Appendix C C-4 C.2.13 Helicopter En Route Descent Area (HEDA) [HEDA]. An ins trument operation that provides an en route descent and transition from instrument flight rules (IFR) to visual conditions within a specified area of operation. A HEDA is not an instrument approach procedure (IAP), and it is not authorized as an alternate destination on an IFR flight plan.
C.2.14 HEDA Coordinates [HEDA]. A po int in space (PinS) that is the MAP for the HEDA.
C.2.15 Intermediate Approach Fix (IF). The IF may be a Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) distance measuring equipment (DME) fix or a waypoint based upon an approved Area Navigation (RNAV) system. The IF connects the en route structure to the intermediate segment of the operation.
C.2.16 Minimum Descent Altitude (MDA). The MDA for OSAP, ARA, and HEDA operations is based on either a radio or barometric altimeter. The radio altitude (RA) MDA is prefixed by the RA and the barometric altitude MDA is prefixed by an asterisk.
C.2.17 Minimum Descent Height (MDH). A preselected RA used in the (AUTO) logic of the flight management system (FMS). The selected MDH is used to calculate the decent gradient required from the final approach fix (FAF) to arrive at the preselected altitude
0.25 NM prior to the MAP.
C.2.18 Minimum En Route Altitude (MEA). The lowest published altitude between radio fixes which ensures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes. The MEA prescribed for a Federal airway or segment thereof, area navigation low or high route, or other direct route applies to the entire width of the airway, segment, or route between the radio fixes defining the airway, segment, or route.
C.2.19 Minimum IFR Altitude (MIA). Minimum altitudes for IFR operations as prescribed in part 91. These altitudes are published on aeronautical charts and prescribed in 14 CFR part 95 for airways and routes, and in 14 CFR part 97 for Standard Instrument Approach Procedures (SIAP). If no applicable minimum altitude is prescribed in part 95 or part 97, the following MIA applies:
1. In designated mountainous areas, 2,000 ft above the highest obstacle within a horiz ontal distance of 4 NM from the course to be flown;
2. Other than mountainous areas, 1,000 ft above the highest obstacle within a horizontal distance of 4 NM from the course to be flown; or
3. As otherwise authorized by the Administrator or assigned by air traffic control (ATC).
C.2.20 Missed Approach Point (MAP) [OSAP, ARA]. The M AP for an OSAP is a point no closer to the operation target than 0.6 NM for the Delta 30° or 0.7 NM for the parallel offset. The MAP for an ARA is a point no closer to the operation target, as observed on the radar display, than the minimum authorized visibility for landing.
Appendix C C-5 C.2.21 Observed Coordinates. Coordinates established by a GPS TSO-C129, Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS), (World Geodetic System 1984 (WGS 84) compatible) navigation receiver for a proposed offshore landing site or HEDA location.
C.2.22 Offset Approach [ARA]. An oper ating technique used when the radar operator at 1 NM from the operation target provides vectors to position the operation target off the zero azimuth mark by no more than 25 percent of the scan angle being used.
C.2.23 Offshore Operations. Oper ations that routinely have a substantial proportion of the flight conducted over sea areas to or from offshore locations. Such operations include, but are not limited to, support of offshore oil, gas and mineral exploitation, and sea-pilot transfer.
C.2.24 Offshore Standard Approach Procedures (OSAP). An operation designed specifically for helicopters operating at least 5 NM from land. The operation uses GPS for course guidance and airborne weather radar in ground mapping mode for detecting and avoiding obstructions. The OSAP provides the following:
1. A positive fix for the FAP;
2. A positive method of maintaining desired track (DTK) over the surface on the final and missed operation course; and
3. A definite missed operation point.
C.2.25 Operation Target [ARA, OSAP]. A s tationary platform, rig, or ship used as an alignment point. The operation target may or may not be the landing site.
C.2.26 Parallel Offset [OSAP]. A segment of the OSAP operation where the final segment is offset 0.5 NM either left or right of centerline, depending upon the missed operation clear area.
C.2.27 Proceed Visually to the Landing Site [OSAP]. Th is phrase requires the pilot at or prior to the MAP to acquire and maintain visual contact with the landing site. Obstacle or terrain avoidance from the MAP to the landing site is the responsibility of the pilot. A missed operation is not provided between the MAP and the landing site.
C.2.28 Radar Operator. The pilot who operates the radar. The radar operator provides obstacle identification and vector instructions to the pilot at the controls of a helicopter to avoid obstructions during OSAP, ARA, or HEDA operations. The radar operator may be the pilot in command (PIC) or second in command (SIC).
C.2.29 Radio Altimeter. An instrument that uses reflected radio signals to determine the height of the helicopter above the surface.
C.2.30 Radio Altitude (RA). The altitude of a helicopter above the surface determined by a radio altimeter.
C.2.31 Reflector [ARA]. A passive primary radar “skin-paint ” source.
Appendix C C-6 C.2.32 Remote Altimeter Setting Source (RASS). An altimeter setting source that is more than 5 NM but less than 75 NM from OSAP and ARA landing sites or HEDA coordinates.
C.2.33 Single Landing Site Operation [ARA]. An ARA to an offshore landing site located 4 NM or more from any other landing site, rig, ship, or other obstacle.
C.2.34 Turning Point (TP). A turning transition on an OSAP from en route flight to align with the final operation course.
C.2.35 Weathe r Box. An observation area whose boundary is defined by the distance between two weather stations.
C.3 Acronyms.
Acronym Meaning AC Advisory Circular ADS-B Automatic Dependent Surveillance-Broadcast AED Aircraft Evaluation Division ALoS Acceptable Level of Safety ARA Airborne Radar Approach ASOS Automated Surface Observing System ATC Air Traffic Control AWOS Automated Weather Observing System CDI Course Deviation Indicator CFR Code of Federal Regulations DME Distance Measuring Equipment DPA Decision Point Altitude DTK Desired Track ELOS Equivalent Level of Safety ETA Estimated Time of Arrival FAA Federal Aviation Administration FAF Final Approach Fix FAP Final Approach Point
Appendix C C-7 Acronym Meaning FAS Final Approach Segment FMS Flight Management System FOG Flight Operations Group FPAG Flight Procedures and Airspace Group FSS Flight Service Station GPS Global Positioning System HEDA Helicopter En Route Descent Area HSI Horizontal Situation Indicator IAP Instrument Approach Procedure ICAO International Civil Aviation Organization IF Intermediate Approach Fix IFR Instrument Flight Rules IMC Instrument Meteorological Conditions KIAS Knots Indicated Airspeed LAWRS Limited Aviation Weather Reporting System LOA Letter of Authorization LORAN-C Long-Range Navigation-C System MAP Missed Approach Point MDA Minimum Descent Altitude MDH Minimum Descent Height MEA Minimum En Route Altitude MEL Minimum Equipment List METAR Aviation Routine Weather Report MHz Megahertz MIA Minimum IFR Altitude
Appendix C C-8 Acronym Meaning MSL Mean Sea Level NAD North American Datum NASA National Aeronautics and Space Administration NM Nautical Miles NSP National Simulator Program NWS National Weather Service OpSpec Operations Specification OSAP Offshore Standard Instrument Operation PI Principal Inspector PIC Pilot in Command PinS Point in Space POI Principal Operations Inspector RA Radio Altitude RASS Remote Altimeter Setting Source RNAV Area Navigation ROC Required Obstruction Clearance rpm Revolutions per Minute SAWRS Supplementary Aviation Weather Reporting System SIAP Standard Instrument Approach Procedure SIC Second in Command sm Statute Mile SPECI Aviation Selected Special Weather Report STC Supplemental Type Certificate TAF Terminal Area Forecast TC Type Certificate
Appendix C C-9 Acronym Meaning TERPS Terminal Instrument Procedures TIS-B Traffic Information Service-Broadcast TP Turning Point TSO Technical Standard Order UAT Universal Access Transceiver VFR Visual Flight Rules VORTAC Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation WAAS Wide Area Augmentation System WGS World Geodetic System
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