PLT338: Pneumatic Systems
What code PLT338 covers, why the FAA tests it, and how to study Pneumatic Systems before your checkride.
Recall pneumatic system - operation
What this means for your checkride
A pneumatic, vacuum or pressure, system spins the gyroscopic instruments, the attitude and heading indicators, using airflow rather than electricity. An engine-driven pump creates the airflow and a gauge shows suction. If the pump or system fails, those gyros become unreliable, so partial-panel technique matters.
Many airplanes run key gyros on vacuum, so the FAA tests how the pneumatic system works and what fails when it does.
Pilots assume all instruments fail together. A vacuum failure quietly takes the attitude and heading indicators while the electric turn coordinator, altimeter, and airspeed keep working, so recognizing it early is critical.
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.