AN ECONOMY Class passenger on a flight from Hong Kong to Singapore wanted to bring a taste of Hong Kong home with him.

So he smuggled about five live crabs onto the plane in his carry-on baggage - a plastic karung guni bag which he shoved beneath the seat.

'One of the crabs escaped,' recalls Mr Mohd Mazlee, 33, a flight attendant of 12 years who witnessed the incident. 'It started crawling around the cabin and caused quite a hoo-hah.'

In the end, a cabin-crew member cornered the offending crustacean and restored it to its owner.

Although the passenger in question was excused for his little misdemeanour, flouting airline regulations on carry-on baggage size, weight and contents can result in serious consequences.

Just this month, the High Court awarded $600,000 in compensation to Dr Euan Murugasu, who had been hit on the head by a suitcase on board a Singapore Airlines (SIA) flight from Singapore to Manchester in 2000.

A passenger had attempted to squeeze an oversized suitcase into the overhead compartment above him, but it fell and hit his head and back. Since then, he has been plagued with headaches, double vision and tingling sensations. His injuries - which doctors say are permanent - cost him his job as an ear, nose and throat surgeon.

Indeed, five airlines LifeStyle contacted took a strong stand on cabin safety.

A spokesman for Emirates said airport staff take great care to ensure that all carry-on baggage adhere to weight and size regulations to prevent passengers from bringing excess baggage that may be 'a hazard to other passengers'.

Watch what you pack

SO WHAT exactly may you bring as cabin luggage?

SIA, United Airlines, Emirates, British Airways and Qantas recommend that Economy Class travellers carry a medium-sized garment bag. First or Business Class travellers may be allowed an additional laptop or briefcase.

Carry-on baggage should fit under the seat in front of the passenger or in the overhead compartment.

Depending on the airline and class of travel, baggage specifications may vary slightly. (See other story)

But Ms Mary Chan, retail store manager for travel baggage boutique The Planet Traveller at The Paragon, says a good gauge is to ensure 'that the length, breadth and width of the bag do not add up to more than 115cm'.

Inflight security has been tightened since the events of 9/11 and all forms of sharp and flammable objects, coupled with some sporting goods, have been banned from flights.

Sharp objects include seemingly innocuous items like razor blades, letter openers, household cutlery and even knitting needles.

Firearms, flammable liquids or gases and explosives of any kind fall into the second category.

And if you are thinking of going overseas for sports, bats, billiard cues and catapults are some of the items prohibited on a plane.

For the record, crabs and other animals are usually not allowed on flights.

Special arrangements have to be made with the airline beforehand to put them in the cargo hold.

Still, other strange but non-threatening items may occasionally find their way on board.

Mr Charles Leong, 57, a managing director at a marketing representation company, says he once shared a plane with a man who wanted to keep his head warm with an extremely wide-brimmed sombrero.

'He tried to sit down with it, but it got in the way of the other passengers around him. So the cabin crew took it from him and stored it away.'

But there is one prohibited item which will always cause a big stink among passengers, airlines and customs officials alike.

Mr Jack Wong, 26, an IT consultant, says he saw a Chinese national attempting to take a durian on board a plane leaving from Changi Airport.

'He was stopped at the departure gate and made to leave his durian behind,' he says. 'With one last forlorn look, he put it in a dustbin and boarded.'

What's the maximum?

• British Airways: 55x40x20cm; 6kg
• Emirates: 55x38x20cm; 7kg
• Qantas: 56x36x23cm or 60x114x11cm for non-rigid garment bags; 7kg
• Singapore Airlines: Any combination of length, breadth and width that adds up to less than 115cm; 7kg
• United Airlines: 23x36x56cm; 7kg

Specifications are for Economy Class travellers