Definition
An aerodynamic effect in which an aircraft in straight-and-level cruise flight, when accelerated forward (for example by adding power), tends to pitch nose-up. The increase in airspeed produces additional lift on the wings and tail, and because lift now exceeds the weight of the aircraft, the nose rises until a new equilibrium is reached.
Plain English
When you speed up in level flight, the wings make more lift than before. Because lift is now greater than weight, the nose wants to climb until things balance out again.
Context Anchor
Seen in instrument flying when changing from one cruise airspeed to a faster one while holding altitude and heading by reference to the instruments.
Derivation
Acceleration comes from Latin roots meaning “to make faster.” Cruise means steady travel. Together, the phrase points to making the airplane faster after it is already in steady flight, not during takeoff.
Why Pilots Care
Recognizing this normal instrument behavior prevents unnecessary pitch corrections that could disturb level flight.
Grounding Statement
Picture adding power in level flight: the airplane starts moving faster, and you must keep the nose and wings controlled so the flight path stays steady.
Intuition Check
Acceleration does not mean only the takeoff roll or a sudden shove forward. Here it means any controlled increase in airspeed while already in cruise flight.
Example Sentence 1
After leveling off at cruise altitude, the pilot added power and applied slight forward pressure to counter the acceleration in cruise flight that would otherwise have caused the nose to rise.
Example Sentence 2
The student learned to ignore the brief climb indication that appears during acceleration in cruise flight and continued to fly by reference to multiple instruments.