Aer Lingus and Ryanair are awaiting a report from Boeing within the coming weeks which will specify the modifications to be made to 737 aircraft's wiring systems.
The move is expected after a proposal from the US Federal Aviation Administration that the modifications be made. The changes have already been recommended for 747s, jumbo jets, after the TWA Boeing 747 explosion near New York in July 1996.
The new proposal affects the two Irish airlines which fly 737s. Neither uses 747s. It is understood the newer the aircraft the longer an airline will have to make the modification.
Aer Lingus aircraft were put into service in the 1990s, but Ryanair's are on average 16 1/2 years old.
Boeing International Corporation has had discussions with the FAA and has 45 days to respond to the proposal that certain changes be made in the electrical wiring to the fuel-boost pumps in the 737s. At the end of that time, the FAA will issue a directive.
A spokeswoman for Boeing in London told The Irish Times yesterday the FAA had already required the inspection and modification of the fuel quantifier indicator system wiring in 747s.
This week the FAA proposed that changes should also be made in the older 737s. The new-generation 737s, which are classified as 600s, 700s and 800s, would not be affected, she said.
"The modification will provide additional protection in the aircraft. We`ve been talking to the FAA all the time," the spokeswoman said. Boeing would be issuing a service bulletin on the matter to the airlines within the next few weeks, which was a regular process, she added.
Aer Lingus has 16 of the 737s, which are in the 400 and 500 category, so are not among the new generation. However, a spokesman for Aer Lingus said all the aircraft were new from 1990 onwards.
"The time-scale for carrying out modifications is based on the hours the aircraft has flown. A basic time of 30,000 flying hours has been put on it, and we would be way below that. We understand that because of this we would have until January 1st, 2000, to make the modifications," he said.
Any question of cost would not become clear until the Boeing recommendation and the extent of the modification were known.
"We want to make clear that we will comply with any directive. There is no issue of safety here. The 737 is a particularly safe aircraft and has a good record. It is the safest aircraft in the world," the spokesman said.
He said that as yet the FAA had not issued any directive. It had put forward a proposal, and any directive would be some weeks away.
"We understand that within the next few weeks Boeing will be making its own recommendation," he said.
A Ryanair spokeswoman said the airline had 20 Boeing 737s in the 200 category. The airline had received a notice on Thursday morning saying the airworthiness proposal would only apply to the 747s.
"Clearly, if we have any proposals or directives regarding 737s we will embody that and make the modifications," she said.
It is understood that the modification would relate to the fuelboost pumps and the wiring system connected to them. The change would concern the way in which the wires are bundled together.