Another way of categorising errors is to determine whether they are reversible or irreversible. The former can be recovered from, whereas the latter typically cannot be.
For example, if a pilot miscalculates the fuel he should carry, he may have to divert to a closer airfield, but if he accidentally dumps his fuel, he may not have many options open to him.
A well designed system or procedure should mean that errors made by flight crew are reversible. Thus, if a flight crew member incorrectly selects fuel feed which results in an imbalance, the aircraft systems should generate an appropriate alert.