Berlin Brandenburg Airport was originally planned to open in October 2011, five years after starting construction in 2006. However, the project encountered a series of successive delays due to poor construction planning, execution, management, and corruption. The Airport finally received its operational licence in May 2020, and opened for commercial traffic on 31 October 2020, 14 years after construction started and 29 years after official planning was begun. Schönefeld's refurbished passenger facilities were incorporated as Terminal 5 on 25 October 2020 while all other airlines completed the transition from Tegel to Berlin Brandenburg Airport by 8 November 2020.aerotelegraph.com – "Moving schedule" (German) 1 October 2020

Overview The construction of Berlin Brandenburg Airport suffered from continued delays which were caused by an array of issues.

The most significant cause for the continuing delays was the fire protection and alarm system. In the terminal building, the system was not built according to the construction permit and failed the mandatory acceptance test necessary to open the airport. FBB proposed an interim solution employing up to 700 human fire spotters, which the building supervision department of the local Dahme-Spreewald district rejected. Inspectors uncovered flaws in the wiring, programming and implementation of the highly complex system designed by Siemens and Bosch. The system automatically controls sprinklers, smoke extractors and fire doors. For aesthetic reasons, designers decided that the terminal would have smoke extraction ducts in its ceiling but that they would not exhaust to its rooftop. During a fire, smoke would be pumped from the ceiling into a shaft running down and through the basement below the structure. This required the natural rising behaviour of hot air in the shaft to be reversed. Achieving this on the scale necessary for this airport is a unique undertaking and so far this elaborate smoke extraction system has not worked as planned. To meet the acceptance test requirements, large scale reconstruction work of the fire system might be needed. It emerged that Alfredo di Mauro, who designed the fire safety system, was not a qualified engineer. While his business cards stated he was an engineer, he was actually qualified as an engineering draughtsman. Di Mauro was dismissed by the airport company in early May 2014. In the termination notice, the company cited "serious defects" in his work and that trust in their relationship was "now finally shattered". The airport company went on to state that Di Mauro's plans would be "disposed of". The system was to be rebuilt and divided into three areas in order to make it "manageable". The cost of this work was reported as being a nine-digit figure.

Another major factor impacting on the construction of the airport was insolvency of general planner Planungsgemeinschaft Flughafen Berlin Brandenburg International (pg bbi) and the dismissal of the Gerkan, Marg and Partners architects. Inspectors have uncovered many examples of poor workmanship due to a lack of proper supervision and documentation, most notably concerning the wiring. Reports have surfaced about cable conduits that hold too many cables or hold cables in incompatible combinations, such as phone lines next to high voltage wires. A total of of cooling pipes were allegedly installed with no thermal insulation. To correct this, the demolition of numerous walls may be necessary. Furthermore, exterior vents appear to be in improper locations, allowing rainwater from the western facade to enter them.

Timeline + Construction delaysBritta Beeger: Flughafen BER – Eine Chronik des Scheiterns. In: faz.net (6. März 2017). Announcement Opening date 5 September 2006 (original) 30 October 2011 25 June 2010 3 June 2012 7 May 2012 17 March 2013 27 October 2012 27 October 2013 January 2013 on/after 2014 8 January 2014 on/after 2015 24 February 2014 on/after 2016 14 May 2014 on/after 2017 December 2014 2nd half of 2017 21 January 2017 2018 15 December 2017 31 October 2020

2006 After nearly 15 years of planning, actual construction work for Berlin Brandenburg Airport began on 5 September 2006. When construction began, FBB announced 30 October 2011 as the opening day for the new facility. To make way for the new airport, two villages were removed. The 335 inhabitants of Diepensee received compensation and were offered new homes in Königs Wusterhausen, a move that was completed by late 2004. The 35 villagers of Selchow were resettled to Großziethen in mid-2005.

2007 In November 2007, the BER-Infotower opened a public observation tower and information center. It was part of the airport's visitor facilities, which also had a webcam of the construction progress. The transparent and twisted structure was originally intended to be temporary, with a scheduled removal announced in 2016.

2008 Construction of the terminal building began in July 2008.

Tempelhof Airport was officially closed on 30 October 2008.

2010

On 8 and 9 May 2010, the airport celebrated its topping out with open days at the airport site. A few days after 14 June 2010 topping out ceremony, FBB announced that construction deadlines could not be met.

2011 On 30 October 2011, the railway line and terminal station were ready for service, however no scheduled trains would operate until the opening.

Operating tests and service trials began on 24 November 2011, based on the anticipated opening date of 3 June 2012. A total of 12,000 volunteers participated in simulated check-in, security screening, boarding and baggage claim. The tests used 15,000 pieces of luggage in the automated baggage processing system, covered night-time operations and emergency scenarios. This phase also saw the acceptance tests of various airport systems. It became clear on 8 May 2012 that the building could not open on schedule, officially due to the failure of the fire protection system. In reality, according to a Brandenburg State Audit report in February 2016 the usability of the airport was at 56.2%; for example, there were no ticket counters and the escalators did not work. The report went on to say there was no realistic chance that it could be used "reasonably successfully" in 2012. Legal implications concerning the failed 2012 opening were expected after the release of the 2016 report.

2012 As the new date drew nearer, airlines amended their timetables to reflect their plans to operate from BER. On the retail side of the airport, shops and restaurants prepared for the opening. As the airports in Tegel and Schönefeld were to close once the last flights of 2 June had been serviced, a major logistics operation for moving the airports' infrastructure was launched. Vehicles, equipment and supplies that were needed at Tegel until the final moments would have been transported to BER during the night of 2–3 June. To allow this, the authorities planned to restrict the highways linking the two airports (A113, A100 and parts of A111) to airport traffic only. Rundfunk Berlin Brandenburg, the national broadcaster for Berlin and Brandenburg, scheduled 24 hours of continuous live coverage of the airport move. A special Lufthansa flight to Frankfurt Airport, operated with an Airbus A380, was scheduled as the first departure from the new airport on 3 June at 06:00.

On 8 May 2012 just 26 days before the move, FBB again postponed the opening date. The postponement led to the cancelling of moving plans and in some cases reversing actions already completed. It cited technical difficulties, primarily concerning the fire safety and smoke exhaust systems for the delay. As a result, FBB dismissed the director for technical affairs Manfred Körtgen and replaced him with Horst Amann. It also announced 17 March 2013 as the new opening date for BER. However, this was soon met by doubts due to the large number of construction flaws and problems that inspectors continued to find.

In early September 2012, FBB further postponed the opening to 27 October 2013. Again, media and experts (most notably Peter Ramsauer, Federal Minister for Construction and Infrastructure) voiced doubts about the deadline.

2013 FBB announced on 6 January 2013 that the opening would be further delayed, at least until 2014; however, no definite opening date was given. Klaus Wowereit resigned as chairman of the supervisory board and was replaced by Matthias Platzeck, who previously had served as his deputy. The board also dismissed Rainer Schwarz, the CEO of FBB, on 16 January. By January 2013, FBB had announced and cancelled four official opening dates. FBB named Hartmut Mehdorn, previously CEO of Deutsche Bahn (1999–2011) and Air Berlin (2011–2013) as Schwarz's replacement on 8 March 2013.

Due to the rising passenger numbers at Berlin airports and delays to BER, concerns were voiced in 2013 that the new airport might be too small as passenger numbers at existing Berlin airports were approaching the BER design capacity.

2014 On 8 January 2014, FBB announced the airport would not open that year. Mehdorn stated on 24 February 2014 that it was unlikely the airport would open before 2016. In remarks made in August 2014, he pointed towards 2017 or 2018. Mehdorn announced no opening date by 14 October 2014, so a special commission established by the Brandenburg Parliament retained oversight of the project.

The initial design for the main hall, known as "the monster" to construction workers, called for a single exhaust system. Revised plans called for multiple systems controlled by of wiring. By 19 May 2014 Siemens had not yet designed the wire harnesses. These problems forced the initial construction budget to skyrocket.

BBI sought to open the north pier for use by three to ten flights per day as a test, though other parts of the airport would not be operational for some time. It requested that Technischer Überwachungsverein (Technical Inspection Association, TÜV) review the facility for safety and compliance to Brandenburg building codes. In its assessment report issued on 29 July 2014, TÜV found that some lightning rods were missing and that the back-up generator powering the sprinkler system did not provide adequate power. One source with the TÜV stated, "What the airport ordered was sufficient for a circus tent, but [if power fails] not for the dimensions of the terminal." The exhaust system to remove smoke from a fire was also reported to be leaking.

Citing dissatisfaction with construction progress, members of the airport board indicated during their 8 December 2014 meeting that they were beginning the search for a new CEO, although Mehdorn's contract ran through 2016. One week later, Mehdorn announced he would resign as soon as the board named a successor, but no later than June 2015. Karsten Mühlenfeld, former head of Rolls-Royce Germany, replaced him as airport CEO in March.

2015 The search for a general planner was eventually stopped in February 2015.

On 20 March 2015, Mehdorn again faced questions from the Investigative Commission of Berlin's parliament. Mehdorn eventually ceased all public duties on 21 May 2015, citing health concerns. Berlin's mayor Michael Müller was appointed the new head of the supervisory board (Aufsichtsrat) on 3 July 2015. However, he had disagreements with Mühlenfeld, primarily over the opening date. Led by Mayor Müller, the board insisted on an opening in 2017.

A former manager for BER was taken into remand for alleged bribery on 13 May 2015; an Imtech manager was alleged to have given him bribes at a highway gas station in 2012. Imtech built parts of the fire exhaustion system.

The German branch of (Dutch) Royal Imtech filed for bankruptcy on 6 August 2015, and its parent company went bankrupt a few days later. As a result, Martin Delius, leader of the commission of inquiry into the failures during the airport's construction, stated that the planned opening in late 2017 was doubtful.