Clearing for Depature by Datalink

If your scope of activities comprises aircraft movements at a regional hub, you will probably need a highly automated communications tool to secure smooth, safe and economically viable operations. And if the scenario is an international airport, you definitely will reap immediate benefits from implementing an automated and digitized procedure for providing aircraft with departure or pre-departure clearance.

The solution to reduce clearance delivery time, one of the factors behind flight delays, is already at hand: since the mid-90s, Terma has implemented D-PDC/DCL systems at many national and international airports all over the world.

Terms with an Impact

DCL, Departure Clearance, refers to the automated service through datalink for requesting and delivering departure information and clearance that adheres to ICAO’s recommendations on read-back procedures. It provides a point-to-point communication between the aircraft and the ATC tower.

D-PDC, Pre-Departure Clearance via datalink, is provided by an Air Traffic Service via an airline host. The latter then conveys the PDC with the pertinent data to the aircraft upon request from the pilots when it best suits their work planning.

With datalink, the pilot may enter his departure clearance request from 25mins prior to departure on the Aircraft Communication Addressing and Reporting System (ACARS) with flight plan, call sign, gate position, destination, and ATIS letter. In response, the system automatically verifies the data for compliance between the flight plan and the data received from the aircraft. Once this compliance has been established, an automated clearance message including all essential information such as Standard Instrument Departure (SID) and current ATIS letter is generated and transmitted to the cockpit. The pilot can read this information on his ACARS monitor screen or print it out for reference. This entire process, including pilot’s read-back, and controller’s confirmation, is fully automated, requiring no manual interference once the data match. In the case of any data discrepancy, the ATC controller will automatically be alerted to take over the communication with the aircraft via radio frequency.

Huge Benefits

Terma’s D-PDC/DCL solutions have been implemented, also including D-ATIS / VOLMET facilities, at major international airports in Europe and Asia that have already testified to the efficiency and benefits from their operational use. They unanimously prove that these systems increase operational efficiency, reduce flight delays, boost airport regularity, and enhance safety.

“The system greatly reduces stress among controllers, and generates a situational overview which is in itself a major asset,” says Søren Beck, Air Traffic Controller at Naviair, and former Head of Tower Operations, at Copenhagen Airport. Copenhagen Airport reports the average saving of time per aircraft departure clearance to be some 30s, compared to traditional radio procedures with read/read-back communication.

“With the implementation of clearance datalink service, the provision of pre-departure clearance information in respect of the departure routes, altitude restrictions, and cruising levels etc., which are used to be transmitted through radio communication, can now be transmitted via datalink for display or print-out in the cockpit to reduce pilots’ workload,” said Mr Albert Lam, Director-General of Hong Kong Civil Aviation, at the inauguration ceremony in December, 2001.

“We anticipate a decrease in controller workload by one or two man-labour years, which can reduce cost or make it possible to handle more traffic without additional controllers,” says Mr Mosbakk, Project Manager of the DCL project, delivered and implemented by Terma at Oslo Airport AS.

Pilots Agree

98% of the pilots responding to a recent survey by Terma confirmed that they use the system (the remaining 2% of the pilots fly aircraft that are not equipped to this standard). 70% of the respondents reported time savings of at least one minute per departure, compared to manual procedures, while the remaining 30% noted savings in the range between one half and one minute. In either case, this is a significant factor when the work process is at its highest stress level both in the cockpit and in the ATC tower, enhancing safety in both environments. Not surprisingly, all respondents agreed that the datalink-based services are far more efficient and easy to use. And considering the ever-increasing congestion on the radio communication, 98% of the respondents found the datalink services “easy to read”.

Smooth Implementation

According to Mr Beck, Copenhagen Airport, the smooth implementation of D-PDC / DCL owed much to the fact that representatives of the ATC controllers were included, right from the outset, in the project team, which together with Terma and other project team members designed its functionalities and layout, and made decisions on a range of issues in the process. Mr Beck said: “The controllers felt at ease with the new system right from the start, and after a very short period of familiarization everyone was convinced of its inherent benefits. Its basic functionalities are so self-explaining that the basic introduction was actually provided by email to the controllers!”

More About This Company