If the engine failure occurs after oceanic entry, the flight shall leave the assigned route or track by initially turning at least 45 degrees to the right or left. The direction of the turn shall be determined by the distance to the nearest alternate airport, deviation away from tracks, weather at alternate and diversionary airports and SLOP.

If ABLE to maintain the assigned flight level

The pilot shall maintain current altitude until after deviating 10 NM from the cleared track and thence establish the aircraft at a flight level which differs from standard by 500 feet if below FL410, or 1000 feet if above FL410, i.e. FL405 or FL 440. The flight crew shall alert nearby aircraft on frequency 121.5, 123.45 and the current HF frequency using MAYDAY-MAYDAY or PAN-PAN and advise intentions on 121.5 and the current HF frequency, the flight crew shall use maximum illumination of aircraft lighting consistent with limitations, squawk 7700, verify local state contingency procedures and complete relevant checklists.

For aircraft UNABLE to maintain the assigned flight level (due to engine failure, fuel freezing, etc.)

The pilot should minimize the rate of descent and, if continuing in the same direction, shall establish a 15NM offset and descend to a usable flight level which differs from standard by 500 feet if below FL410, or 1000 feet if above FL410, i.e. FL405 or FL 440. IMPORTANT, if it is necessary to reverse course and turn-back, the aircraft shall minimize descent until established on a 15NM offset and then expedite a descent below the majority of traffic, i.e. FL280. prior to commencing the turn back maneuver and then select an altitude which differs from standard by 500 feet if below FL410, or 1000 feet if above FL410, i.e. FL405 or FL 440. (NAT Doc 007.13.3) This is a relatively new procedure which was implemented due to requiring RNP-4 and utilizing half-degree waypoints which results in closer separation between opposite direction tracks (25NM). To summarize, if you need to turn back establish 15NM offset and then expedite descent below 280 degrees before turning. Although this is a NAT HLA procedure it may be advisable to conduct the same procedure

If the medical emergency occurs PRIOR to the oceanic boundary:

The pilot should request a turn toward the nearest alternate airport, increase airspeed to VMO or MMO providing sufficient fuel is available. Deploy passenger oxygen masks and instruct passengers to don masks if chest pain or difficulty breathing is suspected. If in radar environment, divert to the nearest suitable aerodrome, use maximum illumination of aircraft lighting consistent with limitations, verify local state contingency procedures and complete relevant checklists.

If the medical emergency occurs AFTER the oceanic boundary:

The pilot should request a turn toward the nearest alternate airport via HF frequency. If an undue delay occurs in a re-clearance, consider initiating a turn toward the nearest alternate, broadcast MAYDAY-MAYDAY or PAN-PAN, and advise intentions on 121.5, 123.45 and the current HF frequency. Increase airspeed to VMO or MMO providing sufficient fuel is available. Deploy passenger oxygen masks and instruct passengers to don masks if chest pain or difficulty breathing is suspected. Use maximum illumination of aircraft lighting consistent with limitations, verify local state contingency procedures and complete relevant checklists.

In the event of an emergency it is important to establish who will be performing what duties as the workload will increase, crew member may be dealing with physiological issues, confusion, etc. A recommendation from Scott IPC is to assign duties in the event of an emergency. For instance:

Establish Turn – Pilot Flying

Noting Time and Positions - Pilot Not Flying

Declaring Emergencies - Pilot Not Flying

FMS Programing - Pilot Not Flying

Verifying Driftdown Speed and Performance - Pilot Flying

Aircraft lighting configuration- Pilot Flying

Checklist Review- Pilot Not Flying