Appendix B: Acronyms
NOAA—National Oceanic and Atmospheric Administration
NO A/G—No Air-to-Ground Communication
NOPAC—North Pacific
NOTAM—Notice to Airmen
NOZ—Normal Operating Zone
NPA—Non-Precision Approach
NRR—Non-Restrictive Routing
NRS—National Reference System
NTAP—Notice to Airmen Publication
NTSB—National Transportation Safety Board
NTZ—No Transgression Zone
NVS—NAS voice switch
NWS—National Weather Service
O
OAT—Outside Air Temperature
OBS—Omni Bearing Selector
OCS—Obstacle Clearance Surface
ODP—Obstacle Departure Procedure
OpSpecs—Operations Specifications
OROCA—Off-Route Obstruction Clearance Altitude