4-1 CHAPTER 4. HELICOPTER EN ROUTE DESCENT AREAS
4.1 Applicability. This chapter applies to HEDA procedures for offshore landing sites conducted under instrument flight rules (IFR). The procedure criteria in this AC apply to airborne weather radar with ground mapping mode that has a demonstrated navigational capability acceptable to the Administrator for HEDA operations.
4.2 Helicopter Requirements.
4.2.1 R adar and Radio Altimeter. Before being authorized to conduct HEDAs, each operator who applies must have at least one helicopter equipped with airborne radar approved for ground mapping mode use (see paragraph 4.2.4 below), an IFR-approved Global Positioning System (GPS) navigation receiver, and a radio altimeter.
4.2.2 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.)
4.2.3 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).
4.2.4 Airborne Radar.
4.2.4.1 Suitable for Use as Primary Instrument Operation Aid. The airborne weather radar systems that have proved suitable for use as primary instrument approach 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/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
4-2 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.
4.2.5 Radio Altimeter.
4.2.5.1 TSO Requirement. The radio altimeter must meet the requirements of TSO-C87, Airborne Low-Rang e Radio Altimeter.
Note: A radio altimeter must be installed and operational before descent to the radio altitude (RA) minimum descent height (MDH) is authorized.
4.3 Airworthiness.
4.3.1 Minimum Airworthiness Requirements. As a minimum, systems used for HEDA operations must meet the airworthiness requirements of TSO-C63 or TSO-C102. The selected equipment components must, as a minimum, meet the referenced TSO applicable to each requirement and be specifically approved for HEDAs by the responsible Flight Standards office. Equipment not meeting these standards requires further evaluation and approval by FAA engineering before it may be used.
4.3.2 Installation Requirements. Insta llation of a systems used for HEDA operations for IFR use is a major change in type design, and the provisions of 14 CFR part 21, § 21.97 and part 43, §§ 43.5 and 43.7 apply. The following are requirements for system installation:
1. System controls and data displays must be conveniently accessible and visible to radar operators at their duty stations. The system controls should be protected against inadvertent operation.
2. Electrical power for the system should be obtained from a bus that provides maximum reliability for electrical power without jeopardizing other essential or emergency loads.
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3. The systems used for HEDA operations should not be a source of objectionable electromagnetic interference and must not be adversely affected by electromagnetic interference from other helicopter equipment.
4. Any probable malfunction of the systems used for HEDA operations should not adversely affect the normal operation of other systems or equipment installed in the helicopter.
5. System performance should not be adversely affected by helicopter attitude, altitude, or main rotor revolutions per minute (rpm) normally encountered in flight operations.
4.4 Maintenance.
4.4.1 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.
4.4.2 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 HEDAs who do not have an approved maintenance program should establish procedures to annually inspect and test the HEDA 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:
4.4.2.1 Vi sual 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.
4.4.2.2 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.
4.4.2.3 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 HEDA authorization before the operator conducts any IFR HEDA procedure in instrument meteorological conditions (IMC).
4.5 Flight Standards Office Approval.
4.5.1 Maintenance Program. Each operator’s maintenance program must be approved by the Flight Standards office issuing the HEDA authorization before any IFR HEDA
4-4 procedures may be conducted. A certificated air carrier submits a written request with the proposed chart through the responsible Flight Standards office’s Principal Operations Inspector (POI). The responsible Flight Standards office ensures that a particular radar and GPS meet minimum requirements, that the flightcrew training requirements are met, and helicopter and avionics maintenance requirements are adequate. The responsible Flight Standards office should request support from the FOG representative, if required.
Each operator’s maintenance or inspection program must be approved by the Flight Standards office issuing the HEDA authorization before any HEDA operations in IMC may be conducted.
4.6 Procedure Development Criteria.
4.6.1 S ample HEDA. The certificated air carrier or operator submits the operation request including the proposed chart to the principal inspector (PI) of the responsible Flight Standards office. The PI should notify the FPAG for operational coordination within their specified area of operation. For operations outside of the responsible Flight Standards office’s operational area, the FPAG should coordinate with the controlling air traffic facility and Flight Standards office (if required) for the intended operational area. An instrument operation chart example is in Appendix B, F igure B-5, Sample HEDA Chart.
A separate chart for each HEDA is not required. When the operator meets all of the requirements, the responsible Flight Standards office approves the operation and issues operations specifications (OpSpecs) or a Letter of Authorization (LOA).
4.6.2 E n Route. Apply Chapter 2, paragraph 2.10 for en route criteria.
4.6.3 Intermediate Segment. The plan view of the intermediate segment and HEDAs are shown in Figure 4-1, HEDA Descent Criteria. The intermediate approach fix (IF) is the last fix prior to the HEDA. The intermediate area is the same width dimensions as the en route segment at the IF. The outside edges of the intermediate segment at the IF are drawn tangent to the HEDA. The HEDA is a circle that has a radius of 4 NM. The HEDA must be free of all obstacles and must be located over the water. The Required Obstruction Clearance (ROC) for the intermediate segment is 500 ft with a descent charted to no lower than 900 ft mean sea level (MSL) or no lower than the barometric minimum descent altitude (MDA) adjusted for the Remote Altimeter Setting Source (RASS). The HEDA operation requires special authorization and equipment. Chart the following note in the plan view of the chart: “Special Authorization Required. WX RADAR in ground mapping mode, and GPS Required.”
4.6.4 IF. The IF is established at no more than 20 NM from the HEDA coordinates.
4.6.5 Final Approach Point (FAP). The FAP is established on the HEDA circle. A descent is made at the FAP to the MDA.
Figure 4-1. HEDA Descent Criteria
NOT FOR NAVIGATION Plan View NOT TO SCALE 1 HEDA Coordinate HEDA Area (No Obstacles Within This Area) The Intermediate Fix (IF) Final Approach is Established No Farther Point (FAP) Than 20 NM from the HEDA
• Coordinates.
Required Obstacle Clearance (ROC) in the Intermediate Segment is 1 500 ft with Descents to No Lower Than 900 ft MSL 1 Intermediate
• Fix (IF)
- 6 NM En Route S MISSED APPROACH Climb to 900 in the HEDA then Climbing Turn to the 2000, Directto the HEDA Profile View coordinates. Remain within 10 NM and Hold or as directed by ATC.
HOLDING AFTER MISSED APPROACH:
Hold over HEDA coordinates on the In bound course, 3 NM legs, maintain 2000 or as directed by ATC HEDA 400 it RA or *700 it MSL * Barometric MDA Increased 5 ft for Each Mile Over 5 Miles Sea Level Saximum is are coordinates timeter Source is 75 NM 4 NM "4
4.6.6 Altitude Minimums. All required flight and navigation equipment must be installed and operative to descend to the 400 ft RA minimums. Chart the following notes (see Appendix B, Figure B-5):
1. "The MDA is 700' MSL with radio altimeter or airborne radar ground mapping mode inoperative."
2. The MDA is 700' MSL with obstruction in HEDA."
3. "Altimeter source more than 5 NM but less than 75 NM, increase MDA 5' for each NM over 5 NM from HEDA coordinates."
4. "Descent below 700' is not authorized unless HEDA is clear of all obstructions."
5. "Descent from MIA to 900' MSL is not authorized until within 20 NM of the HEDA coordinates."
4.6.7 Visibility Minimums. Chart the following note on the published operation: "Proceed VFR to the Landing Site."
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4.6.8 Missed Approach. A mi ssed approach is made when visual conditions cannot be established and maintained at the HEDA coordinates.
1. Chart the following missed approach instructions: “Climb to 900, then climbing turn to the 2000, direct to the HEDA coordinates. Remain within 10 NM and hold or as directed by ATC.”
2. Chart the following missed approach holding instructions: “Hold over the HEDA coordinates on the inbound course, 3 NM legs, maintain the 2000 or as directed by ATC.”
3. Filing a HEDA as an alternate in an IFR flight plan is not authorized. Chart the following note: “Filing HEDA as an alternate not authorized.”
4.7 Operational Requirements.
4.7.1 Approved Weather Observation and Reporting Requirements. R efer to FAA Order 8900.1, Volume 3, Chapter 18, Section 7, Part H Helicopter Terminal Instrument Procedures and Airport Authorizations and Limitations.
4.7.2 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., LOA, management specification (MSpec), or 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 coordinates must be within 10 NM of an approved wea ther reporting station.
2. Two stations: The operation coordinates must fall within an observed area defined by the location of two approved weather reporting stations.
a. In the Gulf of America as defined in Figure 4-2, Gulf of America Expanded Weather Box Boundary, and excluding the Mississippi Delta bounded area in Figure 4-3, Excluded Area for Gulf of America Expanded Weather Box Boundary:
• 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 80 NM. The centerline must continue on either side of each weather station by 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 100 NM by 80 NM.
4-7 Figure 4-2. Gulf of America Expanded Weather Box Boundary
Figure 4-
3. Excluded Area for Gulf of America Expanded Weather Box Boundary Corner Latitude Longitude NW 30 25'34.82"N 89 43'53.27"W NE 30 21'42.70"N 87 52'19.31"W SW 28 50'26.73"N 89 47'41.13"W SE 28 47'17.53"N 87 56'59.98"W
b. In all other areas:
• 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 must continue on either side of each weather station by 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.
4.7.3 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.
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2. Part 91 operations within oceanic airspace are covered in LOA H104, Helicopter Offshore Instrument Operations: Offshore Standard Approach Procedure (OSAP), Airborne Radar Approach (ARA), and Helicopter En Route Descent Area (HEDA) Operations, and the applicable International Civil Aviation Organization (ICAO) Annex.
4.8 En Route.
4.8.1 N avigation Guidance . Offshore en route navigational guidance may be based upon any approved system appropriate to the route flown. The last en route fix is based on en route facilities. In the Gulf of America, the last en route waypoint prior to destination is the last en route waypoint prior to the HEDA. The radar operator obtains all relevant data for the landing area, identifies the destination area and landing site, and determines the FAP and missed approach clear zone. The radar operator then briefs the operation to the other pilot before arrival at the IF.
4.9 In termediate Segment.
4.9.1 D escent Below Minimum IFR Altitude (MIA). A descent below the MIA is not authorized at any point in the HEDA until the helicopter has departed the last en route fix and is offshore. The en route fix is established prior to the intermediate segment at no more than 20 NM from the HEDA coordinates. A descent to an altitude no lower than 900 ft MSL is made on this segment (see Figure 4-1).
4.9.2 FAP Altitude. The FAP altitude is no lower than 900 ft MSL or the barometric MDA adjusted for the RASS. The FAP is established at 4 NM from the HEDA coordinates.
4.9.3 IF. Upon arrival at the IF, the radar operator will enter the GPS-publ ished coordinates.
Within 20 NM, or at the established IF, a descent is made to 900 ft MSL.
4.9.4 Confirm Clear of Obstacles. Confirmation is made by airborne radar that the HEDA is clear of obstacles.
4.9.5 Confirm Proper Equipment Operation Prior to Descent. The radar operator will assure that the airborne radar and radio altimeter are operating correctly prior to descending below 900 ft MSL or the minimum intermediate altitude adjusted for RASS. The lowest barometric MDA is 700 ft MSL.
4.9.6 Confirm Heading. T he heading from the HEDA coordinates to the landing site should be confirmed in the intermediate segment.
4.10 Fi nal Descent.
4.10.1 S elect Lowest Appropriate Scale. Before descending below 700 ft MSL, the radar operator selects the lowest appropriate scale on the airborne radar and confirms the descent area is still clear and the radio altimeter is still operative.
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4.10.2 Visual Conditions. A descent continues to 400 ft RA. Upon reaching visual conditions, the pilot proceeds to the landing site. If the pilot cannot proceed under visual conditions to the landing site, a missed approach is executed.
4.11 Limitations. D escent below 700 ft MSL is not authorized whenever any of the following conditions exist:
1. Any obstruction is detected in the HEDA.
2. Radio altimeter is inoperative.
3. Airborne radar is inoperative.
Note: Lowest altitude used for IFR flight in any HEDA must not be lower than 400 ft RA. The descent area must be entirely over water.
4.12 Missed Approach.
4.12.1 Climbing Turn. T he missed approach is a climb to 900 ft in the HEDA then a climbing turn to 2,000 ft directly to the HEDA fix coordinates, remain within 10 NM of the HEDA, or as directed by air traffic control (ATC).
4.12.2 Holding. The missed holding procedure is established over the HEDA fix coordinates on the inbound course, with 3 NM legs, maintaining the MIA or as directed by ATC.
4.12.3 Conditions for Missed Approach Point (MAP). The missed approach must be executed when any of the following occurs:
1. Failure to establish and maintain visual conditions at the HEDA coordinates,
2.
Failure of airborne radar or appearance of a radar target in the HEDA below 700 ft MSL, and/or
3. Failure of the radio altimeter below 700 ft MSL.
4.12.4 Lost Communication Procedure After the Missed Approach. Execute the published missed approach and then proceed directly to the alternate at the 2,000 ft.
4.13 Alternate Requirements.
4.13.1 Alternate Destination. When the IFR flight plan destination is a HEDA, an alternate destination must be filed. If the alternate is to an established onshore airport, a standard or special instrument operation other than GPS-based is required unless the aircraft is equipped with approved TSO-C145( ) or TSO-C146( ) avionics and STC for instrument approach procedures (IAP), then the onshore airport can have a GPS-based operation.
4.14 Training.
4.14.1 Experience. Before conducting HEDA operations in IMC, each flightcrew member should have:
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1. Ten hours of flightcrew experience operating IFR (at either crew station) in the offshore route structure.
2. A minimum of ten HEDAs and at least four from each crewmember position. This may be reduced by the POI for the operator based on the flightcrew experience and proficiency.
4.14.2 T raining .
4.14.2.1 All training must be a matter of record.
4.14.2.2 After completing HEDA training, each flightcrew member must pass a HEDA flight proficiency check. They may then be authorized to use the HEDAs to 100 ft above the lowest established ceiling minimums and ½ sm above the lowest established visibility minimums. Each crewmember must then fly and record ten additional HEDAs before receiving authorization to conduct operations to the lowest established ceiling and visibility minimums required by the operator. The POI may reduce these requirements based on total crew experience provided the pilot in command (PIC) meets all the conditions of this paragraph.
4.14.2.3 The flight proficiency check is an annual requirement.
4.14.2.4 Helicopter flight simulators specifically approved for HEDA training by the National Simulator Program (NSP) and the POI assigned to the operator may be used for any amount of required training.
4.14.2.5 In accordance with Order 8900.1, operators requesting authority to use HEDAs are required to satisfactorily train their flightcrew members under an FAA-approved training program before beginning HEDA operations.
Operators should submit a proposed training program to the responsible Flight Standards office, as applicable, for approval. (See Appendix A for a sample training program.)
5-1 CHAPTER 5. REQUESTS FOR OPERATIONAL APPROVAL OF OSAP, ARA, OR
HEDA OPERATIONS
5.1 Submission of Application for Operations Approval.
5.1.1 Wr itten Request . The certificated air carrier or operator submits the operation request including the proposed chart to the principal inspector (PI) of the responsible Flight Standards office. The PI should notify the FPAG for operational coordination within their specified area of operation. For operations outside of the responsible Flight Standards office’s operational area, the FPAG should coordinate with the controlling air traffic facility and Flight Standards office (if required) for the intended operational area. When the operator meets all of the requirements, the responsible Flight Standards office approves the operation and issues operations specifications (OpSpecs) or a Letter of Authorization (LOA). The responsible Flight Standards office may request support from another Flight Standards office or the FOG.
5.1.2 Evaluation. The FAA will evaluate the requests to ensure that particular radar and Global Positioning System (GPS) or other navigation requirement combination meets minimum requirements, flightcrew training requirements are met, and helicopter and avionics maintenance requirements are adequate. FAA engineering flight test and evaluation are required if a radar is installed that has not previously been approved for obstruction avoidance with ground mapping mode. The application should include the following items:
5.1.2.1 O SAPs, ARAs, or HEDAs:
1. A list of helicopters, the type of navigation equipment installed, and evidence of FAA approval of the airborne radar system for obstacle avoidance with ground mapping mode in accordance with the requirement of this AC.
2. A description of the equipment installation, helicopter flight manual supplements and changes, and proposed minimum equipment lists (MEL), if appropriate.
3. The training program.
4. The maintenance program.
5. Location of nearest weather and altimeter setting source.
6. Charted operations. The operator or the FAA may chart the operation on a reimbursable basis. The operator will submit the original charted operation to the responsible Flight Standards office.
7. Platform lighting.
8. Recommendation as to night operations.
9. Communication frequencies.
10. Platform markings.
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5.1.2.2 ARA (only). The request should contain evidence of an FAA approval of any required ground-based transponder beacon and a description of any ground-based transponder beacon installation. The following are required for submission:
1. Navigation systems to be used (shore to platform).
2. Elevation and location of all landing platforms, rigs, or drilling ships, and any other obstacles within the intermediate and final operation areas.
3. Availability and requirement for use of a platform-based radar transponder beacon.
5.1.2.3 HEDA (only):
1. A representative pictorial and written description of the proposed HEDA.
2. HEDA location (latitude and longitude to within the nearest tenth of a second).
3. Operations and training manual revisions to incorporate HEDAs, if it is an initial application.
4. The date of first intended use and the proposed length of service that authorization is sought.
5.1.3 In strument Operations .
1. Helicopter OSAP, ARA, and HEDA operations to offshore platforms/helidecks are classified as instrument operations.
2. The OpSpecs or LOAs usually contain conditional authorizations that apply to individual operators. The responsible Flight Standards office approves operations for their operators. All other operators submit requests directly to the Flight Standards office having jurisdiction over the area of intended operation for approval.
5.2 Specific Operator Requirements and Operations.
5.2.1 N avigation and Facility Requirements . Any operator that wishes to be approved for instrument flight rule (IFR) offshore operations must ensure that the following navigation and facility requirements are met:
5.2.1.1 R oute Requirements. Operators may develop these proposed and specified routes by onshore station reference navigation where adequate signal coverage is available. Outside of the area where signal coverage is available, the operator must provide a suitable means of navigation. By means of validation tests in visual conditions, Principal Operations Inspectors (POI) must ensure that the operator is able to demonstrate adequate navigational performance for these routes before being granted approval to use them. All fix coordinates will be submitted to the responsible Flight Standards office by the operator.