Regardless of difficulty or cost - Is it time to bring VH-MDX home?
While some will have sympathy with your cause, believe me, most people would say it is best put to rest. Most of the aircraft that have crashed into the Barrington Tops area would have been flying in low cloud without knowing their precise position. One typical example was a Lockheed Hudson of the Herald Flying Services that disappeared for many months before the wreckage was spotted by an over-flying airliner. The DCA investigation decided the highly experienced former wartime pilot was trying to fly underneath low cloud and in poor visibility to get from Sydney to Taree and took a risk which didn't pay off.
According to one transcript the pilot of the Cessna 210 reported failure of the engine driven vacuum pump. If that was so, then within one minute the pilot would quickly lose control caused by worsening erroneous attitude information. On the other hand, if he was not an experienced IFR pilot and saw what he perceived both artificial horizons apparently failing, but which actually was loss of control due to poor instrument flying ability, then he may have mistakenly diagnosed vacuum pump failure. Even an experienced instrument rated pilot flying on limited panel in cloud (few pilots are that good) would need all his skill and attention to have to rely on the electrically powered turn coordinator in association with the magnetic compass. Throw in erroneous attitude information, turbulence and thick cloud and his chances of getting out of that alive would be zero.
There is no "Devil's Triangle" in that area. That is nothing more than a journalistic dramatic beat up. Nothing is to be gained by re-visiting the search area. Quite the opposite in fact. There would be a real risk to life and limb of those hardy and well meaning volunteers who would willingly spend their time trying to locate long since deeply hidden wreckage in impossible country.