Hello Emeritus, many thanks for your message, very interesting. Can you recall if there were any instrument panels relating to the slipper tanks in the cockpit? I guess an ANA Flight Engineer would know. I am interested to know how they were used. Were they used at a specific time of the flight? I am guessing that once the main tanks had been used sufficiently to allow the 145 gallons in each slipper tank to be pumped into the main tanks, then thats wahat happened. Cheers, Tom