Definition
A specific paragraph in the Federal Aviation Regulations that requires small airplanes certified under Part 23 to provide an alternate static pressure source for instruments that depend on static pressure, when failure of the primary static source would create a hazard. In practice, this is the regulatory basis for the alternate static air valve found in many general aviation cockpits.
Plain English
It is the rule that says small airplanes must have a backup way to feed outside air pressure to instruments like the altimeter and airspeed indicator if the main opening for that air gets blocked.
Context Anchor
Seen in FAA handbook discussions of the pitot-static system, especially when explaining why an altimeter is required equipment.
Derivation
CFR stands for Code of Federal Regulations. Title 14 covers Aeronautics and Space. Part 23 covers airworthiness standards for normal-category airplanes. The number 23.2615(b)(2) is just the address: Part 23, section 2615, paragraph (b), sub-paragraph (2). Knowing this address structure helps when reading any FAR citation.
Why Pilots Care
Compliance guarantees the instruments pilots rely on for airspeed and altitude remain accurate across the normal flight envelope, directly affecting safe takeoff, cruise, and landing decisions.
Analogy
A regulation citation works like an address. “14 CFR part 23, section 23.2615(b)(2)” tells you exactly where to find one rule inside a large set of aviation regulations.
Intuition Check
Do not read “part” here as a physical aircraft part. In a regulation citation, “part” means a numbered division of the federal rules.
Example Sentence 1
The alternate static source in this trainer is installed to meet 14 CFR part 23, section 23.2615(b)(2).
Example Sentence 2
Before flight, the mechanic confirmed the airplane met 14 CFR part 23, section 23.2615(b)(2) requirements after the static port repair.