Previous poster stated GC distance Monto-Bulolo was 1250nm … @ 180KTAS that’s a tad under 7 hours which is hard to believe is possible.
GC distance is actually 1,086 nm, so 6 hours by Baron, however the GC track would take them virtually directly overhead both Moresby and Rocky. I very much doubt that they would want to be that conspicuous, so suspect there may have been another stop somewhere up on the Cape or elsewhere. That might also explain why the load was so light.
The PNG article states that they departed Bulolo about 0815, so it would be interesting to see what time they arrived at Monto.