Transcript Slide 1

International Flight Inspection Symposium
Oklahoma City, OK USA June 2008
Identifying the
Achilles’ Heels
of Instrument
Flight Procedures
Ivan Ferencz
CAA Slovakia
Overview
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Introduction
Procedure Lifecycle
Design as a process
Factors affecting the design
Known issues
Conclusions
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Instrument Flight Procedures
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Introduction
• Conventional Procedures
– navigation systems are periodically flighttested and eventual defect of the procedure is
discovered as a part of such tests
• RNAV Procedures
– No direct link to particular navigation system
– Data related
– Risk mitigation effect of physical presence of
signal in space is inhibited
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Instrument Flight Procedures
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Procedure Lifecycle (1)
•Airspace re-design
•New NAVAIDs
•Decommission of NAVAIDs
•New operations
Communication between
Originator and Designer
Communication between
Designer and Regulator
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Instrument Flight Procedures
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Procedure Lifecycle (2)
Procedure publication
No responsibility of State
beyond this point
Procedure distribution
Procedure execution
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Instrument Flight Procedures
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Procedure Lifecycle (3)
When to perform Flight inspection:
•After Design
Flight Inspection Report is used
as one of inputs of Validation
•During Validation
Flight Inspection is used as one
of validation tools
•Before Publication
Flight inspection is used to
obtain approval of AIP Amendment
•At the user level
Flight inspection is used to
confirm usability of procedure
-standard FMS Database
-customized FMS Database
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Instrument Flight Procedures
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Design as a Process (1)
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Instrument Flight Procedures
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Design as a Process (2)
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Instrument Flight Procedures
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Design as a Process (3)
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Instrument Flight Procedures
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Factors affecting the Design
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Instrument Flight Procedures
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Known Issues (1)
• Height above THR
– 15.0m versus RDH
• Length of Segments
– Minimum Stabilisation Distance
– Optimum length T-Bar (Y-Bar)
• Descent and Climb Gradients
– Boundaries of the design
– Application of the Earth curvature
– FAF location
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Instrument Flight Procedures
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Known Issues (2)
• Segments Overlap
– Interfaces between segments
• FAF in precision procedure
– FAP versus FAF
• GP verification point
– Missing data
– Distinction from the Stepdown Fix
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Instrument Flight Procedures
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Known Issues (3)
• Stepdown Fix Altitude
Intermediate
altitude
MAPt
SDF
FAF
(Stepdown Fix)
(Final Approach Fix)
OCA
15.0m
MAPt
Intermediate
altitude
SDF
FAF
(Stepdown Fix)
(Final Approach Fix)
OCA
15.0m
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Instrument Flight Procedures
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Known Issues (4)
• NAVAIDs Performance
– ILS Coverage
• 17/25NM versus 10/18NM, GP coverage
– Early phases of Departures
• Minimum Equipment List
– Intersections
– Number of waypoints
• Slow Aircraft
– Track discontinuity after turns
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Instrument Flight Procedures
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Known Issues (5)
• Missed Approach Text
– More than one missed approach in procedure
• Speed restrictions
– Speed limitations below PANS-Ops Margins
– Lower speed / higher bank combination
• ARINC 424 Coding
– Coding Advice versus Real Database
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Instrument Flight Procedures
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Known Issues (6)
• Departure End of Runway
– End of Runway used instead of End of
Clearway
• Environmental Aspects
– Procedure might generates noise problem
• Magnetic Variation
– Magnetic Variation is not accommodated
– Rounding to the nearest whole degree
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Instrument Flight Procedures
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Conclusions (1)
• Huge amount of safety sensitive work lies
on shoulders of sole person - instrument
procedure designer
• flight inspection of procedures represents
a barrier, which mitigates risks associated
with the instrument procedures design
• Effectiveness of such risk mitigation
strongly depends on skills of flight
inspectors
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Instrument Flight Procedures
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Conclusions (2)
• Having in mind continuous transformation
of flight inspection from flight inspection of
systems to flight inspection of procedures,
flight inspectors should become experts in
instrument procedures design
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Instrument Flight Procedures
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Thank you for your attention.
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Instrument Flight Procedures
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