PLT031: Isobars and Winds
What code PLT031 covers, why the FAA tests it, and how to study Isobars and Winds before your checkride.
Define isobars / associated winds
What this means for your checkride
Isobars are lines on a weather chart connecting points of equal barometric pressure. Their spacing shows the pressure gradient: closely spaced isobars mean a steep gradient and strong winds, while widely spaced isobars mean lighter winds. Wind flows nearly along them.
Isobar patterns let a pilot read wind speed and direction from a surface chart, so the FAA tests how spacing relates to wind and how highs and lows are marked.
Pilots read wind as flowing straight from high to low across the isobars. Friction turns it near the surface, but aloft the wind flows nearly parallel to the isobars, faster where they are close together.
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.