8-5-1 Altitude/Flight Level Transition

 When vertical separation is applied between aircraft crossing the offshore/oceanic airspace boundary below FL 180, control action shall be taken to ensure that differences between the standard altimeter setting (QNE) and local altimeter setting (QNH) do not compromise separation. (See Figure 8-5-1).

              Figure 8-5-1
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             Conversion Example
       QNE to QNH Altimeter Setting

    Local Station     Domestic Altitude
   Altimeter Setting        (QNH)

       30.52"              15,600'
       30.22"              15,300'
       29.92"              15,000'
       29.42"              14,500'
       28.92"              14,000'

        Oceanic Altitude = FL 150
         Altimeter 29.92" (QNE)
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8-5-2 Course Divergence

 When aircraft are entering oceanic airspace, separation will exist in oceanic airspace when:
 a. Domestic lateral separation exists at the oceanic control boundary;
 b. Courses diverge by a least 15° until the oceanic lateral separation is established.

8-5-3 Opposite Direction

 When transitioning from an offshore airspace area to oceanic airspace, an aircraft may climb through opposite direction oceanic traffic provided vertical separation above that traffic is established:
 a. Before the outbound crosses the offshore/oceanic boundary; and
 b. 15 minutes before the aircraft are estimated to pass. (See Figure 8-5-2)
 

8-5-4 Same Direction

 When transitioning from an offshore airspace area to oceanic airspace or while within oceanic airspace, apply 5 minutes minimum separation when a following aircraft on the same course is climbing through the altitude of the preceding aircraft if the following conditions are met:
 a. The preceding aircraft is level at the assigned altitude and is maintaining a speed equal to or greater than the following aircraft; and
 b. The minimum of 5 minutes is maintained between the preceding and following aircraft; and
 c. The following aircraft is separated by not more than 4,000 feet from the preceding aircraft when the climb clearance is issued; and
 d. The following aircraft commences climb within 10 minutes after passing:
  1. An exact reporting point (DME fix or intersection formed from NAVAIDs) which the preceding aircraft has reported; or
  2. A radar observed position over which the preceding aircraft has been observed; and
 e. The following aircraft is in direct communication with air traffic control until vertical separation is established. (See Figure 8-5-3)