Figure C - 17: ITP clearance Figure C - 18: Accept the clearance
When the aircraft engages the ITP maneuver and is more than 300 ft from the initial FL, the ATSAW function displays the message VERTICAL MANEUVER IN PROGRESS in the ITP TRAFFIC LIST page (refer to Figure C - 19). The ATSU triggers a report level message when the FL in the report level instruction is reached (refer to Figure C - 20).
Figure C - 20: Report level during the ITP maneuver
Note 1: If ITP is no more possible when the flight crew receives the ITP clearance, the flight crew must refuse the ITP clearance.
Note 2: If a problem occurs during the ITP maneuver, the flight crew must apply the regional contingency procedures as required.
C.3.6. SPECIFIC CASES
When there is no Reference Aircraft in the ITP volume (refer to Figure C -21), the ATSAW function indicates that:
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The ITP is not applicable
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The flight crew should request a standard clearance.
The ATSAW function displays in the MCDU scratchpad the flight level and the range of:
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An aircraft (ADS-B or not) that is at the desired FL in the ITP volume, or
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An ADS-B aircraft that is not on the same direction in the ITP volume..
However, the ATSAW function may display “ITP POSSIBLE” despite the non-ADS-B aircraft. Indeed, the ATSAW function considers only ADS-B traffic to declare the ITP possible or not possible.
The ATC controller remains responsible for the aircraft separation during an ITP maneuver, for the following reasons:
- Some aircraft may not be equipped with an ADS-B OUT transmitter. Therefore, the ATSAW function is not able to detect all surrounding aircraft. Consequently, only the ATC controller has the knowledge of the entire traffic.
- The initial ATSAW function is not designed for self-separation.
Figure C - 21: ITP not applicable Figure C - 22: Non-ADS-B aircraft in the ITP volume
C.4. OPERATIONAL ENVIRONMENT
ITP can be applied in theory in any RVSM / Non-RVSM airspace where procedural control is used. Conditions for operational approval include controller training to ITP. For the procedure to provide the expected benefits, a non exhaustive list of conditions are provided below:
- Separation standards with minima greater than 15 NM,
- Sufficient number of ADS-B OUT equipped aircraft
- Aircraft usually following similar routes (e.g. North Atlantic Organized Track System).
C.5. CRISTAL ITP
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