By Sheila Barter BBC News Online

Air shows can provide the public with a thrilling day out - but visitors in some parts of the world could be dicing with death, safety experts say.

Displays in Western Europe and the US are governed by sheaves of regulations, handbooks, licences and monitoring systems.

We believe that the former Soviet states don't fly to the same safety standards as we do

Air Display Association Europe chairman

Crowd exclusion zones are enforced and pilots are barred from carrying out manoeuvres below a certain height.

Even flying towards a crowd is banned.

The ethos is one of assuming that the million-to-one chance of an accident might actually happen, and crowds must therefore be protected.

But in some other parts of the world, displays are organised on the "nothing will go wrong" theory, said aviation journalist Paul Jackson.

"People don't always think through what could conceivably go wrong," he told BBC News Online.

Strictest Europe guidelines

Straight flights 230m from crowd Manoeuvres 450m from crowd Min aerobatics altitude 500 feet Pilot and plans evaluated before display Safety committee has power to "red card" pilots

"In some countries there could be accidents waiting to happen."

A journalist who attended an air show in Japan the day after the Ukraine tragedy told BBC News Online that the Japanese military display team, Blue Impulse, were performing their display directly over the crowd.

Lax regulations

The Air Display Association Europe, which works with air show organisers, says the former Soviet countries are among the worst offenders for relaxed regulations.

"But we believe that the former Soviet states don't fly to the same safety standards as we do," said chairman Wing Commander John Davis.

"We have always been concerned to get UK and European regulations as far east as possible, and I hope that as a result of this crash the Ukrainians will be looking westwards," he added.

Adrenalin is part of the attraction

Most of the heavily-regulated countries have tightened the rules after their own bitter experience.

In the UK, it was a fatal crash at Farnborough air show in 1952 which sparked heavy rewriting of the rules.

In Germany, the 1988 disaster at Ramstein air base in Germany - which killed 70 - led to tough new regulations.

"It is probably true that there needs to be an accident to concentrate minds," said Mr Jackson.

In Western Europe all reasonable precautions short of not having an air show have been taken

Paul Jackson

Most Western European countries adhere to a set of harmonised guidelines published in 1995, or are working towards enforcing the guidelines.

Every part of safety is laid down. Jet planes of the type involved in the Ukraine tragedy would have to stay at least 230m (250 yards) from the crowd if flying straight, or at least 450m (490 yards) if doing manoeuvres. The manoeuvre would have to be completed at least 500 feet (150m) from the ground.

Pilots and their displays must also be evaluated and approved before the event.

In some countries - including the UK, Belgium and the Netherlands - a safety committee watches the live show and issues an instant "red card" to any pilot who falls foul of the rules, for example straying too close to the crowd.

'Inexcusably risky'

In Ukraine it remains unclear exactly what regulations were in place, or whether they were being adhered to.

But Ukrainian experts were quick to stress that the rules in place may not have been followed at Lviv.

Former Russian air force chief Anatoly Kornukov was quoted after the tragedy as saying it was "inexcusably risky" to have planes flying directly over the crowd.

"It was against all organisational rules," he told Russia's Interfax news agency.

Air show crashes

June 1999: 2 killed when a BA Hawk 200 crashes in Slovakia July 1997: 9 die in a light aircraft crash in Belgium Aug 1988: 70 die when three Italian Air Force jets collide in West Germany Sept 1982: 46 killed when US Army Chinook helicopter crashes in Germany June 1973: 15 die when prototype Russian jet explodes in mid-air

Ukrainian regulations state that demonstrations must not be performed at an altitude no lower than 400m (1,300 feet), said former Ukrainian fighter pilot Colonel Alexei Melnik.

But the pilots might have been under pressure to impress their commanders with their aerobatic skills, he said.

The cause of the Lviv tragedy remains to be unravelled.

Much speculation has focused on whether the pilots lost power at a crucial stage in the manoeuvre, but the position of the crowd and the altitude of the manoeuvre will also be key to the inquiry.

"From what I have seen I believe the pilots entered their final manoeuvre far too low," said Wing Commander Davis.

Even the best-regulated air shows cannot be completely free of risk, but the UK's last fatality involving a member of the public was 50 years ago.

"The chances of a tragedy in the UK are remote in the extreme," said Mr Jackson.

"Things can always go wrong, but in Western Europe all reasonable precautions short of not having an air show have been taken."