CEPAC composite airspace is an organized route system, at or above flight levels (FL) 290 between the west coast of the continental United States and Hawaii, within the Honolulu and Oakland Control Areas (CTA) Flight Information Region (FIR). The organized route system between Hawaii and Los Angeles or San Francisco is comprised of six air traffic service (ATS) routes from FL 290 to FL 410. The same rules used for the North Pacific (NOPAC) routes apply to these routes, including mach number technique and contingencies.


Oakland Oceanic CTA has designated the airspace south of G344 (southernmost NOPAC route) and north of Hawaii as the CENPAC area. Two air traffic routes have been constructed in this area: A 227 and R 339. These are standard ATS routes with no special separation requirements, and there are no special rules to file a flight plan or to fly on these routes. Just south of R 339, a free flow boundary has been established. When operating north of this boundary, flight must be conducted on one of the five NOPAC routes or on A 227 or R 339. Random traffic is only authorized south of the free flow boundary.


A flexible track system (FTS) consisting of two flexible track routes (FTR) is permanently established between Tokyo and Honolulu to achieve more efficient use of the airspace for traffic operating at FL 290 or above. The routes are effective daily between 1200 coordinated universal time (UTC) and 1700 UTC within the Tokyo fix, and between 1300 UTC and 1900 UTC within the Oakland fix. The routes are published daily in Class 1 Notices to Airmen (NOTAM) and are designated "North FTS" and "South FTS." The FTS must be filed on the International Civil Aviation Organization (ICAO) flight plan by coordinates.


a. Communications. Most CEPAC and CENPAC area communications are conducted on high frequency (FM, predominantly by single side band (SSB). Pilots communicate with control centers via oceanic radio stations. Aircraft reports, messages, and requests are relayed by the station to the appropriate air traffic control center (ATCC) by interphone, computer display, or teletype message. The relay function, coupled with the need for intercenter coordination, may cause delays in the handling of routine aircraft requests. There are priority message handling procedures for processing urgent messages that reduce any time tag; however, the crew should take possible delays into consideration when requesting step climbs, reroutes, or other routine requests requiring air traffic control (ATC) action. Delays can be reduced by advance planning of such requests.

b. Frequency monitoring. Aircraft should establish communications with the appropriate oceanic radio station upon entering a specific FIR. The station advises the aircraft of the primary and secondary HF frequencies in use. If possible, the flightcrew should monitor both of these frequencies. If only one frequency can be monitored, the primary should be guarded with the secondary being the first one checked in the event of lost communications on the primary frequency. If the selective calling (selcal) unit is working at the time of the initial contact, the crew should maintain a selcal watch on the appropriate frequencies. If the selcal unit is inoperative, or if the radio station has a malfunctioning selcal transmitter, the crew should maintain a listening watch. The oceanic station guarding for flight operations is normally the station associated with the ATCC responsible for the FIR (that is, Honolulu Aeronautical Radio, Incorporated (ARINC) for the Anchorage FIR and Tokyo Radio for the Tokyo FIR). At the FIR boundary the responsibility for the guard is changed, under normal signal conditions, to the station associated with each new FIR. The flightcrew must ensure that it has established communications with the new guard facility. Normally, each oceanic radio station continuously listens on all assigned frequencies. If enroute HF communications fail, every effort should be made by the flightcrew to relay progress reports through other aircraft. The very high frequency (VHF) frequency 128.95 megahertz (MHz) is for exclusive use as an air-to-air communications channel. In emergencies, however, initial contact for such relays may be established on 121.5 MHz (the frequency guarded by all aircraft operating in the oceanic airspace) and transferred as necessary to 128.95 MHz. In normal HF propagation conditions, appropriate overdue action procedures are taken by ATC in the absence of position reports or relays. In all cases of communications failure, the pilot should follow the oceanic clearance last received and not revert to the original flight plan.


Mach number technique for the South Pacific is identical to that used in NOPAC (see paragraph 5 in Chapter 4).


a. General. The procedures for inflight contingencies are often aircraft specific, and therefore cannot be covered in detail here for every aircraft. However, the procedures listed provide for such cases as inability to maintain assigned FL due to weather, aircraft performance, and pressurization failure. These procedures are primarily applicable when rapid descent, turning back, or both are necessary. The pilot's judgment determines the sequence of actions taken while considering the specific circumstances.

b. Basic Procedures. If an aircraft experiences navigational difficulties, it is essential that the pilot inform ATC as soon as the condition is apparent so that appropriate action can be taken to prevent conflicts with other aircraft. If any aircraft is unable to continue flight in accordance with its ATC clearance, a revised clearance shall, whenever possible, be obtained prior to initiating any action, using the radio telephone distress or urgent signals, as appropriate. If prior clearance cannot be obtained, an ATC clearance shall be obtained at the earliest possible time; in the meantime, the aircraft shall broadcast its position (including the ATS route designator) and intentions on 121.5 MHz at suitable intervals until ATC clearance is received. In such circumstances, communications with certain VHF stations may be practical. Frequencies should be verified before using. A list of these stations follows:

Adak approach - 134.1 MHz Anchorage Center - 127.4 MHz (Dutch Harbor)

Shemya tower - 126.2 MHz Anchorage Center - 127.8 MHz (St. Paul Island)

Anchorage Center - 128.5 MHz (Cold Bay) Anchorage Center - 128.2 MHz (Shemya)

If unable to comply with these provisions, the air-craft should leave its assigned route by turning 90 degrees to the right or left whenever possible. The direction of the turn should be determined by the position of the aircraft within the route system. The turn should be made in a direction that will keep the aircraft within the system and prevent any possible chance of a conflict with other traffic. For instance, aircraft on NOPAC routes should always turn south due to the proximity of these routes to the Russian FIRs. Aircraft on the northern route of the CEPAC route structure should turn south; aircraft on the southern route of the CEPAC route structure should turn north. An aircraft able to maintain its assigned level should, nevertheless, climb or descend 500 feet while acquiring and maintaining, in either direction, a track laterally separated by 25 nautical miles from its assigned route or track.