For AA then .. quick tale regarding fuel gauges .... when the fleet was "metricised" (?) and we went from those simple "lbs"(where we all knew the numbers by instinct) to those weird "kgs" things ... a day was set aside as "metric day" .. a Sunday I recall .. idea being no flying from Thursday PM until Monday AM to give the lines time to do their work.
Late Saturday morning .. 6B call out to take a frame to Washington as a high priority load carrier had gone U/S. Arrive at the line to be told the metrication was just being finished .. phone the front end in planning to tell them to get all the metric pages out and not the "normal" ones... they don't have them ....so Captain draws keys to the squadron and we all meet there to ensure we all have the new paperwork to hand. Eventually get to the frame and start the preflight. Get to the fuel part and I CANNOT reconcile the fuel .. no matter what I do it will not add up correctly to what we want/need in kgs... call out the line and they also cannot get it to add up, although the maths on the F725 appeared correct ... lots of head scratching as there was obviously an error that none of us could see........
Now, for those that don't know.. the actual "mod" simply involved sticking some transparent circles (transfers) with the new markings/quantities over the old gauges ... proper gauges were a very long way away!! .... It was then decided by the SEngO that the only way to sort this problem, and avoid further delay, was to rip off all the "new" transfers, get the fuel load right using "lbs" .. then put a new set of transfers on. So that's what we did.. and half way through realised the problem .... whoever had done the first set had put the auxiliary tank transfers on the external tank gauges and vice-versa .. no wonder it didn't add up !! New set of transfers and off we went !! I believe "questions were asked" about the supervision of the "mod" installation after that!
As an extra ... (and for some stupid reason I think Fergie might have been involved ??) ... the shock and horror of the crew in Washington when they found out they were operating a "metric" Herk home was a sight to see ... we all did a quick swap of documents .. as we would now be taking the "non-metric" frame home once fixed.
I hated the metric numbers.. they never made sense to me and I never managed to memorise them like I had the old "lbs" ... which even after several years I can still recall instantly..