Aviation abbreviations & their meanings - continued

Following on from yesterday's post, here are more abbreviations and their meanings.

Weather

METAR - Meteorological Aerodrome Report
Current observed weather at an airport.

TAF - Terminal Aerodrome Forecast
Forecast weather for an airport.

QNH - Altimeter setting referenced to mean sea level
Allows aircraft altimeters to indicate altitude above mean sea level.

QFE - Atmospheric pressure at the airport elevation
Setting that makes the altimeter read approximately zero at the airport reference point.

ISA - International Standard Atmosphere
Standard atmospheric model used for aircraft performance calculations.

CAVOK - Ceiling and Visibility OK
Indicates good visibility and no significant cloud/weather conditions.

CB - Cumulonimbus
Thunderstorm cloud capable of producing severe turbulence, lightning, hail and strong winds.

TS - Thunderstorm
Thunderstorm reported in aviation weather information.

Pilots & Operations

PIC - Pilot in Command
FO - First Officer
ATPL - Airline Transport Pilot Licence
CPL - Commercial Pilot Licence
PPL - Private Pilot Licence
MEL - Minimum Equipment List
CDL - Configuration Deviation List
NOTAM - Notice to Airmen/Air Missions

ETOPS
Extended-range Twin-engine Operational Performance Standards

EDTO
Extended Diversion Time Operations

RVSM
Reduced Vertical Separation Minimum

IFR
Instrument Flight Rules

VFR
Visual Flight Rules

IMC
Instrument Meteorological Conditions

VMC
Visual Meteorological Conditions

Maintenance & Aircraft History
Routine/light aircraft maintenance inspection

A Check
Every 400–600 flight hours or roughly 200–400 flight cycles

B Check

Intermediate maintenance inspection (less commonly used on modern aircraft)
About every 6–12 months

C Check
More extensive scheduled maintenance inspection
About every 18–24 months

D Check
Very extensive heavy maintenance inspection every 6 - 12 years

MSN
Manufacturer's Serial Number

L/N
Line Number

TSN
Time Since New

CSN
Cycles Since New

TSO
Time Since Overhaul

AD
Airworthiness Directive

SB
Service Bulletin

MRO
Maintenance, Repair and Overhaul

CAMO
Continuing Airworthiness Management Organisation

Surveillance & Tracking

ADS-B - Automatic Dependent Surveillance–Broadcast
Aircraft automatically broadcasts its position and other information to receivers.

ADS-C - Automatic Dependent Surveillance–Contract
Aircraft periodically sends position information to ATC via a contracted data link.

SSR - Secondary Surveillance Radar
Radar system that interrogates an aircraft transponder.

PSR - Primary Surveillance Radar
Radar that detects aircraft by reflected radio energy.

Mode A
Transponder identification mode
Provides the aircraft's four-digit transponder code.

Mode C
Altitude reporting
Provides ATC with the aircraft's pressure altitude.

Mode S
Selective addressing
Provides more detailed aircraft identification and data exchange.

Some Useful Pilot/ATC Terms

SID — Standard Instrument Departure
A published instrument departure route from an airport.

STAR — Standard Terminal Arrival Route
A published route bringing aircraft toward an airport before the approach.

ATC — Air Traffic Control
The people and systems responsible for safely managing aircraft movements.

FL — Flight Level
Altitude expressed in hundreds of feet based on standard pressure. For example, FL350 = approximately 35,000 feet.

CTR — Control Zone
Controlled airspace surrounding an airport.

CTA — Control Area
Controlled airspace extending above a specified lower limit.

FIR — Flight Information Region
An area of airspace in which flight information and alerting services are provided.