Which statement about takeoff distance relative to one-engine inoperative distance is true?

• A. Takeoff distance must be at least 15 percent less than the one-engine inoperative distance.
• B. Takeoff distance must be 15 percent more than the one-engine distance.
• C. Takeoff distance must be equal to the one-engine distance.
• D. Takeoff distance is not influenced by engine failures.

Answer: (A)

When an engine fails during takeoff, the airplane has less thrust and will need more runway to reach takeoff speed and establish a climb. That means the takeoff distance with one engine inoperative is longer than the takeoff distance with all engines operating. The typical rule of thumb used in training is that the normal takeoff distance is about 15% less than the distance with one engine inoperative. So, the statement that takeoff distance must be at least 15% less than the one-engine inoperative distance correctly reflects this relationship. The other options misstate the relationship (they imply the opposite, that takeoff distance is longer when all engines are working, that they’re equal, or that engine failures don’t affect takeoff distance), which isn’t true because reduced thrust from an engine inoperative increases the required runway.