Andrzej Jeziorski/SINGAPORE

The US Federal Aviation Administration is expected to issue an airworthiness directive in March, recommending inspections to 18 Boeing 777-200s affected by a potential tailplane corrosion problem.

Aircraft line numbers 15 to 33, excluding 18, are affected. The aircraft involved are in service with All Nippon Airlines (ANA), British Airways, Cathay Pacific Airways, China Southern Airlines, Emirates, Japan Airlines (JAL), Thai Airways International and United Airlines.

The trouble arises from a production error where fasteners have been improperly installed and wet sealant is missing from the rear spars of the empennage. Boeing issued a service bulletin in November 1997, and upgraded this to an alert service bulletin last October. The bulletin warns that the production flaws could lead to galvanic corrosion of tailplane structural components, and eventually to structural cracking.

The trouble was discovered following an internal Boeing investigation into production line problems at its facility in Frederickson, Washington. "It's a lapse in production quality control," says a senior industry source.

The safety bulletin calls for inspections and repairs to 1,068 fasteners. Cathay engineering director Derek Cridland says that 34 structural zones must be inspected, and if sealant is found to be missing, the existing fasteners must be drilled out and replaced.

JAL and Cathay confirm they have "started negotiations" with Boeing on compensation to cover the cost of the work. The problem is not considered "mission critical" says JAL. The necessary procedures will be carried out on the affected aircraft late this year.

According to JAL, a repair will take up 2,000 man hours and cost some $200,000 per aircraft. The affected aircraft were produced between 21 April, 1995, and 20 May, 1996. Repairs and inspection to five aircraft built in 1995 are to be completed in 2000, while the remaining 13 must have the procedure completed by 2001.

Source: Flight International