FAA Sport Pilot Airplane (SPA)Airspace and NavigationMedium

A pilot is flying VFR at 17,500 feet MSL over the contiguous United States. What class of airspace contains this altitude?

  1. AClass A airspace, since it begins at 17,500 feet MSL
  2. BClass B airspace, since it extends to 18,000 feet MSL nationwide
  3. CClass E airspace, since it extends up to but not including 18,000 feet MSL
  4. DClass G airspace, since it is above the Class E floor
Show answer & explanation

Correct answer: C. Class E airspace, since it extends up to but not including 18,000 feet MSL

Class E airspace extends from its various floors up to, but not including, 18,000 feet MSL across the contiguous United States. Class A airspace begins exactly at 18,000 feet MSL, so 17,500 feet MSL is still within Class E.

Why the other options are wrong

  • A. Class A begins at 18,000 feet MSL, not 17,500 feet.
  • B. Class B is localized around major airports, not a nationwide layer to 18,000 feet.
  • D. Class G airspace only exists at lower altitudes, not at 17,500 feet.

Class E Ceiling

Class E airspace in the contiguous United States extends upward to, but not including, 18,000 feet MSL, where Class A airspace begins.

  • Class A begins at exactly 18,000 feet MSL
  • Class E floor varies by location (700 AGL, 1,200 AGL, surface)
  • IFR flight plan or clearance required in Class A
  • VFR is generally not conducted in Class A airspace

Memory trick: Eighteen-thousand: E stops, A starts

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