Definition
An airplane certified under Title 14 Code of Federal Regulations (14 CFR) Part 25, which contains the airworthiness standards for transport category aircraft. These are typically larger multi-engine airplanes — most commonly turbine-powered — used in airline, cargo, and large business jet operations. Part 25 imposes more demanding design, performance, and safety standards than the standards for smaller airplanes (Part 23), including specific takeoff and one-engine-inoperative (OEI) climb performance requirements, accelerate-stop distance criteria, and obstacle clearance margins.
Plain English
A larger airplane — usually an airliner, freighter, or large business jet — that was built and approved to a stricter set of FAA rules than smaller airplanes. Those stricter rules cover how it must perform on takeoff, how it must climb if an engine quits, and how much room it must leave between itself and obstacles.
Context Anchor
Seen in departure, obstacle-clearance, and performance-planning discussions where the airplane’s approved engine-out takeoff data is used.
Derivation
‘Part 25’ refers to the specific section number in Title 14 of the Code of Federal Regulations that governs these aircraft. ‘Transport category’ comes from the regulatory practice of grouping aircraft into categories by intended use and size — ‘transport’ signaling airplanes built to carry passengers or cargo in scheduled or commercial operations. Knowing the term is just a regulatory address (Part 25) and a category label (transport) helps demystify what otherwise sounds like a special aircraft type.
Why Pilots Care
Only Part 25 airplanes are required to meet the specific one-engine-inoperative climb gradients and obstacle-clearance profiles used in instrument departure planning.
Intuition Check
Do not read “transport” as simply “an airplane that transports people.” Here, “transport category” means a specific FAA certification class with required design and performance standards. Do not read “Part 25” as a part of the airplane. It is a part of the federal aviation regulations.
Example Sentence 1
The published OEI obstacle clearance requirements in this section apply to Part 25 transport category airplanes, not to smaller general aviation aircraft.
Example Sentence 2
Certification data for a Part 25 transport category airplane includes the runway length needed to meet all-engine-operating and one-engine-inoperative requirements.