This report involves a simple taxiing navigation error. As with all incidents, it involves a number of factors and the report goes into great detail in certain areas. One lesson within this report is how instinct can tell you something is wrong. Your brain has sub-consciously processed some information which it knows does not fit your picture of what is going on. You don’t yet know what it is, but something does not add up and instinctively you feel some unease. Unfortunately acting on this feeling in this case was a little too late but instincts can provide important clues.
Another lesson is that aerodrome layouts, signage, markings and lighting need to be constantly reviewed beyond that of the usual regular and maintenance inspections. There is a danger when there is a focus on individual lights, markings and signage that the total picture conveyed to an unfamiliar crew can be misleading or confusing. Aerodrome staff working day in and day out can easily become unintentionally blind to the issues arising from the total picture caused by fading markings and signage and/ or defective lighting. Such issues are significantly multiplied in times of works being conducted on an aerodrome, or for that matter any change in any area of aviation. Everyone has to have heightened awareness during times of change of new or changing hazards and take extra care.
There is a story where an aerodrome lighting manager who knew every light on his aerodrome was in the right seat of an aircraft one night and asked to navigate the aircraft around the aerodrome in low visibility, under supervision. He got lost a number of times. If that can happen to this person it is not surprising that aircrew can get it wrong. I have been in the same situation at an unfamiliar aerodrome. We were being careful but still took a wrong turn on a wet dark night faced with confusing signage; it is very easy to do.
So what can we do? Aircrew should report to aerodromes where they feel improvements can be made. Both operators and aerodromes need to make reporting and sharing of reports easy to do. Aerodrome staff need to be aware to report any issues that may lead to aircrew and drivers being confused. Air traffic staff need to report where people have either made an error or there has been any confusion. The aerodrome and operators must then act to assess the hazards and implement any mitigation in a timely manner. All need to constantly review the hazards. In this case the hazard was known to both the aerodrome and operator. An identical mistake was previously made and mitigations were taken but some of the mitigations employed by both were weakened and so failed. So a section of failed taxiway centreline lights at critical point at this intersection, the faded marking against the refreshed marking along the incorrect routing, taxiway edge light failures at the intersection, the unselected illumination of an information sign and a crew warning on the aerodrome chart through numerous updates lost its meaning.
A number of barriers had fallen. Just by looking at these fallen barriers a number of topics that could be related to your own operation can arise. Sometimes just by asking whether there are any issues or discussing incidents is enough to elicit a response that otherwise would not have be given.
Read the full report on the accident to B747-400 at O.R. Tambo International Airport, Johannesburg: http://www.caa.co.za/Accidents%20and%20Incidents%20Reports/9257.pdf (if slow to load then try cutting and pasting the link into your browser).
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