Astro was much easier with HO249 or ANT pre-computed tables. I never tried spheroidal trigonometry in flight.
Mr WHBM Senior
(WW2 nav, Halifax and later DC3) once told me he took along a few times his log tables and 12" slide rules from school days and on the sector home did the calcs from first principles.
It would be interesting to know if the Equipment Cooling fan was a 'lifed' item and if so when it was last changed, possibly nothing at all to do with the age of the airframe.
I recall being on a BA One-Eleven service out of Birmingham in the 1990s, in the last couple of months of service. The interior was immaculate, totally clean, nothing broken, nothing even discoloured. This after 25 years of service.
In contrast the BA European 767s, even a few years ago, had been allowed to get into a dreadful state internally, and regulars on the Moscow flight on Flyertalk started a list, by aircraft registration, of all the unresolved cabin issues which plagued those flights, including broken, missing or filthy cabin fittings, many of which should have been standard stores items. The worst was G-BZHC, whose cabin lighting had some longstanding intermittent issue that caused all the lights to flash on and off at random - this aircraft gained the long-running soubriquet of "The Disco", and regulars said their hearts would sink when they saw it on the gate. Now at the time ZC was the newest 767 in the fleet, less than 10 years old. There really is no excuse for such maintenance budget cheeseparing, and to be frank, saying that it's only non-vital components that this is done with, having two completely different maintenance regimes for different components, strains credulity.
http://www.pprune.org/passengers-slf...ml#post5777138