347 abbreviations
MLSmicrowave landing system
MMmiddle marker
MMELmaster minimum equipment list
MOCminimum obstacle clearance
MPmanifold pressure
MRBMaterial Review Board
MROmaintenance repair overhaul
MRPMaterial Resources Planning
MRWmaximum ramp weight
MSAminimum safe altitude / minimum sector altitude
MSDSMaterial Safety Data Sheet
MSLmean sea level
MSLWMax. Structural Landing Weight
MSTOWMax. Structural Take-off Weight
MSZFWMax. Structural Zero Fuel Weight
MTOWmaximum take-off weight
MZFWmaximum zero-fuel weight
NDBNon-directional beacon
NDTNon-destructive testing
NOTAMnotice to airmen
OBEovercome by events
OBSomni-bearing selector
OCAobstacle clearance altitude
OCHobstacle clearance height
OEMoriginal equipment manufacturer
OISObstacle identification surface
OMouter marker
OTSout of service
OWoperational weight
P(as a prefix:) prohibited airspace
PANS-OPSprocedures for air navigation services – aircraft operations
PAPIprecision approach path indicator
PARprecision approach radar
PBDplace bearing distance (RNAV waypoint)
PDASpublic domain aeronautical software
PDGprocedure design gradient
PETpoint of equal time
PFpilot flying
PFAFprecision final approach fix
PFDprimary flight display
PIOPilot Induced Oscillations
PIREPPilot Report
PMpilot monitoring
PNFpilot not flying
POHPilot's Operating Handbook
PSRpoint of safe return
PSRpower supply reset
PSUpersonal service unit
QFEthe Q-code for: Atmospheric pressure at aerodrome elevation (or at runway threshold)
QNHthe Q-code for: Altimeter sub-scale setting to obtain elevation when on the ground, i.e. altitude above MSL