Definitions — Page 10, Lesson 13

We're in the definitions section of the Air Law manual now, and I want to walk you through this alphabetically, because these abbreviations are the language of the entire regulatory system. We're picking up at the letter N and going through to W. Let's take them in order. Starting with NDB(L) — that's a Locator, which is a low-powered NDB, a Non-Directional Beacon, that serves approaches. So it's a small radio beacon used to guide aircraft in on an approach path. NOH is Notified Operating Hours — the published hours during which an aerodrome or facility is available. NOSIG means No Significant Change — you'll see this in weather reports, telling you conditions aren't expected to change materially. NOTAM is Notice to Airmen — the system for distributing time-critical information about hazards, airspace changes, and facility status to pilots. NPA is Notice of Proposed Amendment — the document published when a regulator proposes to change a rule, inviting comment. Now, OCA appears twice, and this is a classic trap. First, OCA is Oceanic Control Area — the airspace over the oceans where air traffic control provides separation. But OCA is also Obstacle Clearance Altitude — the lowest altitude above mean sea level that ensures clearance from obstacles. Two different meanings, same three letters. OCH is Obstacle Clearance Height — same concept as OCA, but measured above the aerodrome elevation or threshold elevation rather than sea level. OCL is Obstacle Clearance Limit — the limiting value for obstacle clearance. OCP is Organizations Certification Procedure — the process by which an organization gets certified. OEM is Original Equipment Manufacturer — the company that actually built the aircraft or component. OIS is Obstacle Identification Surface — a defined surface used to identify obstacles that need to be considered. Ops is simply Operations. P is Propeller — the aircraft component. PAD is Proposed Airworthiness Directive — a draft directive before it's adopted. Then we have the Part numbers: Part 145, Part 21, and Part 22. These are regulatory sections — Part 145 covers maintenance organizations, Part 21 covers certification of products and parts, and Part 22 covers specific certification requirements. PANS is Procedures for Air Navigation — ICAO's detailed procedures that supplement the Standards and Recommended Practices. PAR is Precision Approach Radar — a radar system that gives precise guidance during approach. PAPI is Precision Approach Path Indicator — the lights that show you whether you're on the correct glide path. Pax is Passengers. PCM is Project Certification Manager — the person managing a certification project. PCP is Products Certification Procedure — the procedure for certifying products. PIC is Pilot-in-command — the pilot responsible for the flight. PICUS is Pilot-in-command Under Supervision — a pilot acting as PIC while supervised, typically during training. POA is Production Organization Approval — approval for an organization to produce aircraft parts. POE is Production Organization Exposition — the document describing how that organization operates. PPA is Products, Parts and Appliances — the items covered by certification. PT is Public Transport — carrying passengers or cargo for hire. RCC is Rescue Co-ordination Centre — the centre that co-ordinates search and rescue efforts. RG is Rulemaking — the process of making regulations. RIA is Regulatory Impact Assessment — an assessment of the impact of a proposed regulation. RIS is Radar Information Service — a service providing radar-derived information to aircraft. RLCE is Request Level Change En route — a request to change altitude during the en-route phase. RNOTAM is Royal NOTAM — a specific type of NOTAM. RP is Responsible Party — the party held accountable. RTA is Request for Technical Advice — a formal request for technical guidance. RTF is Radio Telephony — voice communication over radio. RTOW is Regulated Take-off Weight — the maximum take-off weight as regulated. RTG is Radio Telegraphy — communication using Morse code or similar telegraphy. RTR is Radar Termination Range — the range at which radar service terminates. RVR is Runway Visual Range — the distance a pilot can see along the runway, critical for low-visibility operations. RVSM is Reduced Vertical Separation Minima — the reduced vertical separation between aircraft in specific airspace. Rwy is Runway. SAR is Search and Rescue. SARP is ICAO Standards and Recommended Practices — the international standards. SARSAT is Search and Rescue Satellite Tracking System — the satellite system used for locating distress signals. SDF is Step-down Fix — a fix where you descend in steps during an approach. SELCAL is Selective Calling — a system that alerts the crew to incoming calls. Sfc is Surface. SID is Standard Instrument Departure — the published departure procedure. SIGMET is Significant Meteorological Warning — a warning of significant weather. SNOCLO is Closed by Snow — a NOTAM term meaning the aerodrome is closed due to snow. SoD is State of Design — the state that designed the aircraft. SoR is State of Registry — the state where the aircraft is registered. SPECI is Special Met Report — a special weather report issued when conditions change significantly. SPIC is Student Pilot-in-command — a student acting as PIC under supervision. SPL is Supplementary Flight Plan — an additional flight plan filed during flight. SSCC is Safety Standards Consultative Committee — a committee advising on safety standards. SSR is Secondary Surveillance Radar — radar that relies on transponder replies. STAR is Standard Instrument Arrival — the published arrival procedure. STC is Supplemental Type Certificate — approval for a modification to a type-certificated product. STD is Synthetic Training Device — a training device that simulates the aircraft. STCH is STC Holder — the holder of a Supplemental Type Certificate. SVFR is Special Visual Flight Rules — VFR clearance in conditions that don't meet standard VFR. TAF is Aerodrome Meteorological Forecast — the forecast for an aerodrome. TAS is True Airspeed — the actual speed of the aircraft through the air. TC is Type Certificate — the certificate for a type of aircraft. TCA is Terminal Control Area — controlled airspace around a terminal. TCDS is Type Certificate Data Sheet — the document with the type's data. TCH is Type Certificate Holder — the holder of the Type Certificate. TMA is Terminal Manoeuvring Area — airspace around a terminal for manoeuvring. TMG is Touring Motor Glider — a motor glider used for touring. ToA is Terms of Approval — the conditions of an approval. TODA is Take-off Distance Available — the distance available for take-off. TOM is Take-off Minima — the minimum conditions for take-off. ToR is Terms of Reference — the scope of a task. TORA is Take-off Run Available — the runway length available for the take-off run. TP is Turning Point — a point where you turn. TR is Type Rating — the rating for a specific aircraft type. TRE is Type Rating Examiner — the examiner for type ratings. TL is Transition Level — the altitude where you transition from QNH to standard pressure. TVOR is Terminal VHF Omni-ranging — a VOR at a terminal. TVP is Type Validation Principles — principles for validating a type. Twr is Tower (Aerodrome Control) — the control tower. UAV is Unmanned Aerial Vehicle — a drone. UHF is Ultra High Frequency — a radio frequency band. UIR is Upper Information Region — airspace above a certain altitude. U/s is Unserviceable — not working. UTC is Co-ordinated Universal Time — the standard time reference. VASI is Visual Approach Slope Indicator — lights showing the glide path. VFR is Visual Flight Rules — rules for flying by visual reference. VHF is Very High Frequency — a radio frequency band. VLA is Very Light Aeroplane — a light aircraft category. VLR is Very Light Rotorcraft — a light helicopter category. VMC is Visual Meteorological Conditions — weather conditions allowing VFR. VOR is VHF Omni-ranging — a navigation aid. VSTOL is Very Short Take-off and Landing — aircraft with very short take-off and landing capability. WA is Working Arrangement — an agreement on how to work together. WEF is With Effect From — the date something takes effect. WG is Working Group — a group working on a specific task. WIP is Work in Progress — work underway. Wpt is Waypoint — a defined point in space used for navigation. That's the full set from N to W. These abbreviations will appear constantly in NOTAMs, flight plans, and regulations, so knowing them cold is essential.