If flying gives you a headache, imagine the feeling of hitting your head on the seat in front of you at 16 times the force of gravity. That is what new airline seats are required to withstand today in order to keep you relatively in place and to prevent such unfortunate body-to-seat confrontations. But what if you're flying on an older aircraft?

As of October 2009, the U.S. Federal Aviation Administration (FAA) required that all new commercial aircraft be delivered with seats strong enough to withstand forces 16 times that of gravity. Known as the "16g Rule", the mandate replaced a standard of 9 times the force of gravity (9g) that had been in place since 1952. Not only do the seats need to withstand such forces but they must not break free from the floor tracks they are bolted to.

When the rule was first proposed nearly a decade ago, many airlines feared that the cost would far exceed the benefits, given the infrequency of airline crashes. However, because most crashes occur when the aircraft is at its slowest speeds (takeoff and landing), they are survivable. The original plan by the FAA was to require that all older aircraft be retrofitted to comply with the new standard. Many new aircraft at the time were already being outfitted with the stronger seats but the requirement addressed only entirely new models built after 1988 such as the Boeing 777 and not variants of models already in production such as the 737 series of aircraft. The newest requirement targeted all new commercial aircraft built on or after 27 October 2009.

The 16g standard requires airline seats be able to withstand the forces of deceleration of up to 16 times the force of gravity so that passengers are sufficiently protected from becoming unconscious due to being thrown toward a rigid, immovable obstacle. Typical aircraft seats have some "give" and can cushion a passenger from the force of impact to a great degree. The trouble lies with seats that face an aisle, such as the angled premium class seats contained in a pod or shell, and seats facing bulkheads and other rigid surfaces. For these seats, the airlines had to consider installing airbag devices, which cost roughly US$1,250 each, or removing revenue-generating seats in order to ensure the necessary safeguards were in place.

The airbags are one way (but not the only way) airlines can meet new FAA standards enacted to keep passengers conscious through an impact. The European Aviation Safety Agency (EASA) expects to introduce the same rule by the end of 2011, according to a Bloomberg News report. AmSafe Inc., the company that makes 95 per cent of all seatbelts for aircraft, is contracting with airlines to provide the airbags. AmSafe's airbags are stored in the seatbelt and inflate within 90 milliseconds of a crash, expanding up and away from the passenger to accommodate head movement in all directions. The company predicts that airbags will become standard by 2020, according to the Bloomberg News report.

How do you know if your seatbelt is equipped with an airbag? Look at the portion of the belt that does not have the buckle. If you see what looks like a thick "pouch" wrapped around the traditional belt, then you have an airbag. Interestingly, Southwest Airlines which has an all-economy configuration will comply with the 16g rule by installing devices that will allow a seat back to move forward on impact to protect the passenger sitting behind the seat.

AmSafe claims that it has more than 50 airline customers for seatbelt airbags worldwide. The following are some notable carriers that are either using airbag technology on some or all seats or have contracted to do so:

• American Airlines: Boeing 777s and 737s
• Delta Air Lines: Boeing 777s and extended-range 767s
• US Airways: Airbus A330s and A320s
• Singapore Airlines
• Emirates
• Japan Airlines
• Swiss International Air Lines
• Air France-KLM
• Cathay Pacific
• Virgin Atlantic

Have you sat in a seat that had an airbag? One IAPA member once complained that a seat-side airbag created pressure and discomfort on a Cathay Pacific flight. Incidentally, Cathay has installed the seatbelt airbags on all seats on its aircraft that feature "shell" type seating in all classes. In this setup, the seat bottom moves forward within the rigid shell to achieve a reclining position. Since the rigid cocoon that surrounds the seat remains stationary, there is a potential impact hazard for the person seated behind. The airbags mitigate this risk. What are your thoughts?

Photo: AmSafe