Ahmad Seth, son of captain Zaharie Ahmad Shah, said he knew what kind of man his father was.
"I've read everything online. But I've ignored all the speculation. I know my father better," Seth, 26, was quoted by the New Straits Times as saying.
"We may not be close as he travels so much. But I understand him," the language student added in his first public remarks.
Zaharie, 53, along with his co-pilot Fariq Abdul Hamid, 27, has come under intense scrutiny after Malaysian authorities said flight MH370's disappearance on March 8 was due to "deliberate" action by someone on the plane.
A relative of a passenger aboard Malaysia Airlines flight MH 370 reacts after hearing a briefing from Malaysian government officials at the Lido Hotel in Beijing. (Reuters)
Malaysian police have already questioned the family members of the pilots and other crew and seized a home-built flight simulator which Zaharie installed in his house.
But they have not announced finding any evidence against him.
The US Federal Bureau of Investigation will complete its analysis of data deleted from the flight simulator "within a day or two", its director said yesterday in Washington.
Malaysian officials had asked the FBI to help recover files deleted from the simulator's hard drive.
Crew members aboard the Australian Navy ship, HMAS Success, look at a large clump of seaweed in the southern Indian Ocean during the search for Malaysia Airlines Flight MH370. (Reuters)
FBI chief James Comey did not indicate whether the results of the analysis would be made public.
Malaysia announced Monday that, based on fresh satellite analysis, the flight with 239 passengers and crew crashed into the southern Indian Ocean.
There has been no explanation why it diverted from its Kuala Lumpur-Beijing flight path and ended up thousands of miles away.
No wreckage has been found despite an intensive international search, making it hard for families of those aboard to accept their loss.
"Now, we are just waiting for the right confirmation (for the wreckage or bodies)... I will believe it (that there are no survivors) when I see the proof in front of my eyes," Ahmad Seth said.
The family of Zaharie, including his three children, have so far been avoiding the media.
Zaharie was a member of an opposition party led by veteran politician Anwar Ibrahim, who was convicted of sodomy - illegal in the Muslim-majority country - hours before the flight's take-off.