Tests of Australia's 737 AEW&C aircraft on hold after performance issues force radar antenna-mounting modifications
Boeing has suspended flight and radar tests of the first 737-700 airborne early warning and control (AEW&C) aircraft to make significant modifications to the Northrop Grumman multirole electronically scanned array antenna (MESA).
The change to the MESA, dubbed the "top hat" radar, interrupted the programme just as it was transitioning from initial airworthiness testing to radar certification check-out and high-power radar tests. The former trials had been completed with the exception of cross-wind tests when the test aircraft, YG201, was handed over to Boeing Integrated Defense Systems for the radar work. This was due to begin in Victorville, California in mid-December.
However, problems are believed to have been discovered with the radar performance at this stage, and instead of flying to California, the aircraft undertook cruise performance tests in its baseline configuration before modification.
The aircraft is now back in Seattle where it is undergoing a "top hat" modification programme in the "B-52" hangar at Boeing Field, which is thought to involve raising the profile of the 10.7m (35.5ft) -long, 2,950kg (6,500lb) MESA antenna.
The additional work involved with raising the height of the radar is expected to take more than a month, and is likely to require the repeat of many of the initial airworthiness tests. However, Boeing insists that the overall programme schedule remains unaffected.
It says: "We're performing to our plan and are on schedule. This is a development programme and we're always looking for ways to provide the best possible product to our customer. We plan to deliver the first two 737 AEW&C aircraft to Australia on schedule in 2006."
Although full mission hardware and operating software will not be installed until January 2006, with a second test effort to clear the mission systems between March and August 2006, it is not known if the latest development will affect the mission radar flight tests. As currently scheduled these are due to be conducted under a development, test and evaluation phase that will begin in late May using the second test aircraft and run through to the end of June 2006.
The Royal Australian Air Force is set to take delivery of its first two of six aircraft for the Wedgetail programme in late November 2006, with a further two to follow in 2007.
The Australian Department of Defence (DoD) says the Wedgetail project is currently capped at a total cost of A$3.43 billion ($2.61 billion) with A$1.55 billion already spent. In its annual report to the Australian Parliament on 18 November, the DoD claimed "the project remains on schedule and on budget, with a planned in-service date of 2007".
GUY NORRIS / LOS ANGELES
ADDITIONAL REPORTING BY PETER LA FRANCHI IN CANBERRA
Source: Flight International
