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Minimum Navigation Performance Specification - IVAO - International Virtual Aviation Organisation
MINIMUM NAVIGATION PERFORMANCE
SPECIFICATION
INTRODUCTION
In geographical areas where air traffic control can track aircraft with limited coverage, Minimum
Navigation Performance Specification has been designed .
This requires aircraft to operate with enhanced tracking capabilities and redundant navigational means.
These requirements enable to diminish separations between aircraft to maintain an air traffic flow well
above operational limitations otherwise.
AREA OF REFERENCE
The area of reference for this article is the North Atlantic Region - High Level Airspace (NAT HLA).
If local provisions exist, they can be found in national AIPs.
PRE-FLIGHT REGULATIONS
FLIGHT RULES
Flights shall be conducted in accordance with the Instrument Flight Rules when operated at or
above flight level (FL) 60 or 600 m (2 000 ft) above ground, whichever is the higher.
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FLIGHT PLANS
The following items must be stated in the flightplan of any aircraft operating through the NAT region:
REG/ in field 18 if the aircraft registration is not the aircraft callsign
CODE/ in field 18 stating the aircraft address if available
Mach number at any portion of oceanic transit should be inserted in field 15.
Any requirements regarding the route formatting can be found in the subchapter navigation
In addition to the previous prerequisites, the following table will summarize the required serviceable
items to be present in the flightplan of any aircraft operating through the NAT HLA:
Navigation equipment
Communication equipment
Surveillance equipment
Item
Case 10a designator Case 18 designator
RNP 10 or/and RNP 4 capabilities R
PBN/A1 or/and PBN/L1
MNPS capability
X
Nil
RVSM capability
W
Nil
CPDLC capability
J2 or J5 or J7
CODE/
Item
Case 10b designator Case 18 designator
ADS-B
B1 or B2
Nil
ADS-C
D1
Nil
Note that the required PBN differs depending on the FIR in which the aircraft operates. Refer to navigation
chapter for conditions of applicability.
Estimated Elapsed Time (EET/) should not be inserted on the IVAO network due to software
limitations. The risk is to generate a too large flightplan which will not be visible by the ATCs.
An aircraft which is not meeting MNPS requirements shall not be allowed to operate in NAT HLA
unless:
ATS surveillance service is being provided
Direct controller-pilot VHF voice communication is maintained
Equipment to maintain navigation accuracy is serviceable and used to navigate along the
cleared track.
The Minimum Equipment List (MEL) of the aircraft may include possible deviations with or without
operating restrictions depending on failed system's redundancy.
OPERATIONAL REGULATIONS
AIR TRAFFIC CONTROLLER
AIR TRAFFIC SERVICES
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LATERAL SEPARATIONS
We assume in the following table that the applicability automatically includes holding a valid MNPS
certification.
If no additional requirements are mentioned, then it is applicable to any aircraft simply holding a
MNPS certificate.
Applicable FIR
Minimum distance between 2 aircraft
Applicability/Restrictions
CZQX
BIRD
EGGX
23 NM
RNP 4
CPDLC
ADS-C
KZWY
LPPO
30 NM
RNP 4
ADS-C
KZWY
LPPO
50 NM
RNP 10
RNP 4
All
60 NM
Both traffic MNPS
All
90 NM
One traffic not MNPS
All
120 NM
Both traffic not MNPS
LONGITUDINAL SEPARATIONS
Applicable
FIR
CZQX
BIRD
EGGX
LPPO
Minimum
separation
5 minutes
Type of
aircraft
All
Separation technique
Applicability/Restrictions
Nil
CPDLC
RNP 10 or RNP 4
ADS-C
KZWY
LPPO
30 NM
All
Nil
CPDLC
RNP 4
ADS-C
KZWY
LPPO
50 NM
All
Nil
CPDLC
RNP 10
ADS-C
Turbo-jet
Mach number
Common reporting
point
Diverging track
Nil
All
10 minutes
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All
15 minutes
Turbo-jet
Nil
Nil
All
30 minutes
Non turbojet
Nil
Nil
VERTICAL SEPARATIONS
As the NAT HLA region is RVSM, between FL290 and FL410 inclusive, 1 000 ft of vertical separation
should be provided between two aircraft.
For supersonic aircraft only: when operating at or above FL450, at least 4 000 ft should exist
between a supersonic aircraft and any other traffic.
COMMUNICATIONS
This part does not deal with phraseology but solely with regulatory aspects in relation to
communication means and requirements.
See phraseology accordingly.
CLEARANCE
Before entering the NAT control areas, flight crews are required to request their oceanic clearance.
The contents of this message must include:
The track code if navigating by use of the Organised Track System; or, the full routing that the
aircraft must follow using waypoint identifiers and geographical coordinates as appropriate
The cleared flight level
The cleared Mach number
the part "SEND MET REPORTS" if in-flight meteorological information is sought by ATS.
The flight crew is required to read-back the clearance in its entirety, including the full routing as
applicable.
Depending on the sector, flight crews are required to retrieve their oceanic clearance at least a
minimum of time before effective entry.
Due to air traffic flow management, traffic may be assigned a time of entry into NAT airspace. This
time will be indicated in the clearance using the 4-digit format.
POSITION REPORTS
When operating inside the NAT airspace, flight crews are required to transmit their position by means
of position reports. These reports must take place at the following locations:
For east-west direction:
Any intermediate meridians between 5°W and 65°W at intervals of 10 degrees of
longitude south of 70°N
Any intermediate meridians between 10°W and 50°W at intervals of 20 degrees of
longitude north of 70°N
For south-north direction: as applicable by the cleared route.
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Whenever the aircraft reaches a significant waypoint as applicable on an organised track.
The contents of these messages must include:
The current position in latitude and longitude or using the waypoint identifier
The current time, or if posterior, the time at which the point of report was overflown
The current flight level
The current Mach number
The next waypoint to be flown
The estimated time at which the next waypoint will be overflown
The waypoint to be overflown thereafter
In-flight meteorological information only if sought explicitly by ATS in the clearance.
The flight crew should expect a full read-back of the report by the ATC.
Contrary to the general phraseology rule indicating to express time by solely using minute reference,
time in position reports should be indicated using the 4-digit format.
If the expected time of arrival overhead the next waypoint is found to be in error of 3 minutes or
more, a revised estimate should be given to the ATS unit as soon as possible.
CPDLC OPERATIONS
When fitted with the appropriate equipment, flight crews should endeavor to maximise use of CPDLC
while flying through the NAT region.
This can be achieved on the IVAO network by using the text interface of the IVAO Pilot interface.
SELCAL OPERATIONS
SELCAL watch fulfills the requirement to maintain an active air-ground communication watch.
However, when serviceable and aimed to be used, it requires:
the inclusion of the SELCAL code in the flightplan in field 18 using identifier SEL/
an operational check of the SELCAL equipment prior to or at the entry point
Air traffic controllers can review the use of the SELCAL with consulting the adequate documentation
corresponding to his IVAO ATC software.
SATCOM & HF OPERATIONS
Not applicable on the IVAO network.
FLIGHT CREW
NAVIGATION
PERFORMANCE-BASED NAVIGATION
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Prior to operating in the NAT FIRs between FL285 and FL420, at least one of the following
Performance-Based Navigation items should be achieved for MNPS certification:
RNAV 10
RNP 4
ORGANISED TRACK SYSTEM (OTS)
When necessary in order to optimise the flow of air traffic inside the FIRs of CZQX, EGGX, KZWY, LPPO
and BIRD, an organised track system (OTS) can be established.
The OTS consists of establishing routes for the day allowing the flow of traffic to be divided onto
different tracks, enabling the use of separation between traffic more accurately and more precisely.
Flight crews should plan to file a route using the OTS when possible.
In that case, the flightplan should mention the track to be used in the route (field 15) using the
following format: NATx; where x is the track identifier according to the OTS message.
It is a requirement to carry a copy of the OTS message to allow for a crosscheck of routing if deemed
necessary.
The OTS message can be found here: official OTS message (https://www.notams.faa.gov/common/nat.htm
l)
Depending on the traffic levels on each track, an aircraft can be re-routed and assigned a new track
by the ATC when copying its oceanic clearance.
Subsequently, it is vital to perform the new route insertion, crosscheck the FMC route against the
OTS message, and clarify any doubts about the routing if necessary.
RANDOM ROUTING
When planning the route, if it becomes necessary that the use of organised track system is not suitable,
then it is possible to plan a route across the NAT region using waypoints formed by the intersection of
parallels and meridians, often referred to as random routing.
The following rules must be applied when planning the route:
The elapsed time between two waypoints must not be less than 30 minutes and must not be
more than 60 minutes.
A deviation to this rule is applicable to polar flights only when it is required to smooth turns onto
next significant waypoints. In that case, intermediate waypoints may be used without being
referenced in the flight plan route.
For east-west direction (considered as default for Europe-North America flights), significant
waypoints are formed by:
South of 70°N inclusive: intersection of half or whole degrees of latitude with meridians
spaced at intervals of 10 degrees from the Greenwich meridian to longitude 70°W
North of 70°N and at or south of 80°N: the intersection of parallels of latitude expressed
in degrees and minutes with meridians normally spaced at intervals of 20 degrees from
the Greenwich meridian to longitude 60°W, using the longitudes 000W, 020W, 040W and
060W
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North of 80°N: the intersection of parallels of latitude expressed in degrees and minutes
with meridians expressed in whole degrees
For south-north direction (considered as default for any polar flights), significant waypoints are
formed by:
South of 80°N inclusive: the intersection of whole degrees of longitude with parallels of
specified latitude spaced at intervals of 5°.
North of 80°N: the intersection of parallels of latitude expressed in degrees and minutes
with meridians expressed in whole degrees.
For flights operating south of 80°N in an east-west direction, if the flight time between two
significant waypoints as defined exceeds 1 hour, intermediate waypoints should be established:
South of 70°N inclusive: at intervals of 10 degrees of longitude (between 5°W and 65°W)
North of 70°N and south of 80°N inclusive: at intervals of 20 degrees of longitude
(between 10°W and 50°W)
Anytime the flight time between a significant point and an intermediate waypoint defined
as above becomes less than 30 minutes, the intermediate waypoint can be ignored.
SPECIAL PROCEDURES
DEVIATION FROM CLEARED ROUTE
In a non-radar environment, deviation from the intended flightpath is a serious threat to flight safety.
This is why flight crews should regularly ensure that the aircraft’s position is still within the regulatory
margins defined by their PBN capabilities, following the assigned routing.
In case of deviation, the flight crew shall take all appropriate measures to fly back onto the cleared
routing within a 100 NM from the position where the deviation was discovered.
EMERGENCY DESCENT
In case of emergency descent, whether it be resulting in turning back or continuing further toward the
end of the NAT region, it is expected from the flight crew to fly initially to a waypoint conveniently
located between two OTS tracks as applicable.
As soon as possible, communications with the responsible ATS unit should be established. If no
contact is established when reaching the waypoint, the aircraft must follow a parallel track located
midway from two OTS tracks as applicable.
LOSS OF COMMUNICATIONS
There are many possible ways of losing communications (partial or total, transmit and/or receive...) and
they cannot be all described. The following part will focus on NAT-specific loss of communications.
Whenever a loss of communication is recognised, the flight crew will attempt as a general rule to
establish communications with another aircraft (on GUARD frequency 121.5 for example) or with
another ATS unit. If it fails, the flight crew will make sure to try again with different equipment:
headset, hand microphone, VHF 2...
If this general procedure fails, the following must be followed:
Prior to entering NAT region:
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If the oceanic clearance has been received: the flight crew will comply with the oceanic
clearance. Any change of speed or flight level to comply must be done as close as
possible to the oceanic entry point.
If the oceanic clearance has not been received: the flight crew will comply with the filed
flight plan at least until reaching the oceanic exit point.
Prior to exiting NAT region:
Oceanic clearance matches filed flight plan: the flight crew will comply with the last
acknowledged instructions regarding route, flight level and speed parameters. At the exit
point, the aircraft shall continue onto the filed flight plan route
Oceanic clearance differs from filed flight plan: the flight crew will comply with the last
acknowledged instructions regarding route, flight level and speed parameters. At the exit
point, the aircraft shall rejoin as fast as possible the filed flight plan route by using the
regional ATS route network.
DIVERSION TO AN EN-ROUTE ALTERNATE AIRFIELD
When initiating a diversion, the flight crew should observe the following practice to reduce the threat
of a loss of separation:
If able, climb above FL410 or descend below FL280, then initiate the diversion while
communicating with the ATC toward a conveniently located waypoint.
If unable to comply with the previous altitude constraints, a 45-degree turn must be initiated to
rejoin a 15-NM track offset at which the aircraft will climb or descend by intervals of 500ft. If
unable to contact the ATS unit, a turn toward a conveniently located waypoint should be
initiated.
PHRASEOLOGY
We encourage you to read the documentation article dealing with oceanic phraseology.
SEE ALSO
None
REFERENCE
ICAO Document 7030 - NAT SUPP - Version 5, Amdt 9 - 25 April 2014
AUTHOR
VID 200696 - Creation
DATE OF SUBMISSION
15:12, 23 February 2021
COPYRIGHT
This documentation is copyrighted as part of the intellectual property of the International Virtual
Aviation Organisation.
DISCLAIMER
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The content of this documentation is intended for aviation simulation only and must not be used for
real aviation operations.
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