Before boarding a plane, all the cargo must be calculated and place properly to avoid accident occurring. Just like the video of overweight aircraft where the pilot miscalculates the weight of the cargo and caused the aircraft to be overloaded to the aft. This entire thing happened because of the CG of the aircraft moved backward beyond its range.
I keep thinking about one thing. Inside the aircraft, there are a lot of human beings with different weight. As we know, every passenger and crew keeps moving in the aircraft. Can this moving object cause danger to the aircraft?
How can we relate the center of gravity movement with the aircraft stability?
Animation of Air Midwest Flight 5481 accident
Yes, passengers moving up and down the aisle could tip the aircraft nose up and down very slightly while it is cruising along in the air.
In reality, most modern planes have built-in safety buffer to compensate for this; the computers would offset the imbalances by making slight adjustments to the power or control surfaces. Where no such automation exists, then the pilots may have to offset these changes on the flight controls by manually trimming the plane.
Besides passengers’ movement, the other factor that affects the center of gravity (CG) shifting is fuel being consumed. In some planes like the Airbus A330/A340, this is automatically done by fuel being trimmed or compensated to ensure that the CG is within a safe range. If the nose is too heavy, the fuel flows to the back at the tail plane and if too tail heavy, it would flow to the front.
However, if smaller airplane is really off balance, the pilots would have a harder time dealing with this situation. For example, those that are very tail heavy could cause the plane to crash during the approach to land or take off whilst others could aggravate into tail strikes!
In normal cases, all planes are properly trimmed before take off and landing as there are no passengers moving about because they are supposed to be at their seats securely fastened to their safety belts.
If you like what you read, more stories are found in my book LIFE IN THE SKIES (Preview here) and you can purchase a copy here. To check for any latest updates or postings, you can follow my Twitter at @CaptKHLim or Facebook here