Visible turbulence

High humidity on a foggy day makes the vortex around the wings visible as a Boeing 747 lands at Zurich airport. The US aircraft manufacturer was drawn deeper into the Kobe Steel scandal yesterday amid reports that it used products falsely certified by the Japanese firm. Boeing has stressed it does not consider the issue a safety problem but is carrying out a survey to ascertain the extent and type of Kobe Steel components in its planes. The Japanese firm this week admitted it had falsified data on aluminium, iron and other products, after they failed strength and quality tests.