(Reuters) – Shares in Airbus Group fell on Monday after the fatal crash of an A400M military plane weighed on Europe’s largest and repeatedly delayed defence project, while the planemaker pledged to overcome the tragedy.

The huge military plane crashed outside Seville on Saturday, killing four crew and prompting Britain, Germany, Malaysia and Turkey to ground their fleets of Europe’s new troop and cargo carrier..

France said it would keep flying its planes, while Airbus pledged to resume flight testing on Tuesday with the head of its military aircraft business, Fernando Alonso, on board.

There was no official word on the cause of the crash but investigators’ attention was expected to focus partly on the plane’s turboprop powerplants. Germany’s Der Spiegel magazine reported that one of the survivors had said the plane suffered “multiple engine trouble” shortly after takeoff.

A source familiar with the matter confirmed that engines were one of the areas under scrutiny following the testimony but stressed it was too early to say what had caused the crash, with the crucial black box flight recorders yet to be analysed.

Airbus declined to comment. “We have to wait for the results of the investigation,” a spokeswoman said.

Shares in Europe’s largest aerospace group, which hit a record high in April, fell as much as 4.5 percent before closing at 62.09 euros, down 2.1 percent.

The A400M Atlas was developed for seven European NATO nations — Belgium, Britain, France, Germany, Luxembourg, Spain and Turkey — at a cost of 20 billion euros ($22 billion).

So far Malaysia is the only export customer.

The plane entered service in 2013, more than three years behind schedule, and just 12 of 174 aircraft sold have been delivered.

Problems in the development of the West’s largest turboprop engines helped to generate billions of euros of cost overruns and a bailout by the seven launch nations in 2010.

New technical problems with A400M military features surfaced last year, leading to fresh delays and a management shake-up.

SOURCE REUTERS, Read more. Photo M. van Leeuwen Z.A.P.P.