Aeroplane Performance Legislation, Definitions and Terminology
The regulatory frame
Brunei DCA certification and operations rules mirror the ICAO Annex 6 and EASA/CS-23 performance framework. A CPL candidate must know that performance requirements are prescriptive (the operator must be able to show compliance before every flight) and are expressed as scheduled performance, not demonstrated best effort. Key terms: Take-off distance available (TODA) - runway plus clearway; take-off run available (TORA) - runway only; accelerate-stop distance available (ASDA) - runway plus stopway; landing distance available (LDA) - normally the runway, reduced if a displaced threshold exists. Clearway must be under the operator's control, clear of obstacles, and sloped within limits; stopway must be capable of supporting the aeroplane without structural damage.
Declared distances and the 'available' trap
Questions love to give a runway with a displaced threshold and a clearway. Remember: a displaced threshold reduces LDA but not TORA/TODA/ASDA at the far end; a clearway increases TODA only; a stopway increases ASDA only. Never add clearway to ASDA or stopway to TODA.
Performance classes and masses
Know MTOM, MLM, MZFM, MTOW-limited, performance-limited take-off mass (PLTOM) and regulated take-off mass (RTOM) - the lowest of field-length, obstacle, climb and tyre/speed limits. Definitions such as V1, VR, V2, VLOF, VREF, VAPP and the meaning of balanced field length must be exact: balanced field length is where the accelerate-stop distance equals the take-off distance to 35 ft.
Worked rule of thumb
If TORA = 2,000 m, clearway = 150 m, stopway = 60 m and threshold displaced 100 m: TODA = 2,150 m, ASDA = 2,060 m, LDA = 1,900 m. Use each figure only in its own calculation.
Traps
Watch for 'clearway slope 1.5%' (limit is 1.25%), 'stopway included in TODA', and questions mixing scheduled with actual masses.