* Much-delayed airport opening planned for second half of 2017
* Red tape, contractor problems cause delays
* Owners invest more in current airports Tegel and Schoenefeld
By Victoria Bryan
BERLIN, Oct 15 (Reuters) - The chief executive of Berlin's much-delayed international airport still hopes for it to be completed in the second half of 2017, even though the deadline is getting increasingly tight.
The 5.3 billion euro-airport ($6 billion), meant to replace the capital's three Cold War-era hubs, has been under construction since 2006 and was originally planned to open in 2011.
Now the six-month buffer that new CEO Karsten Muehlenfeld built into his 2017 deadline has been partially eaten away because of amendments to the planning application needed to fix errors and comply with updated security guidelines. The insolvency of contractor Imtech has also caused a delay.
"Because of all the delays we have accumulated of three to four months, it definitely will not be on the first day of the second half of 2017," Muehlenfeld told journalists during a tour of the airport's terminal building on Thursday.
At first glance, Berlin Brandenburg Airport, situated to the south of the current Schoenefeld airport looks like it could be ready. The new runway is even in use while the one at Schoenefeld is being renovated. But weed-covered parking spaces outside, crossed-out motorway signs to the new hub plus scaffolding inside betray the illusion.
The current team under technical project manager Joerg Marks is working through a raft of problems, including faulty smoke removal systems, cabling issues and more recently the discovery that some of the ventilators installed in the terminal were too heavy, meaning supports had to be strengthened.
Muehlenfeld, who took over in March, said workers had checked the building from top to bottom for problems, even removing ceiling and wall panels to check cables and ensure the structure meets fire safety regulations.
"I think we have found most of it, but that (doesn't mean) that we will have one or another one that we still haven't found yet," Muehlenfeld said, adding that even if new issues were found they would not necessarily lead to more delays.
The airport is jointly owned by the city of Berlin, the state of Brandenburg and Germany's federal government. The delays mean the owners have had to invest more into Tegel, to the north-west of the city, while also coming up with plans for more check-in space and a new low-cost terminal at Schoenefeld to keep up with rising passenger numbers into Berlin as the likes of Ryanair offer more flights. ($1 = 0.8780 euros) (Editing by Elaine Hardcastle)