The following Figures C21 and C22 represent the JAR-OPS departure sectors: 

Figure C21: JAR-OPS Departure Sector (Track change ≤ 15o)

* The start of the departure sector is: -The end of TOD when the turn starts before the end of TODA, or -The end of TODA when the turn starts after the end of TODA 

Figure C22: JAR-OPS Departure Sector (Track change > 15o) 

Note that the ICAO recommendations for the departure sector (Annex 6) are the same as the JAR-OPS definitions. 

FAR 121.189 Subpart I 

“FAR 121.189 (d)(2) No person operating a turbine engine powered transport category airplane may take off that airplane at a weight greater than that listed in the Airplane Flight Manual […] that allows a net takeoff flight path that clears all obstacles […] by at least 200 feet horizontally within the airport boundaries and by at least 300 feet horizontally after passing the boundaries.” 

 

5. OUTSIDE ELEMENTS 

Determination of the performance limited Takeoff Weight must be done considering the external conditions of the day. These conditions affect the MTOW, which can vary considerably from one day to the other. 

“JAR-OPS 1.490 

(c) an operator must take account of the following [when determining the maximum takeoff mass]: 

.

Not more than 50% of the reported head-wind component or not less than 150% of the reported tailwind component; 

 

The pressure altitude at the aerodrome; 

The ambient temperature at the aerodrome; 

The runway slope in the direction of take-off; 

The runway surface condition and the type of runway surface“ 

5.1. Wind 

The wind component along the runway axis is an important influencing factor for takeoff. It affects the takeoff ground speed and, therefore, the takeoff distances, which are reduced in case of headwind and increased in case of tailwind. 

The MTOW calculated prior to takeoff, must be determined considering 50% of the actual headwind component, or 150% of the actual tailwind component. This condition forms part of the Airbus performance software, so that an operator just has to consider the actual wind component for the MTOW determination. 

 

“JAR/FAR 25.237 

(a) A 90° cross component of wind velocity, demonstrated to be safe for take-off and landing, must be established for dry runways and must be at least 20 knots or 0.2 VS01, whichever is greater, except that it need not exceed 25 knots.” 

The crosswind component does not affect takeoff performance. Nevertheless, it is necessary to demonstrate the safety of takeoff and landing procedures up to 25 knots of crosswind. The maximum demonstrated value must be published in the Aircraft Flight Manual. 

5.2. Pressure Altitude 

Pressure altitude influences airframe and engine performance. When the pressure altitude increases, the corresponding static pressure Ps and air density ρ decrease. 

5.2.1. Effect on Aerodynamics 

The force balance in level flight can be illustrated as follows: 

Weight = m g = Lift = ρS TAS2 CL/2

1 VS0 is the reference stall speed in clean configuration. 

As a conclusion, when the pressure altitude increases for a given weight, the true air speed (TAS) must be increased to compensate for the air density reduction. Therefore, the takeoff distance is increased. 

5.2.2. Effect on Engines 

When the pressure altitude increases, the available takeoff thrust is reduced. Therefore, takeoff distances are longer and takeoff climb gradients are reduced. 

5.2.3. Summary 

5.3. Temperature 

5.3.1. Effect on Aerodynamics 

When the Outside Air Temperature (OAT) increases, the air density ρ decreases.  As mentioned above, the true air speed (TAS) must be increased to compensate for the air density reduction. As a result, the takeoff distance is increased. 

5.3.2. Effect on Engines 

The Takeoff thrust (TOGA) remains constant, equal to the Flat Rated Thrust, until the OAT reaches the Flat Rating Temperature (Tref). Above this temperature, the takeoff thrust starts decreasing (Figure C25) . 

 

Consequently, when the Outside Air Temperature increases, the takeoff distances are longer and takeoff climb gradients are reduced. 

5.3.3. Summary 

5.4. Runway Slope 

A slope is generally expressed in percentages, preceded by a plus sign when it is upward, or a minus sign when it is downward.