Another piece of Swiss cheese that I did not know even existed. Unfortunately for the BA crew, one of its holes might have lined up with holes in the other pieces of Swiss cheese. Thanks to BOAC, Gerald D. & others (and myself), it is now uncovered.
On that same chart, there is another box at the top titled CAUTION / RESTRICTION and the first point therein is:
1. ACFT to exercise caution when taxiing on TWY B southbound to THR RWY 03L due to Apron taxilane M extending from TWY B in a Southerly direction.
No, that box is not there on my screen. Here is a picture of the chart from my screen:
I have been playing around trying to establish what happened. I have no doubt that the box described above IS ACTUALLY THERE and I have just seen it on another of my computers. What has got me worried is that it is not there on my screen.
I thought a .pdf file was pretty bullet-proof. I am sure that the South African authorities published the chart in good faith including all the warnings that they thought were needed. I downloaded it in good faith and opened it up, and obviously expected to find all that I needed. But I didn’t. I hadn’t realised that there was a gap in the system such that a .pdf file might not show everything. I am not sure that a .pdf file should be considered bullet-proof anymore. That is more than a bit worrying for all of us who rely on .pdf files to see charts, AIPs, ICAO manuals, etc.
I think I have tracked down some of the relevant issues which include the software that converted the drawing to a .pdf, and the publishing process of the .pdf. Rather than let get this thread side-tracked by Adobe issues, I suggest that if anyone wants to discuss those aspects then PM me or open a new thread in Tech Log. BTW – I am running Acrobat X pro, Windows 7 on all my machines.