The tragedy of July 1st, 1999, has very seriously affected the Plateau de Bure staff. Five staff members have lost their lives. They have played a key role for the technical maintenance of the entire observatory, including the telepherique and keeping clear the tracks in winter time. The accident has also disrupted the only regular means of access to the Plateau de Bure site.
All this will have important consequences on the life at the Plateau de Bure in the short and medium term, specifically for the next winter. A first consequence is that a fixed schedule for access to the site can no longer be guaranteed. Permanent presence on the site is required for the safety of the equipment, human safety rules implying that at least 4 people be present. This minimum requirement will be preserved, but it may happen, under bad weather conditions, that a given team be trapped on the Plateau de Bure for several days, without being replaced. Since this will obviously impose an extra load on the staff, it is likely that the normal team will be kept smaller than usual.
The maintenance period will also most likely take longer than foreseen, since the current situation already imposes limitations on the crew size, as well as on the weekly available working hours. The staff has also been busy with priority tasks, such as preparing an autonomous water supply.
We have already started hiring an extra operator to cope with unforeseen situations next winter. We started training astronomers to the interferometer control, in order to allow the operator to focus more efficiently on safety issues in case of longer than average stays.
We also anticipate that snow cleaning will be more difficult than usual, since access could become difficult, or since the snow cleaning engines may be required for transport of personnel. A new crew has also to be hired and trained for that very specific work. Finally, repair time in case of failures could become significant.
Despite the situation described above, so far, the observations have remained relatively unaffected. However, as an immediate consequence, current observing projects will be carried out on a ``best effort'' basis. Because of manpower limitations, we indeed can no longer guarantee that all configurations will be scheduled, even for ``A'' grade proposals. This is especially true for proposals requiring long baselines (B configurations). Astronomers with such proposals are invited to check regularly with Roberto Neri.
Logistics and manpower limitations will unavoidably result in a delay in the construction of antenna 6. So far, the transport of the central hub to the site remains an unsolved problem (this piece weighs 5 tons and has a diameter of 4.4 m). The installation of the new correlator on the site will also be delayed, since we want to minimize modifications until easier access becomes possible. Finally, station N46 will not be available this winter.
Accordingly, the Plateau de Bure Interferometer configuration remains identical to that of last year.