Embraer on Tuesday revealed or confirmed 15 E-Jet orders from four airlines, a mix of new orders, converted options and leased aircrft from the Brazilian airframer’s leasing arm.

Embraer disclosed a firm order from Japan Airlines (JAL) for another four E-170 jets, lifting the operator’s number of firm orders for the E-170 to 15. This firm order had previously been included in Embraer’s backlog as belonging to an undisclosed customer.

Like the previous E-170s ordered by JAL, these new ones will be configured with 76 seats in a single-class layout and will be operated by J-AIR, JAL’s wholly owned subsidiary, which serves the company’s domestic network. Embraer has also signed an extension of its pool program with JAL to include these additional four aircraft.

As reported earlier on AWIN, Air Costa of Vijayawada, India, acquired three E-Jets to launch its scheduled regional service in India. The new carrier bought one new E-190 from Embraer and secured two E-170s from ECC Leasing, Embraer’s wholly owned subsidiary.

As was the case with the JAL order, the firm portion of Air Costa buy was included in Embraer’s backlog as being placed by an “undisclosed” customer.

Air Costa plans to link underserved markets in India with more direct flights, and the E-170 and E-190 are “ideal in size and range,” says CEO K.N. Babu. “We can add frequencies and routes without adding too much capacity, thus serving places with seasonal demand, as well as key secondary and tertiary business centers.”

Air Costa will initially connect cities in southern India such as Bangalore, Chennai, Hyderabad and Vijayawada, as well as key secondary cities in the north and northwest of the country.

Venezuela’s Conviasa exercised options for seven E-190 jets, bringing the number of firm orders it holds for the model to 13. It still has options for another seven E-190s. Conviasa currently operates six E-190 jets on regional routes in Venezuela and in the Caribbean. By the end of 2013, the airline will be operating twelve E-190 jets, all configured with 104 seats in a single class.

Lithuanian start-up Air Lituanica signed an agreement with Embraer’s leasing arm for one E-175. The carrier will launch scheduled service on June 30 with one E-170 from embattled Estonian Air operating on the Vilnius–Brussels route. The airline intends to add routes between Vilnius and Amsterdam, Berlin, Prague, Munich and Moscow.