PERFORMANCE
GENERAL 01
Performance legislation 01.01
CS23, CS25 - describe the general differences between aeroplanes certified
Performance Class A aeroplanes
● Multi-engine aeroplanes powered by turbo-propeller engines with a MOPSC > 9, or MTOM >
5700kg, and all multi-engine turbo-jet powered aeroplanes.
Performance Class B aeroplane
● Aeroplanes powered by propeller engines with an MOPSC <=9, or MTOM <= 5700kg
Performance and safety
● Aeroplane performance required for commercial air transport may limit the weight of a
dispatched aeroplane in order to achieve a sufficient level of safety.
● Minimum level of safety required for commercial air transport is ensured through the
combination of airworthiness requirements and operational limitations.
Gross Performance
● Average performance that a fleet of aircraft should achieve if satisfactorily maintained and
flown in accordance with the techniques described in the flight manual.
● Calculated performance with no safety factor
Net Performance
● Gross performance diminished to allow for various contingencies that cannot be accounted
for operationally, for example, variation in piloting technique, or temporary below average
performance.
● Net Performance = Gross performance + safety margin
● Net climb gradient is based on the gross climb gradient, reduced to account for safety
margins based on the number of engines.
1
, General Performance theory 01.02
Climb Gradient
● Ratio of the altitude gained to horizontal air distance travelled (in still air), and therefore the
tangent to the climb angle y.
● Climb gradient = ((Thrust – Drag) / Weight) x 100
● Climb gradient = altitude difference x 100 / ground distance
Climb/Descent angle
● Angle between the local horizon and TAS vector. Assumed to be air-related and independent
on wind
Flight Path Angle
● Angle between the flight path of the aircraft and the (horizontal) ground/water surface.
● Influenced by wind.
● Headwind increases the flight path angle and a tailwind will decrease.
Flight-path gradient
Descent Gradient
Absolute ceiling -
Stopway
● An area on the ground beyond the end of TORA which is prepared and designated as a
suitable area in which an aeroplane can be stopped in the event of an abandoned take-off.
● The width of the stopway must not be less than the width of the runway
● Provided for infrequent use and it need not have the same bearing or wearing qualities as
the runway
● Increases the ASDA
2
, Clearway
● Area that may be provided beyond the end of TORA that is free from objects which may
cause a hazard to aeroplanes in flight.
● Provides an area over which an aeroplane can safely transit from lift-off to the required
screen height.
● Does not need to have the same strength, may be land or water and may extend outside the
aerodrome boundary; must be under the control of the aerodrome authority.
● Not less than 152m (500ft) wide.
● Upward slope not exceeding 1,25% above which no object or terrain protrudes.
ASDA – Acceleration Stop dis. Available
● Upslope increases the ASDA
● Increases with a stopway.
● TORA + stopway
TODA
● Length of the take off run available plus the length of the clearway available
● TORA + Clearway
TORA
● Take-off run available
Screen height
● Height of imaginary screen which the aeroplane would just clear when taking off or landing
in an unbanked attitude with landing gear extended
Range -
Endurance -
3
GENERAL 01
Performance legislation 01.01
CS23, CS25 - describe the general differences between aeroplanes certified
Performance Class A aeroplanes
● Multi-engine aeroplanes powered by turbo-propeller engines with a MOPSC > 9, or MTOM >
5700kg, and all multi-engine turbo-jet powered aeroplanes.
Performance Class B aeroplane
● Aeroplanes powered by propeller engines with an MOPSC <=9, or MTOM <= 5700kg
Performance and safety
● Aeroplane performance required for commercial air transport may limit the weight of a
dispatched aeroplane in order to achieve a sufficient level of safety.
● Minimum level of safety required for commercial air transport is ensured through the
combination of airworthiness requirements and operational limitations.
Gross Performance
● Average performance that a fleet of aircraft should achieve if satisfactorily maintained and
flown in accordance with the techniques described in the flight manual.
● Calculated performance with no safety factor
Net Performance
● Gross performance diminished to allow for various contingencies that cannot be accounted
for operationally, for example, variation in piloting technique, or temporary below average
performance.
● Net Performance = Gross performance + safety margin
● Net climb gradient is based on the gross climb gradient, reduced to account for safety
margins based on the number of engines.
1
, General Performance theory 01.02
Climb Gradient
● Ratio of the altitude gained to horizontal air distance travelled (in still air), and therefore the
tangent to the climb angle y.
● Climb gradient = ((Thrust – Drag) / Weight) x 100
● Climb gradient = altitude difference x 100 / ground distance
Climb/Descent angle
● Angle between the local horizon and TAS vector. Assumed to be air-related and independent
on wind
Flight Path Angle
● Angle between the flight path of the aircraft and the (horizontal) ground/water surface.
● Influenced by wind.
● Headwind increases the flight path angle and a tailwind will decrease.
Flight-path gradient
Descent Gradient
Absolute ceiling -
Stopway
● An area on the ground beyond the end of TORA which is prepared and designated as a
suitable area in which an aeroplane can be stopped in the event of an abandoned take-off.
● The width of the stopway must not be less than the width of the runway
● Provided for infrequent use and it need not have the same bearing or wearing qualities as
the runway
● Increases the ASDA
2
, Clearway
● Area that may be provided beyond the end of TORA that is free from objects which may
cause a hazard to aeroplanes in flight.
● Provides an area over which an aeroplane can safely transit from lift-off to the required
screen height.
● Does not need to have the same strength, may be land or water and may extend outside the
aerodrome boundary; must be under the control of the aerodrome authority.
● Not less than 152m (500ft) wide.
● Upward slope not exceeding 1,25% above which no object or terrain protrudes.
ASDA – Acceleration Stop dis. Available
● Upslope increases the ASDA
● Increases with a stopway.
● TORA + stopway
TODA
● Length of the take off run available plus the length of the clearway available
● TORA + Clearway
TORA
● Take-off run available
Screen height
● Height of imaginary screen which the aeroplane would just clear when taking off or landing
in an unbanked attitude with landing gear extended
Range -
Endurance -
3
