U.S. Depart ment of Transportation Federal Aviation Administration Advisory Circular Subject: Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas Date: 3/22/24 AC No: 90-80C Initiated by: AFS-400 Change: 1
1. PURPOSE OF THIS ADVISORY CIRCULAR (AC). This AC provides criteria and describes acceptable methods for obtaining approval to use Offshore Standard Approach Procedures (OSAP), Airborne Radar Approaches (ARA), and Helicopter En Route Descent Areas (HEDA) to descend in uncontrolled airspace to an altitude where the pilot can proceed to land using visual references to the surface. This AC provides operational approval information for operators conducting operations under Title 14 of the Code of Federal Regulations (14 CFR) parts 91, 91 subpart K (part 91K), and 135 to support issuance of operations specifications (OpSpecs) or Letters of Authorization (LOA). The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, and the document is intended only to provide information to the public regarding existing requirements under the law or agency policies.
2. PRINCIPAL CHANGES. This change revises weather reporting requirements in paragraphs 2.8.2, 3.8.2, and 4.7.2. This change also updates references throughout the AC.
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Hugh Thom as for Lawrence Fields Executive Director, Flight Standards Service
U.
S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas Date: 12/21/17 AC No: 90-80C Initiated by: AFS-400 Change:
This advisory circular (AC) provides guidance for instrument operations to offshore landing facilities. This AC includes application and procedures to show an alternate means authorized by the Federal Aviation Administration (FAA) for compliance with the regulations contained in Title 14 of the Code of Federal Regulations (14 CFR) part 91, which address instrument approach requirements. Specifically, this AC provides guidance for obtaining approval for Offshore Standard Approach Procedures (OSAP), Airborne Radar Approaches (ARA), and Helicopter En Route Descent Areas (HEDA). This AC retains the ARA, parallel offset OSAP, Delta 30° OSAP and the HEDA along with Global Positioning System (GPS) navigation for the OSAP and HEDA operations contained in AC 90-80B. Approvals issued to U.S. operators may be used as a basis for authorization by other state authorities to conduct equivalent operations.
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CONTENTS Paragraph Page
Chapter 1. Mandatory and Optional Paragraphs1-1
1.1 Purpose of This Advisory Circular (AC)1-1
1.2 Audience1-1
1.3 Where You Can Find This AC1-1
1.4 What This AC Cancels1-1
1.5 Explanation of Changes1-1
1.6 Applicability1-2
1.7 Airworthiness Guidance1-2
1.8 Background1-2
1.9 Weather1-3
1.10 AC Feedback Form1-5
Chapter 2. Offshore Standard Approach Procedures2-1
2.1 Applicability2-1
2.2 Helicopter Requirements2-1
2.3 Airworthiness2-2
2.4 Maintenance2-2
2.5 Flight Standards Office Approval2-3
2.6 Procedure Development Criteria2-3
2.7 Missed Approach Procedure Construction2-5
2.8 Operational Requirements2-5
2.9 Guidelines2-7
2.10 En Route and Intermediate2-7
2.11 Final Approach Segment (FAS)2-8
2.12 En Route Fix Departure2-8
2.13 Final Approach Course2-9
2.14 Missed Approach2-10
2.15 Delta 30° OSAP2-10
2.16 Parallel Offset OSAP2-11
2.17 Missed Approach and Holding Procedures2-13
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2.18 Minimums2-13
2.19 Training2-14
Chapter 3. Airborne Radar Approaches3-1
3.1 Applicability3-1
3.2 Helicopter Requirements3-1
3.3 Airworthiness3-2
3.4 Maintenance3-2
3.5 Flight Standards Office Approval3-3
3.6 Procedure Development Criteria3-3
3.7 Missed Approach Segment3-7
3.8 Operational Requirements3-8
3.9 Course Guidance3-10
3.10 Planning3-10
3.11 System Limitations and Procedural Consideration3-11
3.12 Missed Approach Area3-12
3.13 Flightcrew Duties3-13
3.14 Missed Approach and Holding3-13
3.15 Training3-15
Chapter 4. Helicopter En Route Descent Areas4-1
4.1 Applicability4-1
4.2 Helicopter Requirements4-1
4.3 Airworthiness4-2
4.4 Maintenance4-3
4.5 Flight Standards Office Approval4-3
4.6 Procedure Development Criteria4-4
4.7 Operational Requirements4-6
4.8 En Route4-8
4.9 Intermediate Segment4-8
4.10 Final Descent4-8
4.11 Limitations4-9
4.12 Missed Approach4-9
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4.13 Alternate Requirements4-9
4.14 Training4-9
Chapter 5. Requests for Operational Approval of OSAP, ARA, or HEDA Operations5-1
5.1 Submission of Application for Operations Approval5-1
5.2 Specific Operator Requirements and Operations5-2
Appendix A. S ample Training Program for OSAP, ARA, OR HEDAA-1
Appendix B. S ample Offshore Instrument ChartsB-1
Appendix C. A dministrative InformationC-1
List of Figures
Figure 2-1. Gulf of America Expanded Weather Box Boundary2-6
Figure 2-2. Excluded Area for Gulf of America Expanded Weather Box Boundary2-6
Figure 2-3. En Route Criteria2-8
Figure 2-4. OSAP Initial, Intermediate, Missed Approach, and Holding Segments2-9
Figure 2-5. Delta 30° OSAP2-11
Figure 2-6. Parallel Offset OSAP2-12
Figure 3-1. Single Approach Target Area3-5
Figure 3-2. Cluster Approach Target Area3-7
Figure 3-3. Clear Zone and Clear Sector3-8
Figure 3-4. Gulf of America Expanded Weather Box Boundary3-9
Figure 3-5. Excluded Area for Gulf of America Expanded Weather Box Boundary3-9
Figure 4-1. HEDA Descent Criteria4-5
Figure 4-2. Gulf of America Expanded Weather Box Boundary4-7
Figure 4-3. Excluded Area for Gulf of America Expanded Weather Box Boundary4-7
Figure B-1. Sample Delta 30° OSAPB-2
Figure B-2. Sample Parallel Offset OSAPB-3
Figure B-3. Sample ARA Chart for Single PlatformB-4
Figure B-4. Sample ARA Chart for Platform ClusterB-5
Figure B-5. Sample HEDA ChartB-6
List of Tables
Table 3-1. No Wind3-12
Table 3-2. Cross Wind3-12
1-1 CHAPTER 1. MANDATORY AND OPTIONAL PARAGRAPHS
1.1 Purpose of This Advisory Circular (AC). This AC provides criteria and describes acceptable methods for obtaining approval to use Offshore Standard Approach Procedures (OSAP), Airborne Radar Approaches (ARA), and Helicopter En Route Descent Areas (HEDA) to descend in uncontrolled airspace to an altitude where the pilot can proceed to land using visual references to the surface. This AC provides operational approval information for operators conducting operations under Title 14 of the Code of Federal Regulations (14 CFR) parts 91, 91 subpart K (part 91K), and 135 to support issuance of operations specifications (OpSpecs) or Letters of Authorization (LOA). The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, and the document is intended only to provide information to the public regarding existing requirements under the law or agency policies.
1.2 A udience. The primary audience for this AC is the helicopter proponent, Principal Operations Inspectors (POI), and the Flight Technologies and Procedures Division’s Flight Operations Group (FOG) and Flight Procedures and Airspace Group (FPAG) when establishing offshore instrument operations.
1.3 Where You Can Find This AC. You can find this AC on the Federal Aviation Administration’s (FAA) website at https://www.faa.gov/regulations_policies/advisory_cir culars a nd the Dynamic Regulatory System (DRS) at https://drs.faa.gov.
1.4 What This AC Cancels. AC 90-80B, Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas, dated April 12, 1999, is canceled.
1.5 Explanation of Changes. Editorial changes to this AC reflect current language and structure of the Flight Technologies and Procedures Division’s updated organizational nomenclature. This AC retains the OSAP, ARA, and HEDA that were in AC 90-80B. It updates the approval and maintenance procedures for an operator to obtain permission to fly the operations. All references to the use of long-range navigation-C system (LORAN-C) have been removed.
1.5.1 O peration Terminology. An OSAP, ARA, and HEDA are not considered special instrument approach procedures (IAP); therefore, the appropriate term is “instrument operations.” These operations allow helicopters to make an instrument flight rule (IFR) en route descent/letdown offshore within a specified area of operation. Upon reaching visual conditions, the pilot proceeds using visual references to a landing location to execute an offshore landing on an oil rig or platform. These instrument operations are approved by the FAA for individual operators and issued through OpSpecs or LOAs. The FAA does not verify that the procedure is clear of obstructions, only that it is over water.
The pilot verifies there are no obstructions using their approved weather radar. The FAA also does not verify that positive course guidance is available, provided the proponent is using a Global Positioning System (GPS) and has procedures to verify GPS availability for the operation. No flight inspection or other validation is provided or required.
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1.5.2 R esponsibilities. Clarified the responsibilities for the POI and added guidance for the FPAG.
1.5.3 Weath er. Added new guidance for approved weather sources and weather reporting requirements for OSAP, ARA, and HEDA (see paragraph 1.9). This guidance reflects the weather requirements that have been available via OpSpecs.
1.6 A pplicability . For onshore guidance, refer to FAA Order 8260.19, Flight Procedures and Airspace, and FAA Order 8260.42( ), United States Standard for Helicopter Area Navigation (RNAV). In lieu of following the guidance in this AC without deviation, operators may elect to follow an alternative method, provided the alternative method is found to be acceptable by the FAA.
1.6.1 Man datory terms used in this AC, such as “must,” are used only in the sense of ensuring applicability of these particular methods of compliance when the acceptable means of compliance described herein are used. This AC does not change, add, or delete regulatory requirements or authorize deviations from regulatory requirements.
1.6.2 Most of the document references in this AC are the current version as designated by parentheses ( ) placed at the end of the document title. In some cases, the actual version will be indicated by a letter. Documents without ( ) or a letter after the end of the document title designates all versions apply. As a convenience, most references are hyperlinked to the source website for that document.
1.6.3 It is not the intent of this AC to imply that operators with approvals to older or expired documents must recertify to the current version. Operators with prior approvals may continue to operate under those approvals.
1.7 Airworthiness Guidance. Airworthiness guidance is provided in this AC primarily for awareness of general legacy standards by the operator community, but it is incomplete for airworthiness applicants (refer to 14 CFR parts 27 and 29).
1.8 Background.
1.8.1 C riteria . The criteria for developing offshore instrument operations are unlike that used for IAPs. Offshore instrument operation course alignment may vary from one operation to the next at the same location. The offshore instrument operation courses depend on the direction and velocity of the wind and the location of transient obstacles, such as barges with cranes, and ships. Airborne weather radar in ground mapping mode is used to maintain separation from obstacles. The first instrument operation approved for helicopters operating under IFR over water was the HEDA. This operation allowed helicopters to make an IFR en route descent to a radio altitude (RA) of 400 feet (ft) within a specified area of operation that is clear of obstructions. Upon reaching visual conditions, the helicopter proceeds to its destination. HEDAs permit a single instrument operation to serve multiple offshore landing sites. Helicopter ARAs evolved from HEDAs. AC 90-80, Approval of Airborne Radar Approach (ARA) Procedures for Helicopters to Offshore Platforms, dated May 18, 1981, contained an acceptable means for operators to obtain approval of ARA. ARAs were intended to replace HEDAs.
1-3 However, HEDAs were retained because they required less time for approval and served larger areas. By the time an ARA is approved, the platform may have been moved to a new location, making the operation obsolete. It became apparent that a new type of operation was needed that incorporated the advantages of both HEDAs and ARAs while providing an Acceptable Level of Safety (ALoS). This resulted in OSAPs, which may be automated using a unique aircraft-patented solution. For automated OSAPs, there are avionics and application requirements of an OSAP in addition to required aircraft automation equipment.
1.8.2 Testing. In January 1980, the FAA and the National Aeronautics and Space Administration (NASA) conducted a helicopter flight test program in the Gulf of America to evaluate the feasibility of using airborne weather radar in ground mapping mode as an operation system for offshore drilling platforms. In September 1984, the FAA conducted further testing in the Gulf of America. In these later tests, airborne weather radar in ground mapping mode was evaluated to determine if it was feasible to use radar as a primary device for detecting and avoiding obstructions. The radars that were tested were found acceptable for obstruction detection and avoidance only when the cross-wind correction angle did not exceed 10 degrees on final approach course. Recommendations from reports of these tests were used to develop guidelines for the OSAP. OSAPs apply to helicopter operations to and from offshore platforms, rigs, or ships, and are not to be used less than 5 nautical miles (NM) from land. Previously, the OSAP had only an offset final; then, AC 90-80B added the use of GPS and the Delta 30° OSAP.
1.9 Weather.
1.9.1 Approved Weather Sources. The following are approved weather sources:
1. Providers using National Weather Service (NWS) weather as their source (including contract observatories).
2. Flight Service Stations (FSS).
3. Automated Surface Observing System (ASOS).
4. Automated Weather Observing System (AWOS).
5. Supplementary Aviation Weather Reporting System (SAWRS).
6. Limited Aviation Weather Reporting Stations (LAWRS).
7. Onsite certified weather observers.
1.9.2 Weather Report Requirements for OSAP, ARA, or HEDA.
1.9.2.1 Aircraft Performance. Aircraft performance is predicated on aircraft weight, ambient temperature, wind direction, wind speed, and altimeter setting. In order to ensure aircraft takeoff and landing limitations are met and obstacles avoided, an aviation weather report must contain at least the following elements:
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• Station identifier (e.g., airport code);
• Date and time of observation (to establish relevance of the report);
• Ambient temperature at the station (e.g., airport or seaport);
• Wind direction;
• Wind speed;
• Altimeter setting at the station;
• Visibility; and
• Ceiling.
1.9.2.2 ASOS and AWOS. An ASOS or AWOS supplies an automated surface weather observation. ASOS and AWOS observations in Aviation Routine Weather Report (METAR) and Aviation Selected Special Weather Report (SPECI) formats are transmitted electronically to the NWS where they are processed (conversion to international units) and retransmitted worldwide.
The NWS requires METAR and SPECI for the generation of the Terminal Area Forecasts (TAF). The NWS commissions ASOSs and the FAA commissions AWOS sites. The AWOSs, though not approved directly by the NWS, are approved by agreement and in collaboration with the NWS. The FAA follows the NWS commissioning and installation guidelines.
1. All ASOS are automatically NWS/FAA-approved weather sources.
2. All AWOS-3s (or better) are automatically FAA/NWS-approved weather sources. AWOS systems below the AWOS-3 level are not FAA/NWS-approved weather sources, with the exception of an AWOS-2, which is approved for limited use (see item 3 below).
3. AWOS-2 is approved for limited use only. An AWOS-2 does not report ceiling information; therefore, an AWOS-2 is not an NWS/FAA-approved weather source, for use under the following circumstances:
• IFR operations that require ceiling information are prohibited at airports where AWOS-2 reports are the only official source of weather information.
• Terminal visual flight rule (VFR) operations are prohibited at airports at which an AWOS-2 is the only official source of weather information.
• An airport at which an AWOS-2 is used solely as the official source of weather information is prohibited for use as an alternate airport.
• At airports where ceiling information is required to comply with nonstandard takeoff minimums dictated by 14 CFR part 97 or OpSpecs, IFR takeoffs are prohibited if an AWOS-2 is the sole source of weather information.
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1.9.3 Minimum IFR Altitude (MIA). The offshore MIA is as directed by air traffic control (ATC).
1.9.4 Holding. Holding may be accomplished at each of the waypoints depicted in Figure 2- 4, OSAP Initial, Intermediate, Missed Approach, and Holding Segments. A standard Area Navigation (RNAV) holding pattern with 3 NM leg length, flown at 100 knots indicated airspeed (KIAS), must be executed to remain within ATC-protected airspace.
1.9.5 Automatic Dependent Surveillance-Bro adcast (ADS-B) Installation. ADS-B equipment should be installed in accordance with AC 20-165( ), Airworthiness Approval of Automatic Dependent Surveillance-Broadcast OUT Systems. The operator’s installed ADS-B Out equipment must meet the performance requirements of one of the following FAA Technical Standard Orders (TSO) or later revisions: TSO-C154c, Universal Access Transceiver (UAT) Automatic Dependent Surveillance-Broadcast (ADS-B) Equipment Operating on Frequency of 978 MHz; or TSO-C166b, Extended Squitter Automatic Dependent Surveillance-Broadcast (ADS-B) and Traffic Information Service-Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 Megahertz (MHz).
1.9.6 Compliance. F lightcrews must comply with the procedures prescribed in the Air Traffic Offshore IFR Helicopter Operations Letter of Agreement for the given area of operations.
Note: Flightcrews should be made aware that not enabling or stopping altitude s quawk on some transponders that are certified to TSO-C166b while operating in “ADS-B Only” airspace will lead to a condition where their aircraft’s ADS-B signal will not appear on ATC displays.
1.10 AC Feedback Form. For your convenience, the AC Feedback Form is the last page of this AC. Note any deficiencies found, clarifications needed, or suggested improvements regarding the contents of this AC on the Feedback Form.
2-1 CHAPTER 2. OFFSHORE STANDARD APPROACH PROCEDURES
2.1 Applicability. This chapter applies to helicopter OSAP for a descent into uncontrolled airspace to proceed using visual references to offshore landing sites conducted under instrument flight rules (IFR). The operations criteria in this AC apply to airborne weather radar with ground mapping mode that has a demonstrated navigational capability acceptable to the Administrator for OSAP.
2.1.1 T ypes of OSAP. OSAP consists of two types of procedures: Delta 30° and parallel offset OSAP. For the standard OSAP operations, the Delta 30° OSAP is preferred. A parallel offset OSAP may be used when obstructions do not allow for a Delta 30° OSAP.
2.2 H elicopter Requirements.
2.2.1 R adar and Radio Altimeter. Before being authorized to conduct OSAPs, each operator who applies must have at least one helicopter equipped with airborne radar approved for OSAP use, an IFR-approved Global Positioning System (GPS) navigation receiver, and a radio altimeter.
2.2.2 Navigation Equipment Requirements. T he navigation equipment must meet the minimum requirements of Technical Standard Order (TSO)- C129, Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS); TSO- C145, Airborne Navigation Sensors Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS); or TSO- C146, Stand-Alone Airborne Navigation Equipment Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS); with an external course deviation indicator (CDI) or horizontal situation indicator (HSI) mounted in the pilot’s primary instrument scan.
(Refer to AC 91-70( ), Oceanic and Remote Continental Airspace Operations.)
2.2.3 Reference System Requirements. The reference coordinate datum system used for all operations must be World Geodetic System 1984 (WGS 84) or North American Datum of 1983 (NAD 83).
2.2.4 Airborne Radar.
2.2.4.1 Suitable for Use as Primary Instrument Operation Aid. The airborne weather radar systems that have proved suitable for use as primary instrument operation aids are short-range pulse radars, manufactured and approved for the purpose of weather avoidance rather than navigation. Minimum system components for operations based on airborne radar only (with or without beacon capability) are as follows:
1. Meet the requirements of either TSO-C63, Airborne Weather Radar Equipment, or TSO- C102, Airborne Radar Approach and Beacon Systems for Helicopters.
2. C ontain a stabilized 120-degree/60- degree sector scanning antenna with scan rates no less than 12/minute (min) and 24/min respectively.