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PARIS, Feb 5 (Reuters) - Airbus is renegotiating delivery schedules for its revamped A320neo jet and has told some airlines the aircraft will be delayed by about two months, industry sources said.

The European planemaker missed a 2015 target for delivering the first aircraft, an upgraded fuel-saving version of its best-selling medium-haul jet, by a few weeks due to what it described as issues with documentation for new Pratt & Whitney engines.

Industry sources have also pointed to delays in deliveries of the newly developed Geared Turbofan engine from its U.S. manufacturer, a subsidiary of United Technologies .

Airbus and Pratt & Whitney confirmed they are in talks with airlines over deliveries, but declined further comment.

"We are in talks with our customers on deliveries and once these talks will have concluded, then we'll finalise the aircraft and deliver to our customers as agreed," an Airbus spokeswoman said.

"We are working closely with Airbus," a spokeswoman for United Technologies unit Pratt & Whitney said.

"We are in talks with our operator customers on delivery schedules and once these are concluded we will finalise the schedules as agreed," she said.

The A320neo is designed to save 15 percent in fuel consumption. So far, Airbus has delivered one aircraft to Germany's Lufthansa .

The launch customer was originally supposed to be Qatar Airways but it rejected the aircraft due to a longer than expected process for warming up the engines before taxiing, which needed extra fuel.

Speculation about last-minute fine-tuning resurfaced after the first aircraft was delivered to Lufthansa after an unusually extensive series of 11 pre-delivery test flights, according to data from aviation website Hamburg Finkenwerder News.

In December, Indian budget carrier IndiGo said it would not receive its first A320neo on time for "industrial reasons" and warned of further delays.

Pratt & Whitney said its engine was "meeting or exceeding" its specifications on fuel consumption, noise and emissions.

The A320neo is sold with a choice of engines from either Pratt & Whitney or CFM International, owned by France's Safran and General Electric . CFM also powers the competing Boeing 737 family, including the revamped 737 MAX.

The first CFM-powered A320neo is expected to be delivered in July.

(Reporting by Tim Hepher; editing by James Regan and David Clarke) ((tim.hepher@thomsonreuters.com; +33 1 49 49 54 52; Reuters Messaging: tim.hepher.thomsonreuters@reuters.net))

Keywords: AIRBUS A320NEO/