Tragedy struck early Monday morning at the Hong Kong International Airport after a cargo plane skidded off the runway and plunged into the sea, killing two ground staff members.

The Emirates flight EK9788, which was arriving from Dubai, reportedly veered off course around 3:50 a.m. local time (7:50 p.m. GMT) before colliding with an airport patrol vehicle stationed near the runway.

According to airport officials, the two people in the patrol vehicle — both members of the ground operations team — died instantly. The four crew members onboard the Boeing 747 cargo plane survived the crash.

Authorities have since launched a full investigation into what went wrong, describing it as one of Hong Kong’s deadliest aviation incidents in recent years.