Passengers on an American Airlines flight at Philadelphia International Airport got quite the surprise over the weekend when smoke entered the cabin and slides deployed while the aircraft was parked at the gate.

The incident, which was first reported by xJonNYC, occurred Sunday at Philadelphia International Airport (PHL) as American Flight 1776, operated by a Airbus A319 with the registration N716UW, was preparing to depart for a flight to Boston Logan International Airport (BOS).
According to reports, the aircraft was performing an air-start of the engines when smoke from the cart entered the cabin. Flight Attendants seated in the rear of the cabin were unable to contact the flight deck and they elected to deploy both of the rear slides.
No injuries were reported during the incident and the flight was cancelled. A replacement aircraft was ferried to Boston with the aircraft involved in the incident undergoing repairs in Philadelphia overnight. According to FlightRadar24 the aircraft is expected to re-enter service tomorrow.
Summary
Slides were deployed on an American Airlines Airbus A319 yesterday while parked at the gate at Philadelphia International Airport after smoke entered the cabin. While no injuries were reported, flight 1776 to Boston was cancelled. The aircraft is currently being repaired in Philadelphia and is scheduled to re-enter service tomorrow.