A Complete Manual for Conducting International Flight Operations
HF Check & SELCAL
Prior to Oceanic
The time spent prior to “coasting out” is fairly busy for a flight crew. It is during this phase that the crew shall establish enroute communications via HF, perform SELCAL checks, verify RVSM capability and compliance, receive an oceanic clearance, verify that all fuel, hydraulic and engine systems are functioning properly, verify that all navigation systems are functioning and capable of navigating to the level required within the oceanic airspace, ensure that the aircraft will enter oceanic airspace at the cleared level at the appropriate time, obtain last minute weather updates to ensure that the cleared oceanic route is acceptable and establish the cleared Mach number for the crossing.
Enroute Communications HF Check and SELCAL
Establishing enroute communications can be a very time consuming task due to the fact that the flight crew must determine what frequency is appropriate. This changes daily due to the propagation of HF signals. It may also be time consuming because there may be many other aircraft on frequency attempting to establish communications and requesting clearances at the same time.
For an aircraft departing the US, Westbound toward Hawaii, the following procedure shall be used.
Determine VHF Frequency
First, determine the VHF frequency for San Francisco radio. San Francisco Radio is the controlling agency for a giant portion of the CEP airspace. In this case the appropriate VHF frequency would be 129.4 or 131.95. On initial check-in the flight crew shall advise San Francisco radio of the tail number, the intended track and initial entry point, the destination and the estimated time at the destination, and request the HF frequencies for the flight.
“San Francisco radio, N74GG enroute Dinty for the Delta Track, destination Kona, estimating Kona 1200, request HF frequencies.”
The radio operator will then readback all items that you advised and then issue a primary and secondary HF frequency for the flight.
“Roger, N74GG enroute Dinty for the Delta Track, estimating Kona 1200, today’s HF frequencies are 5574, primary, 8843 secondary.”
Establish Enroute Communications via HF Frequency
After a readback of the HF frequencies to the radio operator, the Flight Crew shall establish enroute communications via HF frequency. The number one HF shall be tuned to 5574 and the second HF shall be tuned to 8843. It is important to keep in mind that if the aircraft shares the same antenna for both HF transmitters that both HF’s are not tuned to the same frequency when transmitting, and it is recommended that the other unit be placed in STBY to avoid damage to the HF system. Pilots should, however, review their aircraft specific HF installation for details.
On initial contact with San Francisco radio via HF, the flight crew shall advise the same information that was provided via VHF frequency and request a SELCAL check and provide their aircraft specific SELCAL identifier.
“San Francisco radio, N74GG enroute Dinty for the Delta Track, destination Kona, estimating Dinty 0800, request SELCAL check GMBC, over.”
At this point the radio operator will reconfirm all the information the flight crew has provided and issue a SELCAL check. SELCAL is a system onboard the aircraft that recognizes discrete tones sent over the HF which trigger a CAS message in the aircraft to alert flight crews that a radio operator is trying to raise the aircraft. The advantage of a SELCAL system is that the flight crew does not need to conduct a listening watch on a frequency which, due to the nature of HF, may have significant static and distortion.
Important notes regarding HF communication:
1. Communications with radio operators should be precise, read in a slow, deliberate manner with no jargon or non-essential phraseology. The radio operators may be thousands of miles away and there may be a great deal of distortion on the receiving end. It is also important to understand that you are now in international airspace and ICAO rules apply. All aircraft shall address their aircraft as N- November registered aircraft.
2. The radio operator that you are speaking to is just that, a radio operator. If a climb, turn or descent is requested, the radio operator will take your request and tell you to standby. The radio operator will then relay your request to an ATC unit who will then approve or deny the request. It is not unusual for it to take 10-15 minutes for a request to be granted or denied. For that reason, flight crews must provide ample time to request weather deviations, speed changes or flight level changes. Should an emergency weather deviation be required, the crew shall broadcast “Weather deviation required” or “PAN-PAN”. Aircraft deviating less than 10 miles shall maintain flight level. Aircraft deviating more than 10 miles shall maintain flight level until greater than 10 miles from track and thence, if eastbound, climb 300 feet for deviations to the south or descend 300 feet for deviations to the north. For aircraft that are westbound, the aircraft shall descend 300 feet for deviations to the north and climb 300 feet for deviations to the south once 10 miles off track. An easy way to think about this is climb to the equator; descend toward the poles. For more detailed procedures flight crews shall reference ICAO DOC 4444 15.2.4.
Eastbound Flights Over the Atlantic
Procedures for establishing enroute communications for eastbound flights over the Atlantic are very similar. Using the Atlantic Orientation Chart, the enroute frequency can be determined.
Once the proper HF frequency has been obtained and SELCAL checks have been conducted, the aircraft shall advise the current ATC controller that enroute communications have been established. One key difference between flights departing out of the United States over the Pacific versus flights over the Atlantic is that the initial clearance received on the ground also constitutes a Pacific oceanic clearance, whereas a flight over the Atlantic generally requires the flight crew to obtain an oceanic clearance. Exceptions to this would be New York airspace, for example. Regardless, it is important for the flight crew to determine in advance whether they are cleared into oceanic airspace prior to entry.
Revision date: July 29, 2015
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