Minimum safe altitude warning

MINIMUM SAFE ALTITUDE WARNING- A function of the ARTS III computer that aids the controller by alerting him when a tracked Mode C- equipped aircraft is below or is predicted by the computer to go below a predetermined minimum safe altitude.

E-MSAW is a FAA Acronym for: En-Route Automated Minimum Safe Altitude Warning
Related Definitions from Aviation Glossary
GSA
GHA
Military Operations Area (MOA)
ATA - Air Transport Association
MRO ...

Additionally, the FAA's National Flight Data Digest has an additional 20,000+ lines of change related to the Minimum Safe Altitude Warning (MSAW) program which now totals over 80,0000 obstacles.

Minimum Safe Altitude Warning (MSAW): a tool that alerts the controller if an aircraft appears to be flying too low to the ground or will impact terrain based on its current altitude and heading.

See also: Aircraft, IFR, Ident, Direct, Air traffic