The anniversary of Mr Saxton's helicopter crash passed on Sunday, and, if the dive team is able to recover the engine on Saturday, the find will come a year to the day after his body was recovered from the bottom of Lake Wanaka.
A specialist dive team - headed by recently appointed LandSAR director Bill Day, his colleague Dr Simon Mitchell, and Mr Saxton's best friend, Wanaka helicopter pilot Toby Wallis - is trying to find the missing R22 Robinson engine, which is believed to be about 80m underwater.
The group hopes to provide the Transport Accident Investigation Commission (TAIC) with the last piece in a puzzle which could reveal why Mr Saxton crashed into Lake Wanaka during a routine flight in near-perfect flying conditions in November last year.
The group was unsuccessful in its attempt to locate the engine near Mou Waho Island during June, because the water was too murky.
Mr Day, who runs the multimillion-dollar global marine services company Seaworks, said visibility was better now.
Divers would use "rebreathing" equipment during the 80m-deep expedition - a setup which mixes oxygen and helium, instead of the traditional scuba gear of "straight air", Mr Day said.
Dr Mitchell is an Auckland dive physician, anaesthetist, and specialist in decompression illness, who set a world record deep-wreck dive of 178m in 2006.
The weather forecast for the weekend search seemed reasonable and the team stood a "reasonable chance" of locating the wreckage, Mr Day said.
TAIC communications manager Peter Northcote, of Wellington, said if the engine was found it could be a valuable addition to the commission's inquiry.
The commission had decided to end its search for the engine, which was seen in early searches by a navy submersible in November but could not be located later.
Any further evidence found by searchers would be added to the commission's inquiry.
A report from TAIC into the helicopter crash is not expected to be completed before February next year.
