Chapter 24 - While we are waiting - the route

The route from USA to Australia is shown on the image, with stop over locations for fueling and accommodation shown.

First leg is the long one to Hilo, Hawaii. It is on this leg, which is 2061 NM and 13:31 hours of flight time, that we need the massive load of fuel which puts the aircraft 30% above its maximum take off weight. The next longest leg is Pago Pago, American Samoa to Noumea which is 1397 NM and 8:41 hours.

For non aviators, the maximum take off weight of an aircraft does not mean that the aircraft will not fly if it is heavier. It is the maximum weight for which flight is approved and the weight the landing gear is capable of withstanding if forced to return immediately for landing. Naturally there are safety margins built in, but 3600 lb is the maximum take off weight for which this aircraft is approved. Also, the published performance data for the aircraft including take off distance and rate of climb will be degraded. An application for special approval together with engineering data is required and after inspection of temporary fuel tanks etc, FAA gives approval for flight above the take off maximum. Approval is given subject to conditions in relation to turbulence, non use of automatic pilot, advice to controllers etc..

The aircraft will take much longer to get airborne and will climb slower. As we get closer to our destination, and have used the overweight fuel, the aircraft will be back to its normal flying weight.

Initially, the settings of Manifold Pressure, propellor RPM and mixture will be based on maximum range and not on maximum speed or endurance, as distance is our main priority. This will mean lower MP, and the fuel mixture set for exhaust gas temperature (in our case Turbine Inlet Temperature) 50 degrees F Rich of Peak. Later as we burn off fuel and are sure of reaching our destination with fuel to spare (3 hours looks good to me) we will increase the speed (and fuel burn) to get there quicker.

Click on image to enlarge