, etc.), and runway conditions (contamination).

  6. TAKEOFF SPEEDS V2 (Takeoff Safety Speed) • The greater ofa speed at 35 feet above the takeoff runway or a speed at least 20% above the stall speed, with the aircraft in the takeoff configuration. • The correct V2 is a result ofproper rotation and liftoff procedures and allows the aircraft to maintain a specified gradient in the climb. • This is essentially the best one-engine operative angle of climb speed for the aircraft and should be held until clearing obstacles after takeoff, or until at least 400 feet above the ground also known as “first segment climb”.

  7. TAKEOFF SPEEDS Vmc (Minimum Control Speed) • Minimum control speed with the critical engine inop. Vmcg (Minimum Control Speed/Ground) • Minimum speed at which directional control can be maintained on the ground using only control surfaces after an outboard engine fails during takeoff. Vmca (Minimum Control Speed/Air) • Minimum speed at which straight flight can be maintained with zero yaw and no more than 5 degree bank towards the operative engine after an outboard engine fails and takeoff power on the operative engine(s).

  8. CLEARWAY & STOPWAY • Clearway refers to specific conditions existing in conjunction with a particular runway that may be used by the operator to improve the performance margin of the aircraft through extension of the runway length requirement when operationally advantageous. • A Clearwayis defined as an area beyond the runway, not less than 500 feet wide, centrally located about the extended centerline of the runway, above which no obstacles protrude. • AStopwayis an area beyond the takeoff runway able to support the aircraft during an aborted takeoff, without causing structural damage to the aircraft. Cannot be used in takeoff computations.

  9. DECLARED RUNWAY DISTANCES • TORATakeoff Run Available (Takeoff Ground Run Available) • TODATakeoff Distance Available (TORA + Clearway) • ASDAAccelerate-Stop Distance Available (TORA + Stopway) • LDALanding Distance Available • These distances are the basis for runway performance calculations and do no necessarily correspond to the lengths depicted on the Jeppesen charts.

  10. TAKEOFF • The regulations require specific operational limitations for operations on or near the runway environment and during initial climb away from the terminal environment. • Weight planning and establishing weight limitations for the aircraft allows the airline to ensure the aircraft meet these requirements depending on ambient conditions. • Separate weight limitations are created for the Runway (the Runway Limit Weight) for operations up to 35 feet above the surface, and for the Climb (the Climb Limit Weight), which covers initial climb from 35 feet to 1500 feet. • This data is created through testing during aircraft certification and is further refined by engineers (Jeppesen, Aerodata, etc.) and published in the “Runway Analysis.”

  11. MGTOW The Maximum Gross Takeoff Weight is computed by finding the most restrictive (lowest weight) of the following: 1. Takeoff Runway Limit Weight (Performance) 2. Takeoff Climb Limit Weight (Performance) 3. Structural Takeoff Limit Weight (Structural)

  12. TAKEOFF RUNWAY LIMIT WEIGHT • The minimum takeoff length required varies with gross weight, temperature, altitude, wind, runway gradient, & clutter. • The Takeoff Runway Limit Weight ensures, that based on ambient conditions, we will have enough runway available to comply with all the following distance requirements:Accelerate-Stop DistanceTakeoff with an Engine Failure DistanceAll-Engine Take-Off Distance • Dispatchers & crews will make sure the airplane is within weight limitations that ensure there is enough runway to either reject the takeoff and stop, or climb to a prescribed altitude above the runway with one or all engines operating (35 feet).

  13. TAKEOFF RUNWAY LIMIT WEIGHT Accelerate-Stop Distance • The distance required to accelerate to the decision speed (V1) with all engines operating normally, experience the loss of an engine at V1, retard the thrust lever(s) on the operating engine(s), and bring the airplane to a full stop. • Only spoilers and anti-skid brakes are used for stopping. Reverse thrust is not utilized in demonstrating this distance. • A stopway can be calculated as part of this distance, but not all airlines do this. Stopway

  14. TAKEOFF RUNWAY LIMIT WEIGHT Takeoff Distance With an Engine Failure • Distance required to accelerate to V1 with all engines operating normally, experience the loss of an engine, continue to accelerate on the remaining engine(s) to Vr at which time rotation is commenced so as to reach a height of 35 feet above the runway surface at V2. • The clearway distance can be used in this computation. • Sometimes referred to as the Accelerate-Go Distance.

  15. TAKEOFF RUNWAY LIMIT WEIGHT All Engine Takeoff Field Length • Demonstrated distance from brake release to a point where a 35 feet height above the surface is reached with all engines operating normally plus 15% of the runway distance. • Essentially 115% of our distance to reach 35 feet on all engines operating must still put us over the runway surface. • A clearway can be used in distance calculation.

  16. TAKEOFF RUNWAY LIMIT WEIGHT Balanced Field Length • The runway length (or runway length plus clearway) where, for the takeoff weight, the engine-out accelerate-go distance equals the accelerate-stop distance. • The stopway is not used in computing a balanced field. • When the runway length is balanced, this often results in the shortest runway distance required and the highest allowable takeoff weights. • Takeoff speeds are usually calculated in such a way to create a balanced field length.

  17. AIRPORT/RUNWAY ANALYSIS Takeoff • Data ensures compliance with basic takeoff limiting conditions - Field Length, Minimum Climb Gradient, Obstacle Clearance, Tire Speed, and Brake Energy. • Jeppesen combines required runway performance and obstacle clearance into the published runway limit weight. • The published runway limit weight assures required performance and obstacle clearance up to 1500’ AGL or until all obstacles are cleared up to 30 NM from the departure airport. • The published Climb Limit Weight does not guarantee obstacle clearance - just a positive single-engine rate of climb at the temperature and pressure altitude on the chart to meet 2nd segment climb requirements.

  18. AIRPORT/RUNWAY ANALYSIS Takeoff • Limit Codes: F =FieldT =Tire SpeedB =Brake EnergyV =VMCG* =Obstacle or Level-Off AltitudeW=(Tail)Wind Takeoff Not Allowed

  19. REDUCED-THRUST TAKEOFF • Used when required thrust would be more than what is safely required for takeoff and climb. • The engines assume the OAT (Outside Air Temperature) is higher (using the Assumed Temperature column) and allows the use of a lower thrust (N1) setting. • Saves on engine wear and reduces fuel burn. • Adjusted takeoff speeds and thrust settings found by using performance charts or the FMS. • Safety margins are maintained on performance as the true airspeed at the actual temperature is always less than it would be at the assumed temperature = more runway remaining to stop at V1. • Pilots may still go to full thrust at anytime during takeoff or climb. • Offers a lower noise footprint departing the airport.

  20. REDUCED THRUST TAKEOFF • Should not be utilized when: The runway is contaminated or slippery. There is a temperature inversion or windshear. The Anti-Skid system is inoperative. The runway analysis does not allow it. end

  21. TAKEOFF CLIMB LIMIT WEIGHT • After the aircraft has reached the 35 foot height with one engine inoperative, there is a requirement that it be able to climb at a specified climb gradient. The aircraft’s performance must be considered based upon a one-engine inoperative climb up to 1,500 feet above the ground. • The aircraft must clear all obstacles either by a height of at least 35 feet vertically, or by at least 200 feet horizontally within the airport boundaries and by at least 300 feet horizontally after passing the boundaries. • The takeoff profile is broken down into 4 segments with specific operating requirements in each segment. • The Climb Limit Weight allows us to maintain operational compliance with these requirements.

  22. TAKEOFF CLIMB LIMIT WEIGHT Gradient Requirements • This method ofcalculating climb performance during the various flight path segments is basically a percentage ofthe horizontal distance traveled in zero wind. • Example: if a 2.4% climb gradient is required, for every 1000 feet that the aircraft travels horizontally, it must climb 24 feet.

  23. TAKEOFF CLIMB LIMIT WEIGHT • First Segment : This segment is included in the takeoff runway charts, and is measured from the point at which the aircraft becomes airborne until it reaches the 35-foot height at the end of the runway distance required. Must achieve V2 at 35 ft AGL. • Second Segment : This is the most critical segment of the profile. The second segment is the climb from the 35 ft height to 400 feet above the ground. The climb is done at takeoff power on the operating engine(s) at V2 speed and the first flap retraction occurs. The required climb gradient in this segment is 2.4% for two-engine aircraft, 2.7% for three-engine aircraft, and 3.0% for four-engine aircraft. • The aircraft can be banked up to 15 degrees. • This is the most restrictive of the climb segments due to speed, weight, height above ground, and outside air temperatures.

  24. TAKEOFF CLIMB LIMIT WEIGHT • Third Segment : During this segment, the airplane is considered to be above 400 feet AGL and accelerating from the V2 speed to the final climb speed. The remaining flaps are raised and power may be maintained at the takeoff setting up to 5 minutes maximum. • Fourth Segment: This segment continues to 1,500 foot AGL with power set at maximum continuous thrust. The required climb in this segment is a gradient of 1.2% for two-engine airplanes, 1.55% for three-engine airplanes, and 1.7% for four-engine airplanes.

  25. TAKEOFF CLIMB LIMIT WEIGHT

  26. TAKEOFF CLIMB LIMIT WEIGHT 1500’ AGL Gross Path Final Climb Net Path (Gross - 0.8%) 35’ min 3rd Accelerate 2nd 35’ min Min 400’ AGL 1st Existing Man-made obstacle Existing Terrain obstacle VR 35’ V1 Accelerate-stop or 1 Engine take-off distance V2 Take-off Flight Path

  27. ACCELERATE/GO The distance required to accelerate to V1, suffer a failure of the critical engine, & continue the takeoff to 35 ft above the runway surface (V2). This distance must be completed over the rwy.

  28. ACCELERATE/STOP The distance required to accelerate to V1, suffer a failure of the critical engine, & bring the to a complete stop.

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