Clearly safer

 作者:东方驺蘖     |      日期:2019-03-08 09:15:00
By Paul Marks WHAT do you do if the cockpit of the plane you are flying fills with smoke so thick that you can’t even see the instruments? A Hawaiian company thinks it has the answer. The transparent airbag it has developed creates a clear bubble of air that allows crews to see enough of the instruments and windows to land a crippled plane safely. After air disasters in which smoke in the cockpit might have been a factor, such as the ValuJet DC-9 crash in Florida in May 1996 and the loss of a Swissair MD-11 off Nova Scotia last September, interest in techniques for keeping aircraft aloft in such emergencies is growing. Vision Safe Corporation of Kaneohe, Hawaii, the company that makes the new device, says it has been “deluged” with requests for information on its patented invention. The $9000 Emergency Vision Assurance System (EVAS) system consists of a box no bigger than a flight navigation manual, says Christian Werjefelt, the company’s operations manager and son of the inventor, Bertil Werjefelt. Inside the box is a powerful battery, a smoke filter, a continuous pressure air pump and an “inflatable vision unit”, or transparent airbag, shaped for a specific type of aircraft. If smoke enters the cockpit, the pilot follows normal safety procedures, such as donning an oxygen mask and goggles. Then the EVAS box is fixed to a strip of Velcro on the instrument panel. The device inflates in about 20 seconds, forming a two-lobed airbag. One lobe fits over the panel and the other underneath it, a configuration that makes the bag fit snugly. The pilot then presses his or her smoke goggles against a plastic window on the front of the bubble—and gets on with flying the aircraft. There is not enough room between the airbag and the instruments for smoke to gather and obscure the view, so the pilot gets a clear view of the instruments that would otherwise be hidden. A pressure release valve ensures that the bubble does not interfere with the pilots’ movements of the steering yoke, Werjefelt says. If the yoke is pushed forward slightly, the bag deflates a little, and re-inflates when the yoke is pulled back. He says that in simulator tests, pilots using the system have landed safely “with smoke in the cockpit so thick that they could not see their hand in front of their face”. Although the device is proving popular with private jets, the US Federal Aviation Administration has approved the EVAS for use in only two commercial aircraft, the DC-9 and MD-80,