y. Weather Deviations. Temporary diversions from track are sometimes necessary, but obtain prior ATC clearance. Such diversions can cause GNEs if you do not re-engage the navigation mode of the AP. Selection of the AP turbulence mode (if applicable) can disengage the AP from the navigation system. After using turbulence mode, fly the aircraft back to the desired track before re-engaging the AP. For inertial platform aircraft, the following steps are useful in preventing GNEs as a result of diversions around severe weather:
• Use the AP turn control knob to turn the aircraft in the desired direction.
• The AP engage switch will automatically move from “command” to “manual.”
• The altitude mode switch will either remain on “altitude hold,” or if in the “altitude select” mode, will trip to “off.”
• Set the steering CDU selector to XTK/TKE to provide a continuous display of cross-track data.
• If encountering turbulence, you may use the “turb” setting on the speed mode selector. In this case, the altitude mode switch automatically positions to “off.”
• Both radio INS switches remain in the INS position. This provides a visual display of the navigation situation on the HSI. Even if more than 8 NM off the track, the pegged needle on the HSI is a reminder of that fact and confirms whether the aircraft is tracking towards, away from, or parallel to the desired track.
• Use the turn control knob to maneuver the aircraft as necessary.
• When clear of the severe weather, steer the aircraft back to the desired track, guided by the steering CDU to zero the XTK indication.
• When the aircraft returns to the desired track, set the AP engage switch to “command” and the altitude mode switch to “altitude hold.” The navigation mode selector should still be in the INS position.
• The captain and first officer, or the entire crew if possible, should monitor the diversion maneuver to ensure that the aircraft has returned to the desired track and if you properly re-engaged the AP for command INS operation.
• After completing return to route, check the assigned Mach number and advise ATC.
z. ATC Re-Clearance. Scrutiny groups determined that a re-clearance scenario is the greatest contributor to an oceanic error (e.g., GNE, Large Height Deviation (LHD)). Experience suggests that when ATC issues a clearance involving rerouting and new waypoints, the risk of error increases. The procedures used to copy the ATC clearance, load and check the waypoints, verify the flight plan information, and prepare a new plotting chart should be the same as the procedures for beginning a flight. Designate one pilot to fly the aircraft while the other pilot reprograms the navigation systems and amends the cockpit documents. In the event that a Par 3-6 Page 35
re-clearance involves a direct routing, retain the data relevant to the original route in case ATC requires the aircraft to return to its original course.
aa. Detecting Failures. Inertial and global positioning system (GPS) installations typically include comparator and/or warning devices, but the crew must still make frequent comparison checks. With three systems onboard, identification of a defective system should be straightforward. Identifying system failures with two systems is more difficult. If a significant deviation occurs in oceanic airspace, contact nearby aircraft on 123.45 MHz and obtain information to aid in identifying a system failure. Maintain and keep a record of GPS or inertial performance available for crews. The following are suggestions for recordkeeping:
• Before takeoff and while stationary, note the inertial groundspeed and position indicators. These may give an indication of system accuracy.
• Note the accuracy of each unit before reaching oceanic airspace, preferably while passing a convenient short-range facility. Make a further record at the destination regarding terminal error after first canceling any in-flight updates made.
• You can make compass deviation checks (inertial only) to determine deviation values for the magnetic compass systems so that you can check the accuracy of the inertial heading outputs in-flight.
bb. Identifying Faulty Systems.
• Check malfunction codes for indications unserviceability.
• Refer to records for indications of prior problems.
• Obtain a fix, possibly using the weather radar, in order to determine position relative to information from other systems.
• Communicate with nearby aircraft on air-to-air VHF to compare information on spot wind, groundspeed, and drift. Compare information from the prognostic chart to the system readout if there is no contact with any aircraft. Use this method as a last resort and preferably should use it with another method of verification.
• Use the heading method (inertial only). Simultaneously read both the inertial and magnetic compass indicators. Obtain the mean to the nearest degree to get an acceptably accurate true heading value to compare to the inertial readings and determine what reading is inaccurate.
• Situations may arise when distance or cross-track differences develop between two LRNSs, but the crew cannot identify the faulty system. If three systems are onboard, accept the two agreeing systems as reliable signals. If, however, only two systems are onboard and they disagree, most operators believe that the best procedure in this instance is to fly the aircraft halfway between the cross-track Page 36 Par 3-6
differences as long as uncertainty exists. Inform ATC that the flight is experiencing navigation difficulties so that you may obtain the appropriate clearance.
• Compare the number of satellites received (GPS or GPS-augmented systems) by each receiver.
cc. Attributes of a Failed System. Crews must be able to determine when an inertial or GPS system fails. Crews must notify ATC. The red warning light, self-diagnostic indications, or an error over a known position exceeding the value agreed upon by the operator and the certifying authority may indicate inertial failure. Generally, if there is a difference of greater than 15 NM between the two aircrafts’ navigation systems, it is advisable to split the difference to determine the aircraft’s position. If the disparity exceeds 25 NM, assume one or more of the systems have failed.
dd. Loss of Navigation Capability. There are various navigational requirements for oceanic operations. One example refers to the navigation performance (or accuracy) that you should achieve; a second example is the need to carry standby equipment with comparable performance characteristics. Some aircraft carry three or more LRNSs so that if one system fails they still meet the requirements. The following guidance is for aircraft with two systems:
• If one system fails before takeoff, the pilot must delay departure until repairs are made.
• If a system fails before the aircraft reaches an oceanic boundary, the pilot must land at a suitable airport before the boundary, return to the departure airport or request an ATC clearance on a route that does not require dual LRNS.
• If a system fails after the aircraft crosses the oceanic boundary, the pilot should continue the flight according to the ATC clearance already obtained while keeping in mind that the reliability of the navigational information is significantly reduced.
The pilot should assess the reliability of the remaining system and contact ATC with a proposed course of action. Before making any deviation to the existing clearance, obtain ATC clearance.
• While continuing flight in oceanic airspace with a failed system, the pilot should monitor the following:
• The operation of the remaining system(s);
• Check the main and standby compass reading against available information; and
• Check the performance record for the remaining system.
• If there is doubt about the reliability of the remaining system, the pilot should attempt visual sighting of other aircraft contrails for a track indication, call the appropriate ATC facility to get information on the location of adjacent aircraft, and establish air-to-air communication with nearby aircraft on 123.45 MHz.
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• If the remaining system fails or indicates degradation of performance, the pilot must notify ATC, obtain all possible information from other aircraft, keep visual watch and monitor TCAS for other aircraft, use all possible outside lights, and use any necessary, applicable contingency procedures.
3-7. OCEANIC OPERATIONS.
a. Overview. The chapters in this AC discuss operational factors required for various geographic regions. This AC also discusses various types of navigation equipment. It is the pilot’s responsibility to read the sections that pertain to his/her flights and in addition the general discussion in this chapter. The most stringent conditions exist in the Northern Atlantic due to the high density of traffic between North America and Europe. The most critical area for light aircraft is the long route between the U.S. West Coast and the Hawaiian Islands. Oceanic operating procedures are different depending upon many factors:
• The size of the aircraft.
• Type and number of power plants.
• Range with or without long-range tanks installed.
• Operation type (general or commercial).
• Navigation equipment installed.
• State (country) of the operator.
• Body of water traversed.
• Qualifications of the flightcrew.
• Airspace-specific requirements.
b. U.S.-Registered Aircraft. Offshore operations in both the Atlantic and Pacific oceans may require FAA authorization issued through OpSpecs, MSpecs or LOAs. The improper application of contingency procedures can result in the loss of separation with other aircraft. It is also a requirement to contact ATC whenever the aircraft is unable to continue flight according to its current ATC clearance. This includes situations when the aircraft is off course and/or unable to maintain its assigned altitude. A failure to comply with this requirement prevents ATC from taking measures to provide separation between adjacent aircraft and the aircraft deviates from its clearance. Failure to contact ATC is also contrary to ICAO Annex 2 and § 91.703, the latter of which requires compliance with Annex 2 by all aircraft of U.S. registry.
3-8. EXTENDED OPERATIONS (ETOPS). Part 121 and 135 operators desiring to obtain approval to operate over a route that contains a point further than 1 hour flying time from an adequate airport should refer to AC 120-42, Extended Range Operations (ETOPS and Polar Operations), current edition. This AC defines the tasks that an operator must accomplish in preparation for the monitoring process that the FAA principal maintenance inspector (PMI) will undertake. This monitoring process is necessary to obtain an ETOPS authorization as stated in the current edition of AC 120-42, which requires an approval from the AFS Director for a
deviation to the operating rule of § 121.161. To meet the requirements of this deviation, the operator must be able to substantiate that the type design reliability and the performance of the proposed airplane/engine combination have been evaluated per the guidance in AC 120-42. In addition, the operator must be suitable for Extended-Range Operations (ER-OPS) and submit an application package that includes supplemental maintenance requirements and programs that allow for safe operations under an ETOPS authorization.
3-9. STRATEGIC LATERAL OFFSETS IN OCEANIC AIRSPACE TO MITIGATE COLLISION RISK AND WAKE TURBULENCE. Pilots should use the Strategic Lateral Offset Procedure (SLOP) as standard operating practice in the course of normal operations to mitigate collision risk and wake turbulence. The SLOP is in force throughout the New York, Oakland and Anchorage Oceanic FIRs and in oceanic airspace in the San Juan FIR.
Internationally, operators implement the SLOP in the NAT, the Pacific (including the NOPAC, Central East Pacific (CEP) and Pacific Organized Track System (PACOTS)) and South Pacific airspaces. Use this procedure for both the heightened risk of collision when non-normal events such as operational altitude deviation errors and turbulence-induced altitude deviations occur due to highly-accurate navigational systems and to mitigate wake vortex encounters.
a. Guidelines. Apply SLOPs using the following guidelines:
• Make strategic lateral offsets and those executed to mitigate the effects of wake turbulence to the right of a route or track only.
• In relation to a route or track, there are three positions that an aircraft may fly:
centerline (CL) and 1 or 2 NM right.
• Offsets are not to exceed 2 NM right of CL.
b. Reducing Risk. The intent of this procedure is to reduce risk (increase the safety margin) by distributing aircraft laterally and equally across the three available positions. In this connection, pilots must take into account the following:
• Aircraft without automatic offset programming capability must fly the CL.
• Aircraft programmed with automatic offsets may fly the CL or offset 1 or 2 NM right of CL to obtain lateral spacing from nearby aircraft.
• Pilots should use whatever means are available (e.g., TCAS, communications, visual acquisition, ground proximity warning system (GPWS)) to determine the best flightpath to fly.
• Any aircraft overtaking another aircraft is to offset within the confines of this procedure, if capable, so as to create the least amount of wake turbulence for the overtaken aircraft.
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• For wake turbulence purposes, pilots are also to fly one of the three positions in the second bullet above and never offset to the left of the CL nor offset more than 2 NM right of CL, appropriate to any given situation and have the final authority and responsibility for the safe operation of the aircraft. You may use air-to-air frequency 123.45 to coordinate the best wake turbulence offset option.
NOTE: The FAA recognizes that the pilot will use his/her judgment to determine the action most appropriate to any given situation and has the final authority and responsibility for the safe operation of the aircraft. You may use air-to-air frequency 123.45 to coordinate the best wake turbulence offset option.
• Pilots may apply an offset outbound at the oceanic entry point, but must return to CL at the oceanic exit point.
• Aircraft transiting radar-controlled airspace (e.g., Bermuda) may remain on their established offset positions.
• This procedure does not require ATC clearance and it is not necessary to advise ATC.
• Base voice position reports on the current ATC clearance and not the offset positions.
3-10. OCEANIC EMERGENCY PROCEDURES.
a. Introduction. When conducting flights, especially extended flights outside the United States and its territories, crews should give full consideration to the quality and availability of air navigation services in the airspace used. Operators should obtain as much information as possible concerning the location and range of NAVAIDs and availability of SAR services.
Annex 12 to the Convention contains SAR International Standards and Recommended Practices (ISARP). Each ICAO region has published air navigation plans that include the facilities, services, and procedures required for international air navigation within that particular region.
b. Pilot Procedures. Any pilot who experiences an emergency (alert, distress, or uncertainty) during flight should take these steps to obtain assistance:
• If equipped with a radar beacon transponder and unable to establish voice communication with ATC, switch to Mode A/3 and Code 7700. If a crash is imminent and the aircraft has an ELT equipped, activate the emergency signal if possible.
• Transmit as much of the following message as possible on the appropriate air-ground frequency, preferably in the order shown below:
• “Mayday, mayday, mayday” for distress, “pan, pan, pan” for other types of emergency.
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• Who – name of station addressed, circumstances permitting.
• What – nature of the distress or emergency condition, intentions of the person in command.
• Where – present position, FL, altitude, and any other useful information.
c. Aircraft in Distress. The most important parts of the message are who, what, and where. If you receive no response on the air-ground frequency, repeat the message on 121.5 MHz. Other useful distress frequencies are 2182 or 4125 kHz. An aircraft in distress may use any available means through communications and signaling to alert ATC and other aircraft.
d. Two-Way Communication Failure. The FAA expects pilots of flights that experience two-way communication failure to follow the applicable airspace procedures. Initially, the pilot should squawk 7600 on the transponder for loss of communications. Subsequently, you determine that an emergency condition exists, change to 7700.
e. ICAO Doc. 4444 (PANS-ATM) Procedures for In-flight Contingencies in Oceanic Airspace. Although you cannot cover all possible contingencies, the procedures in the PANS-ATM 15.2.2 and 15.2.3 provide for the more frequent cases such as:
• Inability to maintain assigned FL due to meteorological conditions.
• Aircraft performance or pressurization failure.
• En route diversion across the prevailing traffic flow.
• Loss of, or significant reduction in, the required navigation capability when operating in airspace where the navigation performance accuracy is a prerequisite to the safe conduct of flight operations.
f. Applicable Procedures for Rapid Descent and/or Turn-back or Diversion. With regard to 15.2.1.1a) and b), the procedures listed above in subparagraph 3-10e are applicable primarily when rapid descent and/or turn-back or diversion is required. The pilot’s judgement will determine the sequence of actions to take, having regard to the prevailing circumstances.
ATC will render all possible assistance.
(1) General Procedures. If an aircraft is unable to continue the flight in accordance with its ATC clearance, and/or an aircraft is unable to maintain the navigation performance accuracy specified for the airspace, obtain a revised clearance, whenever possible, prior to initiating any action. Use the radiotelephony distress signal (MAYDAY) or urgency signal (PAN PAN PAN), preferably spoken three times, as appropriate. The intentions of the operator and the overall air traffic situation will determine subsequent ATC action with respect to that aircraft.
(2) Obtaining Prior Clearance. Use the following procedures if you cannot obtain prior clearance. Obtain an ATC clearance at the earliest possible time and, until receiving a revised clearance, the pilot will leave the assigned route or track by initially turning 45° to the Par 3-10 Page 41
right or to the left. When possible, determine the direction of the turn from the position of the aircraft relative to any organized route or track system. Other factors that may affect the direction of the turn are:
• The direction to an alternate airport and en route terrain clearance;
• Any lateral offset flown; and
• The FLs allocated on adjacent routes or tracks.
NOTE: Crews should also consider sensitive airspace, NOTAMs, and low-altitude weather, all of which can affect safety of flight en route to a diversion airport.
(a) Procedures Following a Turn. Following the turn, the pilot should:
• If unable to maintain the assigned flight level, initially minimize the rate of descent to the extent that is operationally feasible;
• Take account of other aircraft that are laterally offset from their track;
• Acquire and maintain, in either direction, a track laterally separated by 28 km (15 NM) from the assigned route; and
• When 10 miles offset, start climb or descent to select a FL which differs from those normally used by 150 m (500 ft).
• Establish communications with and alert nearby aircraft by broadcasting, at suitable intervals: aircraft identification, FL, position (including the ATS route designator or the track code, as appropriate), and intentions on the frequency in use and on 121.5 MHz (or, as a backup, on the inter-pilot air-to-air frequency 123.45 MHz);
• Maintain a watch for conflicting traffic both visually and by reference to ACAS (if equipped);
• Turn on all aircraft exterior lights (commensurate with appropriate operating limitations);
• Keep the Secondary Surveillance Radar (SSR) transponder on at all times;
and
• Take action as necessary to ensure the safety of the aircraft.
(b) Leaving an Assigned Track. When leaving the assigned track to acquire and maintain the track laterally separated by 28 km (15 NM), the flightcrew, should, where practicable, avoid over-shooting, particularly in airspace where you apply a 55.5 km (30 NM) lateral separation minimum.
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g. ETOPS. If an aircraft employs the contingency procedures as a result of an engine shutdown or failure of any critical system, the pilot must advise ATC as soon as practicable, reminding ATC of the type of aircraft involved, and request expeditious handling.
h. SAR. SAR is a life-saving service provided by many governments assisted by aviation and other organizations. This service provides search, survival aid, and rescue of personnel of missing or crashed aircraft. Before departure, a pilot should file a flight plan and itinerary and communicate that information to an appropriate authority at the departure point. Search efforts are often wasted, and rescue is delayed, because a pilot departs without informing anyone of the flight plan. To protect all personnel on the aircraft, follow these steps:
• File a flight plan with the appropriate authority.
• Close the flight plan with the appropriate authority immediately upon landing.
• If the flight lands somewhere other than the intended destination, report the landing immediately to the appropriate authority.
• If an en route landing is delayed for more than 30 minutes (for turbojets), notify the appropriate authority.
• Failure to close a flight plan within 30 minutes of landing may initiate a search.
i. Crashed Aircraft. If a crashed aircraft is observed, and it is marked with a yellow cross, it has been reported and identified. If the site is not marked with a yellow cross, determine, if possible, the type and number of aircraft and whether there is evidence of survivors. Fix the location of the crash as accurately as possible and transmit the information to the nearest appropriate communication facility. If possible, orbit the scene to guide other assisting aircraft until relieved by another aircraft. Immediately after landing, make a full report to the appropriate authority.
j. Crash Landing Survival and Rescue. To enhance the chances of survival and rescue in the event of a crash landing, it is important to carry survival equipment suitable for the geographic area. If a forced landing occurs at sea, the crew’s proficiency in emergency procedures and the effectiveness of water survival equipment onboard the aircraft govern survival chances. In the event that requires an emergency water landing, the crew should contact the Coast Guard and request Automated Merchant Vessel Rescue (AMVER) system information.
Within minutes the crew will receive the name and location of every merchant vessel within 100 miles of the aircraft’s reported position. The speed of rescue on land or at sea depends upon your accuracy in determining the position. If you follow the flight plan and the position is on course, it will expedite rescue. Unless there is good reason to believe that search aircraft cannot locate the crash site, it is best to remain near the aircraft and prepare to signal when search aircraft approach.
k. Ditching and Evacuation. When ditching is imminent, the first step is to communicate with oceanic control and the passengers. The PIC should initiate the distress call to the appropriate agency per ATC instructions or as indicated in the IFIM. When contacting oceanic Par 3-10 Page 43
Page 44 Par 3-10 control, give the following information: aircraft identification and type; position; time; altitude;
groundspeed; true course; fuel remaining (quantity or time); a description of the emergency;
pilot’s intentions; number of occupants; and the assistance desired. Oceanic control will report the situation to the Coast Guard. The Coast Guard activates the AMVER system, sending a seagoing vessel to the area.
(1) International Procedures. A Coast Guard station or a nearby ship can furnish information on the surface wind, recommended ditching heading, and sea conditions in the event of a ditching. The pilot in range of a ship should ditch in close proximity to the vessel, which will stand by to pick up passengers and assist in any other way.
(2) Preparation of Passengers and Crew. Prepare the passengers prior to ditching to put on life vests, fasten seatbelts, assume impact position, and stow loose articles. Then, brief the passengers on life vest inflation and evacuation of the aircraft. Crewmembers should make an inspection to ensure the passengers are properly wearing the life jackets. Personnel should be paired off in preparation for evacuation. To avoid injury, passengers must remain in their seats during the ditching and must brace themselves to meet at least two impacts in the manner instructed by the flightcrew. Operators must ensure to prepare the cabin crew to handle procedures such as evacuation, the use of life rafts, rescue signaling, and methods of survival.
3-11. COMMUNICATION, NAVIGATION, SURVEILLANCE, AND AIR TRAFFIC MANAGEMENT (CNS/ATM) TECHNOLOGY. CNS/ATM technology has been in development for the past 15 years or more. It is now in use in the Asia/Pacific and North Atlantic/European regions, though in some places on a trial basis. ICAO is in the process of developing procedures and an implementation strategy for the Caribbean/South American (CAR/SAM) region.
FIGURE 1. DATA LINK DIAGRAM
We have provided a description of CNS/ATM so that you will have an understanding of what will be the future.
CNS/ATM = Communication/Navigation Surveillance/Air Traffic Management Communication
• Airline Operational Control (AOC) – AOC data link.
• Air traffic control (ATC) – ATC data link.
• Satellite Communication (SATCOM) Voice.
Navigation
• Integrated global positioning system (GPS) position and time reference.
• Required Navigation Performance (RNP) function.
Surveillance
• Automatic Dependent Surveillance (ADS).
• Required Time of Arrival (RTA).
• Communication philosophy.
a. Voice and Data Link. Voice and data link are complimentary modes of communication. Pilots should select the most appropriate mode for each situation. Data link is designed for routine messages including ATC clearances, position reports, and flight plans. In non-routine circumstances when safety or complexities are factors, voice may be the mode of preference. Flightcrew responsibilities are identical using either voice or data link. The pilot communicating is responsible for all communication-related duties. The Controller-Pilot Data Link Communications (CPDLC) application is a means of dialogue between controller and Par 3-11 Page 45
Page 46 Par 3-11 flightcrew, using data link instead of voice ATC communications. It includes a set of message elements, which correspond to existing phraseology employed by current ATC procedures.
b. FANS 1/A System. The FANS 1/A system provides enhanced Communication, Navigation, and Surveillance (CNS) capabilities for airspace users and ATS providers. However, there are many interrelated issues that have an effect on availability of benefits. End-to-end system performance, regional airspace differences, airspace procedures, and availability of ground equipment all have an effect. In the early days of FANS operations, end-to-end system performance was the dominant factor affecting availability of benefits. Many of the developed processes and procedures improved and stabilized system performance. As a result, airlines are using a new procedure in the South Pacific called Dynamic Airborne Route Planning (DARP). It provides monetary and efficiency benefits. New procedures called User Preferred Routings will enable qualified airlines to flight plan routes based on airline-specific parameters.
c. ATC Communication Between a Pilot and Controller.
• Clearances.
• ATC reports.
• FMC loadable clearances and routes.
• FMC-AOC communication between a pilot and controller.
• FMC loadable wind data.
• FMC loadable routes.
• Position reports.
d. General—AOC Communication Between a Pilot and Company.
• Aircraft Communications Addressing and Reporting System (ACARS) (Airline specific).
• Weather.
• Gate.
• Fault reporting.
e. Benefits. The FANS 1/A system provides enhanced CNS capabilities.
3-12. MONITORING OF PERFORMANCE-BASED NAVIGATION (PBN) AND COMMUNICATION.
a. The Monitoring Process. To ensure compliance with oceanic navigation requirements
(e.g., MNPS, RNAV or RNP), states need to establish procedures for the systematic or periodic monitoring of the navigation performance actually achieved. The FAA requires close cooperation between flightcrews, operators, and aviation authorities to ensure recognition and correction of unsatisfactory performance. Incident reporting procedures that encourage cooperation by the flightcrew members involved are essential to safe operations. The event of a significant deterioration in navigation performance, whether it’s a random excursion by the operator or the result of an equipment system’s unacceptable performance level, requires corrective action.