IT WAS A TRAGEDY occurring so suddenly and with so devastating a conclusion. And determining the cause of the crash of Swissair Flight 111 off Nova Scotia is now unfolding painfully slowly and, so far, without final answers.

As Canadian officials investigating the incident conceded Monday, they have yet to pinpoint the specific reasons for the crash. Indeed, they may never know what started the deadly fire that ended with the crash in waters off our coast, claiming the lives of all 229 crew and passengers.

It's especially hard on the relatives of those who perished not to be told with exactitude why they lost their loved ones. It's also unsettling for the many Nova Scotians whose own lives were changed by the tragedy that unfolded in their midst.

While not to sound alarmist in any way, failure to detail what started the fire that led to the Swissair crash is a bit troubling for all air travellers, who are forced to fly the skies without the certainity of definitely knowing what brought down Flight 111.

That said, the latest recommendations from the Transportation Safety Board of Canada are still helpful in trying to avoid another tragedy.

Monday's recommendations, the third set released by the TSB since the 1998 mishap, relate to detecting fire on aircrafts, and how best to handle such an outbreak as occurred on Flight 111.

Airborne less than an hour out of New York on their way to Geneva, crew members reported an unusual smell in the cockpit. Three and a half minutes later, smoke invaded the cockpit, leading the crew to declare an international emergency while they engaged in a lengthy checklist designed to deal with such a crisis.

But about 20 minutes after the problem was first detected, the jet came crashing down in the waters of St. Margarets Bay.

The board is calling for adoption of smoke and odour detectors in more areas of airplanes than is currently the case. And it wants steps taken to provide easy access to such equipment.

There are also calls for better training and equipping of crews to fight in-flight fires, a shortfall that has become evident among all flight crews in the course of the two-year probe.

Its detailed look at the Swissair crash has also led the board to recommend changes in the way air crews respond to the detection of smoke or odours onboard their aircraft.

Swissair pilots followed then-routine procedures by trying to locate the source of the smoke and by emptying fuel tanks for a possible emergency landing in Halifax. But Canadian safety officials are now suggesting pilots in the future be told to "expeditiously" land their plane in the event of unsourced smoke and odours.

And likewise, to respond more quickly to future emergencies, it's being suggested that checklists used by pilots be tightened, ensuring any review is finished before the fire goes out of control.

Some of the latest recommendations are already being considered by Swissair. A Boeing spokesman says his company has teamed up with the Swiss airline to develop fire detection equipment, which is already being tested.

The latest findings in no way will give complete closure to those so deeply affected by such a disaster, but they do represent the taking of a few more steps towards someday unravelling the mystery that still hangs over events that fateful night off Peggy's Cove.

More definitive answers - if indeed they ever come - must await the release of the TSB's final report that could take a year or more.

Failure to pinpoint the exact cause of the fire isn't due to lack of trying. The TSB probe has already cost $50 million to $60 million, and has included the partial reassembling of the doomed MD-11 jet in a hangar at 12 Wing Shearwater.

In the meantime, the family of those who perished onboard Flight 111 are left to cope as best they can, hopeful they may someday be given all the answers about the horrific crash that changed their lives forever.