The plane was parked at Isphani Hangar when the customs officials conducted a raid.
Sources informed that the raiding officials recovered nine packets of heroine hidden in a lavatory. The flight PK-305 had landed at Karachi airport via Lahore a night ago.
The jet was scheduled to fly again Wednesday morning but it wasn’t allowed to take off in the wake of raid.
According to PIA spokesperson, the investigation into the incident has been ordered, while night shift of the PIA plane is also under interrogation.
The spokesperson added that PIA officials were extending all-out cooperation to the customs officials.
In February this year, the Anti Narcotics Force hadcarried out a raid and recovered 16 tonnes of chemical acid and 4,000 kilograms of hashish.
ANF had conducted two major operations in which huge amounts of drugs were seized. One operation was carried out at the Hub River road while the other at Karachi port.