CPL Meteorology · Mock exam

At an aerodrome with elevation 2,000 ft and QNH 1013 hPa, the OAT is 35°C. The ISA temperature at 2,000 ft is 11°C. What is the ISA deviation and what is the primary performance implication?

• A.ISA −24°C — colder than standard
• B.ISA +24°C — reduced air density raises density altitude and degrades take-off and climb performance
• C.ISA +0°C — no correction needed; OAT equals ISA so all performance figures apply directly
• D.ISA +24°C — aircraft operates in warmer air with higher molecular speed; engine power output is significantly increased by the additional thermal energy