PLT249: Fuel
What code PLT249 covers, why the FAA tests it, and how to study Fuel before your checkride.
Recall fuel - air mixture
What this means for your checkride
The mixture control sets the ratio of fuel to air. As you climb, the thinning air makes the mixture richer, so you lean it for smooth operation and efficiency; you enrich it again as you descend and for takeoff at low elevations.
Correct mixture management affects power, temperature, and fuel economy, so the FAA tests when and why to lean or enrich.
Pilots think leaning always helps. Leaning at high power or without watching temperatures can raise cylinder head temperature and cause detonation.
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.