PLT137: Environmental Control Systems
What code PLT137 covers, why the FAA tests it, and how to study Environmental Control Systems before your checkride.
Recall aircraft systems - environmental control
What this means for your checkride
Environmental control systems keep the cabin livable: heating and cooling for temperature, pressurization to hold a comfortable cabin altitude as the airplane climbs, and oxygen as a backup or for unpressurized high-altitude flight. On many airplanes bleed air from the engines drives heating and pressurization.
A failure of the environmental system directly threatens the occupants, so the FAA tests how pressurization, heating, and oxygen work together and what happens when one fails.
Pressurization does not fill the cabin with pure oxygen; it raises the cabin pressure so the ordinary air holds enough oxygen, which is why a rapid decompression still requires supplemental oxygen.
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.