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 Types 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 Helicopter Requirements.
2.2.1 Radar 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. The 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.
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2. Contain a stabilized 120-degree/60-degree sector scanning antenna with scan rates no less than 12/minute (min) and 24/min respectively.
3. Contain an adjustable, bright display.
4. Contain an alphanumeric display for selected ranges and azimuth markers; however, alphanumeric displays of selected ranges are not required when a positive means of determining the range that has been selected is available and the radar operator is appropriately trained.
5. Contain an indicated range error that does not exceed ±0.2 NM for display ranges of 5 NM or less.
6. Contain a lowest selectable range display of 2.5 NM and a range mark display of 0.5 NM increments or smaller.
7. Contain tilt control of ±15 degrees.
8. Display a test pattern.
9. Be operable in the primary mode.
10. Be equipped with a fault monitor or self-test function.
Note: An operational course bearing cursor that provides course guidance may be used to supplement navigation track accuracy.
2.2.5 Radio Altimeter.
2.2.5.1 TSO Requirement. The radio altimeter must meet the requirements of TSO-C87, Airborne Low-Range Radio Altimeter.
Note: A radio altimeter must be installed and operational before descent to the radio altitude (RA) minimum descent height (MDH) is authorized.
2.3 Airworthiness.
2.3.1 Equipage and Installation Requirements. Equipment required for OSAPs must be installed and maintained in a manner that meets all applicable airworthiness standards.
The selected equipment components must, as a minimum, meet the referenced TSO applicable to each requirement and be specifically approved for OSAPs by the appropriate Flight Standards office. Equipment not meeting these standards requires further evaluation and approval by FAA engineering before it may be used. Installation of airborne radar, radio altimeter, and GPS equipment may constitute a major alteration to the aircraft. Each person who approves a helicopter for return to service after modification for OSAPs must comply with the provisions of 14 CFR part 43, §§ 43.5 and 43.7.
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2.4 Maintenance.
2.4.1 Title 14 CFR Part 135. Part 135 operators must maintain their aircraft under part 135 requirements and their approved maintenance program. Airborne radar, radio altimeter, and GPS maintenance must be performed for this equipment installed in the aircraft.
2.4.2 Title 14 CFR Part 91. Part 91 operators must maintain their aircraft under part 91 operating procedures. Airborne radar, radio altimeter, and GPS maintenance must be performed for this equipment installed in the aircraft. Operators under part 91 using OSAPs who do not have an approved maintenance program should establish procedures to annually inspect and test the OSAP equipment. These procedures should include methods for analyzing malfunctions and defects to determine whether established inspections and tests reasonably ensure the equipment is maintaining its accuracy. In addition to the equipment manufacturer’s recommendations and Supplemental Type Certification (STC), the following test and inspections should be included:
2.4.2.1 Visual Inspection. A visual inspection to determine the condition and security of the equipment mounting, electrical wiring and connectors, radome, antennas and cables, wave guide and couplings, indicator mounts, knobs, etc.
2.4.2.2 Functional Test. A functional test of the airborne radar ground mapping mode, radio altimeter, and navigation system to determine operating condition. Tests should be performed in accordance with appropriate manufacturer’s procedures.
2.4.2.3 Other Tests/Inspections (as appropriate). Other appropriate tests and inspections are used to determine whether the complete system is operating properly.
Note: The inspection and test procedures will be approved by the Flight Standards office issuing the OSAP authorization before the operator conducts any IFR OSAP in instrument meteorological conditions (IMC).
2.5 Flight Standards Office Approval. Each operator’s maintenance program must be approved by the Flight Standards office issuing the OSAP authorization before any IFR OSAPs may be conducted. A certificated air carrier submits a written request with the proposed chart through the certificate-holding district office (CHDO) principal operations inspector (POI). The CHDO ensures that a particular radar and GPS meet minimum requirements, the flightcrew training requirements are met, and helicopter and avionics maintenance requirements are adequate. The CHDO should request support from the appropriate Flight Standards office or the NextGen Branch (AFS-480) representative.
Each operator’s maintenance or inspection program must be approved by the Flight Standards office issuing the OSAP authorization before any OSAP operations in IMC may be conducted.
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2.6 Procedure Development Criteria.
2.6.1 Sample OSAP. The certificated air carrier or operator submits the operation request including the proposed chart to the principal inspector (PI) of the appropriate Flight Standards office or CHDO. The PI should notify AFS-480 for operational coordination within their specified area of operation. For operations outside of the appropriate Flight Standards office operational area, AFS-480 should coordinate with the controlling air traffic facility and Flight Standards office (if required) for the intended operational area.
Instrument operation chart examples are in Appendix B, Figure B-1, Sample Delta 30° OSAP, and Figure B-2, Sample Parallel Offset OSAP. A separate chart for each OSAP is not required.
2.6.1.1 Procedure Identification. The procedure is identified as either, “DELTA 30° OSAP” or “PARALLEL OFFSET OSAP.”
2.6.1.2 Procedure Construction. En route construction provides separation of aircraft 6 NM either side of course to as small as 4 NM either side of course on airways or routes. The Minimum IFR Altitude (MIA) in offshore airspace and within oceanic airspace is charted on the operation chart. Figure 2-1, En Route Criteria, shows the plan view and cross-sectional view of these criteria in the grid system in the Gulf of Mexico. Sample OSAP charts are in Appendix B, Figures B-1 and B-2. Chart the following notes in the plan view:
1. “Special Authorization Required. WX Radar in ground mapping mode and GPS required.”
2. “Maintain MIA until departing the en route fix.”
3. “Select a maximum of 1 NM CDI sensitivity when departing the en route fix.”
2.6.2 Initial and Intermediate Segment Construction. The initial and intermediate segment construction consists of a route segment that extends from an en route fix (grid fix in the Gulf of Mexico) to fly over the approach target with course reversals that extend to the final course. Seven-NM arcs are also constructed for optional routing to the final course.
A 7-NM fix is charted from the approach target site for optional direct routing to the final segment. These segments are flown no lower than 900 ft mean sea level (MSL) until the Final Approach Point (FAP) inbound to the approach target (see Figure 2-2, OSAP Initial, Intermediate, Missed Approach, and Holding Segments). Chart the following note in the plan view: “Clear all obstructions by at least 0.5 NM laterally by radar after FAP inbound.”
2.6.3 Final Segment Construction. The final segment construction consists of either the Delta 30° or parallel offset OSAP, which are described in paragraphs 2.15 and 2.16.
Figure 2-3, Delta 30° OSAP, and Figure 2-4, Parallel Offset OSAP, depict the Delta 30° and parallel offset OSAPs. Chart the following notes on the Delta 30° OSAP and parallel offset OSAP:
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1. “Proceed Visually to the Landing Site.”
2. “Maximum Ground Speed is 70 knots between FAP and MAP.”
3. “DPA (Not less than 2 NM from approach target).” The Decision Point Altitude (DPA) must not be lower than the barometric minimum descent altitude (MDA) adjusted for the Remote Altimeter Setting Source (RASS).
The DPA is charted as follows: “500 MSL or no lower than barometric MDA adjusted for RASS.”
4. “Δ 30° heading at 1.1 NM from landing site.” In addition to Figure 2-4, annotate on the chart: “0.5 NM offset.”
2.6.3.1 Minimums. Chart the following note when the radio altimeter is not available for an operation: “Altimeter source more than 5 NM but less than 75 NM, increase MDA 5 ft for each NM beyond 5 NM.” (See Appendix B, Figures B-1 and B-2.)
2.6.4 Departure and Alternate. Chart the following notes for the departure and the alternate:
1. “Avoid radar targets by 0.5 NM laterally until reaching 900′ MSL when making IFR departures.”
2. “When an offshore facility is designated as an alternate, use 800-2 instrument procedure alternate minimums or as approved by OpSpecs, or LOA (Letter of Authorization).”
2.7 Missed Approach Procedure Construction.
1. Chart the following missed approach instructions for the Delta 30° OSAP:
“Climb to 900′ via the Δ 30° heading, then climbing turn to 2000′, direct to the approach target within 10 NM and hold, 3 NM legs, or as directed by ATC.”
2. Chart the following missed approach instructions for the parallel offset OSAP:
“Climb to 900′ via the offset course, then climbing turn to 2000′, direct to the approach target within 10 NM and hold, or as directed by ATC.”
2.7.1 Missed Approach Holding [Delta 30° OSAP, Parallel Offset OSAP]. Chart the following holding instructions: “Hold over the approach target on the inbound course, 3 NM legs, maintain 2000′ or as directed by ATC.”
2.8 Operational Requirements.
2.8.1 Approved Weather Observation and Reporting Requirements. Refer to FAA Order 8900.1 Volume 4, Chapter 7, Section 1, Instrument Flight Rules Offshore Operations.
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2.8.2 Offshore Environment Operation. Operators approved to conduct IFR operation in the offshore environment in accordance with parts 91, 91K, and 135 for the appropriate operational approval (e.g., letter of authorization (LOA) or operations specification (OpSpec)) may comply with the requirements by any one of the following methods or one with an equivalent level of safety approved by the Administrator:
1. One station: The operation coordinate shall be within 10 NM of an approved weather reporting station.
2. Two stations: The operation coordinates shall fall within an observed area defined by the location of two approved weather reporting stations.
• The observation area centerline is established by the actual bearing between the two stations. The actual distance between the two stations is not to exceed 40 NM.
The centerline shall continue on either side of each weather station by a distance of 10 NM.
• The lateral width of the observed area may not be greater than 40 NM on either side of the established centerline.
• The resultant maximum observation area is a rectangle 60 NM by 80 NM.
2.8.3 Parts 91 and 135 Operators—Authorized Areas of En Route Operations, Limitations, and Provisions.
1. Operators conducting IFR operations in areas authorized by OpSpec B050, Authorized Areas of En Route Operations, Limitations, and Provisions, will comply with the requirements of the OpSpec.
2. Part 91 operations within oceanic airspace are covered in LOA H104, Helicopter Offshore Instrument Operations, and the applicable International Civil Aviation Organization (ICAO) Annex.
2.9 Guidelines. Procedures and guidelines of OSAP are as follows:
1. Minimum equipment lists (MEL) must be modified to account for the effect of inoperative equipment on OSAP.
2. Flightcrews are provided with current observed coordinates for landing sites.
Before departure, the flightcrew enters the observed landing site coordinates into the navigation system receiver flight plan. This action designates the landing site as a “waypoint.”
3. Flightcrews should use detailed procedures to ensure clearly defined crew duties for two-pilot operations. GPS or wide area augmentation system (WAAS) is used for course guidance, and airborne radar in ground mapping mode is used for obstruction identification and avoidance.
4. All OSAPs are applicable only to helicopter operations to and from offshore platforms, rigs, or ships, and are not to be used less than 5 NM from land.
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5. Throughout this operation, the airborne radar antenna sweep must not be less than 120 degrees. Less than a 120-degree antenna sweep will limit the radar operator’s ability to accurately observe and locate obstructions. Smaller sweep angles increase the possibility of premature loss of peripheral radar targets.
2.10 En Route and Intermediate.
2.10.1 Individual OSAP Accommodation. Accommodations for individual OSAPs is not required for flight from the last fix (or en route grid waypoint in the Gulf of Mexico) on the airway or route segment to the intermediate approach fix (IF) along a Very High Frequency Omnidirectional Range Collocated Tactical Air Navigation (VORTAC) or Area Navigation (RNAV) routing. Procedures unique to an OSAP begin at the IF, which may begin over the approach target, on an arc, or at the IF if approaching “straight-in” to the IF.
2.10.2 Descent Authorization. A descent below the MIA is not authorized at any point until the helicopter has departed the last en route fix and is offshore (see Figure 2-1).
Figure 2-1. En Route Criteria
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2.11 Final Approach Segment (FAS).
2.11.1 Alignment with FAS. Alignment with the FAS may be achieved by:
1. Proceeding directly to a user-defined transition waypoint generated 7 NM from the approach target on the final approach to the target;
2. A teardrop 7-NM procedure (the procedure turn must remain within 10 NM of the approach target); or
3. A 7-NM arc entry to the final segment.
2.12 En Route Fix Departure. A CDI sensitivity of 1 NM or less is set when departing the last en route fix.
2.12.1 Airborne Radar and GPS Monitoring. During all phases of the en route and intermediate segments, the flightcrew monitors the airborne radar and GPS systems to determine reliability and operational correctness.
2.13 Final Approach Course. For radar detection and avoidance of obstructions, the final approach course is flown into the wind within 10 degrees of the wind direction for Delta 30° and parallel offset OSAPs. This course is flown to the delta change point for the Delta 30° OSAP and to the missed approach point (MAP) for the parallel offset OSAPs. After turning to the final course (Delta 30° OSAP, parallel offset OSAP), a descent is made to no lower than 900 ft MSL prior to reaching the FAP. The crew establishes the FAP at not less than 5 NM from the approach target. At the FAP, a descent is made to no lower than 500 ft MSL prior to reaching the DPA. The crew establishes the DPA at not less than 2 NM from the approach target. At the DPA, the crew confirms the final approach course is clear laterally of all obstacles by at least
0.5 NM before a descent is made to the MDA. If lateral separation is not assured by
0.5 NM, a missed approach is initiated. For the Delta 30° OSAP, a 30-degree turn is made at 1.1 NM from the approach target to the clear area either to the left or right of the approach target. The Delta 30° course is determined by adding 30 degrees to or subtracting 30 degrees from the inbound heading (see Figure 2-2).
Figure 2-2. OSAP Initial, Intermediate, Missed Approach, and Holding Segments
NOT FOR NAVIGATION 10 NM Plan View NOT TO SCALE Select 1 NM CDI Sensitivity when Departing the En Route Fix.
En Route Fix Missed Approach Gulf of Mexico). (Grid Fix in the and Holding, 5 NM (Approach Target) Landing Site Initial Segment 3 Teardrop Divergence between Outbound ! A Descent Below MEA Gulf of Mexico:
Course and Reciprocal of Inbound 3 NM Legs must be in Offshore Environment.
Course is between Maintain MEA within 15° and 30° Intermediate Offshore or Oceanic Segments Airspace until Departing (7 NM Teardrop 5 NM the En Route Fix.
PT Initials 7 NM Arc from the 7 NM Arc from the Approach Target Approach Target 7 NM Waypoint Clear All Obstructions by at Least for Direct Routing 0.5 NM Laterally by Radar after FAP Inbound. Remain 900 ft MSL or Above until FAP Inbound.
10 NM
2.14 Missed Approach.
2.14.1 Conditions. During the final approach course, if the navigation system and airborne radar display difference exceeds 10.2 NM in range or azimuth, or the approach target is lost from the airborne radar display for one full sweep, an immediate missed approach must be made.
2.15 Delta 30° OSAP. The following operations are required for the Delta 30° OSAP (see Figure 2-3):
1. The DPA is established after the FAP but not less than 2 NM from the landing site, depending on obstacles within 0.5 NM of the final approach course.
2. The Delta 30° heading is made either to the right or left of the straight-in portion of the inbound course depending on the clear area determined by the radar operator. The Delta 30° heading is maintained until the MAP if visual reference is not established with the landing site.
3. Between the FAP and the MAP, the maximum ground speed is 70 knots.
4. While on the Delta 30° heading and prior to the MAP, when visual reference with the landing site is established, the pilot proceeds visually to the landing area. If visual reference with the landing site is not established prior to the MAP and the pilot cannot proceed visually to the landing area, a missed approach must be executed (see Figure 2-3).
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Figure 2-3. Delta 30° OSAP Plan View NOT TO SCALE ~ MAP 0.6 NM from the Approach Target.
Д.30° DPA Not Less than 2 NM from the Approach Target.
Final Approach Track from the FAP to 4 30° within 10° of Wind Direction FAP 5 NM % NOT FOR NAVIGATION Profile View MISSED Approach Climb to 900 via 4 30° Heading, then FAP Climbing Turn to 2000, Direct to the 900 ft MSL Approach Target. Remain within 10 NM DPA and Hold, or As Directed by ATC
- 018° 500 ft MSL or No Lower МАР than Barometric MDA Adjusted for RASS 200 ft RA or 250 ft MSL with Radio Altimeter Inop.
ENMI Sea Level
1.1 NM A 30 PROCEED VISUALLY TO THE LANDING SITE 4 Not Less than 5.0 NM from the Operation Target →
2.16 Parallel Offset OSAP.
2.16.1 Procedures. The following procedures are required for the parallel offset OSAP (see Figure 2-4):
1. Departing the FAP inbound, either a left or right turn is made to a heading that is established from the FAP on the 0.5 NM parallel offset inbound course.
2. The direction of turn is selected based on the clear area determined by the radar operator.
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3. The DPA is established after the FAP but not less than 2 NM from the landing site, depending on obstacles within 0.5 NM of the offset course. This depends on the radar return of obstacles within the final area. The helicopter must be established on the parallel offset course prior to the DPA.
4. Between the FAP and the MAP, the maximum ground speed is 70 knots.
5. After passing the DPA, a descent is made to the MDA on the parallel offset course. The parallel offset course is maintained until the MAP or visual reference is made with the landing site.
6. A turn is made to the landing site after visual reference is established.
7. If visual reference with the landing site is not established by the MAP and the pilot cannot proceed visually to the landing site, a missed approach is executed (see Figure 2-4).
Figure 2-4. Parallel Offset OSAP Plan View NOT TO SCALE Missed Approach Parallel Offset
0.5 NM Landing
• Site.
MAP 0.7 NM MAP 0.7 NM from the from the Approach Target. / Approach Target.
DPA Not Less than 2 NM from the Approach Target.
TFAP 5 NM Final Approach Track on the NOT FOR NAVIGATION Parallel Offset within 10° of the Wind Direction.
Profile View FAP .....
900 ft MSL DRA
MISSED APPROACH Climb to 900 via 0.5 NM Offset Course, then Climbing Turn to the MAP 200 ft RA or 250 ft 500 ft MSL or No Lower than Barometric MDA Adjusted for RASS 2000, Direct to the Approach Target. MSL with Radio Remain within 10 NM and Hold or as . 0. Altimeter Inop.
directed by ATC. | NME Sea Level
PROCEED VISUALLY TO THE LANDING SITE * Not Less than 5.0 NM from the Approach Target → 2-11
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2.17 Missed Approach and Holding Procedures.
2.17.1 Delta 30°OSAP MAP. The MAP is a point on the course established by the Delta 30° heading at 0.6 NM from the landing site.
2.17.2 Parallel Offset OSAP MAP. The MAP on the parallel offset final approach course is a point on the offset course at 0.7 NM from the landing site.
2.17.3 Missed Approach Procedure. The missed approach procedure for both operations is a climb to 900 ft MSL via the Delta 30° heading or parallel offset course, then a climbing turn to the 2,000 ft direct to the approach target while remaining within 10 NM of the approach target and hold 3 NM legs, or as directed by air traffic control (ATC) (see Figure 2-2).
2.17.4 Holding After the Missed Approach. Holding is over the approach target fix on the missed approach inbound course with 3 NM legs, maintaining the 2,000 ft, or as directed by ATC (see Figure 2-2).
2.17.5 Executing a Missed Approach. A missed approach is executed when any one of the following events occurs:
1. Visual reference with the landing site is not made at the MAP.
2. Failure of the navigation system.
3. Failure of the airborne radar.
4. The approach target is lost from the airborne radar display for one full sweep.
5. When the radar operator determines the helicopter’s track will not avoid all obstacles by at least 0.5 NM.
6. When within close proximity of the MAP, if visual contact is not established, make only minor heading changes to avoid flight closer than 0.5 NM to any radar returns while following GPS course guidance during a missed approach.
7. Lost communication procedure after the missed instrument operation. Execute the published missed approach and then proceed directly to the alternate at the MIA.
2.18 Minimums.
2.18.1 Takeoff Minimums:
1. The takeoff visibility for offshore landing sites is ½ statute mile (sm) or lower if authorized by OpSpecs or LOA. In the event that the takeoff is conducted from a facility without weather reporting, the flightcrew may determine the available required visibility.