Captain Bill Royce
Senior Technical Pilot
Flight Operations Training, Technical & Standards
Boeing Commercial Airplanes
RNAV/RNP Operations &
VNAV Approaches
The Boeing Company W100.2
Discussion Objectives
• Discuss current RNAV status – US and Europe
• Provide safety-related background information
• Provide an understanding of basic RNP/ANP
concepts and operations
• Provide an understanding of VNAV approach
selection, execution and related topics
The Boeing Company W100.3
RNAV Use is Growing…
• We are now seeing a gradual transition from groundbased
navigation aids to satellite based navigation
• More routes and procedures with no underlying
navigation aids are being published
• RNAV capabilities are now being exploited further by US,
European and other air traffic service providers
– RNP operations
– Increased traffic capacity en-route
– SIDs, STARs and approaches
• Operators taking advantage of RNP operations
– Improved airport access; lower minima
– Increased safety; less reliance on VOR/ADF
– Increased payloads from special procedures
The Boeing Company W100.4
RNP/RNAV = Higher Payload
Example:
• Hong Kong (departing RW07)
• Weight limit governed by distant obstacle
• Engine-out SID developed with immediate turn after
takeoff (RNP 0.15)
• Payload increased by several tonnes
The Boeing Company W100.5
Current US RNAV Status
• Use of RNAV widespread and growing
• Many RNAV and GPS approaches
• Lower VNAV minima available
• GPS approaches being re-designated as RNAV
• RNP 1.0 SIDs and STARs available and increasing
in number
• Some special procedures developed (as low as
RNP 0.11)
The Boeing Company W100.6
RNAV – VNAV examples
The Boeing Company W100.7
Current Euro-control RNAV Status
• BRNAV (RNP 5.0) established for airways
• PRNAV (RNP 1.0) is implemented for terminal
operations (before FAF) – TGL 10 published.
• Requirements for Baro-VNAV and RNAV/RNP
approaches being established – TGLs being drafted
• Some RNAV approaches available
The Boeing Company W100.8
Safety History of Non-ILS
Approaches Suggests RNAV/RNP
• 60% of CFIT accidents occur on NP approaches
• 47% occurred during step-down NP approaches
• Almost all accidents occurred in darkness or IMC
• 48% in mostly flat terrain
• Most common cause: descent below MDA
The Boeing Company W100.9
Map Location of Recent CFIT
Accidents/Incidents
The Boeing Company W100.10
Vertical Profile of Recent CFIT
Accidents/Incidents
The Boeing Company W100.11
RNP/ANP Operations
• Definitions
• Why RNP?
• RNP vs ANP
• Airplane capability
• RNP/ANP displays and entries
• Crew Alerting summary
The Boeing Company W100.12
Definitions
• RNP – Required Navigation Performance.
– Specified navigation accuracy for a route or
departure/approach procedure in NM units
– Enroute RNPs usually 2.0 or greater
– Approach RNPs can be as low as 0.11
• ANP – Actual Navigation Performance
– The FMC calculated certainty of the airplane’s
position in NM units
– There is a 95% probability that the airplane is
within the displayed ANP
The Boeing Company W100.13
Why RNP?
• Required Navigation Performance, or RNP, was
developed as a method for certifying the navigation
certainty for RNAV systems that can use multiple
sensors for position updating
• RNP is used as a criteria for design of terminal area
procedures and en-route segments
• RNP relates to obstacle clearance and/or traffic
separation criteria
The Boeing Company W100.14
Factors Influencing ANP
• Method of FMC position updating (GPS, DME-DME,
etc)
• GPS Receiver Autonomous Integrity Monitoring
(RAIM) – only when using GPS updating
• If using navigation radio updating, geometry and
proximity of stations to airplane position
• Time since last radio or GPS update (for the 737,
without updating the ANP gradually increases)
The Boeing Company W100.15
ANP - a Measure of Position
Certainty and Route Containment
FMC position
ANP
95% Probability
(NM)
2xRNP 2xRNP
RNAV route
The Boeing Company W100.16
What FMCs Have RNP Capability?
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