PLT121: Aircraft Loading Computations
What code PLT121 covers, why the FAA tests it, and how to study Aircraft Loading Computations before your checkride.
Recall aircraft loading - computations
What this means for your checkride
Loading computations confirm the airplane is within its weight and center-of-gravity limits. Each item's weight times its arm, the distance from the datum, gives a moment; total moment divided by total weight is the CG. Manufacturers provide a loading graph and moment table so you can do this without raw multiplication.
A load outside the weight or CG limits changes stability and control, so the FAA tests both the arithmetic and the ability to read the manufacturer's loading graph and moment table.
Reading the loading graph in the wrong units, or leaving fuel in gallons instead of converting to pounds, can make an unsafe load look legal on paper.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.