PLT313: Loading Terminology and Limitations
What code PLT313 covers, why the FAA tests it, and how to study Loading Terminology and Limitations before your checkride.
Recall loading - limitations / terminology
What this means for your checkride
Loading terminology describes how an airplane is balanced: the datum is a reference point, the arm is the distance from the datum to an item, and the moment is weight times arm. Total moment divided by total weight gives the center of gravity, which must fall within published limits.
Every weight and balance computation uses this vocabulary, so the FAA tests the terms datum, arm, moment, and station and the limitations they define.
Arm and station are measured from the datum, which is an arbitrary reference chosen by the manufacturer, not necessarily the nose. Getting the reference wrong throws off every moment.
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.