The Lynx MRGB requires some ridiculous quantity of oil. Thirty eight pints, from memory. The oil alone is/was dangerous air cargo, but the gearbox, with oil in, was not. Ships allowance of oil was something limited, maybe 10 or 15 l, because the gearbox doesnt use much oil and inflam store space is scarce.
Every time HMS Something or other flight had a MRGB need replacing somewhere in farflung a gearbox was usually available, but the gearbox oil, which needed changing after a few hours could not be sent by air.
The supply solution was to send the box to Portland. There as much oil as the gearbox would hold was poured into it and the gearbox rebagged and put back in its transit container. It could then be shipped by air. On arrival at farflung, enough oil for an oil change was decanted from the gearbox into temporary containers and the gearbox fitted, test flown and in due course the oil was changed.
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