pbn operational approval rnp ar apch navigation specification · icao pbn operational approval...

ICAO PBN Operational Approval Course

PBN Operational Approval

RNP AR APCH Navigation Specification


Introduction

• Based on operational experience in: • United States (Alaska Airlines), Canada (West Jet), New Zealand,

(Qantas, Air NZ) Australia (Qantas), China (Air China South West)

• Utilizes capability of FMS/GNSS aircraft

• “AR” = “Authorization Required” • Derived from early US RNP SAAAR approvals

• ICAO abbreviated to AR

• Identifies additional requirements for approval

• Operations to smaller navigation tolerances

• Provides for additional CAA oversight of aircraft and operator

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ICAO PBN Operational Approval Course 3

• Reduced Lateral & Vertical Obstacle Clearance

• Radius-to-Fix (RF) legs used to advantage

• Improved runway alignment • APV • Enables low minimums is

significant terrain • Missed Approach Guidance

provides improved safety and operating minima

• Improved efficiency, reduced emissions

• Many other benefits


Stakeholders

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Airport & Facility Regulator

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Airline

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Aircraft Air Traffic

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and must be shown to provide a safe operation using a FOSA, when necessary.

All the elements MUST be in place


Characteristics

• Characteristics of RNP AR APCH • Supports RF legs

• Avoid terrain instead of overflying

• RNP < 0.3 supported

• 2 x RNP lateral obstacle clearance

• Baro VNAV obstacle clearance using Vertical Error Budget

• Capability retained in missed approach

• ICAO RNP AR Procedure Design Manual design criteria

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Candidate Scenario

LOWI – Innsbruck, Austria


Obstacle Clearance

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RNP APCH vs RNP AR APCH

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RNP APCH LNAV/VNAV RNP AR APCH

Obstacle Evaluation

VNAV Baro Baro FAS Vertical 75m MOC Vertical Error Budget

Lateral Accuracy GNSS GNSS RNP (Final) 0.3 0.3 to 0.1 Final XTK 0.15NM 0.15 NM to 0.05

Turns (Final) None RF Missed Approach Terminal Mode (RNP 1.0); TF/RF RNP 1.0 or less; TF/RF

Initial/Intermediate Terminal Mode (RNP 1.0); TF/RF RNP 1.0 to 0.3; TF/RF Lowest DH 250ft 250ft Equipment Single Dual (Typically)

Safety Assessment Standard QA FOSA


Performance

• Monitoring and alerting consistent with reduced obstacle clearance

• Both lateral and vertical monitoring required • Lateral Accuracy:

• Range of accuracy values (0.1 to 1.0 NM)

• Vertical navigation: • Vertical Error Budget accounts for all contributing factors

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Aircraft Eligibility

• Typically established by OEM • In accordance with requirements in State of Manufacture

• Airworthiness Compliance Document in ECAC • Requirements differ in some respects • Operating capability basically the same • Some operating procedures may differ

• In special cases eligibility may need to be determined by State of Operator • Based on evaluation of aircraft systems • Assistance should be sought from experienced States

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Aircraft Eligibility

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• Typically RNP AR capable aircraft are equipped with redundant systems

• 2 or 3 IRU • 2 GNSS • 2 Display systems • 2 FMC

• Redundant systems are NOT required by PBN Manual • Some limitations apply to non-duplicated systems • FOSA provides a mechanism to evaluate requirements

for redundancy


• Accuracy of navigation needs to be supported by adequate performance monitoring alerting capability

• Lateral navigation • Normal operations < ½ RNP

• Non-normal operations < 1 RNP

• Vertical navigation • Maximum vertical deviation 75ft

• Resolution 10ft

Displays

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• Standard displays do not provide lateral deviation indicator • Available as option

• L/DEV (Airbus) or NPS (Boeing)

• Evaluation of XTK monitoring required • Ensure tolerances can be maintained

• Normal and non-normal operations

Display Considerations

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Standard Boeing 737NG Display

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CDU

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NPS

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Boeing ND with NPS option

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ANP 35

RNP 100

0.1L

ANP 0.07

RNP 0.50 GPS

XTK deviation in 1/100th NM

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Airbus ND without L/DEV Scales

Standard display in 1/10th NM Initial indication 0.2NM at XTK 0.15NM

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Airbus ND with L/DEV Option

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Airbus PFD with L/DEV Option

L/DEV Scale 0.2NML/DEV Scale 0.2NML/DEV Scale 0.2NM

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• Normal operations usually use AP (not mandatory) • Very small FTE values • XTK monitoring by exception

• XTK deviation events • Operating outside design limits for RF legs • Failure to operate aircraft in correct mode • Autopilot connect/disconnect • Engine failure

• Display must be assessed adequate to: • Enable crew to readily identify deviation • Provide sufficient time to correct; and • Maintain flight within acceptable tolerances

Display Assessment

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Map display/scaling • Sufficient for observation/estimation of XTK deviation

Numeric indication of XTK error in 1/10th NM or less • On map display (preferred) • On CDU/MCDU monitored by PM/PNF

Supported by suitable crew procedures • PNF/PM heads up unless deviation observed • Callout procedures/recovery action

Considerations

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Displays B787

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Go-around LNAV Guidance

• Legacy aircraft configured for IRS track hold • Not compatible with RNP AR ops

• Can be managed using crew procedures

• Preferred functionality retains LNAV guidance on TOGA • Commonly called TOGA to LNAV or TOGA to NAV • Continued accurate adherence to LNAV path

• LNAV remains engaged

• PBN requirement for < RNP 0.3

• Recommended for all RNP AR ops

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Altimetry Functions

• Two independent altimetry sources in pilots’ primary field of view

• Flight crew altimeter crosscheck within ±100’ • Confirm satisfactory input to FMC providing the vertical path

• Requirement may be met by automated comparator monitor function

• When flight crew sets altimeter, this must also set RNP system’s (FMC) altimeter input through a single action

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Approaches with RF Turns

• RF functionality required

• Electronic map required

• FMC, flight director and Autopilot must be capable of commanding 25° of bank at or above 400’ AGL and 8° of bank below 400’ AGL

• Lateral nav guidance available in go-around i.e. TOGA to NAV function

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Caution: Commonly FMC logic restricts bank angle at low RADALT and can result in deviation from RF path if not

managed correctly.


RNP < 0.3

• Single point of failure must not cause loss of approach guidance. Typically reversion to IRS if GNSS updating is lost; and dual GNSS sensors, dual FMS, dual air data systems

• Loss of display of lateral guidance is hazardous

• Alternate means of navigation for go-round due to loss of GNSS

• Lateral nav guidance available in go around i.e. TOGA to NAV function

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Typically RNP AR capable aircraft are equipped with dual systems, IRS and TOGA to NAV function

Most current RNP AR operations require this capability for all RNP AR approach procedures (i.e. including RNP 0.3)


Missed Approach < RNP 1

When RNP 1 < 1.0 NM required for the missed approach: • Single point of failure must not cause loss of guidance • Dual equipage (same as RNP AR APCH < 0.3) • Upon loss of GNSS, aircraft must revert to another means of

navigation which provides the required navigation accuracy (IRS)

• Lateral nav guidance available in go round i.e. TOGA to NAV function

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RNP < 1 in the missed approach is typically used to provide lower minimums and obstacle clearance in the missed

approach segment


Pre-Flight

• Minimum Equipment List (MEL) • Depends on operation & required navigation accuracy • May require dual equipment • RNP < 0.3, or RF legs require flight director or autopilot

• RNP Prediction • RNP must be available at the destination at ETA • RNP prediction must:

• Account for known outages in navigation services • Use the same prediction algorithms as the airborne system

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During Approach

• May need to disable radio updating (aircraft and procedure specific)

• Limit cross-track deviation to: • ½ the required navigation accuracy

• Go-around if : • Lateral deviation >1 x required navigation accuracy

• Vertical deviation >75 feet

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Navigation Database

• Documented data management process • Responsible data manager • Cyclic data validation

• Detect unintended changes in navigation database

• Initial data validation by operator • Ensure that the data is compatible with the aircraft

avionics • For each aircraft/configuration

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• Major manufacturers provide guidance • Experienced operators may be consulted • AP normally mandated by operators • Availability prediction services required • Required list of equipment (to commence approach) • Track deviation monitoring • Vertical deviation monitoring • Temperature effects • Action in event of an alert • Go-round track adherence

Operating Procedures

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• RNP selection • Approach briefing • Required equipment • Intercepting approach • Vertical Intercept Point (VIP) • Navaid deselection • Stabilised approach • Monitored Approach/Use of automatics • RF legs/TOGA to NAV • Turns in final segment • Visual segment management • Limiting temperatures

Training

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• Highest RNP should be selected

• Lower RNP selected where lower DA required

• Consideration of RNP availability prediction

• Check current RNP performance status (ANP/EPE)

• Lower RNP increases alerting probability

RNP Selection

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• Reliance placed on database validity procedures

• Not necessary to brief all tracks/distances

• Brief must cover significant points

• Correct procedure

• Altitude and speed limitations

• RNP/DA/Altimeter

• Missed approach altitude

Approach Briefing

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Flight Operational Safety Assessment (FOSA)

• FOSA may not be needed in some cases • As for all SMS evaluations, FOSA should address:

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• System definition • Establishment of safety

criteria • Hazard identification • Causal analysis • Likelihood estimation • Consequence analysis

• Mitigation identification • Risk assessment • Final report


FOSA Inputs

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FOSA

Navigation Services

Infra-structure

Aircraft Performance

Flight Crew

Operations

Aircraft Failures

Operating Conditions

ATC Operations


Depth of FOSA Analysis

Depends on:

– Operating environment

– Aircraft equipment

– Complexity of procedure

– Operator’s previous experience

– Previous safety assessments

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QUESTIONS?

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