The captain of a missing Malaysian jet is an engineering buff who assembled his own home flight simulator, while friends of the co-pilot have defended his reputation after one report portrayed him as a cockpit Casanova.

Captain Zaharie Ahmad Shah, 53, joined Malaysia Airlines in 1981 and is praised as a passionate pilot who has logged 18,365 hours of flying time at work and still more at home on his sophisticated simulator.

A tribute page that has garnered more than 400 comments largely from well-wishers, shows pictures of the complex set-up including Zaharie posing in front of it.

His YouTube channel at www.youtube.com/user/catalinapby1 features videos showing him cheerfully explaining how to fix an air-conditioner, patch damaged windows, and other DIY projects.

Among the channels he subscribes to are ones on making balloon animals, Comedy Central and the Richard Dawkins Foundation for Reason and Science.

Malaysian media reports have quoted colleagues as calling Zaharie a "superb pilot", who also served as an examiner, authorised by the Malaysian Civil Aviation Department, to conduct simulator tests for pilots.

Authorities said police had searched the pilots' homes and were examining the flight simulator the captain had built at home, although aviation commentators have said this is not uncommon.

- 'Good boy' -

His first officer Fariq Abdul Hamid, who joined the airline at the age of 20, studied piloting at a flight school on the Malaysian resort island of Langkawi.

An Australian television report made waves this week by broadcasting an interview with a young South African woman who said Fariq and another pilot colleague invited them into the cockpit of a flight he co-piloted from Phuket, Thailand to Kuala Lumpur in 2011.

Passengers have been prohibited from entering cockpits during a flight since the 9/11 attacks on the United States. Malaysia Airlines said it was "shocked" by the reported security violation, but that it could not verify the claims.

The son of a high-ranking official in the public works department of a Malaysian state, he is a mild-mannered "good boy" who regularly visited his neighbourhood mosque outside Kuala Lumpur, said the mosque's imam, or spiritual leader.

Fariq also attended occasional Islamic courses, said Ahmad Sharafi Ali Asrah, who rejected the account of the supposed cockpit security breach.

"This story doesn't make sense and I feel it's just an effort to discredit Fariq or the airlines," Ahmad Sharafi said.

"He is a good boy and keeps a low profile."

Fariq had a brief brush with fame when he appeared in a CNN travel segment with the network's correspondent Richard Quest in February, in which Fariq helped fly a plane from Hong Kong to Kuala Lumpur.

The segment portrayed Fariq's transition to piloting the Boeing 777-200 after having completed training in a flight simulator.

"It was interesting to watch the way he brought the aircraft in to land," Quest said, according to the CNN website, calling Fariq's technique "textbook-perfect".

- Shadow of suspicion -

Prime Minister Najib Razak announced Saturday that satellite and radar data clearly indicated the plane's automated communications had been disabled and the plane then turned away from its intended path and flown on for hours.

In three of the four flights used for the 9/11 attacks, hijackers who seized control of the aircraft are believed to have manually turned off each plane's transponder, which sends flight data back to air-traffic control.

Terence Fan, an aviation expert at Singapore Management University, cited the crash of EgyptAir Flight 990 in October 1999 in the Atlantic Ocean -- which killed 217 people -- as an example of a crash allegedly deliberately caused by a pilot.

A US investigation said the first officer crashed the jet when the captain went on a break, findings disputed by Egyptian officials.

"I am not saying such a scenario happened here, we don't have any evidence at all, but this is one possible scenario," he said.

"Certainly, the pilots play a very crucial role."