A passenger plane in the US carrying 136 people was forced into an emergency landing after the engine cover snapped off as the aircraft ascended.

American Airlines Flight AA403 to San Francisco landed safely back at Phoenix Sky Harbor minutes after the terrifying incident.

No one was injured.

Photos taken from inside the plane show both sides of the engine snapped open shortly after take off.

Advertisement

Local TV station KRMG reported that a Federal Aviation Administration spokesman had confirmed that the incident happened at around 8.30am, local time.

American Airlines have launched an investigation into the incident and say they recovered that engine parts on airport land.