Performance
Performance examines whether the aircraft can safely take off, climb, cruise and land within the available distances and gradients. Kuwait's hot climate and occasional dust make density altitude and runway condition central issues.
Core concepts
- Declared distances: TORA, TODA, ASDA and LDA. Know which obstacle or stopway each includes.
- V speeds: V1 is the decision speed; VR is rotation; V2 is takeoff safety speed. V1 is not a speed at which the aircraft is guaranteed to fly.
- Density altitude combines pressure altitude and temperature. High temperature, high pressure altitude and high humidity reduce performance.
- Takeoff and landing distances must be factored for wind, slope, runway surface, contamination and obstacle clearance as required by Kuwait CARs and the aircraft manual.
- Climb gradients, WAT limits, derated thrust and assumed temperature all trade performance for engine life.
- Dispatch requires the aircraft to meet the applicable takeoff, en-route and landing performance requirements before departure.
Worked example
Pressure altitude is 2,000 ft and OAT is 45°C. ISA temperature at 2,000 ft is about 11°C, so the ISA deviation is +34°C. Using the common approximation of 120 ft per °C, density altitude is about 2,000 + (120 × 34) = 6,080 ft. Takeoff distance and climb gradient must be read from the performance chart at that density altitude, not at 2,000 ft.
Traps
Using pressure altitude instead of density altitude; applying a tailwind as if it were a headwind; ignoring contaminated-runway corrections; and treating V1 as a fixed speed for every mass and runway.