Operators may need to

retrofit their airplanes

to ensure existing fleets
are properly equipped
for RNP operations.

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equipping a Fleet for
required Navigation
Performance
required navigation performance (rNP) is the global benchmark for all future aviation
navigation. operators need a properly equipped fleet to receive rNP operational approval
and take advantage of the benefits offered by rNP operations.

By Dan Ellis, avionics Design engineer, Flight management Systems;

Gary Limesand, model Focal, Flight Deck/crew operations; and
Bill Syblon, Flight operations Specialist, modification Services

rNP operations can improve the safety, REquiRED NaviGatioN availability: the probability, using general
capacity, efficiency, access, and environ­ PERfoRmaNcE DEfiNED risk, that the navigation service (e.g., global
mental impact of the greater airspace positioning system [gPS], distance measur­
system, providing real economic benefits rNP is a statement of the navigation ing equipment [Dme] infrastructure) providing
for rNP operators. rNP also is the foun­ performance necessary for operation within the required accuracy and integrity will be
dation to evolving atm operations and a defined airspace. Specifically, rNP can be present during the intended operation.
establishes a basis for global interoperability. visualized as the requirement to keep the
continuity: the probability, using specific
operators must understand the airplane actual airplane position within a specified
risk, that the navigation system (e.g., flight
equipage requirements for rNP operations radius for a given percentage of the time.
management system [FmS] and other equip­
in order to determine what level of capa­ rNP is formally defined by four main terms:
ment) will provide the required accuracy
bility and operational approval will offer
accuracy: the requirement to keep the and integrity during the intended operation.
them the greatest benefit.
actual airplane position within a radius that
this article provides a standardized the required level of availability and
is 1xrNP for 95 percent of the time.
equipage configuration for each model, continuity for a given route or procedure is
suitable for all rNP applications. it also integrity: the requirement to keep the established by the regulator and optionally
explains concepts surrounding rNP and actual airplane position within a radius that improved upon by the operator. Figure 1
explores existing rNP standards. is 2xrNP for 99.999 percent of the time. provides an example of a boeing analysis
for generalized availability while gPS
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 figure 1: Example of worldwide navigation availability for selected required navigation performance (RNP) with GPS updating
the availability of an rNP operation varies depending on the number of satellites operating in the global positioning system (gPS) constellation. For example,
this table shows that general availability for an rNP 0.3­nmi operation is 99.98 percent when there are 24 satellites operating. this means the required
accuracy and integrity will be unavailable one out of every 5,000 attempts. operators can use estimates like this to evaluate whether the benefits of performing
the intended operation outweigh the challenges posed by the given availability. operators should refer to the applicable rNP capabilities document for the
specific availability values for their fleet.

Number of availability availability availability availability availability availability availability

Satellites in gPS rNP rNP rNP rNP rNP rNP rNP
constellation 10 nmi 4 nmi 2 nmi 1 nmi 0.5 nmi 0.3 nmi 0.15 nmi

24 >99.999% >99.999% >99.999% >99.999% 99.99% 99.98% 99.62%

23 >99.999% >99.999% >99.999% 99.98% 99.87% 99.67% 97.76%

22 >99.999% 99.99% 99.99% 99.82% 99.30% 98.61% 94.29%

21 >99.999% 99.96% 99.89% 99.33% 98.10% 96.60% 89.34%

figure 2: Performance-based navigation standards

required navigation performance (rNP) and area navigation (rNaV) are both part of performance­based navigation, a framework for defining navigation
performance requirements that can be applied to an air traffic route, instrument procedure, or defined airspace.

area Navigation (rNaV) required Navigation Performance (rNP)

rNP10 rNaV5 rNP4 basic­rNP1 rNP

oceanic rNaV2 oceanic rNP approach additional
remote rNaV1 remote rNP requirement
route authorization 3D & 4D
required approach
terminal
Various Phases

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figure 3: Required navigation performance (RNP) and area navigation (RNav) standards*

applicable regulatory Document

Navigational european aviation Safety
accuracy Federal aviation agency/Joint aviation
Navigational Specification area of application (nmi) administration authorities
rNP authorization required terminal and approach ≤0.3 ac 90­101a amc 20­26

rNP approach approach 0.3 ac 90­105 amc 20­27

rNaV 1 terminal and en route 1 ac 90­100a tgl­10/amc 20­16

rNaV 2 terminal and en route 2 ac 90­100a N/a

rNaV 5 terminal and en route 5 N/a amc 20­4

rNP 4 oceanic and remote 4 order 8400.33 N/a

rNP 10 oceanic and remote 10 order 8400.12b amc 20­12

* the Faa and eaSa standards have not been completely harmonized.

updating. route­ and region­specific implement changes in their atm systems, a fixed lateral flight path also affords
analysis tools are available outside boeing and more are expected. these changes will better energy management and quieter
and may yield different results. allow airlines with rNP­capable airplanes to climbs (i.e., up and away quicker at best
actual navigation performance (aNP) derive value from their existing capabilities. climb gradient via a more direct path) and
represents the current 95 percent accuracy as the new atm environments grow, pro­ descents (i.e., idle or near­idle). Finally,
of the boeing FmS position. aNP and rNP viding more opportunities for operational rNP enables airlines to precisely control
are displayed in nautical miles on the efficiencies, it is expected that such benefits what their airplanes are flying over, such
navigation displays and the control and will offset the cost of equipage changes as avoiding noise­sensitive areas.
display units. for airplanes. in the future, use of rNP routes and
When aNP exceeds rNP, an uNable procedures is likely to be the best way to
rNP message is displayed to the flight efficiently and cost­effectively accommo­
BENEfitS to aiRLiNES, aiRPoRt
crew. this indicates that the FmS position authoRitiES, aND commuNitiES
date and coordinate the various demands
does not meet the required accuracy, so of all airspace users globally, from transports
the procedure (such as an approach) must and unmanned aerial vehicles, to business
rNP allows airlines to use safer and more
be aborted. and sport aviation, to security and military
efficient flight paths that will enable a variety
uses of airspace.
of possible benefits, including airspace
increased application of rNP instrument
RNP iN aiR tRaffic coNtRoL efficiency through reduced separation,
procedures will allow for better use of
reduced fuel burn/emissions from shorter
multiple airport runway configurations for
rNP is a key component of the basic air­ flight paths, and improved runway access
increased airport capacity.
traffic services triad of communication, from lower minima. rNP can be used in
navigation, and surveillance (or monitoring) conjunction with rNaV or even with an
that is required for a safe and efficient instrument landing system (ilS) or global quaLifyiNG foR RNP oPERatioNS
airspace system. navigation satellite system landing system
rNP is a subset of performance­based (glS). rNP allows for better transition to perform rNP operations, operators must
navigation (PbN), which also includes area routes to these landing systems and better apply for and receive operational approval
navigation (rNaV) (see fig. 2). (For an accommodation of missed approach paths. from the applicable regulator. it is not
explanation of rNaV, see AERO second­ the rNP concept enables airlines to gain enough for an operator to simply purchase
quarter 2008.) efficiency by optimizing the use of available and enable the rNP options in their fleet
as air traffic management (atm) oper­ airspace, enabling reductions in aircraft and confirm the airplane flight manual–
ations in the world evolve, there is an separation, and enabling shorter routes demonstrated rNP supports the intended
increasing dependence on rNP operations by not being constrained by overflight of operation. instead, operators must equip
as a foundation for improvements in air­ ground navigational­aid locations. rNP also their fleets and establish appropriate
space design and management, safety, allows for better use of all other airspace, procedures, documentation, and training
operational efficiencies, and environmental such as oceanic and remote areas. as specified in the regulator’s published
improvements. many states have begun to

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 figure 4: 737-600/-700/-800/-900: Standardized equipment configuration
required configurations for other boeing models are available in the online version of this article (see www.boeing.com/commercial/aeromagazine).

u.S. federal aviation administration and European aviation Safety agency Requirements

rNP capability — required Hardware/Features ■■ multi­mode receivers (included in basic airplane configuration)

rNP ar 0.30 nmi Final and ■■ Speed and altitude intervention activation (boeing recommendation).
1.0 nmi missed approach ■■ two flight management computers (Fmcs) (dual).

rNP ar <0.30 nmi Final and/or ■■ captain’s Fmc, multipurpose control and display unit (mcDu), and inboard display unit on standby power.
<1.0 nmi missed approach ■■ Default distance measuring equipment (Dme) update to off (if required by procedure).
■■ Navigation performance scales (airplane flight manual rNP 0.10).
737­3c data frame software update to digital flight data acquisition unit.
common display system (cDS) operational software (oPS) 2004a software or later.
■■ takeoff/go­around (toga) to lateral navigation (lNaV) go­around.
Flight control computer 710 or P3.0 software or later.
cDS oPS 2004a software or later.
Fmc u10.6 software or later.

rNP standard as part of the application EquiPPiNG aN ExiStiNG fLEEt foR ■ identifying and managing suppliers and
process (see fig. 3). RNP oPERatioNS contractor services.
boeing provides full services around the ■ instituting the rigorous navigation data
world to completely equip and train opera­ boeing has defined the specific equipment services necessary for rNP operations
tors for rNP operations. additionally, boeing requirements for each of its commercial and regulatory approval.
completes applications for operational airplane models that are available for rNP ■ Developing avionics configuration
approval to qualify operators to become equipage retrofit: 737­300/­400/­500, recommendations to support fleet
rNP certified through their regulators. Next­generation 737, 757, 767, 747­400, rNP capabilities and providing a
777, mD­10, mD­11, 717, mD­80, and modification kit, if required.
mD­90. Figure 4 provides one example, ■ Providing flight crew and dispatcher
RNP StaNDaRDS
listing the rNP ar equipage requirements training, if required.
for a Next­generation 737. ■ Supporting airlines in gaining regulatory
existing and upcoming rNP standards
While specific airplane equipment approval for rNP operations.
will increasingly leverage rNP­capable
requirements must be met for each level
systems in order to derive additional air­
of operational approval, boeing has defined
space system benefits (e.g., any one or all SummaRy
a minimum demonstrated rNP for each
of capacity, efficiency, safety, or access).
airplane model.
the current set of possible rNaV and rNP Depending on the types of intended opera­
operations has differing equipage require­ tions and the evolving nature of air traffic
ments. before determining which type of RNP EquiPaGE REtRofittiNG operations globally, retrofitting an operator’s
rNP operations to equip for, airlines must aND oPERatioNaL aPPRovaL existing fleet for rNP operations may be
SERvicES fRom BoEiNG
understand their operational needs — required. boeing is prepared to support
including the primary level of operations rNP implementation by guiding operators
boeing provides an integrated rNP retro­
and what level is acceptable for contin­ through the entire retrofit and operational
fitting and operational approval program.
gency operations at destinations served approval process.
boeing works with operators to identify the
and planned. For more information, please
markets and airplanes in their fleets that
the standards for each level of rNP are contact boeing modification Services
will offer the greatest return on their rNP
defined by various regulators, including the at modservices@boeing.com.
capability investment and then manages
u.S. Federal aviation administration (Faa)
all phases of the implementation process.
and the european aviation Safety agency
this includes:
(eaSa) (see fig. 3). the Faa and eaSa
have slightly different definitions of what ■■ Designing and validating rNP procedures.
constitutes an rNP­capable system. ■■ establishing operational specifications
and operations manual revisions, as
required by the airline.

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