NavList:

re: Probably off-topic but  aircraft flying across the southern ocean use a step [c]limb technique. Given the little traffic why not cru[i]se climb?

Dave,

Between 2015 and 2017 I often crossed the South Indian Ocean, e.g. from Mauritius to Perth Australia on A340 (interestingly enough Perth is almost "dead on" the extended departure runway - RWY 14 - centerline) .

I also crossed the South Pacific Ocean a few times on same type of A/C (eg. Falklands to Melbourne Australia) later on.

In all cases we were allocated altitudes blocks - e.g. [FL320 - FL 370] - during a few hours in a row. We could then pick which ever altitude would best suit us within this block.

As regards "climbing cruise" ... yes that's what the theory says. If you take a closer look, for an A/C GW (Gross Weight) about 280 Tons, and Fuel Consumption about 8 tons/hour, the computation is easy and straightforward. I forgot the general formula - probably dGW/GW = d(Static Pressure) / (Static pressure) - but I do remember that it translates here into about +1,000ft / hour, in all cases that is within the [+700'/hour, +2,000' / Hour] range. With the sole possible earlier exception of the Concord A/C, I know of no other A/C auto pilot able to fly at around +15 ft to +20 ft/min vertical speed. On the first generation Glass cockpit A/C (e.g. A330 / A340 / B777) the lowest decrement / increment you could select was +/- 100 ft/min. It might be possible that on the 2nd generation class cockpit A/C (B787, A350) you can even select a lower rate (+/- 50 ft / min) but being able to fly exactly +/- 15 ft / min when already by 35,000 ft is a real technical challenge (just translate it into hPa / second) ...

I would surmise that the South Oceans ATC regulations have not significantly changed in the past 10 years or so.

Back to our main topic:

All in all, I do agree with the position advocated by Gary and others. Princess Earhart most likely simply ran both first out of course and then out of fuel.

Kermit