ENR 2.2 OTHER REGULATED AIRSPACE
REQUIRED NAVIGATION PERFORMANCE (RNAV1/RNAV5) IN THE MUSCAT UTA
1. RNAV1/RNAV5 NAVIGATION REQUIREMENTS
1.1 RNAV1/RNAV5 airspace is established and ATC will apply 1/5 NM lateral separation with radar monitoring to RNAV1/RNAV5 approved aircraft operating on airways and in the Muscat UTA above FL280.
1.2 Pilots must advise ATC of any deterioration or failure of the navigation system below the navigation requirements for RNAV1/RNAV5. ATC shall then provide alternative separation and/or alternative routing.
1.3 Operators of aircraft meeting RNAV1/RNAV5 PBN requirements must indicate /R in item 10 of the ICAO Flight plan. Due to significant differences between RNAV1/RNAV5 (as applied in adjacent FIR), operators are reminded of the requirements of ICAO Doc. 4444 (PANS-ATM) Appendix 2 (Item 10 Note 5) which states: ”Inclusion of letter R indicates that an aircraft is PBN approved for the route segment(s), route(s) and/ or area concerned.”
2. OPERATIONS BY AIRCRAFT NOT MEETING RNAV1/RNAV5 REQUIREMENTS
2.1 ATC units receiving a request for a non-RNAV1/ RNAV5 approved aircraft to operate in RNAV1/RNAV5 route and airspace specified in paragraph 1.1 will coordinate with adjacent ATC units affected by the flight. In deciding whether or not to approve the flight, each ATC unit will take into consideration:
a) traffic density
b) communications, including the non-availability of normal communication facilities
c) weather conditions on route; and
d) any other factors pertinent at the time.
3. SAFETY ASSESSMENT CRITERIA
3.1 The safety case criteria associated with the introduction of the reduced lateral separation minima applied between RNAV1/RNAV5 routes will be in accordance with the requirements of RNAV1/RNAV5 navigation performance, i.e. aircraft navigation performance shall be such that the standard deviation of lateral track errors shall be less than 5 NM.
4. MONITORING OF AIRCRAFT NAVIGATION PERFORMANCE
4.1 Monitoring of aircraft navigation performance is a joint responsibility between Operators, States of Registry, States of Operators (as applicable), regulatory authorities and the ATS providers. The detection and reporting of non-conformance with the navigation requirements against the following parameters will rely primarily on radar monitoring by radar units:
a) lateral deviations: a deviation of 5 NM or more from track centerline based on radar observations; and
b) longitudinal deviations:
I) where time separation is being applied by ATC - when the reported separation based on ATC verified pilot estimates varies by 3 minutes or more from the expected separation at the reporting point; or
II) where a distance-based standard is being applied by ATC based on either ADS, radar observation or RNAV distance reports - when the distance varies by 5NM or from the expected distance.
4.2 ATC will advise the pilot in command when such deviations are observed and implement the required investigation procedures.
4.3 The ATC authority will investigate the cause of such deviations in conjunction with the aircraft operator, and the State of Registry, or the State of the Operator, as applicable.
5. SEPARATION MINIMA
5.1 Lateral Separation Minima
a) The separation minima specified in 1.1 will be applied between RNAV1/RNAV5 approved aircraft.
b) When an aircraft not meeting the requirements of RNAV1/RNAV5 is approved to operate in the airspace specified in paragraphs 1.1 and 1.2, radar separation and/or vertical separation will be applied with aircraft operating on adjacent routes.
5.2 Longitudinal Separation
a) 80 NM RNAV or 10 minutes (or less) Mach Number Technique (MNT) or the appropriate radar separation may be applied between aircraft.
5.3 Vertical Separation
a) Vertical separation minima of 1000 FT, including the use of non-standard levels, will be applied between aircraft operating at FL410 or below and 2000 FT above FL410, on the ATS routes and areas specified in paragraph 1.1.
6. OPERATORS PROCEDURES
6.1 The operator shall ensure in-flight procedure, crew manuals and training programs are established in accordance with RNAV1/RNAV5 requirements.
7. CONTINGENCY PROCEDURES (INCLUDING WEATHER DEVIATION)
7.1 In the event of several weather or other factors disrupting the use of RNAV1/RNAV5 routes and airspace in the Muscat FIR, vertical separation and/or radar and/or procedural separation shall be applied to all airspace users. These minima may also be applied to traffic exiting the Muscat FIR if requested by the accepting unit.
8. MEANS OF COMPLIANCE
8.1 The State of Registry or the State of Operator, as appropriate, shall verify conformance to the navigation requirements and the necessary approval processes.
8.2 Operators of Omani registered aircraft not having a prior approval to operate in RNAV1/RNAV5 airspace shall submit a request for approval to the Director of Flight Safety. Such requests shall contain the following information:
a) aircraft type and series
b) navigation equipment (list by name, type, model and manufacturer)
c) communications equipment (list by name, type, model and manufacturer)
d) B/RNAV and RNAV1/RNAV5 time limit (number of hours or unlimited)
e) a statement that flight crews have been trained in accordance with the requirements of the ICAO PBN Manual (DOC 9613)
8.3 Aircraft already approved to operate in designated European Flight Information Regions in accordance with those requirements for B/RNAV or RNAV1/ RNAV5 satisfy the requirements for RNAV1/RNAV5 operations in the Muscat FIR. A copy of this approval letter should be submitted to the Director of Flight Safety at the address: Civil Aviation Authority, P.O. Box 1, POSTAL CODE 111, MUSCAT, Sultanate of Oman.
Guidance on navigation accuracy and other operational requirements for the application of navigation based on performance to a given route or area are contained in the ICAO Document DOC 9613 - “Performance based navigation (PBN) Manual”.
9. FLIGHT PLAN REQUIREMENTS
9.1 Operators of aircraft equipped with RNAV having a navigation accuracy meeting RNAV1/RNAV5 shall insert the designator “R” if PBN approved in item 10 of the standard ICAO flight plan.
9.2 Operators of aircraft not equipped with RNAV having a navigation accuracy meeting RNAV1/RNAV5, or whose equipment is no longer capable of providing the required accuracy, shall not insert the designator “R” in item 10 of the standard ICAO flight plan. Since such flights require special handling by ATC, “STS/NORNAV” shall be inserted in item 18 of the flight plan.
10. PROCEDURES FOR OPERATION IN RNAV1/RNAV5 AIRSPACE
10.1 Correct operation of the aircraft RNAV equipment shall be verified before joining and during operation in RNAV1/RNAV5 airspace. This shall include confirmation that:
a) the routing is in accordance with the clearance; and
b) the aircraft navigation accuracy meets RNAV1/ RNAV5.
10.2 If, as a result of failure of the RNAV system or its degradation to below RNAV1/RNAV5, an aircraft is unable to either enter airspace designated RNAV1/RNAV5 or continue operations in accordance with the current ATC clearance, a revised clearance shall, wherever possible, be obtained by the pilot.
The pilot should advise ATC by means of the phrase “NEGATIVE RNAV” immediately following RNAV failure or degradation below RNAV1/RNAV5.
10.3 Subsequent ATC action in respect of that aircraft will be dependent upon the nature of the reported failure and the overall traffic situation. Continued operation in accordance with the current ATC clearance may be possible in many situations. When this cannot be achieved, a revised clearance may be required to revert to VOR/DME or other forms of navigation.
11. CANCELLATION OF RNAV1/RNAV5 AND B/RNAV APPROVAL
11.1 When appropriate, the CAA may consider any navigation error reports in determining remedial action. Repeated occurrences of navigation errors , specific piece of navigation equipment or air crew errors, may result in cancellation of the Letter of approval by the CAA - Oman.