data-link: fact and fiction kim o’neil advanced aviation technology ltd
TRANSCRIPT
Data-link: Fact & Fiction
Decision Process Safety Key Factors Comparison of Data-links Conclusions…….
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Decision Process Who Chooses?
– ICAO? CAAs? Airlines? Eurocontrol? ECAC?
What Criteria?– Safety? Cost? Benefits? Functionality?– Commercial Interest? Spectrum Efficiency?– Political expediency? Vested Interest?– ……...or something else?
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Decision Process
Probable Answer: All of the above…….
Implies - No Perfect Solution– i.e. some one’s going to be unhappy……..
Also implies - A LOT of Confusion!
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Decision Process WHAT Application?…….
– CPDLC?– AOC?– ASAS? ADS-B? Etc. Etc.
Different Datalinks for each?– Aerials????
Or one Datalink for all?
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Safety Is Safety an Issue?
– Application dependent Typical Factors:
– Integrity– Reliability– Availability– Communication delays– Security
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Certification
Certification:– Equipment, installation, maintenance– People, procedures, safety management– HMI, human factors…..– Operations….. – Applications…….
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Certification
“End to End” Certification? Implies certification of Network
– NEVER been done before……. “Legally” impossible
– Outside authority of CAAs…. Regulators will have to work hard……..
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Certification
Certification Necessary– e.g. for time critical applications
If no application safety standards– then no operational certification…..
Conformance is NOT Safety Safety Cases are not enough…….
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Decision Factors Many Players:
– Airlines– ATC– Telecom providers– Manufacturers
Many priorities– Consensus difficult
Vested Interests….
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Decision Factors Commitment?:
– Airlines watch service providers– Service providers watch ATC– ATC watch airlines………– Manufacturers watch everyone.
Or lack of comittment? CAAs not installing VDL2
– BUT want others to…….
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Decisions: VDL mode 4 Russia
– Entire Surveillance System– Communication Services, more…….
European States– Intensive evaluation and trials….– NEAN/NUP, FARAWAY etc. etc. etc.– CPDLC over VDL4 prototypes
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Functionality
CPDLC:– A long road– Required functionality depends on timescales….– “Quick Fix” may be counter-productive– Beware dead-end solutions
NEED a highly adaptable data-link
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Spectrum Efficiency
Key Issues:– NEED 25 kHz service– Essential for frequency planning– No interference to voice– Frequency re-use– Capacity– No special protection
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Transition
LONG Transition period NEED a Transition Strategy MUST coexist with existing system VDL2&3 increase pressure on spectrum ACARS to VDL2 requires more frequencies CPDLC and AOC share frequencies????
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Feasibility
VDL mode 4 widely demonstrated– 100,000 flight hours on commercial aircraft– many demonstrations, evaluations, simulations – including CPDLC!
VDL mode 2? VDL mode 3?
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Cost/Benefits Airlines sensitive to costs
– Equipment, installation, certification– Maintenance, crew training, – Operating fees……….
Minimal cost to ATC– Favourable contracts with service providers
Communication providers business drivers:– Want to expand and want more spectrum…..
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Cost/Benefits NEED to address entire operational life
– the future? Ideally fit ONLY one data-link
– with operational redundancy NEED to compare datalink options
– assess each against future needs– calculate the cost– “guestimate” the benefits
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Comparing Datalinks…. A A T
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Global Standard VDL2 VDL3 VDL4
Block to Block No No YesAvailability No Yes YesIntegrity Yes Yes YesRobustness No ? YesSpectrum Efficiency No No YesCapacity No No YesFuture Needs No ? YesTransition ? ? Yes
Conclusions ICAO sets Standards
– Does not mandate technologies– States decide
VDL 2 has severe limitations VDL 3 has limitations …..and when?
– Risk loss of both Voice and Data– Transition?
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Conclusions
VDL mode 4 meets known requirements VDL mode 4 widely demonstrated VDL mode 4 can provide CDTI and ASAS
– Situation Awareness essential for CPDLC VDL mode 4 meets time critical requirements VDL mode 4 has higher capacity VDL mode 4 has graceful degradation
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Conclusions VDL mode 4:
– Spectrum Efficient– High capacity– Long range– Redundant– Robust– Expansible
VDL mode 4 provides Seamless Transition
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