PLT406: Inoperative Instruments and Equipment
What code PLT406 covers, why the FAA tests it, and how to study Inoperative Instruments and Equipment before your checkride.
Recall regulations - equipment failure
What this means for your checkride
No person may take off an aircraft with inoperative instruments or equipment installed unless operation is authorized under an approved Minimum Equipment List, or, absent an MEL, the inoperative items are not required for the flight and are removed or deactivated and placarded as inoperative. Items required by the equipment rules, an airworthiness directive, or the type certificate may not simply be ignored.
It defines exactly when an aircraft with a broken item may still be flown legally.
An inoperative item does not always ground the aircraft, but it also cannot just be ignored; it must be handled under an MEL or the deactivate-and-placard process.
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.