LONDON , England ( CNN ) -- Fifteen crew members of a South African Airways flight spent the night in jail after customs officials found marijuana and cocaine worth nearly half a million dollars hidden aboard a long-distance flight to London , British customs officials said Wednesday . South African Airways said it has a zero-tolerance approach towards any criminal activity . The 10 women and five men -- who include three pilots -- were detained on arrival from Johannesburg , South Africa , after customs officials found 50 kilograms ( 110 pounds ) of marijuana and 4 kilograms ( 8.8 pounds ) of cocaine in three pieces of baggage , HM Revenue and Customs said . The drugs are estimated to be worth a total of £310,000 ( $ 428,000 ) , customs officials added . Border agents arrested the crew at London 's Heathrow Airport on suspicion of involvement in smuggling prohibited drugs into the United Kingdom , customs spokesman Bob Gaiger said . He said he was not able to disclose what led investigators to believe the suitcases belonged to the crew members . Customs officials interviewed the crew members overnight , and all were released on bail Wednesday pending further inquiries , Gaiger said . They were not charged , according to the airline . South African Airways said it launched its own investigation involving the airline 's security and the South African Police Service . `` SAA has a zero-tolerance approach towards the use of the airline 's services for any criminal activity , '' airline spokeswoman Robyn Chalmers said .
5 women and 5 men were detained on arrival from London . marijuana customs officials found Johannesburg and cocaine in baggage . Officials : The drugs are estimated to be worth $ 310,000 . South African Airways said it launched its own investigation .