This document addresses Enhanced Vision Systems (EVS),
Synthetic Vision Systems (SVS), and Combined Vision Systems
(CVS) technologies. The MASPS provides the high level system
requirements for Enhanced, Synthetic, and Combined Vision
Systems when installed in aircraft with the expressed purpose
of gaining no additional operational credit.  Currently, only
EVS technology incorporating an approved Head-Up Display (HUD)
is eligible for operational credit under Title 14 US Code of
Federal Regulations (CFR) §91.175 with the Federal Aviation
Administration (FAA).  An approved combination of EVS and HUD
is termed an Enhanced Flight Vision System (EFVS) by the FAA. 
For the FAA, EVS for operational credit is called "EFVS", and
the term "EFVS" is used in this document. The EFVS subsections
of this MASPS provide the high level system requirements for
Enhanced Flight Vision Systems when installed in aircraft with
the expressed purpose of gaining additional operational
credit.  
The European Aviation Safety Agency (EASA) uses the term “EVS”
as equivalent to the FAA description of EFVS.