SAFETY SYSTEMS the “thrown clear and survived” re- ports that are sometimes made after accidents are nonsense. A human being, even in excellent condition, Airbag Seatbelts: cannot survive hitting the ground at 60 MPH. He or she will either stop instantly or bounce across the sur- Pricey, But Effective face like a rag doll, suffering repeated impacts that will cause massive trau- ma to internal organs and the brain Airbag seatbelts are now available for retrofit in 150 that is not survivable. For example, one of the chief causes of death in different types of general aviation airplanes. We think automobile rollover accidents is that the added occupant protection is worth the cost. occupants who aren’t wearing seat- belts get thrown out of the vehicle and come to a quick stop against the by Rick Durden ground or an obstruction. After World War II there was e’ve long urged aircraft pants during an impact—the airbag extensive research into airframe owners to retrofit shoul- seatbelt from AmSafe (www.amsafe. crashworthiness. By the 1960s Wder harnesses for all seats com), a Phoenix, Arizona, manu- Cessna, Piper and Beech were doing of their airplanes if at all possible. facturer that specializes in occupant full-scale impact testing. Cessna and The simple reason is that a restraint protection testing and products for Piper gave NASA some airplanes for system that keeps your head and cars and aircraft. it to crash under varying conditions upper torso from smacking into the Before we go into details of ret- for the in-depth studies it was doing instrument panel or seat in front of rofitting airbag seatbelts—they’re on impact dynamics and modeling you during an accident sequence is now standard features for most seats what went on during a given crash the single most effective mod you of nearly all new general aviation sequence to help develop ways to can make to your airplane to radi- aircraft—we’ll take a look at the re- keep aircraft occupants alive. cally increase the chance of everyone alities of accident dynamics and how aboard surviving an accident. to reduce your risk of injury. LESSONS LEARNED As technology has improved, we’re Simplified, the testing demonstrated now strong advocates of a system THE QUICK STOP that: The slower the impact, the bet- that goes further to protect occu- We’ll start out by pointing out that ter. The longer in time and distance the deceleration can be spread over, the better (airbags use this fact). The more impact load that can be ab- sorbed by a progressively collapsing aircraft structure and not transmitted to the occupants, the better. Occu- pant restraint is essential—keeping the full torso restrained to the seat during the impact sequence vastly improves the odds of survival—the FAA says shoulder harnesses cut fatality rates by 20 percent and injury rates by a whopping 80 percent. Finally, designing the cabin area in front of the occupants to be free of objects that can hurt the occupants as they go forward during airframe deceleration and the panel comes back due to impact forces improves survivability (airbags also take ad- vantage of this fact).

The AmSafe seatbelt airbag deploys when impact is sensed, providing occupant protection in addition to the shoulder har- ness.

8 • The Aviation Consumer www.aviationconsumer.com June 2017 In a three-point restraint sys- tem, the airbag is installed in the seatbelt, above right. For a four-point restraint, there is an airbag in each shoulder harness, below right.

Because of constraints of weight and keeping cabins small to mini- mize frontal area to reduce drag and maximize speed, most general avia- tion aircraft cabins have limited “flail space.” Flail space is the area in front of an occupant’s seat in which his or her arms, legs and head are going to flail around—uncontrollably—in an impact sequence. If there’s some- thing in that space, the occupant is going to hit it, hard. While it seems beyond foolish, we keep running into people who claim they can “brace” and protect positioning provided themselves from getting hurt in a by the belt and torso re- crash. It’s not possible. You cannot straint an airbag system keep your head off the panel if you ranges from worthless don’t have a shoulder harness—the to counterproductive— impact forces will either overpower and protects against you in an instant or snap your locked impact forces with elbows, adding to your injuries an airbag specifically and stunning you or rendering you tailored for the shape of unconscious, delaying your exit. the space. Further, jackknifing over the seatbelt can give you a spinal injury that can CABIN SHAPE cause paralysis. Do we have your Because the shape of attention? the space of general aviation cabins varies TECHNOLOGY EVOLVES widely, seatbelt airbags Shoulder harnesses provide good are not one size fits all. protection in the general aviation They have to be devel- environment of limited flail space. oped for the individual The next step up is a five-point belt seat in the individual restraint system—two lap belts, two airplane, including the shoulder harnesses and a crotch degree of seat travel strap that keeps you from subma- and occupant sizes— rining under the belts. The top tier, which means from the under current technology, of oc- smallest five percentile cupant protection is a combination adult female through of a two-, three-, four- or five-point the largest 95-percen- restraint system and a smart airbag tile adult male. As that deploys when an impact is might be imagined, the sensed. development process In the world of general aviation, is complex; nevertheless, more than is sewn and folded onto one of the the only purveyor of FAA-certified 150,000 AmSafe airbag seatbelts belts. A gas hose runs from the bag airbag restraint systems is AmSafe. have been installed and are approved to the inflator. A wire runs from Using a two-, three-, four- and for installation in some 150 different the inflator to a sensor that tells the five-point restraint with airbag(s), types of general aviation airplanes, system when to activate. inflator(s) and sensor, the AmSafe according to Jim Crupi, AmSafe’s The airbag is designed to deploy system positions the occupant business development and technol- some 50 milliseconds into an event with the seatbelt and shoulder ogy support manager. that meets the design parameters for harness(es)—without the occupant During manufacture, each airbag the sensor to trigger—longitudinal

June 2017 www.aviationconsumer.com The Aviation Consumer • 9 AMSAFE’S NEW CHILD AVIATION RESTRAINT SYSTEM—CARES While we were researching this article on AmSafe’s Priced at $74.95 and sold through Kids Fly Safe (www. aircraft seatbelt airbag restraint systems we came across kidsflysafe.com), CARES is designed for children from two a new product developed by AmSafe—its Child Avia- to four years old with a weight range of 22 to 44 pounds tion Restraint System, acronym: CARES. While it is not an and who are less than 40 inches tall. It may only be used airbag system, we are including it in this article because in forward-facing aircraft seats. we are passionate about occupant protection during We were very impressed to see that AmSafe also devel- accidents and from what we’ve seen, CARES looks like a oped versions of CARES it refers to as “Special CARES” for product that offers comparable impact protection to a special needs children from 41 to 56 inches tall as well as car seat without the bulk and at children and adults more than a fraction of the weight. five feet tall. Using one of the CARES is FAA-certified for Special CARES systems requires use in general aviation and an exemption letter from the airline aircraft. It’s one of those FAA; however, the Kids Fly Safe creatively simple designs that website explains how to apply causes folks to slap their fore- for and get an exemption and heads and ask why they didn’t provides a template for the ap- think of it—upper photo. plication. The system includes a band The entire CARES unit weighs that wraps tightly around the a pound and folds into a small seat in which the child will carrying case—lower photo. be sitting at a level above It is NOT to be used in auto- the child’s shoulders. A set of mobiles—it does not replace shoulder straps hang from the the car seat in a car, but it does band. The regular seatbelt for allow the car seat to be stowed the seat is threaded through the in the luggage compartment loop at the base of each shoul- of a general aviation airplane der strap and the seatbelt is or checked as baggage on an then buckled at the child’s waist airliner. and tightened. The next step Having installed car seats is to fasten the clip connecting into the back seats of a number the two shoulder straps about of general aviation airplanes midway between the child’s and experienced the gyrations waist and shoulders. Finally, the required—and sometimes be- shoulder straps are tightened. If ing unable to get one secured the seat the child is occupying without a second person help- has shoulder harnesses, they ing out—we think CARES may are not used; the CARES unit has simplify life for general aviation its own, designed for the size of pilots flying with kids. the child, built in. Taking kids in general avia- That’s it. We watched videos tion airplanes requires some of one person settling a child planning and effort to keep into the seat and securing her them safe and happy. We think with CARES within a minute. AmSafe’s CARES system just In an emergency, all that’s made things a little easier for necessary to release the restraint system is to unbuckle pilots who want to do so. For more information on flying the seatbelt and lift the CARES unit over the child’s head. with babies and kids, see our sister publication AVweb It looked to us to take about five seconds. We’ve used a (www.avweb.com) and search on flying with babies and number of car seats that took longer. kids.

(and only longitudinal) decelera- We are aware of unsuccessful mounted in the instrument panel tion greater than between 6 and 9 G testing carried out by an aircraft and deployment meant that the stick (varies slightly with installation). A manufacturer exploring the idea of was forced aft violently. During an hard landing, no matter how impres- installing automotive-style airbags impact sequence there was concern sive, won’t cause a seatbelt airbag to into agricultural airplanes starting that the aircraft was still moving fast deploy. in the 1970s. As with cars, they were enough that rapid up-elevator deflec-

10 • The Aviation Consumer www.aviationconsumer.com June 2017 A retrofit seatbelt airbag system laid out ready for installation. tion could have unintended, and bad, consequences. Inadvertent deployment of a panel-mounted airbag in flight that shoved the stick aft could be cata- strophic. That led us to inquire about testing for inflight deployment of a seatbelt airbag. As part of the testing for certifica- tion of the seatbelt airbag system under 26-G requirements of FAR 23.562 (and 18-G requirements for older seat designs), AmSafe had to demonstrate that an inadvertent in- flight deployment would not adverse- ly affect control of the aircraft and would not knock the pilot’s hand off of the yoke or stick. Certification also required demonstration that the risk of inflight activation was so small that it approached zero. AmSafe has numerous videos on retrofits two adjacent seats. Most examples of seatbelt airbag deploy- its website of full-scale, dynamic installations do not require modifica- ments in general aviation aircraft. crash testing. They show that the tion of the airframe. Scott Utz, direc- A CFI who was almost able to get a airbag deploys primarily upward tor of maintenance of Arapahoe Aero Cirrus to an airport after an engine to protect the occupant’s head and on Denver’s Centennial Airport, an stoppage and discovered the terrain chest. In describing how that works AmSafe-approved service center, where he touched down was rough to protect the occupant as well as told us that installation times range enough to violently stop and flip the avoid hitting the controls, AmSafe from eight to 40 hours per seat and airplane after only rolling 100 feet says, “The occupant hitting the bag is depend on the type of airplane and walked away from the crash un- resisted by increasing air pressure, es- the options, notably TKS, installed. hurt. Things happened fast enough, sentially creating a pneumatic spring. He said that retrofits on Pipers and he said, that he was unaware of The maximum compression of the Cessnas are the easiest—Mooneys the airbags deploying. It was only bag occurs before the occupant’s take the longest. during an inspection of the aircraft head hits the interior structure. The There are ongoing maintenance afterward that he learned they had venting of the bag acts as a damper, requirements: The crash-sensing functioned as designed. He credited reducing the rebound and dissipating electronic module (one for each two the airbags with preventing injury to the energy through the air flowing seats) has a seven-year service life— the occupants. out of the bag.” it’s currently $1031 for replacement While individual reports and Jim Crupi told us that AmSafe and $385 for refurbishment—and it videos are anecdotal, they, combined seatbelt airbag systems have logged can be refurbished once. The infla- with the hard data on impact loads, more than 400 million hours of tors also have to be replaced at the are powerful evidence of the value of service and that there has not been a 10-year mark—they are currently seatbelt airbags in saving lives and reported inflight activation. $590 each. The seatbelts must be reducing the level of injury. inspected at the annual inspection RETROFIT using a dedicated system diagnostic CONCLUSION AmSafe’s website has a full list of tool—which means going to one of We’re strong supporters of retrofit- aircraft for which its seatbelt airbags the many AmSafe-approved service ting AmSafe’s advanced-technology can be installed as retrofit equip- centers or buying or renting the tool occupant restraint systems to reduce ment. In general, if you own an from AmSafe. the risk of injury in a general avia- all-metal or composite aircraft built AmSafe recommends that any tion aircraft crash. We especially like after 1960, there’s a good chance time any component of the system the magnitude increase in occupant that you can have seatbelt airbags is disconnected that the full system protection airbag seatbelts provide installed for at least the front seats. diagnostic be run after the system is for seats that only have a seatbelt— Often the rear-seat retrofits replace a reconnected. no shoulder harness. We’re watching seatbelt-only system, greatly improv- to see whether they will eventually ing occupant protection. FIRING IN ANGER be made available for older airplanes Prices for seatbelt airbags range We were directed to a number of in which it’s not possible to retrofit from $4000 to $5000 per kit—a kit videos on AmSafe’s website for shoulder harnesses.

June 2017 www.aviationconsumer.com The Aviation Consumer • 11