Gavin Grimmer
As there are so many variables to calculate accurately the exact track, it would take a computer program to work it out which is way beyond me. Maybe someone reading this article may be able to produce one?
As pointed out by our CFI, Mike would have had to have been making constant changes in direction as the more they drifted off course, the more the ADF needle would have drifted also, but on more thought we came to the conclusion that in turbulence he may not have noticed, and Mike did comment that the ADF was “all over the place”. It was confirmed by VH-ESV and VH-AZC that there was a thunderstorm out off the coast, and that was causing their ADF's to also do the same thing.
Mike's mind must have been elsewhere due to the stress of the turbulence (and probably fatigue) as I would have thought the general compass heading and the direction shown on the ADF should have given him a clue that he was off course, but obviously this wasn't the case. In turbulence the magnetic compass swings all over the place also, so it was probably a case of blindly attempting to follow the ADF needle and hope for the best!
In various places on the Net, there is quite some discussions as to what airspeeds to use for calculations as normally in rough air conditions it is normal to slow the aircraft down to a safe rough air penetration speed to make it easier on the airframe (not to mention the occupants)... after all, you don't want the wings to break off! With the previous calculations of the distance covered in the time available – these show that Mike did not slow the aircraft down, otherwise it would have been impossible to cover this distance. From this, there is really only one possible conclusion... the turbulence was not that bad!
One thing I have observed is that if you fly most of the time in smooth air and then strike a day where it is turbulent, the turbulence does not have to be very bad to make you very uncomfortable, whereas if you have several days flying in turbulence, your tolerance level goes way up. What you considered rough on one day, becomes nothing as the tolerance level goes up. Mike Hutchins was known as a pilot who couldn't handle turbulence, in fact he was known to go to extreme lengths to avoid it. In saying this, any turbulence experienced at 143 KIAS (160 KTAS as per Flight Plan) would seem 'rough.'
The four minutes he spent climbing from 8000 ft to 8500 ft could not have been at a cruise climb speed as once again, if he had slowed the aircraft down it would have made it impossible to cover the distance to where they were identified on radar, hence I say that all he had done was to increase power and attempt a cruise climb. Had he gone into a normal angle of climb speed with full power, I'm sure he would have reached 10,000 ft.
In saying this, he should have been in an updraught and hence climbed easily:
Google Earth Depicted Ground Profile Of The Area VH-MDX Was Flying In
Freezing level was reported at around 7000 - 7500 ft (VH-CSV at Taree 8000', -2°C) and as he had been in cloud (moisture) for the last 4 minutes, he would have picked up a fair amount of ice increasing his weight and lift capabilities, hence reducing his climb rate, but the point of this is just that he had not gone into a 'serious' climb as is so easily imagined.
You may be wondering what the point of all this is to finding where VH-MDX ended up?
Quite simple – We need to know at what direction MDX was heading when they were initially picked up by Sydney radar. This may not seem important at the present time of this investigation, but it will become more obvious as we progress....
MDX pg 11
