Aircraft
Aircraft
Aircraft questions test the operational characteristics that change ATC decisions: wake category, performance, speeds, systems and failure modes. You do not need to certify the aircraft, but you must predict what it will do.
Core rules
- ICAO wake turbulence categories are Light (MTOW ≤7,000 kg), Medium (7,000–136,000 kg), Heavy (≥136,000 kg) and Super (A380). Separation depends on leader/follower pairs.
- Approach speed and runway occupancy vary widely; a light aircraft may need more spacing behind a heavy than another heavy.
- TCAS provides traffic advisories and resolution advisories; a controller must not issue instructions that conflict with an RA.
- Transponder and altimeter status affect surveillance; Mode C altitude is pressure altitude referenced to 1013.2 hPa.
- Anti-ice and de-icing affect climb performance and holdover time.
Worked example
A Boeing 737-800 has an MTOW of about 79,000 kg, so it is Medium. An Airbus A380 is Super. If the 737 follows the A380 on final, the controller applies the Super/Medium wake pair, not the ordinary Medium/Medium 3 NM radar minimum. The reason is that wake strength depends on weight, wingspan and speed; the follower’s ability to resist wake does not change the leader’s category.
Traps
Do not classify by physical size alone; MTOW defines the category boundary. Do not assume every widebody is Heavy; category is MTOW-based. Do not ignore TCAS RAs when issuing a climb or descent. Do not treat Mode C as QNH altitude.