Regulation Text
No person may operate an aircraft in controlled airspace under IFR unless that person has—
(a) Filed an IFR flight plan; and
(b) Received an appropriate ATC clearance.
The short answer
(14 CFR § 91.173) No person may operate an aircraft in controlled airspace under IFR unless that person has filed an IFR flight plan and received an appropriate ATC clearance. Both conditions — the filed flight plan and the clearance — must be met before IFR operations in controlled airspace.
Research Notes
Common Questions
What is required to fly IFR in controlled airspace?
Two things: a filed IFR flight plan and an appropriate ATC clearance. Both are required before operating IFR in controlled airspace.
“No person may operate an aircraft in controlled airspace under IFR unless that person has— (a) Filed an IFR flight plan; and (b) Received an appropriate ATC clearance.” — 14 CFR § 91.173
Is filing a flight plan alone enough to fly IFR?
No. Filing an IFR flight plan is necessary but not sufficient — the pilot must also receive an appropriate ATC clearance.
“...unless that person has— (a) Filed an IFR flight plan; and (b) Received an appropriate ATC clearance.” — 14 CFR § 91.173
Angle of Attack is an aviation flight-training brand founded by Chris Palmer, a two-time Master Aviation Educator and Gold Seal CFI. We decode the FARs so pilots understand not just the words, but what they mean in the cockpit.
AOA's Decoded pages are plain-English interpretation for training and reference. They are not legal advice and do not replace the official regulation. Always confirm current requirements against the authoritative source before acting.