The term describing the altitude where the rate of climb is zero is ____.

• A. Absolute ceiling
• B. Service ceiling
• C. Cruise altitude
• D. Maximum endurance altitude

Answer: (A)

The main idea is climb performance and ceilings: the altitude at which you can no longer climb, because there is no excess power to overcome drag, is the absolute ceiling. At lower heights the engine can produce more power than needed to hold level flight, giving you excess power to climb. As you gain altitude, power available drops while drag and required power for level flight change, until the excess power falls to zero. At that point the rate of climb is zero, so you can’t ascend any higher. Beyond this, you can’t maintain level flight or climb with the power you have. The other terms describe different limits or flight phases: the service ceiling is where the rate of climb becomes very small, cruise altitude is simply the chosen level for steady flight, and maximum endurance altitude is about staying aloft the longest with given fuel, not climbing capability.