MANILA, Aug. 30 (Xinhua) -- A Philippine Airlines (PAL) flight bound for Cotabato City in southern Philippines from Manila was delayed for several hours on Thursday after a male passenger cracked a bomb joke prompting airport authorities to conduct an investigation.

Authorities said the aircraft was supposed to take off at 7:30 a.m. local time at Manila's International Airport but returned to the terminal due to a faulty air-conditioning system.

While the plane was returning to the terminal a male passenger was heard saying that the cause of the delay was because of a bomb on board.

The passengers who heard the joke reported it to the airline crew, prompting aviation authorities to conduct a thorough inspection of the aircraft, its passenger and their luggage.

The passenger joker is now in the custody of the airport police station.

Under the Philippine law, a person can be fined of not more than 40,000 pesos (roughly 749 U.S. dollars) or face a jail term of not more than five years, or both, depending on the court's decision.