The Federated States of Micronesia expects to publish a preliminary report on the Chuuk lagoon crash landing by the end of October.
The FSM's investigator in charge said essential evidence and flight recorders from the Air Niugini Boeing 737 have been recovered.
Information from the flight data and cockpit voice recorders, and the Automated Flight Information Reporting System recorder will be downloaded and analysed in Port Moresby.
The investigator also said the Enhanced Ground Proximity Warning System and the Flight Management Computer from the aircraft will be downloaded and analysed in the US by the National Transportation Safety Board.
Specialists from the US aircraft manufacturer Boeing and the US Federal Aviation Administration are among those analysing the data and documents.
The FSM investigator-in-charge says it's a complex investigation and the final report is expected to take months to complete.