Definition
The overall difference between a starting value and an ending value after all increases and decreases have been combined. In the energy-management context of the Airplane Flying Handbook, it refers to the resulting change in an airplane's energy state (altitude, airspeed, or both) once the competing effects of thrust, drag, and pitch have offset one another.
Plain English
The final result after everything has added up. If something goes up by 200 and then down by 50, the net change is +150.
Context Anchor
Seen in energy-management discussions when comparing whether the airplane is gaining, losing, or holding speed, altitude, or overall energy.
Derivation
From the older accounting use of 'net,' meaning what is left after deductions. Pairing it with 'change' just means the leftover amount of change once gains and losses are combined.
Why Pilots Care
Knowing the net change tells a pilot whether the airplane will have surplus energy for a maneuver or will need to trade altitude for speed, or vice versa, without separate calculations for each force.
Grounding Statement
If thrust adds more energy than drag removes over a given distance, the net change is positive and the airplane gains either altitude or speed.
Intuition Check
Net change does not mean every small change by itself. It means the final overall difference after increases and decreases are considered together.
Example Sentence 1
After the climb and level-off, the net change in altitude was 1,500 feet.
Example Sentence 2
The pilot adjusted pitch attitude to produce a zero net change in energy and thereby held both altitude and airspeed constant in level flight.