Definition
121.103 refers to 14 CFR Part 121, Section 103 — the section of the Federal Aviation Regulations covering the navigation facilities that an air carrier may use when operating under Part 121 (scheduled airline operations). It specifies that en route navigation must be conducted using facilities approved by the Administrator, including ground-based navigation aids, area navigation (RNAV) systems, and other approved means.
Plain English
It is the airline rule that says which navigation systems and ground-based aids an airline is allowed to use to find its way from one airport to another. The airline can only use navigation methods the FAA has approved.
Context Anchor
Seen in FAA handbooks or training material when a regulation is cited to support a requirement about navigation facilities or air carrier operations.
Why Pilots Care
Ensures air carrier flights maintain the navigation capability required for safe and legal arrival procedures.
Intuition Check
Do not read 121.103 as a radio frequency just because it looks like one. In this context, it is a regulation section number.
Example Sentence 1
The airline's operations specifications list the navigation systems approved under 121.103 for use on transoceanic routes.
Example Sentence 2
During the briefing the captain noted that the RNAV approach complied with the standards in 121.103.