Edit (30th Sept): Edited to include the first flight of the first production A320NEO, which is destined for IndiGo. Edit includes a confirmation of a Space Flex cabin.

Indian domestic market leader IndiGo’s first Airbus A320 NEO (New Engine Option) – part of the July 2011 order for 180 aircraft, has rolled out of the Hamburg (Germany) final assembly line fully painted in the airline colors, but without the Pratt & Whitney Geared Turbo Fan (GTF) Engines. This is the third such airframe of the airline. Two have no engines fitted. The cabin has not been fitted yet.

MSN 6720, destined for IndiGo, first flew on September 25th at Toulouse, France. The aircraft fuselage has however not been painted in the airline’s colors, but the wings are in the airline’s markings. MSN6720 is the 6th NEO to be produced, and the first ‘production’ NEO. The to-be Indian Registration of MSN 6720 is yet unknown, but will likely be the first A320 NEO for IndiGo.

A320-271N MSN 6744, which is expected to be registered VT-ITA, is the 7th NEO produced, and likely the second for IndiGo. A320-271N MSN 6799, to be registred VT-ITC, is likely IndiGo’s third A320 being assembled at the Toulouse (France) final assembly line, and is the 9th NEO to be produced. All Airbus A320 NEOs that IndiGo will accept will be powered by the Pratt & Whitney PW1127G engines.

The same engines had a problem with a clip holding seals inside the engine. This had caused concerns on the NEO program schedule, which has invariably slipped a bit. However, launch customer Qatar Airways expects to receive the first aircraft by the end of the calendar year. Interestingly, Qatar’s A320 NEO is MSN 6772 – the 8th NEO – which means it is later down the assembly line sequence when compared to IndiGo’s 6744 and 6720.

The NEOs rely on the sharklets and new, ultra-high bypass geared turbofan engine technology to together deliver fuel savings of upto around 15% (over and above today’s CEO A320’s without sharklets) . Such high fuel savings will however be realized only on very long flights that approach the maximum range of the airplane.

Airbus’s “Space Flex” concept allows airlines to increase the seating capacity of the Airbus A320 (both current engine options (CEO) and NEO) to 189 seats, without compromising on seat pitch and comfort. This is achieved by moving the two rear lavatories closer to the bulkhead, eating into the galley space. This makes more sense to no frills carriers which do not carry much meals on board. The space for service trolleys in the aft galley of the aircraft reduces from 7 to 3. The space where the aft lavatories were fitted are replaced with 1.5 rows of seats.

This increase in number of seats reduces unit costs by 5% to 6%. It is not known if IndiGo will adopt the space flex concept yet. No physical changes to the emergency exits are required. However, opting for a mix of 189 seat and 180 seat A320s may reduce operational flexibility for the airline. Opting for a higher capacity however seems inevitable.

IndiGo is believed to have opted for the Space Flex cabin, but details on when it will appear are not known.