Yong said this report had been kept confidential at the request of the Malaysian Government.
"The Australian Government had done their own investigation since the aircraft (Nomad) was made by an Australian company.
But they will not reveal the results of their investigation because of this request.
"To get them to reveal, it must come from another foreign government which in this case, at least the State Government. We are wondering why the Malaysian government had asked them not to reveal this.
"Don't talk about MH370 (which mysteriously disappeared about 100 days ago enroute to China from KLIA). Even this flight they cannot sort out and this one is in Sembulan, not somewhere in the ocean. This is an issue that will remain in Sabah and we will keep asking the question," he said.
Meanwhile, more than 100 people took part in the Double-Six wreath laying ceremony organised by the Sabah Progressive Party, the biggest attendance of its kind for the event so far.
Yong said the event, hosted by the party's Moyog division, also attracted more young people this year, who came together to commemorate the event and pay their respect to the fallen leaders.
"These young people were not even born 38 years ago and we hope this annual event, especially through the media, will be able to remind our people about this part of Sabah's history which, sad to say, is not sufficiently covered in our school syllabus," he said, after the ceremony which was also attended by Sabah Star Chairman Datuk Dr Jeffrey Kitingan.
Dr Jeffrey said the event is an important reminder to the future generations on the importance of defending the rights of the people and the land, especially since the tragedy is closely related to the oil issue.
He also praised the young people who came and participated in the ceremony and urged the people to not be afraid to make sacrifices the way the leaders did for the common good of the people and the future.