Brunei DCA CPL(A) Performance flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Take-off distance required

The horizontal distance from the start of the take-off roll to the point where the aeroplane reaches 35 ft above the take-off surface, or the screen height specified for the aeroplane class.

Accelerate-stop distance available

The length of the take-off run available plus the length of any stopway. It limits the distance in which a rejected take-off must be brought to a full stop.

V1 decision speed

The speed at which, following an engine failure, the take-off can be continued to the screen height or rejected within the accelerate-stop distance available, whichever is limiting.

Clearway definition

A defined rectangular area beyond the take-off run available, clear of obstacles, over which the aeroplane may climb to the screen height. It adds to TODA only.

ISA sea-level values

Temperature 15 degrees Celsius, pressure 1013.25 hectopascals, density 1.225 kilograms per cubic metre, with a lapse rate of 1.98 degrees Celsius per 1000 feet.

Density altitude

The altitude in the International Standard Atmosphere at which the prevailing air density would occur. It combines the effects of pressure altitude, temperature and humidity.

Pressure altitude

The altitude indicated when the altimeter subscale is set to 1013.25 hectopascals. It is the reference used for all flight manual performance charts.

Humidity effect on density

Water vapour is less dense than dry air, so increasing humidity lowers air density and degrades lift, thrust and propeller efficiency at a given pressure altitude and temperature.

Balanced field length

The runway length at which the accelerate-stop distance equals the all-engines-operating take-off distance. At this length the decision speed V1 is at its optimum.

Net take-off flight path

The gross take-off flight path reduced by 0.8 percent for two-engine aeroplanes, 0.9 percent for three and 1.0 percent for four, used to demonstrate obstacle clearance.

Second-segment climb gradient

The minimum one-engine-inoperative climb gradient with gear up and V2: 2.4 percent for two engines, 2.7 percent for three and 3.0 percent for four.

Obstacle clearance requirement

The net take-off flight path must clear all obstacles by at least 35 feet vertically, or by a specified lateral distance if the obstacle lies off the extended centreline.

Landing distance factor

The multiplier applied to the demonstrated landing distance: 1.67 for turbojets and 1.43 for propeller aeroplanes, with a higher factor for wet or contaminated runways.

Landing distance available

The length of runway declared available for the landing ground run, from the threshold to the end of the runway, used to compare against the landing distance required.

Approach speed VREF

The landing reference speed, normally 1.3 times the stall speed in the landing configuration. Excess speed above VREF increases the landing distance substantially.

Wet runway landing penalty

An increase of about 15 percent applied to the dry landing distance when the runway is wet, unless the flight manual provides specific wet-runway data.

Best glide speed

The speed for minimum drag, which gives the maximum glide range in a power-off descent. It is higher than the speed for minimum power required.

Service ceiling

The altitude at which the maximum rate of climb falls to 100 feet per minute. The absolute ceiling is the altitude at which the rate of climb is zero.

Maximum range speed

The cruise speed at which specific range is greatest, occurring where the ratio of lift to drag divided by specific fuel consumption is highest for the weight.

Drift-down requirement

The ability, following engine failure at cruise altitude, to descend at a specified rate to an altitude where level flight can be maintained on the remaining engines.

Forward centre of gravity effect

A forward CG increases the pitch-down moment, raises the stall speed and increases take-off and landing distances, and reduces elevator authority for rotation.

Aft centre of gravity effect

An aft CG reduces longitudinal stability and control authority, and may make recovery from a stall or spin impossible if the limit is exceeded.

Zero-fuel mass

The mass of the aeroplane and its contents excluding usable fuel. It must not exceed the maximum zero-fuel mass specified in the flight manual.

Centre of gravity calculation

Total moment divided by total weight gives the CG position. Moment is weight times arm, and the result is often expressed as a percentage of mean aerodynamic chord.

Headwind ground roll effect

A headwind reduces the ground speed and therefore the ground roll. A 10 percent headwind component reduces the take-off ground roll by roughly 19 percent.

Tailwind effect on distance

A tailwind increases ground speed and therefore take-off and landing distance. A 10 percent tailwind component increases the distance by about 20 percent.

Runway slope effect

An upslope increases the take-off ground roll and shortens the landing roll. A 1 percent upslope adds roughly 10 percent to the take-off distance.

Contaminated runway

A runway covered by standing water, slush, snow or ice. Braking friction is reduced and flight manual contaminated-runway data must be used for take-off and landing.

Flight manual authority

The approved document for the aeroplane type. Its certified performance data must be used in preference to any other source and must not be extrapolated beyond plotted limits.

Chart interpolation

The process of deriving intermediate values between plotted lines on a performance chart. Values outside the plotted range are not certified and must not be extrapolated.

Chart reference conditions

Flight manual charts normally assume ISA, zero wind, a level dry runway and a specified flap setting. Any deviation requires the stated corrections to be applied.

Density altitude rule of thumb

Density altitude in feet approximates pressure altitude plus 120 times the temperature deviation from ISA in degrees Celsius at that pressure altitude.

Hot and high effects

High elevation and high temperature reduce air density, lowering lift and thrust, increasing true take-off speed and ground roll, and reducing climb gradient.