BA, I used a couple of sites,`gaisma.com`,and the NOAA site to sort out sunsets ,azimuths ,and back timed the variation. The link to the story is a little short on detail,ie what time was the Mayday made, and so on. Another curiosity is that it was picked up by Auckland,so presumably on HF ,as Jay was out of range from NI.Later it says that an HF position line was obtained by the DC10 to confirm position(line). I would have thought that it could have been earlier . I recall reading the full article in the early 80s ,which I`m sure had a lot more detail....Anyway all the more reason to make sure your Standby compass is swung accurately...not sure if an AgWagon would have a full system....
Nevertheless,a truly outstanding bit of flying ,and navigating,by both parties,so never go with fuel left in the bowser....