If one long-range navigation system fails before takeoff, the crew should consider the following options:

Delaying the departure until the system is repaired, or

Filing a revised flight plan using special routes, which have been issued for aircraft with partial loss of navigation capability.

Note: These special routes are available only if the remaining navigation equipment meets the minimum navigation performance specifications (MNPS) and the requirements in ICAO Annex 6, Part 1 are met using short-range navaids. Request a clearance above or below MNPS airspace.

If one long-range nav system fails after takeoff, but before the aircraft reaches the oceanic boundary, the crew should consider the following options:

Landing at an en route airport that has suitable repair capabilities, or returning to the departure airport.

Filing a revised flight plan using the special routes as just described.

Requesting a clearance above or below MNPS airspace.

If one long-range nav system fails after the aircraft crosses the Oceanic Control Area boundary, the crew may continue to operate the aircraft in accordance with the oceanic clearance received, recognizing that the reliability of the total navigation system is significantly reduced.

If, after entering oceanic airspace and losing one navigation system, the remaining system fails or gives an indication of degraded performance, the flight crew must immediately advise ATC of the loss of navigation equipment.

After assessing the circumstances, consult with ATC to select one of the following optional courses of action:

Continuing to destination.

Diverting to a suitable alternate.

Turning back.

In addition to the forgoing,

Obtain an appropriate clearance from ATC prior to any deviation from the current oceanic clearance.

Keep a special lookout for possible conflicting traffic, and use all available outside lights.

Using VHF radio, attempt to establish voice contact with adjacent aircraft to assist in maintaining separation.

Monitor the aircraft position on the plotting chart every 5 min. If no instructions are received from ATC within a reasonable period (approximately 10 min.) after notifying them of the loss of navigation systems, the pilot should clear the oceanic track and use dead-reckoning procedures to continue the flight.

Immediately climb or descend 500 ft., if at or below FL 290; or 1,000 ft., if above FL 290.

Initiate a turn 90 deg. right/left of course, preferably in a direction away from any organized track in the area.

Continue on the 90-deg. offset heading until 30 nm from the original assigned track. Use timing procedures to estimate the distance flown. (If ground speed is 360 kt., or 6 nm per minute, fly the offset heading for 5 min.)

When offset by 30 nm, turn back to the original heading to parallel the original track and continue the flight.

Plot new waypoints (now offset by 30 nm from the originals), using the heading and ETE between points on the master flight plan to define them. Note: The ETA to the next waypoint will be later than planned because of the time spent flying to the offset course (5 min. in the example above). Adjust all subsequent ETAs by that amount.

Over each waypoint, turn to maintain a new course, if required, using the magnetic compass. Make note of the course, time of waypoint passage, time to the next point, fuel remaining and fuel burn between points on the master flight plan.

Continue to monitor both the assigned HF frequency and the appropriate VHF frequency (121.5, 131.80 Atlantic; or 128.95 Pacific) for any position reports in the vicinity. Use the information on winds and temperature aloft to update flight plan estimates.

Monitor all Volmet (i.e., meteorological) reports, significant weather (SIGMETs) and forecasts for selected airports that are broadcast at specified times on HF frequencies. The HF frequencies and times of broadcast can be found on the Atlantic Orientation Chart or in the meteorology section of the Atlantic Jeppesen binder. Monitoring these reports en route helps crews select a suitable alternate landing site if the weather is below VFR at the intended destination.

If radio contact can be re-established, advise ATC of the situation and actions taken. Request an amended clearance, if necessary.

Again, with proper preparation, flying the oceans can be a highlight in a professional aviator's career and deliver cultural insights, new experiences and vistas that make a life of travel so rewarding. BCA

Excerpted from Practical Applications in Business Aviation Management, by James Cannon and Franklin Richey, published by Government Institutes, 2012; www.govinstpress.com