By John Fyfe, Director of Air Force Programs, UTC Aerospace Systems

As you read this sentence, you are experiencing life at 1 G—gravity is pulling down on you at 32 feet per second squared. If you happen to be flying some aerobatics and executing a 3 G barrel roll right now, things are different. At 3 G’s, you’re feeling triple the pull on every pound of your body and whatever is attached to it. That means a 150-pound airman with 50 pounds of flight gear would experience 600 pounds of force. During an ejection, you would experience at least 8 G’s of force on your body. An additional ejection hazard is wind blast -- the magnitude of which approaches that of a Category 5 hurricane. 

At UTC Aerospace Systems, our mission for 40 years in the ejection seat business has been to overcome the challenges of high speed ejections, heavier helmets with helmet-mounted devices, and safely accommodating aircrew of all sizes. Constant ejection seat innovation is required to keep military aircrew safe—to not only successfully get them out of their aircraft, but also bring them to the ground safely with the ability to walk away with little to no injuries. 

So how will ACES 5® make flying even safer for aircrew? 

1. Safely ejecting at higher speeds. Since the early 1980s, ejecting above 450 KEAS has posed a high risk of injury for military aircrew. Initially, these risks were deemed acceptable. Thanks to the ingenuity and innovation of our ejection seat engineering team, aircrew no longer have to accept that risk. A critical feature of the ACES 5 design is the ability to safely project aircrew at all airspeeds.

ACES 5 expands the safe ejection envelope out to 600 KEAS and uses passive arm and leg restraints to protect aircrew against “flail” injuries that historically result from high airspeed ejections. Upon ejection, these devices provide supportive webbing that extends to catch an airman’s arms and restraints that secure their legs, holding them firmly to the seat structure until seat separation.

2. Safely ejecting wearing helmet mounted devices. Aircrew helmets used to be simple: light, round, and smooth. Air would flow over them evenly during an ejection, and an airman’s head was more likely to stay straight and safely aligned into the windstream. As new technologies entered the cockpit, helmet-mounted devices (night vision goggles, helmet-mounted cueing systems, etc.) became the norm, providing aircrew with improved sensing and targeting cues. Initially, the ejection risks posed by these devices were not fully appreciated. Some of these helmets weigh up to five pounds, with every pound being affected during an ejection by an extra 9-12 G’s of force. The additional windstream forces can be asymmetrical and, without adequate protection, can violently force the head to either side, creating a potentially fatal injury.

3. Safely accommodating aircrew of all statures. Great airmen come in all shapes and sizes, and in 2016 the U.S. Air Force expanded injury requirements so that ejection seats would safely accommodate all occupants from 103-245 pounds. Seat stability is a key requirement toward providing safe ejections across the entire aircrew spectrum.

The ACES 5 ejection seat stability package contains a gimbaled rocket that ensures the seat remains upright, preventing forward or aft seat pitch caused by the different centers of gravity from varying sized aircrew. This unique feature helps maximize the height of the ejection seat trajectory, while minimizing risk of injury by keeping the seat in the upright stabilized attitude that optimizes aircrew position during opening of the parachute.

Different sized aircrew experience different acceleration forces during an ejection. When ACES 5 ejects, the main catapult rocket propelling the seat from the aircraft automatically compensates for aircrew weight by adjusting acceleration and speed, minimizing the risk of spinal compression and other back-related injury. Because of this step change in innovation, aircrew of all sizes can safely eject. With ACES 5, airmen don’t need to worry about dangerous acceleration forces or selecting manual seat/cockpit settings.

To further address cockpit fit accommodation, we updated our ACES 5 to include both height and tilt adjustment capabilities so that aircrew of any size are best positioned in the cockpit to complete their mission.

ACES 5 is the product of a team comprised of innovative engineers and pilots. Our entire organization holds itself to the highest quality standards and is committed to safely bringing our aircrew home on their worst possible day. We have flown in ACES seats, and our friends and family still do, so we know firsthand what’s at stake. While ACES II® ejection seats already have a historical spinal injury rate of less than one percent, our team designed ACES 5 to move that statistic closer to zero – so that airmen safely exit their aircraft, return safely to the ground, fly again tomorrow, and have a great story to share with others!

ACES 5 is the next step in our longstanding mission: protecting those born to fly so that they may live to walk away.