As Boeing prepares to conduct at least one and possibly two test flights as part of the certification of its redesigned 787 lithium-ion battery system, the airframer also is seeking FAA clearance for a series of ferry flights for aircraft stranded around the world.

Several 787s remain at airports where they have been stuck since the fleet was grounded in mid-January. Boeing is working with the airlines and the FAA for some of them to be cleared for one-off ferry flights by the end of this month to relocate them to modification centers.

Airline sources say the negotiations concern flight clearance without the need for modification of either the battery or the addition of the redesigned stainless steel enclosure and its related titanium vent tube.

The affected aircraft include a LOT Polish Airlines 787 at Chicago O’Hare International Airport and another at Warsaw Chopin Airport, both of which, if approved, would be ferried to Houston. A United Airlines 787 at Los Angeles International Airport also would be flown to Houston.

Several Qatar Airways aircraft are expected to make ferry flights to Doha International Airport by March 31, including one aircraft stored at London Heathrow Airport and four others at various sites in Qatar. In addition to the battery tests and checks required by the FAA for the one-off ferry flight approved in February, the batteries in each aircraft will be required to pass Boeing’s new inspection procedure before flying.

In addition, Boeing also is gearing up to restart production test flights, a move that will mark an important first step toward the eventual recovery of the 787 production line. Although the start of these flights still awaits formal FAA approval of the battery fix, industry sources say that plans to resume work are in progress at Everett, Wash.; Charleston, S.C.; and Fort Worth, where a number of completed aircraft are located.

The aircraft will fly only if they have been modified with the new battery enclosure and venting system. Airline sources say the batteries on each aircraft also must be either original “901” units that have passed Boeing’s new inspection system or be of the updated design agreed with lithium-ion battery manufacturer GS Yuasa.