A Flight Inspection is nominally performed as part of Site Acceptance Testing and prior to Commissioning. Successful completion of the Flight Inspection is critical to assure that the system is operating as intended and any restrictions on the use of the GBAS have been appropriately identified and promulgated. 

The primary intention of conducting a GBAS Flight Inspection is to verify that VHF Data Broadcast (VDB) field strength requirements are met throughout the GBAS Approach Service Volume defined in the ICAO Annex 10, Volume 1, Standards and Recommended Practices and identify any interference or degradation to the GBAS signal in space.

Flight Inspection of GBAS additionally serves as a means to conduct a Position Domain Functional Check and a check of the Final Approach Segment (FAS) Data. The Position Domain Functional Check however is not intended to provide a statistical confidence level of the position measurement as GNSS errors change over time as detailed in ICAO Annex 10, Volume 1. 

Some States or ANSPs additionally include a requirement to Flight Inspection for GBAS at routine intervals. The intervals is at the discretion of the State or ANSP. The primary intention of routinely Flight Inspecting a GBAS is to detect changes to the environment surrounding the site that may impact on VDB coverage. Additionally, routine Flight Inspection serve as a means to detect nearby GNSS RFI sources.