Performance 2 Interne Prüfung

The cost index is defined as the ratio of flight time related costs to fuel costs.

In section [2] the payload is reduced and fuel loading is increased.

At the beginning of section [2] the MTOM is the limiting factor. To increase the range the fuel loading must be increased. This is only possible if payload is exchanged by fuel load.

At the end of section [2] the fuel tank capacity limit is reached. No further fuel loading possible.

A standard climb speed schedule is established for each aeroplane type in airline operation.

A constant IAS is maintained at lower altitudes. During climb the TAS and the Mach number increase. When passing the cross-over altitude the climb is conducted with a constant Mach number. The TAS and IAS decrease.

The crossover altitude solely depends on the combination IAS / Mach number.

Climbing at a small climb angle in an incompressible airflow, drag and angle of attack remain almost constant when flying with constant IAS.

When changing from constant IAS to constant Mach number the rate of climb initially increases before continuing to decrease with higher altitudes.

* Structural limit
* Obstacle limit
* Field length limit (TODA, TORA, ASDA)
* Climb limit
* Tyre speed limit
* Brake energy limit
* Noise limit
* Runway load limit
* Landing mass limit

A higher flap setting results in a lower V1.

The lower take-off speeds result in a shorter ground roll distance and shorter take-off distance.

With a given TODA, the field limited take-off mass increases due to the higher flap setting.
The climb limited take-off mass decreases because the climb performance with a higher flap setting deteriorates.
The effect on the obstacle limited take-off mass depends on the obstacles position in relation to the brake release point and the obstacles height. The nearer and/or higher the obstacle, the higher the optimum flap setting. In this case a higher flap setting increases the PTOMObstacle.

V1 is selected in that way, that the accelerate-stop distance equals engine failure take-off distance (accelerate-go distance).

The balanced field length concept results in the highest possible field length limited take-off mass for a given TORA, as long as the take-off isn't all-engine-limited.

If the actual TOM is lower than the PTOMField, and a balanced V1 is selected, the difference between field length required and field length available is at a maximum.

The balanced V1 is usually applied if neither CWY nor SWY are available,
or if both CWY and SWY are available and have identical length.

* Anti-skid INOP => ASD increases
* Higher V1 => ASD increases
* Higher mass at a given V1 => ASD increases
* Higher flap setting => lower take-off speeds => lower V1 => ASD decreases
* Brake release before take-off power is set => ASD increases
* Runway contamination => ASD increases
* Use of thrust reverser on a dry runway => ASD virtually not effected
* Use of thrust reverser on a wet / contaminated runway => ASD decreases

* Thrust setting
* Flap Setting
* Outside Air Temperature, when above flat rated temperature
* Pressure Altitude
* Engine Bleed Air
* Selection of V2 (see chapter Improved Climb)

The corner of the sharp drop marks the flat rated temperature.

At temperatures above the flat rat temperature the thrust decreases, thus resulting in a lower climb limited take-off mass.

Additional Information
Above the flat rated temperature the thrust is limited by the maximum turbine inlet temperature (TIT). Less fuel must be injected with increasing OAT to maintain the TIT at maximum. Less fuel results in less thrust.

a) A HWC increases the PTOMObstacle

b) In case of obstacles located close to the end of the TORA a higher flap setting increases

the PTOMObstacle.

In case of distant obstacles the PTOMObstacle is decreases.

c) A contaminated runway results in a lower PTOMObstacle.

d) Closed engine bleed air valves result in an increased PTOMObstacle.

e) A higher PA decreases the PTOMObstacle.

f) A higher OAT decreases the PTOMObstacle.

* Improvement of climb gradient due to increased of V2. 
* Higher take-off mass possible without falling below the required minimum climb gradient
* Increase of PTOMClimb and/or PTOMObstacle
* The increased V2 is closer to VX, one engine INOP
* Due to the increase of V2, the V1 and VR must also be increased.

* The improved climb procedure is only possible if the take-off isn't already field length limited.
* The tire speed limit has to be respected.

v1

Full take-off thrust is applied if:
* the actual take-off mass is identical to the field length limited take-off mass
* windshear is reported along the take-off flight path
* the runway is contaminated
* even at low mass, when a high safety level concerning stop margin or obstacle clearance is desired

Furthermore, an abnormal take-off configuration (such as an inoperative anti-skid system) usually requires full take-off thrust.

* Landing distance required (LDR) has to be determined from charts, diagrams or tables. 
* Landing distance available (LDA) has to be determined from AIP

=> Check if LDR lower / equal LDA

• The required thrust determines the required fuel 
• Speed for max. endurance is close to min. drag speed
• Speed for max. specific range is higher than the speed for max. endurance
• Specific range has its maximum in the optimum altitude.
• Endurance has its maximum in the optimum holding altitude
• Extension of flaps and gear reduces endurance and range
• changes in OAT have almost no effect on the max. specific range and
• the optimum altitude / optimum holding altitude
• changes in OAT have an influence on the fuel flow and thus on the endurance