N90, another amazing pic! The mass of hicopleters parked alongside the runway testifies to the intense war being conducted then. If you had performed a R/W excursion similar to my Hastings one, it doesn't bear thinking about what the consequences could have been. Unlike you (serving with the RAAF), I only landed once in Vietnam during the war (which Harold Wilson very resolutely included us out of). We took a load of Red Cross supplies into Saigon (we were told they would be on the streets for sale within hours!). On final approach, gear down and landing flap, a B-57 flew left to right immediately in front of us firing ordnance (the VietCong were attacking the suburbs). We rather irritably reported this to the tower who replied by simply clearing us to land. Once on the ground you had to vacate the R/W ASAP. Someone else was either immediately behind you for Ldg or T/O. To encourage you in this need there were two manned bulldozers, one each side of the R/W. If for any reason you could not vacate, you shut down and evacuated the a/c before it was then forced to vacate as baled metal.
Often flew past Vietnam though, going to/from HK. The Violet Picture indicator (localiser type needle) was either welded to the LHS or RHS of the gauge, depending on which way we were going. It was monitoring 243Mhz!