SITAONAIR invests in multi-frequency network

12 April 2018
These maps show the extent of VDL Mode 2 multi-frequency coverage at FL285 in Europe to date. The left-hand map depicts shared channel coverage, with en route coverage on the right. The red areas are already online, and the blue areas are where implementation is planned. Source: SITAONAIR (data overlay on Google Earth image)

SITAONAIR has reported significant progress over the past 18 months in upgrading datalink ground infrastructure in Europe.

More than 208 VHF Data Link (VDL) Mode 2 stations with multi-frequency Model B capability have been deployed to date in 28 countries, capable of supporting air/ground controller-pilot data link communications (CPDLC).

Data link services will be mandatory from 2020 under the Single European Sky programme. “Deploying CPDLC is a cornerstone on which to implement future SESAR [Single European Sky ATM Research] concepts,” said SITAONAIR Director Air Traffic Solutions François Bardin. “The next step will be initial 4-D trajectory.”

SITAONAIR developed a Centralised VDL Management Entity (CVME) to manage the VDL Mode 2 frequency mechanism and balance the various VDL frequencies. As an aircraft moves from terminal to en route airspace, the ground system automatically instructs the avionics to switch from one frequency to another.

“The issue we are hitting now is we need to see the same improvement on the airborne side,” Bardin explained to Jane’s . “Nearly all aircraft are equipped with VDL data link but to achieve the complete efficiency of multi-frequency, we need all aircraft to be equipped with best in class avionics. Today we only see a small fraction of avionics responding to multi-frequency.”

Nevertheless, SITAONAIR has already reported a reduction in the number of disconnections between ground infrastructure and airborne avionics – known as Provider Aborts – that were previously experienced with VDL Mode 2 technology. In the case of Maastricht Upper Area Control Centre, these have fallen from peaks of 20-25% in 2014, to only 2% today.

VDL Mode 2 multi-frequency represents a first step towards achieving robust data link communications, as envisaged under the European Data Link Services (DLS) recovery plan. “We need to think about the technology that will deliver the bandwidth capacity necessary to enable full 4D [trajectories],” said Bardin.

Want to read more? For analysis on this article and access to all our insight content, please enquire about our subscription options at

(331 of 404 words)



    PIS/LFBI AIRFIELD REF PT.: N46 35.15 E000 18.24 ELEVATION : 423' 129m CFR : 5 MAX RWY LENGTH : 7,710' 2,350 m General Information SURFACE : Rwy 03/21, 7,710' 2,350 m, width 148' 45 m, asphalt, PCN 44 F/C/W/T. ADDITIONAL RUNWAYS : Rwy 03R/21L, 2,297' 700 m, width 148' 60 m, grass, Rwy 03L/21R,


    HOR/LPHR AIRFIELD REF PT.: N38 31.19 W028 42.95 ELEVATION : 118' 36m CFR : 6 MAX RWY LENGTH : 5,233' 1,595m General Information SURFACE : Rwy 10/28, 5,233' 1,595 m, width 148' 45 m, asphalt. ADDITIONAL RUNWAYS : None. RUNWAY LIGHTING : Rwy 10: LIRL, REIL, ALSF-2, PAPI.Rwy 28: LIRL, REIL, ALSF-2,

  • PICO

    PIX/LPPI AIRFIELD REF PT.: N38 33.16 W028 26.29 ELEVATION : 109' 33m CFR : 0 MAX RWY LENGTH : 5,725' 1,745m General Information SURFACE : Rwy 09/27 Twy, 5,725' 1,745 m, width 148' 45 m, asphalt, PCN 80 F/B/W/T. ADDITIONAL RUNWAYS : None. RUNWAY LIGHTING : Rwy 09: LIRL, PAPI.Rwy 27: LIRL, ALSF-2,


    SMA/LPAZ AIRFIELD REF PT.: N36 58.28 W025 10.24 ELEVATION : 308' 94m CFR : 7 MAX RWY LENGTH : 10,000' 3,048m General Information SURFACE : Rwy 18/36, 10,000' 3,048 m, width 197' 60 m, concrete. ADDITIONAL RUNWAYS : Rwy 15/33, 6,004' 1,830 m; Rwy 04/22, 4,345' 1,324 m; both asphalt; both closed.