David Learmount/LONDON
SEAT-DESIGN CHANGES, which could improve passenger safety, are unlikely to be adopted because of their extra weight, according to a Japanese research agency. The Japanese Civil Aviation Bureau (JCAB) confirms that the changes are effective, but concludes that manufacturers and carriers will ignore them because their weight will greatly reduce payloads.
Airline-passenger safety would be improved either by fitting seats with shoulder-harness safety belts or by fitting purpose-designed rearward-facing seats, says the JCAB research presented at the Aircraft Cabin Safety Symposium in Tokyo in October. The JCAB report concludes, however, that: "Both airlines and aircraft manufacturers are [unable to] introduce these seats."
Measures which would improve safety, include:
the adoption of the "brace position for impact [which is] effective [against] head injury";
seats with a shoulder harness: effective in preventing head injury;
purpose-designed aft-facing seats: the "most effective" overall injury-reducing measure.
The shoulder-harness seat under study has a three-point harness with a single inertia-reel strap in the headrest. Disadvantages of the new types of seat are:
both types would be higher than today's average by about 50mm, reducing the crew's cabin view;
a shoulder harness may increase passenger-evacuation time;
rearward-facing seat makes the passengers more vulnerable to objects flung forward on impact;
rear-facing seats cause "discomfort during take-off and landing".
A 440-seat Boeing 747, for example, could be 3,960kg heavier if shoulder-harness seats were fitted. Rearward-facing seats would be likely to weigh 7,040kg more, not including weight added by seat floor-anchorage strengthening.
Seat prices compared with current certificated seating would increase by 35% for the shoulder-harness type, and by 20% for the rearward-facing seat, estimates the JCAB.
Source: Flight International
