Massport officials are urging citizens not to be alarmed by a sudden surge in activity in the waters near Logan Airport this weekend.
It’s only a drill.
More than 600 people from local, state and federal agencies, as well as hospitals and airlines, are expected to participate in the Saturday morning simulation of an airliner crashing into Boston Harbor.
As many as 40 boats are scheduled to take part in the water search and rescue portion of the exercise.
Agencies participating in the drill include the Coast Guard, FBI, state and Boston police, the Red Cross and the Animal Rescue League.