In most cases a drive is marked Dead, PFA or Stale due to disk errors and the disk should not be reused.

Stale disk:

If a disk is marked Stale it should not be reused. However there are some conditions a disk may go stale on an otherwise good disk.

Unless you are absolutely sure the disk is good and know why the stale state happened, a stale disk should not be reused. 

PFA disk:

If a disk is marked PFA, we believe the disk will fail and it should not be reused. Disks with SMART errors, physical errors or frequently time-out are often marked PFA.

A disk marked PFA should not be reused.

Dead disk:

If a disk is marked Dead, it should not be reused. However disks could be marked dead for reasons other than disk failure. Accidentally removing a disk or power cycle the unit in an incorrect order may create dead disks. These disks would otherwise be good, except for user error.

Unless you know the specifics on why the disk is marked dead, a dead disk is likely a failing disk and should not be reused. 

Do not force Dead disks online unless you know the array data is current and not stale. Please contact Promise Technical Support and provide the system service report (subsysteminfo) before forcing any dead disk online.