Data-link: Fact and Fiction Kim O’Neil Advanced Aviation Technology Ltd.

Data-link: Fact & Fiction F Decision Process F Safety F Key Factors F Comparison of Data-links F Conclusions…….

Decision Process F Who Chooses? –ICAO? CAAs? Airlines? Eurocontrol? ECAC? F What Criteria? –Safety? Cost? Benefits? Functionality? –Commercial Interest? Spectrum Efficiency? –Political expediency? Vested Interest? –……...or something else?

Decision Process F Probable Answer: All of the above……. F Implies - No Perfect Solution –i.e. some one’s going to be unhappy…….. F Also implies - A LOT of Confusion!

Decision Process F WHAT Application?……. –CPDLC? –AOC? –ASAS? ADS-B? Etc. Etc. F Different Datalinks for each? –Aerials???? F Or one Datalink for all?

Safety F Is Safety an Issue? –Application dependent F Typical Factors: –Integrity –Reliability –Availability –Communication delays –Security

Certification F Certification: –Equipment, installation, maintenance –People, procedures, safety management –HMI, human factors….. –Operations….. –Applications…….

Certification F “End to End” Certification? F Implies certification of Network –NEVER been done before……. F “Legally” impossible –Outside authority of CAAs…. F Regulators will have to work hard……..

Certification F Certification Necessary –e.g. for time critical applications F If no application safety standards –then no operational certification….. F Conformance is NOT Safety F Safety Cases are not enough…….

Decision Factors F Many Players: –Airlines –ATC –Telecom providers –Manufacturers F Many priorities –Consensus difficult F Vested Interests….

Decision Factors F Commitment?: –Airlines watch service providers –Service providers watch ATC –ATC watch airlines……… –Manufacturers watch everyone. F Or lack of comittment? F CAAs not installing VDL2 –BUT want others to…….

Decisions: VDL mode 4 F Russia –Entire Surveillance System –Communication Services, more……. F European States –Intensive evaluation and trials…. –NEAN/NUP, FARAWAY etc. etc. etc. –CPDLC over VDL4 prototypes

Functionality F CPDLC: –A long road –Required functionality depends on timescales…. –“Quick Fix” may be counter-productive –Beware dead-end solutions F NEED a highly adaptable data-link

Spectrum Efficiency F Key Issues: –NEED 25 kHz service –Essential for frequency planning –No interference to voice –Frequency re-use –Capacity –No special protection

Transition F LONG Transition period F NEED a Transition Strategy F MUST coexist with existing system F VDL2&3 increase pressure on spectrum F ACARS to VDL2 requires more frequencies F CPDLC and AOC share frequencies????

Feasibility F VDL mode 4 widely demonstrated –100,000 flight hours on commercial aircraft –many demonstrations, evaluations, simulations –including CPDLC! F VDL mode 2? F VDL mode 3?

Cost/Benefits F Airlines sensitive to costs –Equipment, installation, certification –Maintenance, crew training, –Operating fees………. F Minimal cost to ATC –Favourable contracts with service providers F Communication providers business drivers: –Want to expand and want more spectrum…..

Cost/Benefits F NEED to address entire operational life –the future? F Ideally fit ONLY one data-link –with operational redundancy F NEED to compare datalink options –assess each against future needs –calculate the cost –“guestimate” the benefits

Comparing Datalinks…. Global StandardVDL2VDL3VDL4 Block to BlockNoNoYes AvailabilityNoYesYes IntegrityYesYesYes RobustnessNo?Yes Spectrum EfficiencyNoNoYes CapacityNoNoYes Future NeedsNo?Yes Transition??Yes

Conclusions F ICAO sets Standards –Does not mandate technologies –States decide F VDL 2 has severe limitations F VDL 3 has limitations …..and when? –Risk loss of both Voice and Data –Transition?

Conclusions F VDL mode 4 meets known requirements F VDL mode 4 widely demonstrated F VDL mode 4 can provide CDTI and ASAS –Situation Awareness essential for CPDLC F VDL mode 4 meets time critical requirements F VDL mode 4 has higher capacity F VDL mode 4 has graceful degradation

Conclusions F VDL mode 4: –Spectrum Efficient –High capacity –Long range –Redundant –Robust –Expansible F VDL mode 4 provides Seamless Transition

The End! Thank You! (updated paper at