Not just Douglas, Glueball - almost everyone else BUT Boeing. Most of the British aeroplanes I worked with in the old days, had the fuel pumps outside the tank with just the plumbing inside. Thus, no heavy duty wiring passed into the wet area, just the very low-energy indication system components and wiring. Though I've been a "Boeing man" for decades now, I've always considered their fuel tank equipment to be a weak area. The tank harnesses are rubbish, the fuel feed systems are crude and the "Dry Bays" are anything but. Then again, Boeings are cheap and cheerful - thats why they've outsold everyone else. So far...
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Through difficulties to the cinema