Performance
What this domain tests
Performance tests takeoff, landing and climb planning: declared distances, V speeds, obstacle clearance, and the effect of mass, temperature, pressure, wind, runway slope and contamination. Mauritius operations add hot, humid and sometimes wet-runway conditions.
Core rules
- Declared distances: TORA is the takeoff run available; TODA = TORA + clearway; ASDA = TORA + stopway; LDA is the landing distance available.
- V1 is the decision speed; before V1 a failure means stop, after V1 continue. VR is rotation and V2 is the takeoff safety speed.
- Takeoff distance increases with mass, altitude, temperature and tailwind; it decreases with headwind and lower temperature. A contaminated runway increases rolling resistance and reduces braking.
- Climb requirements: the second-segment gradient is the critical obstacle-limiting case for twins, typically 2.4% under CS-25/FAR 25.
- Landing distance is factored: the required landing distance is the actual distance divided by 1.67 for a dry runway, or as prescribed.
Worked example
TORA 2,800 m, clearway 150 m, stopway 60 m. TODA = 2,950 m; ASDA = 2,860 m. If the AFM takeoff distance is 2,700 m and the obstacle-limited distance is 2,900 m, the takeoff is legal only if the TODA used is at least 2,900 m and all other limits are met. Here 2,950 m works.
Traps
Mixing TODA with TORA; forgetting that clearway cannot be used for landing; applying a tailwind component in the wrong direction; ignoring the effect of a downslope on accelerate-stop distance.
Key habit
Always draw the runway strip with TORA, clearway and stopway marked, then place each number on it.