NON-NORMAL RECOGNITION
:
What was the 'non-normal?
RA information was irrelevant to their approach and it seems likely (and even understandable) that the captain did not notice it was reading -8ft. Remember that there was probably no fault warning. Even if he had noticed it is possible he did not mentally connect that with any effect on the A/T as this involved fairly esoteric system knowledge.
The non-normal was therefore the inappropriate enunciation of RETARD and the failure of the A/T to apply power when required.
Just thought I would clarify that.