From the Chancellor Airbus to a new parabolic flight aircraft

The aircraft is 16 years younger than its predecessor, has an eventful history, and is continuing a remarkable legacy. The former A310-304 VIP 'Chancellor Airbus' is the new parabolic flight aircraft – unique in Europe. From 27 April 2015, it will conduct experiments in weightlessness, just as the A300 ZERO-G did before it. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) will be making use of the former German government aircraft to carry out research in 'zero gravity'.

In June 2014, the Airbus was converted from a VIP plane to a research aircraft (see info box 1), and was purchased by French company Novespace, which is based at Bordeaux-Mérignac. Since March, the metropolis' airport in south-western France has also been home to the A310 ZERO-G. Prior to this, the aircraft spent six and a half months at Lufthansa Technik AG in Hamburg, undergoing an extensive process of conversion and re-approval as a civilian aircraft, in line with the regulations of the European Aviation Safety Agency, EASA.

Between 27 April and 8 May 2015, once the test flights with – in some cases – up to 50 trajectories have been successfully completed, as well as training sessions with the specially trained crew, the new parabolic aircraft is due to undertake its first scientific campaign.

"This is a joint campaign between DLR, the European Space Agency (ESA) and the French Space Agency, CNES," reports Ulrike Friedrich, who has been in charge of the DLR parabolic flight programme since 1999. "We have a total of 12 experiments on board, of which eight come from Germany – four of these were selected by ESA. In the first week, the scientists set up their experiments in the aircraft and finalise preparations for the second week. On 5, 6 and 7 May, three days of flying are envisaged – each with a total of 31 trajectories," adds the Programme Manager.

DLR has been working with Novespace on the parabolic flight programme since 1999. For 15 years, German scientists and engineers used the previous Airbus A300 'ZERO-G', built in 1973, for experiments in weightlessness. After 5200 flights, 4200 flight hours and 13,180 parabolic trajectories, the special aircraft went into retirement on 31 October 2014, concluding its period of scientific service. DLR organised 25 research campaigns, totalling more than 400 experiments, using the A300 'ZERO-G' – to tackle biological, medical, physical and scientific questions. Technological tests also formed part of the programme; experimental equipment was tested for use in space – on the International Space Station (ISS) for example.

"The older the aircraft are, the more maintenance is required," says Friedrich. At some point, it is no longer worthwhile. For this reason, DLR was keen to support the search for a suitable 'successor'. "The challenge was to find an affordable aircraft, yet one that had not been exposed to too many flight cycles. This is because the aircraft structure is exposed to the strongest loads during take-off and landing." The German Federal Government's A310-304 VIP 'Konrad Adenauer', approximately 26 years old, best met these requirements. Novespace acquired the plane for approximately 2.5 million euros.

Before the aircraft's maiden flight in its new capacity, Lufthansa Technik AG in Hamburg made some 1350 modifications to it. The most notable of these is the approximately 100 square metre, windowless experiment zone, fully clad with white synthetic leather padding in the centre of the aircraft cabin. This is the science centre – surrounded by black nets so that nothing and no one floats too far during the approximately 22 second phase of weightlessness, and equipped with handles, special lighting and flooring.

The control centre remains in the cockpit – just like any conventional aircraft – but even there, a special piece of equipment has been added – an accelerometer, or 'G' instrument – and a system that enables the parabolic trajectories to be flown precisely. Friedrich says: “There are four pilots on board for each day of flying; three sit in the cockpit, one is 'off duty' until changeover. The duty plan is determined daily on a flexible basis – sometimes there is a change after the fifth parabolic trajectory and sometimes after the tenth." During a parabola, the first pilot controls movements about the longitudinal axis, the second controls motion around the transverse axis of the aircraft and the third the thrust of the engines, and hence the velocity of the aircraft.

• A brief history of the A310 'ZERO-G'

  The Airbus A310-304 '10+21' was delivered from aircraft manufacturer Airbus to East German airline Interflug on 24 June 1989, and was used by East German government leaders until 1991. On 27 August 1991, the aircraft became the property of the German Air Force and with the name ‘Konrad Adenauer’, the VIP aircraft was used for journeys and state visits by German Federal Chancellors and government ministers between 1993 and 2011. The A310 '10+21' was stationed at the Cologne-Bonn airport during its mission for the German Federal Ministry of Defence. Exactly 25 years after the initial handover, the 'Konrad Adenauer' was handed over to its new owner, Novespace, on 24 June 2014, after which numerous test flights were carried out. From 3 September 2014 until 18 March 2015, Lufthansa Technik in Hamburg overhauled the aircraft and converted it for use in parabolic flights.

• What happens during a parabolic flight?

  To fly a parabola, the pilots first of all steer the aircraft steeply upward and then put it into a controlled dive. In the upper section of the flight curve, there is a 22 second period of weightlessness. In the phases prior to and after this, the normal forces of gravity are almost doubled. Since the pilots imitate the path of a ball thrown into the air, or a parabolic trajectory, the flights are referred to as parabolic flights. During a parabola, some sections of the aircraft structure are exposed to loads that are almost 30 times greater than those experienced during normal use.

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