Definition
The optimum planing attitude of a seaplane or floatplane during takeoff, in which the floats or hull ride on the rear portion (the step) only, minimizing water drag and allowing the aircraft to accelerate to liftoff speed.
Plain English
The point during a water takeoff when the seaplane is skimming on just the back part of its floats, with the front raised out of the water. This is the position where it slides through the water with the least resistance and can keep building speed to fly.
Context Anchor
Encountered during seaplane training, especially during water takeoffs and high-speed taxi on lakes, rivers, or bays.
Derivation
The 'step' is a deliberate notch or break built into the bottom of a float or flying-boat hull. When the aircraft reaches the right speed and attitude, the water breaks cleanly at this notch, and the float rides only on the rear portion behind the step. 'Step position' simply names the attitude where this is happening.
Why Pilots Care
Maintaining the correct step position shortens takeoff distance, prevents porpoising, and reduces the risk of water handling incidents.
Analogy
Like a speedboat that initially pushes through the water bow-up, then settles onto a flatter, faster planing attitude once it's moving quickly enough — the seaplane on the step is doing the same thing.
Intuition Check
Do not read “step” as a place to put your foot. In this context, the step is a shaped break in the bottom of a float or hull that helps the seaplane skim on the water.
Example Sentence 1
Once the floats came up onto the step, the airplane accelerated quickly and lifted off the lake.
Example Sentence 2
If the seaplane is too far forward of the step position, drag increases and the takeoff run lengthens.