Take-off Performance Flashcards
What is TORA
TAKE OFF RUN AVAILABLE
What is TODA
TAKE OFF DISTANCE AVAILABLE
What is ASDA
ACCELERATE-STOP DISTANCE AVAILABLE
What is EDA
EMERGENCY DISTANCE AVAILABLE
What is QDM
RUNWAY MAGNETIC HEADING
What is TODA made up of
What is ASDA made up of
What is the V speed for best climb rate
Vy
What is the V speed for best climb angle
Vx
REMEMBER: Think of the letter X having multiple angles
What is the definition of best rate of climb (Vy)
Best altitude gain per unit of time
What are the 2 differences of best angle of climb (Vx) to best rate of climb (Vy)
REMEMBER: Steeper ANGLE, bigger gradient, more work!
- Slower ROC
- Slower airspeed
With a headwind on take-off
What happens to the;
1. Ground run
2. Time to get airborne
3. Climb angle
- DECREASES
- DECREASES
- INCREASES (i.e. steeper)
With a tailwind on take-off
What happens to the;
1. Ground run
2. Time to get airborne
3. Climb angle
- INCREASES
- INCREASES
- DECREASES (i.e. shallower)
Generic performance factors
What is the % and factor increases for a tailwind component of 10%
- 20%
- 1.2
Calculate the cross wind and headwind component on the CPR-1
Runway 06. Wind 040° 22 kts
Crosswind - 8 kts
Headwind - 21 kts
- Center dot to zero
- Plotting disc set to wind direction i.e. 040°
- Mark wind down from center dot i.e. 22 kts
- Rotate plotting disc to runway heading i.e. 060°
- Crosswind component is how much the dot has moved from center
- Headwind component is how much down from zero the dot reads
LINK HERE
With small amount of flaps configured for take-off
What happens to;
1. Lift-off speed
2. Take-off safety speed
3. Drag
4. Ground run
5. Time to get airborne
6. ROC
- REDUCED
- REDUCED
- INCREASED
- DECREASED
- DECREASED (i.e. airborne sooner)
- DECREASED (i.e. shallower)
With an increase in mass on take-off run
What happens to;
1. Acceleration
2. Ground run
3. ROC
- DECREASED (i.e. slower)
- INCREASED (i.e. longer)
- DECREASED (i.e. shallower)
The POH performance figures are based on what runway conditions
- Level and Dry
- Hard Paved
A deviation away from a hard paved surface for take-off can affect performance in what 3 areas
- Rolling friction
- Acceleration
- Energy dissipation through oleos
What danger should a pilot be aware of where wheel spats are fitted when planning for a take-off run
INCREASED FRICTION
Due to grass and mud collecting in wheel spat
What is the % and factor increases for dry grass up to 20cm
- 20%
- 1.2
REMEMBER: 1.2 = 20%
What is the % and factor increases for wet grass up to 20cm
- 30%
- 1.3
REMEMBER: 1.3 = 30%
What is the % and factor increases for soft ground or snow
- 25% or more
- 1.25+
With an increase up-slope take-off run
What happens to;
1. Acceleration
2. Ground Run
3. ROC
- DECREASED (i.e. slower)
- INCREASED (i.e. longer)
- REDUCED (to 50 ft)
What is the % and factor increases for a 2% up-slope runway
- 10%
- 1.1
The rule of thumb for aircraft climb
Must be able to climb at ____ angle of the runway slope
TWICE
calculating runway gradient as a %
Runway 24 - 06
R’way 24 elevation: 301 ft
R’way 06 elevation: 287 ft
Runway length = 3700 meters
Calculate the gradient
Landing on runway 24
(neg) -0.11 %
301 - 287 = 14 ft
Convert 3700 meters into feet = 3700 x 3.28 = 12,136 ft
(14 / 12,136) x 100 = 0.11 %
Multiplied by 100 to make it a percentage
Since we land on runway 24, and it slopes DOWN to runway 06, this is a NEGATIVE slope
Calculating runway gradient as a %
Runway 09 - 27
R’way 09 elevation: 246 ft
R’way 06 elevation: 294 ft
Runway length = 850 meters
Calculate the gradient
Take-off runway 09
+1.72%
294 - 246 = 48 ft
Covert 850 meters into feet = 850 x 3.28 = 2,788 ft
(48 / 2790) x 100 = 0.017
Multipled by 100 to make it a percentage
Since we take off on runway 09, and it slopes UP to runway 27, this is a POSITIVE slope
Generic performance factors
The safety factor that MUST be applied as stipulated by CAA for take-off is ____. This takes into account what 4 factors
- 1.33
- Piloting skills
- Engine
- Airframe
- Unseen Circumstances
Non perfect piloting skills
Worn engine
Dirty airframe
Calculate the ground roll using interpolation of the following values
Pressure Alt | 10℃ | 20℃
2000 | 840 | 910
3000 | 925 | 1000
Ground roll in ft for pressure altitude 2600 ft and temperature of 18℃
950 ft
Determine 18℃ and 2600 ft.
2600 ft is between 2000 and 3000, 18℃ is between 10℃ and 20℃
For 18℃ @ 2000 ft; 910 - 840 = 70
There are 10℃ difference between 10℃ & 20℃. 70 / 10 = 7 ft per ℃
7 x 8 = 56 ft (8℃ difference between 10℃ and 18℃)
840 + 56 = 896 ft
Repeat for 18℃ @ 3000 ft = 985 ft
For 2600 ft pressure altitude, now we have take off lengths for 2000 ft and 3000 ft @ 18℃, use the same method to determine 2600 ft.
985 - 896 = 89 ft
89 / 1000 (1000 ft difference between 2000 and 3000) = 0.089
0.089 x 600 ft (difference between 2000 ft and 2600 ft) = 53.4 ft
5.4 + 896 = 949.4 ft
Practical take-off calculations
Instead of using interpolation, what can a pilot do for quick take-off performance calculations if, for example, the temperature is 13℃ and your POH gives 10℃ and 20℃ in the performance table
WORSE CASE FIGURES
Use 20℃ for calculations
Since 13℃ sits between 10℃ and 20℃, 20℃ is the worse case scenario. This can be used to perform take-off calculations.
Use the same worse case for altitude calculations also i.e airfield is 200 ft and your POH gives 1000 ft, use 1000 ft.
If after using worse case figures the end figure still falls within runway distance available, you are safe to go
Calculating obstacle clearance for grass strip
Where TODA is not necessarily stated, but the runway length is, to calculate a distance to/from 50ft, what must the figures fit inside of
RUNWAY LENGTH
Where no Clearway distance is included since no TODA is given, and you know the runway is 1000m, you must be able to obtain 50 ft clearance before the end of 1000m i.e. you must have reached over 50ft before you have cleared the end of the runway run.
