Los Angeles-bound flight returns to Heathrow due to medical emergency involving passengers and crew

An aircraft bound for Los Angeles has declared an emergency and is returning to London following a medical emergency.

The American Airlines flight turned around mid-air after two passengers were said to have suffered from loss of equilibrium, some 1,600miles into the 5,500mile flight. 

The AA109 flight left London Heathrow airport at midday and was due to arrive in LA later today.

An American Airlines aircraft bound for Los Angeles has declared an emergency and is returning to London

The Boeing 777-300 was close to Keflavik, Iceland, when it returned to its origin, some four hours into the flight. It is due to land in London at around 5pm.  

A spokesman for American Airlines said the plane had turned around after a medical emergency and that it was not security-related.

He said it was not clear whether any members of crew were affected.

He added: 'American Airlines Flight AA 109, a Boeing 777-300, operating to Los Angeles International Airport (LAX) from London Heathrow, is returning to Heathrow due to a medical emergency.

'The aircraft departed London Heathrow at 1205 local time and is expected to land at Heathrow at 1700 local time. We apologize to our customers for the inconvenience to their travel plans.' 

Equilibrium loss during air travel occurs when the air pressure in the middle ear fluctuates due to a change in altitude or imbalance in cabin air pressure.