ANOTHER stowaway has been found on a Singapore Airlines (SIA) plane, the second in a month.

The unauthorised passenger managed to get his way into the cabin area of a cargo plane which was flying from Sharjah, in the United Arab Emirates - about 30 minutes' drive from Dubai - to Amsterdam, Holland on Tuesday.

The Straits Times understands that he was caught sitting in one of the six seats, just several metres behind the pilots, after an hour into the seven-hour flight, which was forced to turn back.

It is believed that the first officer of the plane was going to the galley to prepare a meal when he saw the "burly Indian man".

The man could not speak English, did not appear drunk and was calm during the flight. He was served food and drink and was not restrained during the flight.

As a precaution, however, the pilots returned to Sharjah Airport, where the man was taken away by the police there, said an SIA spokesman when contacted. The pilots were concerned that the man would turn violent if he "saw sand instead of tulips", said sources, who added that the shade next to man's seat was pulled down so that the stowaway would not know where the plane was heading.

On Oct 11, a Palestinian fell out of the nose wheel well of an SIA passenger plane at Changi Airport after it arrived from Kuala Lumpur.

Tuesday's incident raises security concerns for pilots of cargo planes because unlike passenger jets, there is no cockpit door protecting them.

Investigations into the incident are underway.

Read the full story in Saturday's edition of The Straits Times.