Cat B,
Not yet suitable for Command Training (to be considered for reassessment after a specified period)
Typical example...not ready for command (poor PC/Line Check)
Cat C,
Not yet suitable for
Further Command Training
Typical example...Failed command course
Cat D1,
Not Suitable for Command Training
(no further assessments to be made)
Cat D2,
Downgraded to F/O from Captain
To remain F/O until considered suitable for retraining
Assessments start when your seniority places you close to command potential. This can be very early if you volunteer for a freighter command.