Center of gravity (CG) is a critical concept to ensure an aircraft is operated within safe margins and design envelopes. Since the beginning of flight training, pilots are trained to calculate CG prior to flight. In essence, center of gravity directly affects aircraft controllability, as well as the tendency for a stall to occur, along with its recovery.
A forward center of gravity is associated with a more stable aircraft. The airplane changes in pitch attitude and tends to settle back into its trimmed position when disturbed. During takeoff, rotation will feel heavier, requiring more back pressure on the flight controls. On landing, the pilot may find that they need a larger control input to raise the nose for the flare, and if the CG is very near the forward limit, it might feel like they are running out of elevator authority. Awareness is necessary to ensure the rate of descent is arrested sufficiently, while still landing in the touchdown zone.
In terms of fuel efficiency, a forward CG is less efficient. The tail must push down harder to counter the nose-heaviness, the wing has to generate a little extra lift to support not just the airplane’s weight but also the downward force from the tail. More lift means more induced drag, which means slightly higher fuel burn.
On the contrary, an aft CG is correlated to a less stable aircraft, particularly in the event of a stall.
Control inputs feel lighter, and it takes less effort to rotate for takeoff or raise the nose during landing. Instead of returning promptly to its trimmed attitude after a disturbance, the airplane may continue to oscillate or require pilot input to bring it back to level flight. As expected, given the tail does not have to push down as much, induced drag is lessened and fuel efficiency increased. In some aircraft types, this difference is significant enough that performance charts specify improved range and endurance at aft CG positions. As mentioned, stall recovery may be comprised if the CG exceeds aft limits, due to the natural nose-up tendency. In extreme cases, an aft CG can lead to a flat spin.
Both forward and aft centers of gravity can be flown safely as long as they are within the manufacturer’s published CG envelope. Typically, the aircraft AFM (with the corresponding POH) is the primary resource to determine envelope limits. In airline operations, weight and balance planning is taken precisely by load planners and dispatchers.
There are documented cases where CG shifting has led to aviation accidents. An example would be National Flight 102, in 2023, in which a Boeing 747 cargo plane crashed shortly after takeoff in Afghanistan, killing all seven crew members. The investigation found that improperly secured heavy military vehicles broke free, rolled to the back of the cargo hold, and crashed through the rear pressure bulkhead, destroying the flight control system. From loading to securing, it is imperative all cargo is properly restrained.
The center of gravity of an aircraft is not just an abstract concept to be overlooked during preflight, as it affects every phase of flight. Pilots must resist complacency and take the time to refer to manufacturers’ charts prior to every single flight, to ensure the limits are respected. Exceeding the limits, even by minimal margins, can compromise flight safety.
