ACES is the acronym for Advanced Concept Ejection Seat o Advanced concept ejection seat. It was developed in the late 70s by Collins Aerospace and has since saved the lives of more than 700 pilots who were able to eject before their plane crashed. ACES IIfull name, was so successful that it quickly spread to most US military aircraft, including the A-10, F-15, F-16, F-22, B-1 and B-2. Currently there more than 6,000 ACES II seats in service, not only in the United States, but including 29 armies of all the world. In 2020, Collins Aerospace was awarded a 700 million dollars to develop and manufacture a next-generation ejection seat, NGES for its acronym in English, which succeeded ACES 2. The result is the ACES 5.
Like its predecessor, the ACES 5 is a multi-platform seat designed for use in F-15, F-16, F-22, B-1, B-2, A-10 and the T-7A Red Hawk of the US Air Force, currently under development by Boeing. It stands out for its advanced safety technology, including head and neck protection, arm and leg strike prevention, and a load-compensating rocket catapult that Its thrust varies depending on the weight of the occupant. And they are manufactured to withstand shock loads of up to 40Geject at speeds of up to 600 knots (1,111 kilometers) and operate up to an altitude of 18 kilometers.
The risk of serious head and neck injury to the pilot is less than 5% and with his new catapult there is only a 1% chance of a spinal injury when using it. It also has a new parachute system that should provide a “smoother ride,” according to Collins, to the ejected pilot.
“Our seat meets the latest MIL-HDBK-516C airworthiness standards of the US Department of Defense, being the first and only seat to complete a US government qualification program based on these latest requirements”says the company on its website.
How the ACES 5 ejection seat works
The ACES 5 is a seat that has restraints for the pilot's head, arms and legs, a CKU-5C catapult and a GR7000 parachute. When the pilot pushes the ejection lever, located between his legs, it sends a signal to the cockpit cover extraction system and the seat itself. In the first moment, a ballistic system ejects the cover so that the pilot does not collide with it.
At the same time, the seat belts, but also the headrest, are automatically adjusted so that the pilot remains in the seat and your arms and legs do not move uncontrollably and may be hit when leaving the plane. The pilot's head is pushed down and held in place.
With the cover removed and the seat belts firmly restraining the pilotthe catapult pushes the seat out of the plane. The ACES 5 then displays the Pitot tubes which are designed to capture total air pressure and measure velocity. They are probes that have a small opening or tube in direct contact with the air flow. They are also used on the aircraft itself, generally located on the outside of the fuselage or on the edge of the wings.
They are important because what happens next depends on the speed and altitude of the plane at the time of ejection. If both are tall, seat rockets activate to control pitch and a brake stabilization system deployskeeping the seat stable until reaching a more manageable speed and height.
When that happens, the parachute deploys. In the event of ejections at low speed and low altitude, the parachute deploys directly, without the need for the braking system to be activated. This is when the seat separates from the pilot so that he can continue his descent.
This entire process takes place in just 1.6 seconds.
Most U.S. aircraft still use ACES 2, and ACES 5 is only present in a few hundred, but it will continue to reach more aircraft and save more lives in the future.