Attitude plus power equals performance: the power-change rule of thumb

Attitude plus power equals performance. Instruments show airspeed, altitude, and rate of climb or descent. Attitude or power changes alter them.

• Same attitude gives different numbers per aircraft. Example: light aircraft at a nose-up attitude might climb 500 ft/min at 90 KT, gaining 2,500 ft in five minutes.
• Learn own aircraft's numbers.

Controls:

• Neither alone controls airspeed or altitude.
• In cruise attitude, changing airspeed needs throttle and elevator adjusted together.

Rule of thumb for a power change of one unit step (100 RPM, or 1 in Hg of manifold pressure):

Worked example:

• Level flight at 120 KT, 2,300 RPM.
• Slow to 100 KT (20 KT reduction): reduce power about 400 RPM, to 1,900 RPM.

Trap: two multipliers (5 KT vs 100 ft/min) for the same step; swapping the level and climb/descent figures is the classic mix-up.

Trap: holding altitude with power alone, or airspeed with elevator alone, instead of both together.

Practice