Post on 08-Jul-2018
DIESER TEXT DIENT DER NAVIGATION
Performance Based Navigation Implementation of Procedures
Dr. Daniel Schaad – Head of Instrument Flight Procedures (ATM/IFP)
Minsk, April 10th, 2015
First of all…
…thank you very much for your invitation to Belarus!
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I am happy to be in your beautiful country!
The concept of PBN
the PBN concept aims at harmonizing the historically grown
RNAV/RNP environment and adds further (future) elements,
such as SBAS under the same umbrella
the overall philosophy of PBN is to define navigation
PERFORMANCE which can then be achieved by various
accepted sensors
PBN also aims at harmonizing charting, naming conventions,
terminology, etc.
in the approach domain, PBN shall become the first layer of
non-precision approach environment (replacing NDB and VOR
approaches). However, ILS remains the standard of precision
approach!
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The concept of PBN – Navigation Application
the APPLICATION (i.e. use of) the Navigation Specification
and NAVAID Infrastructure
mainly an ANS topic
examples:
– routes based on RNAV and RNP specifications (based on a
particular NAVAID infrastructure)
– SIDs/STARs based on RNAV
– Approach procedures based on RNP specifications
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The concept of PBN – Navigation Specification
a SPECIFICATION (i.e. definition) of a particular standard (like
RNAV1, RNP0.3, etc.) including elements like
– navigation performance
– functionalities (like certain path terminators)
– accepted navigation sensors
– air crew requirements (if applicable)
mostly relevant to the aircraft operator
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The concept of PBN – Navigation Infrastructure
The INFRASTRUCTURE required (both land-based and space-
based) to fulfill a given NAV specification to enable a NAV
application. Examples are
– GNSS (GPS, GLONASS, Gallileo)
– DME stations
– VOR stations (for the European P-RNAV only)
mostly a technical CNS topic
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The concept of PBN – performance is the key
concept moves away from the direct technical description of
navigation
nav performance is the requirement (e.g. +/- 1nm for 95% of
flight time in RNAV1, etc.)
technical realization provides various options (e.g. DME-DME
or GPS, etc.)
more options on avionics side, better flexibility and airspace
capacity for ANS providers
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The concept of PBN – a new second layer
world of non-precision approaches to be replaced by PBN
approaches
conventional non-precision approaches to become “third-layer”
back-up for low-equipage aircraft
changes in flight training will reflect that (no more NDB training)
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The concept of PBN – new trends
standard equipage drives the procedure landscape
If LPV/SBAS capability becomes standard on large commercial
airliners, this may chance the approach landscape on hub
airports (same with GBAS, yet not a PBN topic)
mixed conventional/PBN procedures can sometimes provide
benefits – ICAO in the process of producing guidance material
Example:
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The concept of PBN – risks
nomenclature complex
wording partly not yet fully standardized
terms may be misleading (e.g. any RNAV approach is an RNP
approach, why does „RNAV(RNP)“ only refer to RNP AR?)
“overcoding” of conventional procedures “blurs” the line
between conventional and PBN sometimes (esp. to the end
user in the cockpit
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The concept of PBN – coded is not necessarily
PBN!
avionics capabilities like Airbus FLS (FMS landing system) with
FMS LOC (F-LOC) and FMS glideslope (F-G/S) modes enable
the use of conventional 2D non-precision approaches like
3D approaches
yet, these are still conventional non-precision approaches!!!
Boeing has similar elements (Final Approach Course – FAC
and Glide Path - G/P) in its Integrated Approach Navigation
(IAN) concept
no precision like in RNP!
different procedure design criteria in the background
a very good link to an article also addressing this topic:
http://www.skybrary.aero/bookshelf/books/596.pdf
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Implementing RNP Procedures
identifying needs
Where does the need for a new procedure come from?
It all starts with an identified demand:
Airspace changes?
Potentially improved minima?
Better accessibility of the airport?
Changes in fleet and/or equipage?
Requests from operators?
What options are there to accomodate the identified need?
Type of approach
Connection to SID/STAR structure
Approach layout
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
Where does the need for a new procedure come from?
Innsbruck has a long history of RNP procedures: Europe’s first
RNP-AR Approach was published there in 2004
However, in recent years winter weather patterns have changed
and caused a significant number of winter days with very low
ceiling in Innsbruck, which made the existing minimum of the RNP
AR RWY 26 (DH 710‘) insufficient.
Innsbruck subsists on winter charter traffic, and the issue of
diversions are critical to the economic survival of the airport.
Hence, the demand for a new procedure is:
ACCESSIBILITY through lower approach minima
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Implementing RNP Procedures
analyzing procedure options
What procedures can address the identified needs?
Lower Minima? – change from non-precision to precision or RNP
Fleet and Equipage demands? – check available capability
Airspace Changes? – maybe just lateral/vertical changes
necessary
Operator Demands? Is there a procedure type that suits their
demands?
Perform a first feasibility study with a first minimum estimate, if
possible
Can you achieve better or equal minima with the procedure?
Does it fit into the obstacle/terrain environment?
Do the runway characteristics and infrastructure support the
planned procedure type (i.e. lighting, etc.)
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
What procedures can address the identified needs?
Coming from an RNP-AR procedure which even has an RNP 0.15
minimum published, it is difficult to find options for improvement
What options are there to accomodate the identified need for a
lower minimum?
With the highest RNP approach type already in place and no
option for a precision approach (i.e. ILS) due to the Inn-Valley, the
only identified option was a change to the existing RNP approach
When analyzing the obstacle situation and the existing LOC and
RNP-AR approaches, a revolutionary idea was born:
Combining a LOC (final) approach with an RNP missed approach
might lead to a lower minimum!
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Implementing RNP Procedures
including the stakeholders
As early as possible, it is important to get the affected
stakeholders on board
The users: airlines, general aviation, flight schools, etc.
The controllers: all involved ATC units, usually APP and TWR for
terminal ops
The regulators: the national regulatory authority, usually referred to
as CAA
Presenting the initial concepts and ideas to the stakeholder
community during workshop sessions
A key step to ensure early identification of problems (from minor
issues to “show stoppers”) and get people “on board” to avoid later
obstacles to implementation
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
As early as possible, it is important to get the affected
stakeholders on board
We held separate workshops with ATC personnel from Innsbruck
and airline representatives (mostly flight ops experts, pilots) from
the major carriers flying into Innsbruck
Moreover, we informed the Austrian CAA (BMVIT) about our
project and the proposed proceedings at an early stage and got
approval to proceed, with the safety assessment being the final
check-mark
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Implementing RNP Procedures
the design process
Procedure Design Steps (software-based approach)
Initial design with software to establish protection areas
Obstacle assessment based on the protection areas
Iterative adaptation of design to improve procedure characteristics
Initial Desktop Validation
Options like RVT (RNAV Validation Tool) for SIDs and STARs,
Desktop Flight Simulators for Flyability Assessment of Approach
Procedure Trainer/Simulator Trials, if available in organization
Consultation of pilots, flight ops experts
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
Procedure Design Steps (software-based approach)
Obstacle evaluation showed critical obstacle exclusion from
localizer protection area and thereby supported initial expectation
to achieve lower approach minimum
Feasibility of transition from localizer-tracking to RNP Missed
Approach mode was still in question
Initial Desktop Validation
Difficult due to existing FMS/flight guidance questions which could
only be answered by real avionics system application
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Implementing RNP Procedures
flight validation and stakeholder feedback for
safety case (1/2)
Flight Validation
Can be performed either in real flight or in full flight simulators and
provides final certainty about flyability and handling issues.
Real flight validation can also serve as a final confirmation of
obstacle clearance, if obstacle database incomplete
ICAO Doc 9906 Vol. 5 (Quality Assurance for Procedure Design)
states
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Implementing RNP Procedures
flight validation and stakeholder feedback for
safety case (2/2)
Safety Case
Promulgation of procedure in AIP requires safety assessment for
which the flight validation and stakeholder feedback (both ATC and
A/Os) is a key input
In some states, supervisory authority may audit individual
procedure (“product audit”) or the process of safety management
as part of the publication process (“process or organizational
audit”)
The successful safety assessment (as published in a safety case
release) is the prerequisite for approval of a procedure by the
regulator (i.e. CAA)
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
Flight Validation
All major carriers involved in the initial stakeholder workshops were
provided with the procedure design (chart and coding table) to
have the procedure coded by their datahouses for simulator trials
A special focus was directed to the issue of mode change from
LOC tracking to RNP MApp Mode
Sim checkflights were performed on A320, B737 and DHC8 types
Flight Validation Reports were collected for the safety assessment
and additional questions submitted to the operators to complement
the safety assessment
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Implementing RNP Procedures
our real-world example: LOWI LOC R RWY 26
Safety Case
The results of safety assessments proved that with a minor
alteration in the missed approach description, the procedure was
perfectly flyable and the mode change issue was technically and
operationally easy to handle.
The safety assessment also identified requirements for the AR
process (individual authorization of the use of this procedure by
ANSP) as a mitigation of risks
Whilst in most states, a final approval of the procedure by the state
CAA would be required prior to publication in the AIP, this process
is delegated in Austria, so that the publication went ahead directly
after the successful completion of the safety assessment
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Organizational Requirements
Procedure Design Office with qualified designers and
infrastructure
Charting Office
Interface to regulator for approval of IFP work (either process-
oriented or product-oriented)
Safety Office (to carry out and accompany safety assessment
process)
Interface to operational unit (TWR/APP)
Interface to operators (airlines, general aviation, flying
associations/clubs, airport operators, etc.)
Ability to provide operationals approvals for AR operations
(either through CAA or ANSP)
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Infrastructural Requirements
Procedure Design Software with Obstacle and Terrain
Database
Data Exchange with Charting Office
Ability to provide coding tables for preliminary coding in flight
tests
Simulator or test aircraft access (can be done through a
partnering airline operator
GNSS coverage assessment (esp. in mountainous terrain, with
particular criticality in case of LPV procedures)
Provision of GNSS NOTAM service (can be outsourced)
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