On December 1st, 2000 regular astronomical observations have been restarted at the Plateau de Bure Observatory. Since the helicopter accident on December 15th, 1999 all regularly scheduled astronomical observations had been stopped. Following the maintenance work in the summer, only test observations were made to check the performance of each telescope and to verify the overall status of the instrument. This was necessary to prepare the arrival of the new correlator for 6 antennas which was installed in September and has been tested since.
Activities on the Plateau de Bure have focused throughout the last 6 months on the implementation of new safety measures. A new overall safety plan has been worked out and implemented. The conditions for the two accepted means of transport, i.e. helicopter flights and access on the ground, with a 4-wheel-drive vehicle during the summer and a ratrack during the winter season, and passing on foot the area near the ``Fenêtre'', have repeatedly been reviewed. Furthermore, the conditions for executing maintenance work and other tasks have been described in a series of documents.
The improvements mentioned in the previous paragraph have resulted from the technical safety audits by a team from CERN, and from the risk analyses carried out by the IRAM safety engineer, David THIEVENT, with the help of members of the Plateau de Bure team. An important role has also been played by the IRAM-CHSCT (committee for hygiene, safety and working conditions). This committee will regularly review all safety relevant issues. In particular, at the beginning of 2001 it will reconsider the impact of the restart of the observations on the overall safety at the observatory and give its advice.
The aim of all the safety measures is not only to reduce the risks associated with the activities on the Plateau de Bure to a minimum, but also to establish clear rules how to deal with a problem should it arise. This work will continue. New input is expected from a third auditing activity which will be finished soon: a team of experts in ergonomics from CIDECOS/ABILIS has been looking at organizational aspects and at the working conditions on the Plateau de Bure for each category of posts.
The large number of new safety measures already implemented, others which will be completed soon, and plans for further improvements under way, justified in our view the restart of regularly scheduled astronomical observations. It should, however, be clear that this is still on a best effort basis with other, safety related or technical activities taking precedence whenever needed. Full scale observations will be resumed as soon as a new transport system is in place. If all goes well, this could be at the end of 2002.