Many positive aspects of this incident were identified by fmgs and NigelOnDraft, in particular the A321 crew’s awareness of the taxiing situation and indicators of good safety culture. However, although a more serious outcome was averted by autonomous action, much of the industry’s safety strategy still relies on R/T. The weaknesses of this form of communication have been evident ever since Tenerife, a false perception from a stepped-on transmission. Yet in the MCT incident there was a overlaid transmission (although not crucial to the event) and a dual frequency operation that reduced the ability for everyone to have audio awareness. Apparently we still have a great deal to learn.
One common aspect in safety is to have defenses in depth, either through dual path systems, procedures, two people, or the dependency of crew and ATC working together. This incident appears to show that few of these existed in a reliable form that would prevent a runway incursion in the event of a single human error (a common safety issue). Thus what changes are likely; not to prejudge any activity at MCT, but in general could ATC’ers suggest alternatives or make comparisons with other operations. There were two controllers at MCT, is it feasible to have cross monitoring? A RIM warning was given, but not heard/seen, why not, human error, system design? Is there potential for confusion between DZ1 and D1; resulting in false situation awareness by either the crew or controller? I believe that the AAIB could have sought and published answers to a few more of these human factors questions.
For operating crew it is essential to keep eyes and ears up at all times and be aware of traffic even when operating on different frequencies. This may necessitate a change to operating procedures, avoid checks when taxiing, and avoid hurrying during ground operations. Again if there are some good suggestions, then please share them us.