Definition
A five-digit number assigned to a specific WAAS-enabled instrument approach procedure that, when entered into the GPS or flight management system, automatically loads that exact approach into the unit. The channel number uniquely identifies a single approach to a particular runway end at a particular airport.
Plain English
A short ID number that pulls up one specific WAAS approach in your navigation unit, so you don't have to scroll through menus to find and load it.
Context Anchor
Seen on WAAS-enabled approach charts, including LPV approaches, and used when selecting an approach in an approved GPS navigator.
Derivation
WAAS stands for Wide Area Augmentation System, the FAA satellite-based system that improves GPS accuracy. 'Channel' here is borrowed from radio usage — just as a radio channel selects one specific frequency, a WAAS channel number selects one specific approach.
Why Pilots Care
Ensures the receiver applies the correct satellite corrections so the approach meets the required accuracy and integrity for LPV minima.
Intuition Check
Do not treat the WAAS channel number like a radio frequency. It is a database selection number for an approach, not something you tune on a communication radio.
Example Sentence 1
The crew entered the WAAS channel number from the approach plate to load the LPV approach to Runway 27.
Example Sentence 2
Selecting the correct WAAS channel number allowed the receiver to provide vertical guidance down to 200 feet.