EXCLUSIVE-EU set to approve easyJet purchase of parts of Air Berlin - sources

(Adds detail on planned purchase, market shares)

BRUSSELS/LONDON, Dec 4 (Reuters) - British budget airline easyJet is set to win unconditional EU antitrust approval to buy parts of failed German peer Air Berlin, people familiar with the matter said on Monday.

EasyJet will take on some of Air Berlin's operations at Tegel airport in the German capital for around 40 million euros ($47 million). It will also take on leases for up to 25 A320 aircraft, and about 1,000 of Air Berlin's pilots and cabin crew.

The move will allow easyJet to further bolster its position in the German capital, notably against Ireland's Ryanair and Lufthansa's fast-growing budget unit Eurowings.

The European Commission, which is scheduled to decide on the deal by Dec. 12, declined to comment.

Air Berlin was the largest carrier in Berlin before its insolvency, with Ryanair and easyJet the next two biggest airlines serving the capital. German flag carrier Lufthansa has traditionally not been so strong in Berlin, instead doing most of its flying out of its hubs in Frankfurt and Munich.

Lufthansa's budget unit Eurowings plans to expand rapidly should Lufthansa's plans to buy Air Berlin units Niki and LGW receive antitrust approval. It has offered concessions to allay concerns it could become too dominant on German and Austrian domestic routes and the Commission is currently seeking feedback from others on the proposed concessions.

Should the deals be approved, easyJet will become the largest carrier in Berlin with 16 million seats, ahead of 10.7 million for the Lufthansa group (including its planned purchase of Air Berlin units LGW and Niki) and Ryanair on 5.9 million, according to presentation slides from easyJet last month.

EasyJet has previously said if it gets approval it expects to start operations from Tegel in January, at first leasing crewed planes while the Air Berlin crews and planes enter its fleet.

Ryanair is also keen to expand in Berlin though, having previously criticised Lufthansa's purchase of Air Berlin assets as a "stitch-up", and said on Friday it was also seeking slots in the capital in order to base nine new aircraft at Tegel in a challenge to both easyJet and Lufthansa.

($1 = 0.8434 euros) (Writing by Victoria Bryan; Editing by Julia Fioretti and Mark Potter)