LB - I trust no Leading Hand is going to be made to carry the can; those placed in authority over him or her should take the blame. If (and until all investigations and SIs/BOIs are finished it's a big if) the loss was caused by negligence on the flightdeck, then I think most of us know where the buck stops. The MAA is pretty clear on the subject:
Transfer of Custody of Air Systems
2301(1) Custody of, and responsibility for, an Air System shall transfer to the Aircraft Commander from the time the acceptance certificate is signed until the after-flight declaration is completed.
Transfer of Custody of Air Systems (Acceptable Means of Compliance)
1. The Aircraft Commander should ensure that they are satisfied with the declared condition of the Air System when the acceptance certificate is signed. If they are not satisfied, they should declare the Air System unserviceable.
2. Once custody of the Air System has been accepted, the Aircraft Commander should authorize and monitor any subsequent Maintenance activity that may be required prior to, or during flight.
3. The Aircraft Commander should ensure that the technical log (MOD Form 700 or equivalent) has been updated to reflect the condition of the Air System when the after-flight declaration is completed and that the symptoms of any new Air System faults have been adequately briefed to the receiving Maintenance organization.