Class E base where no base is charted

Remote Pilot (Part 107) practice question 6 of 21 on Airspace / Classification. ACS element UA.II.A.K1d · difficulty: standard. Want to answer it in a timed quiz? Use the Remote Pilot (Part 107) practice mode.

Question bank updated 2026-09-22

QUESTIONA remote pilot is reviewing an area where the sectional chart does not depict any base for Class E airspace. At what altitude does Class E airspace begin in that area?

A1,200 feet AGL
B14,500 feet MSL
C18,000 feet MSL, the base of Class A

Show the answer and explanation

Correct answer: B. 14,500 feet MSL

A — incorrect 1,200 feet AGL is the Class E base in most areas, but that base is depicted on the chart; an undepicted base means 14,500 feet MSL.
B — correct The study guide states that charts depict all Class E with bases below 14,500 feet MSL, and where no base is depicted, Class E begins at 14,500 feet MSL.
C — incorrect 18,000 feet MSL is the typical top of Class E and the base of Class A, not the default Class E base.

BACKGROUND

Sectional and other charts depict all locations of Class E airspace with bases below 14,500 feet mean sea level (MSL). Where a chart does not depict a Class E base, Class E begins at 14,500 feet MSL. In most areas the Class E base is 1,200 feet above ground level (AGL), and in many other areas it is the surface or 700 feet AGL. Some Class E airspace begins at an MSL altitude depicted on the chart instead of an AGL altitude.

STUDY TIP

Treat 14,500 feet MSL as the default Class E base that applies only when the chart shows no lower base.

KEY POINTS

Charts depict Class E bases below 14,500 feet MSL.
With no depicted base, Class E begins at 14,500 feet MSL.
Common depicted bases are the surface, 700 feet AGL and 1,200 feet AGL.

SOURCES

remote_pilot_study_guide.txt Chapter 2 "Class E Airspace"

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