Planes nicknamed the Black Cats fascinated MH370 captain Zaharie Ahmad Shah.

They were stealth-like flying boats that used the cover of night to swoop on Japanese ships during World War II. They also plucked stranded servicemen, including downed pilots, from dark waters and certain death.

Zaharie's YouTube username was catalinapby1, a reference to the official title of a plane that continues to enjoy cult status in flying circles.

He built a scaled-down replica of the "PBY Catalina", with RESCUE emblazoned across one wing, and is thought to have practised flying the aircraft on his home flight simulator.


Not so long ago the reaction might have been: "So what".

But as investigators home in on pilot suicide as the most likely reason a Beijing-bound Boeing 777 crashed in the southern Indian Ocean, Zaharie's love of planes that specialised in remote air-sea rescues might take on added significance.

Yesterday the Herald reported a fellow pilot questioning his friend's state of mind in the leadup to the ill-fated flight.

The 53-year-old's private life appeared to be in turmoil. He had split from the wife of his three children and there were relationship problems with another woman he was seeing.

Zaharie, a political activist and democracy campaigner, was also reported to be incensed by the latest development in the continuing persecution of Malaysia's opposition leader Anwar Ibrahim. The day before the Malaysia Airlines flight flew off into the night, Ibrahim was given a five-year jail sentence relating to previously dismissed sodomy charges.

On their own, these details explain little. They might seem at odds with the positive portrait of widely liked "Uncle Ari", who loved cooking and twisting balloons into pirate swords. But they hardly represent evidence of a man on the edge, ready to kill not only himself but 238 others in his care.

Still, according to the friend, Shah's world was crumbling, and investigators convinced the plane's disappearance was deliberate now have a limited pool of suspects; either of the two pilots, or someone else on board who harboured the most extreme death wish.

The latter option, like just about everything in this saga, seems absurdly far-fetched.

That someone would not only needed to have known how to covertly seize the aircraft, but exactly when to do so.

They would also have had to contain any threat from the crew or passengers, and then known how to fly below and around radar towards a sudden end in the depths far from anywhere.

So can it be any wonder that American officials are urging their Malaysian counterparts to focus inside the cockpit, just as they pointed south when all eyes stared at the South China Sea and Straits of Malacca?

FBI agents involved in the case are believed to be frustrated over attempts to build a full profile of Zaharie, who was one of Malaysia's most experienced pilots.

Authorities there are reportedly yet to interview his estranged wife Faizah Khan because it's not considered appropriate to subject grieving witnesses to the "stress of intensive questioning".

Although their marriage had come to an end, the couple still lived together.

What can she reveal about Zaharie's state of mind in the days and weeks leading up to the March 8 flight?

What about his work? He'd flown with a national airline that is majority-government owned for his entire adult life, joining in 1981 at the age of 21.

Was there any anger or resentment towards an employer with whom he had clocked up more than 18,000 hours' flying time?

Were there any previously known psychological issues? Was this really a man who could snap to the point of justifying the premature and violent end of 238 innocent lives?

The PBY Catalinas so loved by Zaharie were regarded as unsung and under-appreciated workhorses that flew in the shadow of more celebrated fighter planes like the Spitfire and Messerschmitt.

Perhaps the most famous incident involving one of the flying boats came when Soviet fighters shot down a Swedish Catalina over the Baltic Sea in 1952.

It had been searching for another downed Swedish aircraft, and lay on the sea floor for more than half a century before eventually being discovered in 2003.

The international search over the far deeper Indian Ocean may be just a few days old, but maybe the perpetrator hoped Flight MH370 would never be found.