8-16. CAR-SAM ROUTES.
a. Takeoffs. Unless specified on the airport pages or stated in the Aeronautical Information Publication (AIP), departures from South American stations do not require the ICAO noise abatement takeoff profile. Mexico, depending on the runway, may require an ICAO takeoff profile.
b. Transponder. The TCAS system depends upon signals from the transponders of other aircraft and vice versa. Some foreign carriers actually turn their transponders off when they leave a Caribbean or South American radar environment. The International Air Transport Association (IATA) is making an effort to correct this situation. This is another reason to maintain extra vigilance during night operations. Look for instructions on the Latin America/South America High Altitude Chart. In South America, there are no alternate instructions in the AIP. Therefore, use code 2000 when beyond radar coverage if there is no specification for another code.
c. Dispatch.
(1) Sample Routing. For the purpose of training, we will use a South American route, as we know to use the same procedures in the Caribbean.
FIGURE 9. MIAMI TO SAO PAULO 1
CONTACT
PORT AU PRINCE
SANTO DOMINGO
CURACAO
CONTACT
PORT AU PRINCE
SANTO DOMINGO
CURACAO SHORT CUT SHORT CUT
MAIQUETIA
CONTROL
MAIQUETIA
CONTROL MM 14
MIAGRU02J MIA SKIPS BR53V SWIMM A315 PJG G446 REPIS UG446 MIQ UA315 MAN U\N9 CPN STN GRU (CLASS 1 FOR RNAV AIRCRAFT FOR ENTIRE ROUTE) (SINGLE LONG RANGE NAV SYS PERMITTED IF DUAL ADF), (2 HF REQD) GRUMIA01J GRU BGC UW2 BRS LIA312 TIM UA324 POS UG449 ANADA G449 DDP A555 ZQA RESIN FOWEE 3 MIA (SINGLE LONG RANGE NAV SYS PERMITTED IF DUAL ADF EQUIPPED) (2 HF REQD), (CLASS 2 NAV FOR RNAV AIRCRAFT FROM STM TO KOXAM) Par 8-16 Page 97
(2) South American Route Validation.
(a) The above represents typical routing between Miami and Sao Paulo. If this route requires a South American route validation, the FAA check airman should look for the following:
• Areas of Class II navigation.
• Areas of in-the-blind broadcasts.
• Areas of critical terrain depressurization escape routes.
• FIRs.
• Notes associated with FIR crossings.
• Critical terrain areas.
• ATC communication boxes.
• Emergency airports.
(b) In this example, different southbound and northbound routes are required to achieve variety. Below is a presentation of the normal sequence of events along a specific route (02J) from Miami to Sao Paulo.
d. Southbound Flights. The first flight to receive a clearance will get the best altitude.
Therefore, call clearance early and request your highest available FL for your weight. Flights tend to arrive at South American destinations at the same time. Holding may be necessary since the acceptance rate may be quite low compared to domestic airports.
e. Miami Center. Normal VHF with radar coverage until into the Port-au-Prince FIR.
Expect clearance direct to ACMEE (not on LEGS page), direct JOSES.
f. Port-au-Prince Control. Contact at JOSES with standard position report. They will clear you direct Cabo Rojo (CRO) if requested.
g. Santo Domingo Control. Contact at least 10 minutes (VETMO) prior to FIR (CRO) for ATC clearance.
h. Curacao Control. Contact 5 minutes prior to VESKA. Request VESKA direct Cabo Codera (CBC). Expect change to Maiquetia Control east of Curacao (PJG) at the RR (REPIS).
i. Maiquetia Control. Has radar but normally requires position reports. Radar coverage extends from 150 miles north to 30 miles south of Maiquetia VOR (MIQ). Set one HF to Maiquetia Radio on 8855, 5526 or 10096 (SAM-2). Use Maiquetia Radio for ATC position reports if assigned VHF frequencies do not respond. Report LODIR, Canaima (CMA) and ISANI. Critical terrain escape routes exist in the vicinity of CIMA.
j. Manaus Center. Contact on VHF or above HF frequency. Expect the use of both VHF and HF ATC frequencies. Operations from TEPIM to TESAL require IFBP reports. You may lose VHF ACARS. Company communication is possible via SATCOM Voice or HF.
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k. Brasilia Center. Contact at TESAL. Expect radar contact south of TESAL. Brasilia Center controls flights all the way to Sao Paulo (GRU). Expect normal VHF handoffs.
l. FIR Boundaries. Unlike the United States, when crossing into airspace controlled by different countries, controlling agencies do not do handoffs efficiently or at all. It may be necessary to make a call in advance to the ATC facility for the national airspace you are approaching. The procedures for this communication are on the Jeppesen high charts for Miami, Port-au-Prince, Santo Domingo and Curacao. Identify the FIR boundaries on the chart. Then, locate the procedure associated with crossing. In most cases, a 10-minute advance call is adequate. Call on the proper frequency and give your estimate for the boundary fix and your FL.
For example: “Curacao control, Aircraft 983 estimating VESKA at 0725, flight level 370.”
Curacao replies: “Aircraft 983, report VESKA.” Make a full position report to the new facility when passing over that boundary fix.
(1) Contact New Facility. After making a position report to the old facility at the boundary fix, you will receive instructions to contact the new facility (the one you made the advance call to) on the appropriate frequency. As mentioned above, another position report will be necessary. Occasionally, a frequency change will be issued prior to reaching the boundary fix.
In that case, wait until passing the boundary fix before giving a position report. A common practice is to advise the old facility prior to reaching the boundary that you are in contact with the new facility: “Santo Domingo control, Aircraft 983 estimating VESKA at 0725 and we are talking to Curacao.” This statement may accelerate the handoff.
(2) Complete Position Reports at Compulsory/Reporting Points. Some FIRs have radar. However, it is best to assume that they do not. Even when radar is available, the controllers may still expect you to make position reports. Unless instructed to omit all position reports or reports at specific fixes, make complete position reports at each compulsory/reporting point. Listen carefully to instructions from the controller as to which position to report next, if any.
m. ATC Separation. In South America, in a non-radar environment, separation between aircraft at the same altitude is based upon position reports to maintain 15 minute spacing. There is movement in getting the countries to work with 10 minute separation standards using certain RNAV routes. Expect this to be the standard in the future.
n. Northbound Flights. Once an operator files a flight plan in South America, it is very difficult to change. Call early for clearance so that there will be time to request any route changes if a delay or a low cruise altitude is assigned. For language problems, ask local operations for assistance. The first flight to receive a clearance will get the best altitude. If the departure SID does not agree with the flight plan, ask for clarification.
o. Low Altitude Cruise. Northbound flights are more likely to receive a cruise altitude clearance well below the optimum cruise altitude than southbound flights. This is the result of fewer converging airways in South America and the never-ending language difficulties with Spanish and Portuguese speaking air traffic controllers.
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p. Navigation. Circle Class II waypoints on the master Flight Plan Forecast. Then, check them against waypoints on the control display unit (CDU) LEGS page. Two independent verifications of course and distance “to each waypoint in Class II airspace” are required before entry. Do a position check within 2 minutes prior to each waypoint by comparing the FMC position with the Flight Plan Forecast waypoint latitude/longitude coordinates. Accomplish another verification of course and distance as you pass each waypoint with a line drawn through circled waypoints. When ATC announces, “radar contact,” it may suspend Class II navigation procedures. South America does not require position plotting. All southbound and northbound flights, regardless of the flight planned route, should have pre-departure and en route Class II navigation checks accomplished on them. En route NOTAMs may reveal NAVAIDs out of service, which can quickly change a Class I route into a Class II route. Use the following Class II checklist for South American operations:
• HF and SELCAL check.
• Compass deviation check.
• Air data inertial reference unit (ADIRU)/FMC gross error check.
• Navigation source validation.
• LDOC.
• VHF 123.45/121.5.
• Transponder 2000.
• Re-dispatch message RDA/IRU.
q. Miami Radio. A facility located at the Miami airport can now provide a strong HF and SELCAL check while at the gate in Miami. Use the following frequencies: 6637, 10033, 21964.
r. Caribbean Airports.
(1) El Salvador, San Salvador. The airport is at sea level and is right off the coast.
Plan on flying the 15 distance measuring equipment (DME) arc to Runway 07. The airport lies among some agricultural fields and it might be hard to see until within 7 DME. Expect tower to clear you for the visual once you have the airport in sight. There is high mountainous terrain east of the airport.
(2) Freeport, Bahamas. Freeport International Airport (elevation 7 feet) is on Grand Bahamas Island. The island is relatively flat. However, there is an airspace restriction (MY (R)-3000) located 25 miles east of Freeport consisting of a tethered balloon, which rises to 15,000 feet.
(3) Georgetown, Paramaribo. The airport (elevation 95 feet) is 25 miles south of Georgetown. The land is low, marshy jungle with numerous small rivers. The terrain rises Page 100 Par 8-16
gradually away from the airport to the south and west reaching elevations of approximately 1,200 feet 60 miles to the south and 1,400 feet 55 miles to the west.
(4) Guatemala City, Guatemala. This is a special airport that requires an entry and an exit for part 121 operations before you can use it. The airport lies in a bowl with high terrain rising all around it. Good SA is imperative to a safe operation. For RWY 01, plan on using the instrument landing system (ILS) DME Arc. Proper speed control is necessary for executing a good approach, so do not exceed 170 knots. The FAA recommends using the autopilot (AP) for this approach. When making the final turn on from the 177 radial of AUR, turn initially to a heading of 330° and keep your track line just outside Vilan on the ND. If you turn too far inside Vilan, you cannot start down until you have the localizer. You will not get the localizer until well inside the final approach fix (FAF). The RWY 01 has a huge down slope at the approach end starting roughly 2,200 feet down the runway. If the airplane has not touched down by this point, execute a missed approach. You will be too far down the other end of the runway before you touch down and will not have enough room for stopping. Visually, there is a crevice at the approach end of RWY 01, giving the illusion that you are too low. For all the non-precision approaches, you must calculate a visual descent point (VDP). The minimum descent altitude (MDA) is usually reached at the VDP for a safe landing.
(5) Kingston, Jamaica. The airport (elevation 10 feet) is just south of Kingston on a narrow peninsula across the harbor. The highest elevation on Jamaica is approximately 7,400 feet and lies 13 miles ENE. of the airport.
(6) Mexico City, Mexico. The airport (elevation 7,341 feet) is on the central peninsula of Central America. The airport is in a bowl-like area with very high terrain rising rapidly around it. There is also an active volcano. SA is critical to a safe operation. The controllers speak English but will speak Spanish to Latin carriers. Expect to be at 250 knots when within 30 DME below FL 180. Arriving into Mexico City from the north or south, expect to have your Standard Terminal Arrival Route (STAR) and approach change frequently. Be careful not to be heads down on glass airplanes when it might be easier to fly raw data and avoid many changes to the FMC. If landing 5R, plan on going over System Management Office (SMO) VOR at a maximum speed of 200 knots for the arrival. From Mateo in-bound, a speed of 160 knots works well for the approach. You will be slowing down and going down at the same time so plan accordingly. ATS may ask you to maintain a higher speed until SMO. Remember you do not accept any clearance you cannot comply with. Give them an option (e.g., “Aircraft XXX maintain 250 knots until Mateo VOR.”) response: “Mexico City, Aircraft XXX cannot maintain two five zero knots until Mateo VOR. I can give you two zero zero knots until Mateo.” The controllers will comply with what you give them. You will also have a higher true airspeed (TAS) due to the elevation and climate. The turn to the final approach course is 110° and false localizer capture can occur. The FAA recommends capturing the localizer via raw data before arming the approach. Runway 5R has a displaced threshold and there is a tendency to dive for the runway. Stay on glide slope as long as possible. Tower may issue you a sidestep maneuver to 5L. Stabilized approach criteria are limits so be cautious accepting this clearance too low. Use maximum reverse thrust when able.
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(7) Montego Bay, Jamaica. The airport (elevation 4 feet) lies directly parallel to the coast and on the shoreline in a locally swampy area. Hills rise gradually in all directions, except for the ocean area, reaching 1,300 feet to 2,000 feet within 10 miles.
(8) Nassau, Bahamas. Nassau International Airport, elevation 10 feet, has relatively flat terrain.
(9) Port-au-Prince, Haïti. The airport (elevation 109 feet) is on a sharp indentation of the western shore of the island of Hispaniola. Elevations of almost 7,500 feet are 14 miles south of the airport, 9,000 feet 23 miles SE. and 4,600 feet 15 miles to the ENE.
(10) Port of Spain, Trinidad. The airport (elevation 57 feet) is approximately 12 miles ESE. of Port of Spain. The terrain is generally quite flat except for a mountain ridge extending east/west along the northern portion of the island, with elevations of 2,400 feet 5 miles north of the airport and almost 3,100 feet some 9 miles NNE. of the airport.
(11) Rock Sound, Eleuthera, Bahamas. Rock Sound International Airport, elevation 10 feet, has relatively flat terrain.
(12) San Jose, Costa Rica. The airport has high mountainous terrain on all sides.
Expect to be held high on the approach with the runway visually sloping up. You will feel very high on the approach. Using 3:1 profile all the way down will let you know how high you are.
For RWY 07 there is a 6,000-foot mountain just off your right on the approach as you are passing 6,000 feet. Stay on the localizer and do not deviate. Approaching the gate, keep your power on as there is a small upslope. For alternate airports, San Salvador is the closest and best response time.
(13) San Juan, Puerto Rico. Puerto Rico International Airport (elevation 10 feet) is on the northeastern shore of Puerto Rico. The terrain is generally level along the immediate coastal section, but a range of hills up to about 500 feet lies about 3 miles directly south of the airport. About 5 miles south are the foothills of an east-west range of mountains. Thirty-five miles SSW. terrain rises to almost 4,400 feet.
(14) Santo Domingo, Dominican Republic. The airport (elevation 58 feet) is on the south coast of the island of Hispaniola. The terrain in the immediate vicinity and to the east of the airport is flat. However, mountains rise to the north and west.
s. South American Airports.
(1) Buenos Aires, Argentina. SAEZ (EZE) - Ezeiza International Airport.
(2) Barranquilla, Colombia. The airport (elevation 94 feet) is about 5 miles south of Barranquilla. The terrain to the south and west of the airport is relatively flat but mountains begin their rise some 40 miles east of the field, reaching almost 19,000 feet 65 miles east of the airport.
(3) Caracas (Maiquetía), Venezuela. The airport (elevation 235 feet) is on the northern coast of South America. A range of mountains running parallel to the coastline rises
abruptly from the airport with an elevation of approximately 9,100 feet 12 miles ESE. of the airport. There is also very high terrain immediately to the south, southeast and southwest of the airport. Use cockpit radar as a NAVAID backup during departures and arrivals.
(4) Maracaibo, Venezuela. The airport (elevation 213 feet) is on the western shore of the channel connecting Lake Maracaibo with the Gulf of Venezuela. The terrain in the vicinity of the airport is flat but mountains rise to an altitude of over 12,000 feet 90 miles west of the airport, and to over 6,500 feet 65 miles to the ESE. Terrain rises to almost 19,000 feet about 120 miles west of the airport.
(5) Montevideo, Uruguay. SUMU (MVD) - Carresco International Airport.
(6) Río de Janeiro, Brazil. The airport (elevation 30 feet) is on an island in the western extremity of a bay. It is in a bowl-like area, but immediately to the south, west and north, the terrain rises rapidly. To the SE., the mountain-ringed bay only provides one small opening to the sea. To the north of the airport at a distance of 20 to 30 miles lies a mountain barrier aligned east/west with peaks reaching 5,000 to approximately 8,000 feet.
NOTE: High terrain in this area requires close adherence to published procedures.
(7) Santiago, Chile. SCEL (SCL) - Arturo Merino Benitez International Airport.
(8) Sao Paulo, Brazil. SBGR (GRU) - Guarulhos International Airport Max gross weight departures from GRU will often require performance adjustments.
Par 8-16 Page 103 (and 104)
Par 9-1 Page 105 CHAPTER 9. GULF OF MEXICO OPERATIONS
9-1. INTRODUCTION. The Gulf of Mexico is unique in that it is international airspace that operates in some respects as U.S. domestic airspace. The Gulf of Mexico also encompasses restricted airspace around Cuba and the flight information regions (FIR) of Mexico as well as several smaller Caribbean countries.
9-2. CHARACTERISTICS OF THE AIRSPACE.
a. General. The airspace above and surrounding the Gulf of Mexico is complex and includes heavy concentrations of multi-altitude military operations, high altitude air carrier operations, and low altitude helicopter activity. There are numerous alert, warning, noise sensitive, and restricted areas: control zones, heavy concentrations of student pilot activity, and areas of communication and navigation unreliability.
(1) Long-Range Navigation System (LRNS) Operations. Any operation conducted in international airspace on an instrument flight rules (IFR) flight plan, visual flight rules (VFR)-controlled flight plan or at night and that continues beyond the published range of normal airways navigation facilities (non-directional radio beacon (NDB), very high frequency (VHF), VHF Omnidirectional Range (VOR)/distance measuring equipment (DME)) is considered to be a long-range navigation operation. Long-range navigation in a control area (CTA) requires operators to navigate the aircraft to the degree of accuracy required for the control of air traffic;
that is, the aircraft should remain within one-half of the lateral separation standard from the centerline (CL) of the assigned track. The aircraft should also remain within the established longitudinal and vertical separation standards for the area of operation. You can find these separation standards in International Civil Aviation Organization (ICAO) Document 7030.
(2) ICAO Annex 2 Requirements for Flights Over High Seas. For flights conducted within international airspace under U.S. jurisdiction, FAA Order 7110.83, Oceanic Air Traffic Control Handbook, current edition, provides a simplified version of these separation standards.
Title 14 of the Code of Federal Regulations (14 CFR) part 91, § 91.703(a) requires that civil aircraft must comply with ICAO Annex 2 when operating over the high seas. Annex 2 requires that “aircraft shall be equipped with suitable instruments and with navigation equipment appropriate to the route being flown.” In addition, Annex 6, Part II stipulates that an airplane operated in international airspace be provided with navigation equipment that will enable it to proceed in accordance with the flight plan and the requirements of the air traffic service (ATS).
Annex 2 further requires that an aircraft will adhere to the “current flight plan unless a request for change has been made and clearance received from the appropriate air traffic control (ATC) facility.”
b. Control of Air Traffic. ATC of the airspace over the Gulf of Mexico is assigned to the Houston air route traffic control center (ARTCC). This center controls airspace within and outside of the U.S. air defense identification zone (ADIZ). The Houston CTA/FIR includes the airspace in the northern part of the Gulf of Mexico. This control extends southward from Houston Center’s coastal CTA to the middle of the Gulf in the vicinity of long. 24°30’ N. The Houston CTA/FIR borders Houston’s coastal control in the west and north and meets Miami’s oceanic CTA/FIR at lat. 86° W. in the east. The southern border of the Houston CTA/FIR is
under the control of several Mexican FIR/upper control areas (UTA) and controlled by Havana CTA in the southeast. Conduct flight operations in this area in accordance with the applicable 14 CFR and ICAO Annex 2. Aircraft must have the navigation and communication equipment required for operations over the high seas installed and fully operational for flight in this airspace.
c. Flight Plans. Unless otherwise authorized by ATC, operators may not operate aircraft in oceanic airspace unless they file a flight plan. VFR operations in oceanic airspace are permitted only between sunrise and sunset at or below flight level (FL) 180. Although offshore airspace (the airspace between the U.S. 12-mile limit and the oceanic control area (OCA)/FIR boundary) permits VFR flights, operators commonly encounter instrument meteorological conditions (IMC). The FAA recommends that pilots hold an instrument rating, have an aircraft equipped for IFR flight, and file an IFR flight plan.
d. Alert Areas. Alert areas are areas wherein that contain a large volume of pilot training flights or unusual aeronautical activity. Conduct all activity within alert areas according to 14 CFR, without waiver, and you may not conduct any activity that may be hazardous to other aircraft. All aircraft within an alert area, both participating and nonparticipating, are equally responsible for collision avoidance.
e. Controlled Firing Areas. Controlled firing areas contain activities such as the firing of missiles and rockets, ordnance disposal, and static testing of large rocket motors. The users of these areas are responsible for immediate suspension of activities in the event that the activity might endanger non-participating aircraft. The controlled firing area locations in the Gulf of Mexico are in Notices to Airmen (NOTAM).
f. Key West International Airport. Title 14 CFR part 121 operations that land or depart from Key West International Airport must meet the special airport requirements of part 121, § 121.445.
g. Noise-Sensitive Areas. Noise-sensitive areas include outdoor assemblies of persons, churches, hospitals, schools, nursing homes, designated residential areas, and national park areas.
As national park areas, wildlife refuges are noise-sensitive areas. Numerous wildlife refuges are along the U.S. coastline surrounding the Gulf of Mexico, and many of these refuges have large bird populations. The heaviest concentrations of these refuges are along the Texas and Florida coasts. VFR flights over noise-sensitive areas should be no lower than 2,000 feet above the surface, weather permitting, even if § 91.119 permits flight at a lower altitude. The surface is the highest terrain within 2,000 feet laterally of the route of flight or the uppermost rim of a canyon or valley.
h. Warning Areas. Warning areas are in international airspace and contain operations hazardous to non-participating aircraft. Pilots can receive IFR clearances through this airspace when hazardous operations are not taking place. Because there is no provision in international agreements for prohibiting flights in international airspace, there is no restriction on flights in these areas. However, pilots should take note of the location of all warning areas along a planned route.
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i. Restricted Areas. Title 14 CFR part 73 designates restricted areas to contain activities considered hazardous to non-participating aircraft. Aircraft may not operate within 3 nautical miles (NM) of a restricted area unless authorized under the provisions of part 73, § 73.13. There are numerous restricted areas near and along the Gulf of Mexico coastline. Pilots should be aware of these areas and plan flights accordingly.
9-3. NAVIGATION AND COMMUNICATIONS IN THE GULF OF MEXICO.
a. Background. ICAO Annex 6, Part II contains standards and recommended practices adopted as the minimum standards for all airplanes engaged in general aviation international air navigation. It requires those aircraft operated in accordance with IFR, at night, or on a VFR controlled flights (such as in CTA/FIR oceanic airspace) to have installed and approved radio communications equipment capable of conducting two-way communication at any time with the appropriate aeronautical stations on the prescribed frequencies.
b. High Frequency (HF) and VHF Communications. Due to the inherent “line of sight” limitations of VHF radio equipment used for international oceanic airspace communications, aircraft operating on an IFR or controlled VFR flight plan beyond VHF communications capability must maintain a continuous listening watch and communications capability on the assigned HF frequencies. Although ATC assigns these frequencies, actual communication will be with general purpose communication facilities such as an international Flight Service Station (FSS) or Aeronautical Radio, Inc. (ARINC). These facilities will be responsible for the relay of position reports and other information between the aircraft and ATC. Except in an emergency, the use of relay on VHF through aircraft operating at higher altitudes is not an acceptable method of communication with ATC.
c. Communication and Position Reporting.
(1) Non-available Communication. The following describes an area in the Houston CTA/FIR where direct air traffic communication is not available:
• N27°28’ W086°00’ to N27°30’ W087°42’ to;
• N25°50’ W088°15’ to N25°37’ W091°55’ to;
• N24°40’ W093°19’ to N24°28’ W088°01’ to; and
• N24°00’ W086°00’ to beginning point.
(2) Communication Requirements. Pilots planning flights through this area should be aware of the communications and position reporting requirements. HF communications are available for all oceanic flights and limited VHF coverage is also available on 130.7 megahertz (MHz). The communication requirements for IFR flights within the Houston OCA are as follows:
• The aircraft must have functioning two-way radio communications equipment capable of communicating with at least one ground station from any point on the route.
• The crew must maintain a continuous listening watch on the appropriate frequency.
• Make all mandatory position reports.
d. Position Reports. When flying an oceanic route in the Gulf of Mexico, position reports must be made over all designated reporting points. A position report must also be made upon crossing the FIR boundary. Unless otherwise required, reporting points should be located at intervals of 5 or 10° latitude (if flying north/south) or longitude (if flying east/west) either north or south of the equator or east or west of the 180° meridian. Aircraft transversing 10° of latitude or longitude in 1 hour 20 minutes should normally report at 10° intervals. Slower aircraft should report at 5° intervals. In the absence of designated reporting points, make position reports if instructed by ATC. Position reports are vital to air traffic safety and control. Inability to comply is a violation of 14 CFR and ICAO requirements.
e. Navigation Requirements.
(1) Class II Navigation in the Gulf of Mexico. You can conduct Class II navigation on routes in the Gulf of Mexico using Area Navigation (RNAV) with global position system (GPS), inertial reference systems (IRS)/inertial navigation system (INS), or VOR/DME sensors. NDB might also be available. These routes are offshore and shown on en route charts. FAA Order 7110.2, Procedures for Handling Airspace Matters, current edition, establishes the areas which serve aircraft operations between U.S. territorial limits, OCA/FIR boundaries, and/or domestic flights operating over the high seas. These transition CTAs permit ATC to apply domestic procedures and separation minimums. Because there is independent radar surveillance within these CTAs, separation minimums are not as large as for other OCAs. As long as you maintain radar surveillance, you may conduct operations on Gulf routes using RNAV, GPS, IRS/INS, VOR/DME, and NDB. Because of the proximity of these routes to shore-based facilities, using shore-based Navigational Aids (NAVAID) can enhance the accuracy.
(2) Single Long-Range Navigation System (S-LRNS). Approval for use of a S-LRNS on these routes, as well as the navigation techniques, are part of the authorizations (operations specifications (OpSpec), management specifications (MSpec), letters of authorization (LOA)) issued to air carrier operators.
f. Use of NDB for Navigation.
(1) Limitations and Restrictions. The use of NDB as a primary source of navigation on long-range flights presents the operator with numerous limitations and restrictions inherent in low frequency radio equipment and the low frequency signals they receive. NDB NAVAIDs of the highest power (2,000 watts or greater) that are maintained and flight checked as suitable for navigation are limited to a usable service and/or reception range of 75 NM from the facility at any altitude. Although the operator may be able to receive standard AM broadcast stations with NDB equipment, primary dependence on these facilities for navigation is a questionable operating practice. The following are some of the inherent problems associated with reception of these stations:
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