This Site is dedicated to all those families of the people that have tragically disappeared on flights in and around New Zealand. I only hope that from all the effort in building this site and from all the effort of those taking part in this venture, that it will bear fruit in bringing ‘closure’ to their memories!
Due to the high angle of climb and descent possible and being of the gravity
feed type, the usable fuel of these tanks has to be rated as to all attitudes of
flight. This causes confusion as some models are listed as carrying up to 5
gallons of fuel in each tank as unusable. This is true only in very unusual
attitudes. In level or normal flight, the 180 will use all but 1- 1 1/2 gallons
of fuel from each cell. Most of this could actually be used in an emergency by
flying with one wing high and then the other wing high to allow this fuel to run
to the pickup area.
This means that out of the 176 litres they should have had on board on their final takeoff, there was 12 litres that they could not count on as being useable, which means they had 164 litres divided by 60 litres/hour = 2.73 hours endurance.
Legally you have to have 30 minutes flying time of fuel left when you land, but this doesn't mean you can't use it in an emergency! The plane doesn’t just fall out of the sky because it becomes illegal!
Ross McDowell said Father Crosbie had dipped the fuel and said he had 65 litres and that was before he did the final top up of another 45 litres = 110 litres, minus unusable 12 litres = 98 litres = 1.63 hours fuel endurance. He should have had 176 litres on board on the final take off, yet after dipping the tanks they took off with 110. There is an amount of at least 66 litres missing from the tanks!
Father Crosbie thought that after dipping the tanks, and adding the extra fuel he had about 2 hours fuel on board and said he would "get a bit more", but it is unclear whether he meant he would get more fuel or he would fly it more fuel consciously (by leaning the mixture, or cruising at a lower speed.) to get more fuel endurance out of it.
The calculation of them only having 30 mins of fuel left when Kevin Hallett ( the opposum trapper) last heard it, must have been based on SAR believing that he had been flying for a little over an hour, but according to my calculations, if this was ZK-BMP, then it had only been flying for 1/4 hr when Kevin Hallett lost ear shot of them (explained further on). This means that they would have had - at the very least (being generous) - 1 1/4 hrs endurance left at that point.
There is another couple of explanations in that either someone was stealing fuel out of his plane, probably at night-time at Big Bay as the plane was unattended, or the plane was using more fuel than usual - fuel leak in flight, or otherwise?
If it was the latter, then this would mean it was using, not 60 litres/hr, but 72 litres/hr!
The only other explanation is that they did not leave Riversdale with full tanks as stated.
2/ Kevin Hallett (the opposum trapper at Lake Alabaster) Discrepancies
The files reveal that Father Crosbie flew two flights within a few hours prior to the fateful final flight. On these flights, he was trying to find a way across the Divide through the bad weather, but had returned to Big Bay on both occasions.
I now don't believe Kevin Hallett heard them on their final flight at all, but instead heard Father Crosbie on his earlier flights that day - checking to see if there was a way through. I will try to explain why here.
You need to bare in mind that Kevin Hallett was going about his normal everyday business and so had no need to take note as, as far as he was concerned, there was nothing out of the usual. He didn't know then that he had to take note, and you will read it shortly in his own words from hand written notes given in an interview a few days after the disappearance.
(Note: My comments in smaller print. I’ve included the crossed out words to show the flow of the interview)