An air pressure whirlwind caused by a Heathrow-bound plane was so strong it sent tiles crashing from the roof of sheltered accommodation in Hounslow.

Elderly residents of Percy Bilton Court, in Skinners Lane, were lucky to be left unhurt after the heavy terractota tiles slid from a walkway's roof as a plane flew overhead on July 1.

Warden Sue Dodd told the Chronicle: "We are right under a flight path so we are used to the unbelievably loud noise of the planes, but this is the first time it has actually caused the tiles to fall off.

"It does sometimes cause the tiles to move slightly in a wave effect, but this time a whole section must have just slipped.

"The tiles fell onto a communal walkway and gardens so we are very lucky that no one was walking underneath when they fell, they could have been killed."

An inspector from BAA went to look at the roof damage on the same day to confirm that it was caused by a 'vortex',  a 'circulating current of air generated by aircraft which can sometimes strike and damage the roofs of houses under the flightpath'.

Although BAA insists less than 0.01 per cent of flights cause vortexdamage, with only properties with pitched roofs affected, during 2004/05 BAA received almost 300 calls to the 24 hour vortex hotline. There were 89 confirmed vortex strikes.

BAA Heathrow runs a Vortex Protection Scheme for homes around the airport and provides a 24-hour telephone service for residents who suspect they have been victims of the phenomenon.

Under the £15million Scheme, Percy Bilton Court received a new roof free of charge with added strengthening measures on the same day the damage occurred.