Aft CG limit relative to center of pressure

Remote Pilot (Part 107) practice question 4 of 25 on Loading and Performance. ACS element UA.IV.A.K1b · difficulty: recall. Want to answer it in a timed quiz? Use the Remote Pilot (Part 107) practice mode.

Question bank updated 2026-09-22

QUESTIONTo retain flight equilibrium, where do aircraft designers fix the aft limit of the center of gravity (CG) relative to the center of pressure (CP)?

AForward of the CP for the corresponding flight speed
BAft of the CP so the nose tends to pitch up in level flight
CExactly at the CP so no pitching moment exists

Show the answer and explanation

Correct answer: A. Forward of the CP for the corresponding flight speed

A — correct The guide states that designers fix the aft limit of the CG forward of the CP for the corresponding flight speed in order to retain flight equilibrium.
B — incorrect A CG aft of the CP would create a nose-up pitching moment; designers keep the aft CG limit forward of the CP.
C — incorrect The guide does not place the CG at the CP; the aft CG limit is set forward of the CP.

BACKGROUND

An aircraft's weight is concentrated at the center of gravity (CG), while the aerodynamic lift forces act at the center of pressure (CP). When the CG is forward of the CP the aircraft tends to pitch nose down, and when the CP is forward of the CG a nose-up pitching moment results. Designers determine how far the CP will travel and fix the aft limit of the CG forward of the CP for the corresponding flight speed. This arrangement retains flight equilibrium.

STUDY TIP

Remember the pair: weight acts at the CG, lift acts at the CP, and the aft CG limit sits forward of the CP.

KEY POINTS

Weight acts at the CG; lift acts at the CP.
The aft CG limit is fixed forward of the CP.
This is done to retain flight equilibrium.

SOURCES

remote_pilot_study_guide.txt ch4 "Weight"

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