Two Bangladeshi passengers returning to Dhaka were detained at Calcutta airport after a life jacket was found in their hand baggage on Sunday morning.

The father-son duo, first-time fliers, were let off after they told the airline and security officials that they could not understand the announcement made on the flight from Chennai that brought them to Calcutta and thought that the jacket was meant to be taken away.

But they could not board the plane and would have to take Monday’s flight.

Mohammad Abul Kalam Azad, 58, a renal failure patient, was returning from Chennai to Dhaka through Calcutta after treatment and was accompanied by his son, Aminul Islam, 17.

Azad’s kidney problem was detected five months ago and on April 12 they went to Christian Medical College, Vellore, for treatment. It was the first time Azad, a contract employee of the forest department in Dhaka, and his son were flying.

On their return journey, they took the Jet Airways flight from Chennai and reached Calcutta late on Saturday evening.

Soon after the flight took off, one of the air hostesses made the routine flight safety announcements. “In case of emergency, life jackets are located under your seat,” she announced and then demonstrated how to wear the jacket if the aircraft landed on water and how to inflate it.

“I had heard from people who had flown that you need to wear a belt (seat belt), jacket and parachute for safety while flying. I thought I would require this life jacket on the Dhaka flight,” Aminul said.

“The announcements were in English and Hindi which I could not follow properly. I thought it was kept for the passenger to take away,” he said.

Aminul put the jacket in a plastic bag in which he was carrying a bottle of mineral water.

“On the Calcutta-Chennai flight too the announcement was made but I could not trace the jacket,” he said.

On Sunday morning, Azad and his son cleared immigration and went for security check to take the flight to Dhaka. “I did not put the jacket inside the registered luggage as I thought I might require it on the flight,” said Aminul.

At the counter, they left their hand baggage for scanning. “The life jacket was found inside the plastic bag and they were detained,” an official said. The security officials found during interrogation that the two were innocent but the flight had left by that time.

The Airports Authority of India (AAI) has asked Jet Airways to explain how the airline could operate the flight with one life jacket less.

According to AAI officials in Calcutta, the airline has tendered an apology.