a. The concept of Minimum Navigation Performance Specifications (MNPS) has been adopted on a world-wide basis by the International Civil Aviation Organization (ICAO). MNPS has the objective of ensuring safe separation of aircraft and of enabling operators to derive maximum economic benefit from the improvement in accuracy of navigation equipment which has been demonstrated in recent years. A condition implicit of MNPS is that all operators must maintain the specified operating standards and be aware of the inherent obligations of the MNPS requirements. The MNPS concept will be implemented on a regional basis. Certain areas of the North Atlantic (NAT) region have introduced the MNPS concept. These areas are known as NAT MNPS airspace and include the following defined airspace boundaries:
1. Between FL285 and FL420.
2. Between latitudes 27°N and the North Pole.
3. In the East - the Eastern boundaries of the controlled areas (CTAs) of Santa Maria Oceanic, Shanwick Oceanic and Reykjavik.
4. In the West - the Western boundaries of the CTAs of Reykjavik, Gander Oceanic and New York Oceanic excluding the area west of longitude 60°W and south of 38°30'N.
b. Aircraft used to conduct flights within the volume of airspace specified shall have navigation performance capability such that:
1. The standard deviation of lateral track errors shall be less than 6.3 NM (11.7 km).
As a considerable simplification, the above can be interpreted as a need for aircraft to stay within 12.6 NM (23.4 km) of track for about 95 percent of the time.
2. The proportion of the total flight time spent by aircraft 30 NM (55.6 km) or more off the cleared track shall be less than 5.3x104 (i.e., less than 1 hour in about 2,000 flight hours).
3. The proportion of the total flight time spent by aircraft between 50 and 70 NM (92.6 and 129.6 km) off the cleared track shall be less than 13x105 (i.e., less than 1 hour in about 8,000 flight hours).
c. Such navigation performance capability shall be verified by the State of Registry or the State of the aircraft operator as appropriate. Guidance material of use to those involved in the initial achievement and continued maintenance of the navigation capability set forth above has been issued by ICAO under the title "Guidance Material related to Air Navigation in the NAT Region'' and will be supplemented and updated as required and as new material becomes available.
d. Flights entering MNPS airspace during any portion of their flight must enter the letter "X" after the letter "S" in item 10 of the ICAO flight plan to indicate that the flight has been certified as complying with MNPS.
e. Aircraft incapable of meeting MNPS in MNPS airspace will be given special consideration only in a very limited number of justified cases. Such consideration will require advance coordination between the requesting operator and the appropriate ATC authorities. The decision as to whether to allow such operations, and if so, the best method of operation will be made by the ATC authorities concerned with that airspace. The decision will be based upon the nature of the operation, the navigation capability of the aircraft, and the amount of air traffic forecast for the proposed time of operation. Final routing and/or handling or any such approved special arrangements will be in a manner that will not interfere with or impose a burden upon aircraft complying with MNPS.
f. The FAA has published Advisory Circulars 91-49 and 91-70 offering a means of obtaining authorization to operate within NAT/MNPS airspace for operations conducted under 14 CFR Part 91 and 14 CFR Part 135. Advisory Circular 120-33 contains guidance for acquiring authorization to operate in NAT/MNPS airspace under 14 CFR Parts 121, 123 and 135.2. Civil operators contemplating use of Loran C in MNPS airspace are advised to follow the MNPS certification process outlined in the appropriate advisory circular.
1-8-2. MONITORING OF NAVIGATION ACCURACIES
a. The data from which MNPS was calculated was derived from previous routine and special data collections involving radar observations and monitoring of equipment performance. In order to ensure that the MNPS are being met, it is necessary to monitor the tracking accuracy of aircraft using the ATC radars which cover the exits from the oceanic airspace. The frequency of occurrence of the larger track deviations will be used as a measure of compliance with the second and third parameters of the specification. In cases of individual large errors, the pilot of the aircraft concerned will normally be notified by the ATC unit observing the error. The subsequent investigation may be carried out by the operator and its State of Registry after notification by the authority providing ATC service. If there is a serious increase in the number of large errors, it may become necessary to increase separation standards until remedial action has been determined. Alternatively, if rapid corrective action cannot be achieved, it may be necessary for the State of Registry or the State of the aircraft operator to temporarily exclude offending types of aircraft, or operators, from the MNPS airspace.
b. An operator with MNPS approval who experiences a partial loss of navigation capability prior to entry in MNPS airspace should consider the following routes:
1. From Stornoway N60°W10°-N61°W12°34' -ALDAN - Keflavik (HF required on this route);
2. From Benbecula N61°W10°-ALDAN- Keflavik (VHF coverage exists, and subject to prior coordination with Scottish Airways and Shanwick, this route can be used by non HF equipped aircraft);
3. From Machrihanish/Glasgow/Shannon/ Belfast N57°W10°-N60°W15°- N61°W16°30'- BREKI - Keflavik (HF is required on this route);
4. Keflavik-GIMLI-Kulusuk-Sondre Stromfjord-Frobay (HF is required on this route)
5. Keflavik-EMBLA-N63°W30°-N61°W40°W -Prins Christian Sund;
6. Prins Christian Sund -N59°W50°- PRAWN-NAIN;
7. Prins Christian Sund- N59°W50°- PORGY-Hopedale;
8. Prins Christian Sund- N58°W50°- LOACH-Goose VOR;
9. From Cork, LOACH - Goose VOR; and Lands End-Gapli (HF is required on this route);
10. Funcha/Porto Santo - Santa Maria/Ponta Delgada/Lajes;
11. Lisboa/Porto/Faro - Ponta Delgada/Santa Maria/Lajes;
12. Between Greenland and Canada (HF is required over the Greenland icecap below FL 195): - Sondre Stromfjord NDB N67°W60°, Cape Hooper NDB; - Kook Islands NDB, N66°W60°, Cape Dyer NDB; - Kook Islands NDB, N66°W60°, N64° W63°, Frobay VOR; and
13. Between Iceland and Greenland: Reykjanesskoli NDB, N69°30'W22°40', Constable Pynt NDB.
c. Operations on the above routes in MNPS airspace are subject to the following conditions:
1. A revised flight plan is filed with ATC, and
2. An appropriate ATC clearance is obtained.
A revised oceanic clearance will be issued only after coordination between all Oceanic Area Control centers concerned.
3. Sufficient navigation capability remains to meet the MNPS (i.e., redundancy may be lacking).
4. The aircraft concerned may have to accept a lower than optimum flight level during peak traffic hours if the organized track structure extends to the northern part of the NAT.
5. Nothing in these instructions override any redundancy requirements placed upon an operator by any Operations Specifications or 14 CFR Parts 121, 123, or 135.2, as appropriate.
1-8-3. ROUTES BETWEEN ICELAND AND NORTHERN EUROPE
a. After a review of the navigation facilities available between Iceland and Northern Europe, it has been agreed upon by the ICAO members that aircraft equipped with normal airways navigation equipment should be capable of meeting the MNPS when operating over certain routes between Iceland and Northern Europe. The routes will be designated G3 and G11 within and outside MNPS airspace.
1. G3 will be established as a route between Fresland via Myggenes and Ingo to Keflavik.
2. G11 will be established between Sumburgh via Akraberg to Myggenes.
b. Operation on certain routes between North Eastern Canada and Ireland or Northern United Kingdom via Iceland:
1. It is anticipated that a continued requirement may exist for selected routes between N.E. Canada and Iceland and between Iceland and points in Ireland or the Northern U.K. which could be used by aircraft not normally used in North Atlantic operations or by aircraft on delivery. The routes listed in subparagraph a.2 above should be used for such operations. Aircraft operating along these routes in MNPS airspace which are equipped with normal airway navigation equipment (VOR/DME, ADF) and at least one fully operational set of the following long-range navigation equipment:
(a) Doppler with computer
(c) GPS; and
(d) Loran C
are considered capable of meeting MNPS while operating along these routes.
2. The above listed long range navigation equipment need not be permanent aircraft equipment.
1-8-4. ROUTES BETWEEN SPECIFIC POINTS IN PORTUGUESE TERRITORY
Aircraft that are equipped with normal airway navigation equipment (VOR/DME, ADF) and at least one fully operational set of the following long-range navigation equipment:
a. Doppler with Computer
are considered capable of meeting MNPS while operating along the following routes:
a. Funchal/Porto Santo-Santo Maria/Ponta Delgada
b. Lisboa/Porto/Faro-Ponta Delgada/ Santa Maria/Lajes