Travel: Simon Calder Column

In six days' time we will experience the first of this year's three Fridays the 13th. In February, March and November people will be touching wood, crossing fingers or simply staying in bed for fear of courting disaster. Some will be deterred from flying.

After Tuesday's horrific accident where a US military aircraft tore into a cable car at the Italian resort of Cavalese, killing 20 holiday-makers, reading Terry Denham's World Directory of Airliner Crashes may seem ghoulish. But this book reveals how relatively safe is aviation, and that, historically, Friday the 13th is no more nor less dangerous than any other day.

On average, four air travellers perish each day somewhere in the world. (Coincidentally, this is the same frequency as British people dying from accidental overdoses of opiates, according to Radio 4's Medicine Now.)

Airlines are loath to boast about safety records, for fear of tempting fate. Qantas, you will recall, was the airline that Dustin Hoffman's character insisted on flying in the film Rain Man, because of its clean safety record. Yet the Australian airline has had its fair share of prangs. Mr Denham records no fewer than 16 accidents, from a crash on take-off from Jericho, Queensland in 1923 to another crash on take-off in Mauritius in 1960. But the airline has never had an accident with a passenger fatality.

For the vast majority of us, the biggest disaster when flying is losing our luggage - or getting films wiped by airport security machines, as happened to the unfortunate BBC crew whose stock was blighted by an X- ray scanning machine at Manchester airport; their five-week filming assignment in Papua New Guinea was nullified by a single blast of radiation.

Permit me to write from the experience of my previous employment as a security guard at Gatwick. As the furious film-makers have now discovered, there are two kinds of airport X-ray machines. Those you see when passing through security controls are puny little devices, the equivalent of a Reliant Robin in terms of the radiation they generate; I happily watch camera film, magnetic tape and computer discs float down the conveyor belt and through the machine, confident that they will survive unscathed. Even the monstrous scanners at Sheremetyevo airport in Moscow have failed to blur words or images.

The stuff that goes on out of sight is a different matter. Ten years after the Lockerbie disaster, the aviation world is trying to make sure that explosives contained within hold baggage can be identified to avoid a repeat terrorist attack. Searching every bag by hand is a logistical impossibility - it used to be tricky enough checking everyone's luggage on the Belfast and Tel Aviv flights. The best alternative so far discovered is a machine called the CTX5000, a Juggernaut of the scanning world. Manchester is leading the world in screening every piece of checked baggage, and the BAA airports like Heathrow and Gatwick are not far behind. No security guard I know, past or present, would ever entrust any sensitive item to such rigorous screening - but then you should never, ever, check in anything you can't afford to lose.