Australian pilot Gilbert Parker and a two-year-old boy are still missing.
Mr Parker, of Victoria, was transporting the sick toddler and his mother to a hospital on 2 August when the incident happened.
The mother's body was recovered by villagers from the Natewa Bay shoreline the next day.
Lead investigator Andrew McGregor told FBC News the tail was located to the north of Natewa Bay.
Mr McGregor said the search teams also found bits and pieces of the wreckage in the same area.
He said this indicated how strong the currents have been.
Mr McGregor said one of the challenges the recovery operation faced is the reef system in the bay which is hazardous for high-tech equipment and boats.
Mr McGregor said the navy, police, military, volunteer divers and search teams are all helping with the search along with people from nearby villages.