.
Before the FAF, minimum altitudes are published with fixed Minimum Obstacle Clearance (MOC).
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The point in the procedure before the FAF from which a constant vertical flight path is defined and can be coded in the Navigation Database (NDB) is called Vertical Intercept Point (VIP) or Final Descent Point (FDP) or is only represented by a symbol. This is the latest point where the pilot is expected to engage the VNAV system (FINAL APP mode).
The other example below is a tailored approach procedure designed in Lassa by Naverus ,
another service company working in cooperation with Airbus.
This approach procedure is airline and aircraft specific (A319).
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6. RNP AR Instrument procedures
Getting to grips with RNP AR
In this approach, the VIP is located at LS 410 and the note
1 indicates that the FINAL APP mode must engaged at this waypoint.
On a tailored approach charts like this one a number of instructions specific to the aircraft type can be indicated, such as required navigation equipment and FMS procedure steps or entries.
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6. RNP AR Instrument procedures
Today (2008), there is no procedure design standard for RNP AR departures.
Naverus has developed its own standards, which meet the concurrence of FAA and other
national authorities.
An example of departure procedure developed by Naverus for Lassa is given below.
The procedure only defines an horizontal flight path and airspeed constraints to avoid reaching bank angle limitations.
Associated to this flight path, the procedures designer must publish the position and height of the obstacles that are within the corridor of ±2*RNP.
These obstacles must be used by the airline to compute takeoff performance data, which ensures that the takeoff flight path clears the obstacles with the regulatory margin.
Adapted flight crew procedures, compatible with the lateral flight path, may have to be developed.
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7. RNP AR Operations and Training
Getting to grips with RNP AR
7. RNP AR OPERATIONS AND TRAINING
As indicated by the FAA acronym “SAAAR”, this type of operations is Aircraft & Aircrew specific, which means that specific flight crew procedures need to be developed and trained. A parallel is sometimes made with CAT III operations giving the impression that RNP AR operations are standardized and identical everywhere. This is obviously not true. If the final vertical flight path has in general a constant slope, preferably about 3°, the choice for the horizontal flight path is quite flexible. This gives its operational efficiency to the RNP AR concept, but also its constraints, as complex horizontal flight paths may require to define adapted flight crew procedures.
The instrument procedure environment may as well impose its own constraints. A procedure designed in a mountainous area requires additional precautions in the development of contingency procedures to maintain an adequate level of safety.
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