Lufthansa is close to placing an order for six Boeing 777-300ERs that will be allocated to its Swiss International Air Lines subsidiary, industry sources tells Aviation Week.

The purchase, although relatively small, would be a major breakthrough for Boeing; Neither Swiss nor Lufthansa has operated a passenger variant of the 777, and sister carrier Austrian Airlines only acquired its four 777-200ERs when it bought Lauda Air.

The 777-300ERs are to replace part of Swiss’ current Airbus A340-300 fleet. The airline operates 15 aircraft of that type and has been evaluating a successor model given the A340’s poor economics. Swiss also has 13 A330-300s and is scheduled to take delivery of two more.

Earlier delivery slots for the 777 are understood to have been one important factor in the fleet decision, as Lufthansa is expected to make a broader decision for next generation aircraft, such as the Airbus A350 or the Boeing 787, later this year. That decision will mainly address the replacement need for the German airline’s 48 A340-300s/-600s.

Part of this larger order also could include fleet needs for Swiss and Austrian. In addition to the four 777s, Austrian operates a fleet of six aging 767-300ERs.

All fleet decisions for Lufthansa Group’s family of airlines are made at the company’s Frankfurt headquarters.

Lufthansa, which recently reduced its Boeing 747-8 commitment from 20 aircraft to 19, also is understood to be planning an order for two Airbus A380s. The airline already has placed orders for 17, according to Airbus’ latest orders and deliveries list, and operates 10. One industry source indicates that the two aircraft are already part of the existing backlog.

Neither Lufthansa nor Airbus is prepared to comment.

The A380 order is part of a broader fleet renewal program that includes 100 narrowbodies. The supervisory board will decide how this single-aisle order will be split between Airbus and Boeing.