Performance

Question 1

TODR

Answer 1

Take Off Distance Required - is the distance required to take-off from a standing start at max T/O power and reach a screen height above the runway at the T/O safety speed

Question 2

Screen Height

Answer 2

Usually 50ft and it is the height of an imaginary screen which the a/c would clear at the end of the runway in an unbanked attitude with landing gear extended

Question 3

Take off safety speed

Answer 3

Speed that gives an adequate margin above the stalling speed (it can’t be less than 1.2Vs in the T/O config)

Question 4

TODA

Answer 4

Take-off distance available - is the length of the take-off run available + any length of clearway.

Question 5

Clearway

Answer 5

A defined rectangular area on the ground or water at the departure end of the runway selected as a suitable area over which an a/c may make a portion of its initial climb to a specific height

Question 6

TORA

Answer 6

Take off run available - it means the length of runway declared by the aerodrome operator as available and suitable for the ground run of an a/c taking off

Question 7

ASDA

Answer 7

Accelerated stop distance available - is the distance specified by the appropriate authority as being the effective length available for use by an a/c that’s executing an abandoned / rejected take-off (the effective length may include a stopway)

Question 8

Stopway

Answer 8

A rectangular area on the ground at the end of the runway in the direction of take-off which is designated and prepared by the competent authority as an area in which the a/c can be stopped in the case off a rejected take-off

Question 9

Gradient of climb

Answer 9

Ratio of height gained over horizontal distance travelled expressed as a percentage

Question 10

An a/c travels a horizontal distance of 8000ft and gains 500ft of altitude what is the gradient of climb?

Answer 10

6.3 %
500/8000 = 0.063 (x100 = 6.3%)

Question 11

Gross flight path

Answer 11

The flight path it is assumed the a/c will follow when flown in a particular config in accordance with specified procedures (the flight path is established from the a/c’s certification performance data and can be accepted as the average fleet performance for the a/c type)

Question 12

Net flight path

Answer 12

Is the gross flight path reduced by specified margins, these margins make allowance for the reduced performance that could be expected in an emergency situation in unfavourable conditions i.e severe turbulence

Question 13

LDA

Answer 13

Landing distance available is the length of runway that is declared by the aerodrome operator as available and suitable for the ground run of an a/c, it starts at the landing threshold

Question 14

Landing threshold

Answer 14

Is the beginning portion of the runway declared usable for landing.

Question 15

LDR

Answer 15

Landing distance required is the horizontal distance measured from a point 50ft above the runway threshold to the point where the a/c can be brought to a complete stop with max braking (it is assumed that the approach to the runway is steady and that the speed at the 50ft point / screen height over the threshold is not less than 1.3vs or the speed published in the flight manual, whichever is greater)

Question 16

Dry runway

Answer 16

Means it’s not wet or contaminated and includes a paved runway that has been specifically prepared with grooves / porous pavement to retain effectively dry braking action even when liquid moisture is present

Question 17

Wet runway

Answer 17

Is a runway with suffiecnt moisture on its surface to cause it to appear reflective without significant areas of standing water

Question 18

Contaminated runway

Answer 18

More than 25% of the runway surface area within the required length + width is covered by surface water, slush or loose snow more than 3mm deep or that there’s ice on any part of the runway surface area

Question 19

Drift down

Answer 19

Means a gradual descent by an a/c with one engine inoperative to an altitude at which it can comply with one-engine inoperative enroute climb performance requirements

Question 20

What factors effect takeoff and landing performance

Answer 20

• Air density
• Weight
• Wind
• Runway slope
• Runway surface + condition
• Anything else listed listed under the performance graphs / tables in the a/c manual

Question 21

Air density on effect takeoff and landing performance

Answer 21

It effects both aerodynamic (airframe) and engine performance. A lower air density at aerodrome level means:
- TODR increases, this is because firstly to reach lift off IAS the TAS (and GS) must be higher than normal and thus a longer ground run is required to accelerate to this higher TAS (i.e aerodynamic performance has been reduced) and secondly there will be a reduction in thrust / power output at the take-off RPM setting
- LDR also increases but not as much, as touchdown speeds for the same IAS are higher and so for the same amount of braking longer landing distances are required

Question 22

Weight effect on takeoff and landing performance

Answer 22

As weight increases:
- TDR increases due to acceleration at T/O power being lower and safe lift off (1.2Vs) is increased
- LDR increases as IAS at touchdown is higher and a given amount of braking is less effective at slowing the a/c

Question 23

Wind effect on takeoff and landing performance

Answer 23

Tailwinds increase both landing and takeoff performance (and headwinds reduce it)

Question 24

Runway slope effect on takeoff and landing performance

Answer 24

Downslope will decrease TDR and increase LDR (vice versa for upslope)

Question 25

Runway surface effect on takeoff and landing performance

Answer 25

Takeoff and landing performance data in the a/c manual will normally be based off a paved, level, dry runway, generally any other surface e.g. grass, gravel, rolled earth will increase TDR and LDR because there is increased wheel drag during T/O and a reduction in braking effectiveness during landing

Question 26

Wet / contaminated runway effect on landing performance

Answer 26

There is an increase in LDR due to decreased braking effectiveness (usually LDA will need to be at least 115% of LDR calculated for dry conditions)

Question 27

Pressure altitude

Answer 27

Is the altitude in the ISA that has the same pressure as actual altitude

Question 28

Calculating PA

Answer 28

PA = ( (1013 - QNH) x 30) + elevation

Question 29

Steps for calculating DA

Answer 29

1. Calculate the ISA temp at PA using the temp lapse rate: ISA temp at PA = 15 - (2 x every 100oft of alt) 2. Calculate the temp deviation from the ISA 3. Calculate the height deviation, an adjustment of 120ft applies per 1°C 4. Add this height deviation to PA if ambient temp is warmer than ISA or subtract it from PA if ambient temp is colder than ISA

Question 30

Density altitude

Answer 30

Reflects the influence of temp on PA

Question 31

Wind component graphs

Answer 31

Is used to calculate headwind + crosswind component, which is then inputted into takeoff and landing graphs + p-chart

Question 32

How to use a wind component graph

Answer 32

Calculate the angle between the wind direction and the direction of the runway and plot this on the the appropriate radiating line at the point which intersects the wind velocity arc. Where this plotted point intersects the x-axis will be the crosswind component and where it intersects the y-axis will be the headwind component

Question 33

Wind component graph - what to do if the angle between the runway heading and wind is greater than 90°

Answer 33

It will be a tailwind component and some graphs may not allow you to plot this, in this case use the reciprocal runway heading and designate the result as a tailwind, the crosswind component remains the same

Question 34

Runway slope and surface correction factors

Answer 34

Are given in part 135 (note: the older style p-charts take into account runway slope and correction factors so you don't need to apply the correction factors)

Question 35

Applying runway surface correction factors

Answer 35

Will be given in a table format and you multiply the distance required by the correction factor given in the table

Question 36

Applying runway slope correction factors

Answer 36

For every 1% upslope (up to 3% max upslope) you increase TDR by 5% or decrease LDR by 5% (vice versa for downslope)

Question 37

Takeoff P-chart

Answer 37

1. using PA + temp box find DA at the intersection point of the 2 2. exiting the box right draw a straight line to the next box until you hit the AUW line 3. Exiting the box up draw a straight line until you hit the surface type line 4. exiting the box right draw a straight line to the slope 0% reference mark 5. track parallel to the curved lines until slope is met 6. exiting the box right draw a straight line until the wind 0 reference line is met 7. track parallel to the curved lines until the headwind component is met 8. using a straight line exit the graph to the right and where the line exits will be the distance required

Question 38

Landing p-chart

Answer 38

Similar to takeoff except aerodrome elevation is the start point (then weight box, surface, slope, wind)

Question 39

Single engine inoperative service ceiling graph

Answer 39

When an engine fails during high-altitude cruise flight in a twin engine s/c there is often a loss of height known as drift down to the single engine ceiling. This ceiling mainly depends on the AUW of the a/c and the DA at which it can operate with one engine. When planning a flight the AUW is adjusted if necessary to enable the a/c to maintain a min safe alt above terrain should one engine fail.

Question 40

Calculating max AUW if the single engine ceiling is known

Answer 40

1. calculate PA and using this value on the y -axis draw a horizontal line across the graph 2. establish what temps you are likely to encounter: using the given temps at selected altitudes calculate the temp deviation from the ISA temp at those altitude's, use this to find the average ISA temp deviation 3. mark where the PA intersects the ISA temp deviation line 4. estimate the AUW by interpolating where the mark sits between the 2 AUW lines either side of it

Question 41

Calculating the single engine ceiling if max AUW is known

Answer 41

1. establish the average temp deviation from ISA 2. draw a line estimating where the AUW of the a/c will lie (using the adjacent AUW lines on the graph) 3. mark where the ISA line and AUW line intersect and where this point intersects the y-axis will give PA 4. convert the PA to actual alt / elevation using QNH