Graham Warwick / Washington DC

New connection between controller and airliner being tested in Miami airspace with national deployment due by 2008

Operational use of controller-pilot datalink communications (CPDLC) in US airspace is to begin in late September, with national deployment scheduled between 2005 and 2008. End-to-end testing began last month in Miami airspace.

The revised schedule extends the initial "Build 1" operational phase from 18 months to 39 months, with the expanded Build 1A service planned to become operational in Miami in December 2005 and nationwide by December 2008. This represents a delay of two years, caused by airlines pushing back plans to equip aircraft for CPDLC (Flight International, 13-19 November, 2001).

American Airlines has now committed to equipping at least 16 aircraft by mid-September, allowing Build 1 to become operational after a slip of only three months. Delta Air Lines and Continental Airlines are interested in equipping aircraft for CPDLC, says the US Federal Aviation Administration.

Technical evaluation of Build 1, providing an initial set of four messages, is under way. These tests involve FAA aircraft equipped with Rockwell Collins VHF datalink Mode 2 (VDL-2) avionics, ARINC ground stations upgraded to handle VDL-2 communications and a new automation system at the Miami air route traffic control centre. Operational evaluation using American Airlines aircraft is to begin in July.

Meanwhile, the FAA plans to issue both a request for proposals (RFP) for the local-area augmentation system (LAAS) and a notice of proposed rulemaking (NPRM) for domestic reduced vertical separation minima (RVSM) this month. Along with CPDLC, LAAS and RVSM are key elements of the FAA's Operational Evolution Plan to increase US airspace capacity.

The LAASRFP will begin a programme to acquire 46 Category I systems, followed by 114 Cat II/III systems, for which Honeywell, Raytheon and Thales are expected to compete. Honeywell and Raytheon completed autoland demonstrations earlier this year. The FAA's first Cat I system is due to enter service at Houston in October next year, while Cat III LAAS is scheduled to be fully operational by October 2011.

The FAA says LAAS will provide the Cat I precision approach capability the wide-area augmentation system (WAAS) was designed to provide but cannot. When it is finally commissioned in December, the Raytheon-developed WAAS will provide approach minima of 350ft (100m) altitude and 2.7km (1.5nm) visibility, compared with the 200ft and 1.85km required for Cat I.

The NPRM for domestic RVSM is expected to propose that vertical separation be reduced from 2,000ft to 1,000ft between flight levels (FL) 290 and 410 (29,000ft and 41,000ft) in December 2004. This would create six additional usable altitudes above FL290.

Following Europe, which implemented RVSM simultaneously in 41 countries in January, the FAA is proposing full implementation in 2004 but some sectors of aviation are pushing for a phased introduction, citing the cost of equipping and approving aircraft for RVSM.

Source: Flight International