By Tim Hepher
PARIS (Reuters) -Airbus is poised to stage the maiden flight of its A321XLR jetliner - a major milestone in the race to improve the range of narrowbody jets - but it is struggling to pin down key certification and delivery dates, industry sources said.
Airbus says the A321XLR can fly 4,700 nautical miles (8,700 km), 15% further than its most capable current narrowbody jet, allowing airlines to serve routes like New York-Rome, Houston-Santiago or Tokyo-Sydney without the cost of a big twin-aisle.
The extra range is made possible by the addition of a new rear-centre fuel tank moulded into the lower fuselage.
But Airbus faces questions from regulators over the risk of fire in the event of a belly landing and has been forced to delay the entry to service by at least three months to early 2024 to allow part of the lower fuselage to be modified.
Although the first flight marks a major step in development following a successful run of advance sales, Airbus remains locked in talks behind the scenes with the European regulators over the scope of any re-design and the rules for certification.
No target date has been established for certification or the first delivery of the plane, something that would typically be at least provisionally set in stone before the first flight, the sources said.
"There is a lot of back and forth discussion to prove various ideas but EASA has not yet accepted (Airbus) proposals," a person familiar with the matter said. Detailed work on design changes cannot begin until the basis for certification is clear.
The European Union Aviation Safety Agency (EASA) has published a "special condition" applicable among other things to the A321XLR and is inviting public comment.
"It is the responsibility of the manufacturer to demonstrate compliance with the special condition," an EASA spokesperson said, adding that a further such condition would be published at a later stage "addressing the crashworthiness of this design".
An Airbus spokesperson said, "We are in contact with EASA on the certification process and have nothing further to add at this stage".
The first A321XLR is expected to carry out its maiden test flight in Hamburg on Wednesday. Airbus says it has sold about 520 of the single-aisle jets since the project began in 2019.