4/7/14 AC 20-181
APPENDIX A. ACRONYMS. AC Advisory Circular ADC Air Data Computer
A/RFMS
Airplane/Rotorcraft Flight Manual Supplement
AHRS Attitude
Heading Reference System ASTC Amended Supplemental Type Certificate
ATC Amended Type Certificate
CFR
Code of Federal Regulations DG Directional Gyroscope
EFVS Enhanced Flight Vision System FMS Flight Management System
GLONASS globalnaya navigatsionnaya sputnikovaya sistema Global Navigation Satellite System operated by the Russian
Aerospace Defence Forces GNSS Global Navigation Satellite System GPS Global Positioning System operated by the United States Air Force HUD
Head-Up Display
IFR
Instrument Flight Rules IMC Instrument Meteorological Conditions MOPS Minimum Operational Performance Standards MRI Magnetic Resonance Imaging
MSL Mean Sea Level
NAVSTAR Navigation
Signal Timing and Ranging POH Pilot Operating Handbook
STC Supplemental Type Certificate
SVS Synthetic Vision
System TC Type Certificate TSO Technical Standard Order A