Last checked at 
* Q3 adjusted EBITA down 24 pct at 58 million euros
* Market conditions for power plant unit worsened in Q3
* Maintains full-year adjusted EBITA guidance (Updates throughout, adds shares, analyst comment)
FRANKFURT, Nov 12 (Reuters) - Struggling German engineeringservices firm Bilfinger saw earnings slide further inthe third quarter after its clients slashed spending in the oiland gas sector and its ailing power plant business still weighedon the balance sheet.
The company, which in its heyday built the Sydney OperaHouse and Munich Olympic stadium, reported adjusted earningsbefore interest, tax and amortisation (EBITA) of 58 millioneuros ($62.4 million) in the third quarter, down 24 percent yearon year.
Its important industrial segment, which includes customerssuch as oil major BP, took a strong hit from weak oilprices as clients reduced spending. Its power plant unit, whichit expects to sell in the middle of 2016, saw a decline inorders.
"The already difficult situation in the power plant businesshas worsened as compared to the beginning of the year," thecompany said in its third-quarter statement.
Despite weak conditions in the energy sector, theengineering firm maintained its full-year outlook for adjustedEBITA between 150-170 million euros and flat year-on-year outputvolume.
Shares in Bilfinger traded up 0.6 percent at 0804 GMT inFrankfurt.
Weighed down by spiralling costs, Bilfinger also said itwould focus on efficiency savings as administrative expenseshave soared above 10 percent of output volume.
"In Q4 we do not see a further slump as we believe thelargest part of cost should have been accrued after ninemonths," said Jasko Terzic, analyst at DZ Bank.
($1 = 0.9296 euros) (Reporting by Karolin Schaps; Editing by Maria Sheahan andVictoria Bryan)
