Most airlines do not allow oxygen servicing on board anymore (apparently some idiot a few years ago used a homemade non-approved adapter and accidentally serviced the oxygen system with nitrogen).
So the only approved method is to physically replace the cylinders (to be refilled using a stationary oxygen rig e.g. in the hangar). For this the cylinder valve will have to be closed. This leads again to the problem of the mechanic/engineer forgetting to open the valve fully after reinstallation.
The only option I see is to make the reinstallation of the oxygen cylinder a duplicate inspection, but there the airlines will cry out about the extra manpower costs at small stations.
Last edited by MD11Engineer; 1st Apr 2007 at 19:28.