UPDATE 3-Thales hit by A400M charge; shares bounce

* Sharper than expected fall in first-half profit

* A400M provision of 102 million euros, seeks compensation

* Shares fall then rise in heavy volume

(Recasts with CEO comments)

By Tim Hepher and Dominique Vidalon

PARIS, July 27 (Reuters) - The new boss of Thales, Europe's largest defence electronics firm, unveiled a deeper-than-expected slide in profits, hit by writedowns and aerospace weakness, sending the shares into a bounce.

The baptism of fire for Luc Vigneron, the former head of state armaments firm Nexter, included reporting a fresh 102 million euro hit from the French company's role in the troubled Airbus A400M military plane project, which helped to slice first-half operating profit by 82 percent.

Delays of the Boeing (BA.N) 787 Dreamliner also hit Thales.

Giving his first set of company results since arriving under a change of industrial shareholding in May, Vigneron withdrew detailed 2009 forecasts, telling reporters that when "big programmes are in difficulty, it is much more difficult to predict the future".

"The results reveal weakness in some areas and my priority will be to put in action what is needed so that the situation is resolved," he said.

Thales shares fell as much as 6.8 percent, removing 400 million euros from the firm's value and pointing to the biggest one-day fall in over 6 years. But by 0900 GMT they were up 3 percent at 30.5 euros as investors looked beyond the one-off items.

Analysts said the results were at least in part a traditional bid by an incoming chief executive to clean the stables, but expressed doubts about his goal of matching recent margins of more than 7 percent in the second half.

French broker Oddo Securities called the results, which included losses in both aerospace and security, "catastrophic".

"Part of these bad results can be attributed to the start of a clean-up of the accounts," said Natixis Securities in a note.

"But it is too early to gamble on the unavoidable rationalisation which the new CEO will have to put in place."

Vigneron said he had no plans to impose significant cuts in Thales's 68,000 workforce but did not exclude any options.