Which term describes long-period oscillations around the lateral axis characterized by slow pitch and airspeed changes?

• A. Pilot report (PIREP)
• B. Pilot in command (PIC)
• C. Phugoid oscillations
• D. P-factor

Answer: (C)

Longitudinal oscillations about the lateral axis that unfold slowly, with gradual changes in pitch and airspeed, are known as phugoid oscillations. These involve a transfer of energy between potential and kinetic forms: when the airplane climbs, it loses speed and pitches nose up, then as it descends it gains speed and pitches down. The result is a long-period motion where the aircraft slowly trades altitude for speed and back again, with the pitch changes being relatively gentle and the motion persisting for many cycles unless damped by aerodynamic forces and propulsion.

P-factor is about asymmetric propeller thrust creating a yawing tendency at high angles of attack, not a long-period pitching oscillation. A pilot report and the pilot in command are related to information and responsibility, not to specific flight-trajectory modes or oscillations.