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By Francesca Landini

MILAN, May 7 (Reuters) - Italian defence group Leonardo warned on Thursday that the coronavirus outbreak would have a bigger impact in the second quarter, after reporting a net loss in the first three months.

The company, which has key production sites in Italy including the Vergiate helicopter facility, kept all its plants open during the lockdown but incurred higher health and safety costs due to the crisis.

In addition, some of its plants ran at a suboptimal rate and shipping finished products slowed down or even halted in some areas, hitting profitability.

An order intake of 3.4 billion euros in the first quarter, up 36% compared with last year, helped cushion the business.

"The second quarter will be worse than the first, as in April we were still in complete lockdown and in May we are experiencing a partial lockdown," CEO Alessandro Profumo told an analysts' conference call.

The group, which has both civil and military customers, said it was suspending its 2020 guidance and pledged to update investors on the full-year outlook when it releases its second quarter results.

However, it said the situation would gradually improve in the second half of the year provided a second wave of the contagion does not materialise.

"We are not able to quantify the COVID-19 impact in 2020 yet but we strongly believe in our solid fundamentals and remain fully focused on executing our industrial plan," Profumo said.

A major problem for the group was delivering finished products to clients around the world at a time when travel was banned or discouraged.ATR aircraft

As a result, Leonardo did not deliver any aircraft from its ATR unit and could only deliver 11 helicopters, compared with 19 last year, during the quarter. The slowdown in deliveries hit both sales and core profits between January and March.

Revenue fell 5% year-on-year to 2.6 billion euros.

Earnings before interest, tax and amortization (EBITA) dropped 75% percent to 41 million euros. The return on sales, which is an indicator of profitability, worsened to 1.6% from 6% in the same period last year.

The group swung to a net loss of 59 million euros compared with a profit of 77 million euros in the same period last year.

"We are getting ready for smart deliveries," said Chief Financial Officer Alessandra Genco, adding this would be done by transferring to customers all the data a helicopter's final tests, without requiring the client's pilots to carry out the test at the production site.

The group said it was postponing non-urgent investment, freezing new hires and would cut non-fixed costs by 10-15%.

It said it could count on more than 5 billion euros of available liquidity and did not face any debt maturity this year. (Reporting by Francesca Landini, editing by Giulia Segreti and Giles Elgood)