Source: The Sunday Times, June 18, 2006

Boeing’s new jet beats the bounce

Dipesh Gadher, Transport Correspondent

TIME to put away the sick bag. Boeing is designing a new passenger jet aimed at countering the effects of turbulence.

The 787 Dreamliner, which is expected to enter service in 2008, will have sensors that detect strong gusts of wind and automatically adjust the movement of the aircraft to prevent it from being buffeted around.

Turbulence, which occurs most frequently when a plane enters the vicinity of a thunderstorm, is believed to be the biggest cause of injury to passengers and crew on flights.

Even for those who are securely strapped into their seats, sudden jumps in a plane’s path can trigger a bout of motion sickness.

The new development by Boeing, the US aircraft manufacturer, is designed to reduce the effects of the lateral and vertical gusts and eddies caused by irregular flows of air in the atmosphere.

Sensors on the 787, which will have a capacity of 250 passengers, will identify changes in air pressure and determine “the angle of attack”. The aircraft’s flaps and wing tips will then be moved accordingly so they counter vertical gusts, while the rudder will be adjusted to reduce side-to-side “tail-wagging”.

“We have done studies showing that on the 787 we can reduce the amplitude of the vertical motion by two-thirds,” said Mike Sinnett, director of the 787 systems team.

“It won’t spell the end of the in-flight sick bag — it may take the elimination of the drinks cart for that — but it should reduce the occurrence (of motion sickness),” he said.

The innovation will not, however, be able to counter all forms of turbulence, particularly when it occurs in “clear air”. For example, if the air is free of the moisture found in thunderstorms, onboard radar may not be able to detect the turbulence and instruct the plane to take pre-emptive action.

Other comfort-related innovations planned for the 787 have been made possible by the fact that 50% of the aircraft, including the fuselage, tail and wings, will be made from plastic and carbon-fibre composite materials instead of aluminium.

Because composites are less likely than metals to suffer from fatigue over time, Boeing claims it will be able to increase cabin pressure so that the air pressure in the plane will be equivalent to 6,000ft above sea level rather than 8,000ft, the norm at the moment.

Farrol Kahn, director of Aviation Health, a non-profit research organisation, welcomed the move, claiming it would increase oxygen levels in the cabin by 5%.

“It will make the environment more comfortable for elderly people and youngsters with weak hearts and lungs,” he said. “It’s significant because the number of people who die on flights, primarily because of heart failure, is the same as the number of people who are killed on the ground in plane crashes.”

Boeing is also planning to increase cabin humidity by up to 10% on the 787. This rise in moisture levels — avoided until now because of its long-term corrosive effect on metal fuselages — will reduce the chances of passengers suffering itching eyes and dry throats.

It may also reduce the spreading of colds. “You are seven times more likely to catch a cold on a plane than on the ground because viruses proliferate in dry conditions,” said Kahn.