I'm rather surprised by the attribution to this accident of making input and output ports different on NRVs . During an FSO course in London, we attended the AAIB's "Black Museum" at Shell Mex House. An ancient NRV there (duly tagged with a cardboard label) was said to have been the cause of the loss of an RAF aircraft (a Vickers Valencia?) in a pre-war accident. We were told It was that accident that ensured that NRV ports were designed thereafter to prevent them being confused and thus fitted the wrong way round.
Last edited by Chugalug2; 2nd Mar 2017 at 08:20.