Engineers dispatched to make urgent modifications to Boeing Dreamliner jets Three hundred Boeing engineers have been dispatched to airports around the world to make urgent modifications to the 50 "Dreamliner" jets that have been grounded since January. The maker of the Boeing 787 has been given the green light to replace the lithium-ion batteries at the root of safety fears with re-engineered power supplies encased in stainless steel. Randy Tinseth, vice-president of marketing for Boeing, told The Independent: "We've had a share of issues with the Dreamliner, but we believe we have an absolutely fabulous airplane." Each aircraft takes around five days to modify; it is then up to the airline to decide when to start flying the jet again. Ethiopian Airlines" reservations system suggests it will begin operations as early as Thursday, but this looks fanciful. The Japanese airlines ANA and JAL are expected to be first to see their fleets modified. Most other carriers will resume flying some time in May. British passengers booked on the 787 with the UK launch customer, Thomson Airways, may be dismayed to learn that there is still no indication of when services may start. The Dreamliner was due to enter service to Florida and Mexico on 1 May. A spokeswoman for Thomson told The Independent: At this point we are still waiting for a delivery date from Boeing. Once we take delivery of the aircraft, there are a number of activities that we need to complete before the aircraft enters commercial service. British Airways also has 787s on order, but it has made no promises about where and when services will begin. A BA spokesman said: We hope today's decision will hasten the arrival of the 787 to the British Airways fleet. The 787 is Boeing's most fuel-efficient aircraft and quieter than any of its predecessors.