Do not go to the posted coordinates. BYOP
The first attempt at flying across the Tasman Sea was attempted by Lieutenant John Moncrieff and Captain George Hood, both from New Zealand. The set off in their Ryan B-1 Brougham plane named Aotearoa from Richmond (west of Sydney) on 10 January 1928 at 2:44 am bound for Trentham racecourse in Upper Hutt. There had been radio contact for 12 hours of the expected 14 hour journey but they, nor the Aotearoa, were ever seen again.
On 11 September 1928, Australians, Charles Kingsford Smith and Charles Ulm, were the first to successfully fly across the Tasman Sea. They flew a Fokker F.VIIb/3m trimotor monoplane called the Southern Cross. They had used this plane earlier in the year to be the first to fly across the Pacific from the Oakland California to Brisbane, stopping in Hawaii and Fiji. For the trans Tasman flight, they were joined by navigator Harold Litchfield and radio operator Thomas McWilliams. As for the first attempt, they also set off from Richmond, NSW at around 5pm on 10 September and after 14 hours 25 minutes they covered the 2670 km landing at Wigram, Christchurch at 9:22 am
Kingsford Smith's Southern Cross in 1928
The first solo flight across the Tasman was made by Australian, Guy Menzies. He feared he would not get permission for his attempted flight, so told authorities and his family he was flying to Perth. He was flying a single engine Avro Avian biplane named Southern Cross Junior and set off from Sydney at 1am on 7 January 1931 aiming to land in Blenheim. Bad weather forced him off course and after 11 hours 45 minutes of flying he attempted to land in a swamp near Harihari on the West Coast, mistaking it for flat ground. The plane flipped upside down but Menzies walked away with a few scratches. There is a memorial near the landing (crash) site which surprisingly doesn't have a geocache there (I think there was a multi that was archived in 2008)
Menzies Southern Cross Junior near Harihari
The cache is located at
S 45° AB.CDE'
E 170° FG.HGC' where:
A = The approximate time the Southern Cross left Richmond
B = The time the Aotearoa left Richmond (2:4B am)
C = The year Moncrieff and Hood made their attempt (192C)
D = Distance flown by Kingsford Smith and crew (267D)
E & F = Menzies flight time was 1F hrs E5 mins
G = The year Menzies made his flight (19G1)
H = The Southern Cross landed at H:22am