As aircraft designs evolve, so must the means of saving the pilot when the aircraft is lost.
Ejection seats for pilots and aircrew were pioneered by the British aviation company Martin-Baker at the onset of the jet age at the end of World War Two. Since 1946 Martin Baker ejection seats and crashworthy seats have saved over 7,700 lives and there are over 16,200 seats currently in service worldwide.
Martin Baker is responsible for supplying all the ejection seats for all three Lockheed F-35 Lightning II variants which are a further development of the Mk16 seat used on other U.S. aircraft including the Beechcraft T-6 Texan II advance turboprop trainer. According to Martin-Baker, the US16E is the only Qualified Ejection Seat that meets the U.S. Government defined Neck Injury Criteria (NIC) across the pilot accommodation range. While older F-16 variants used Collins Aerospace’s ejection seats, the latest variant, the Block 70/72 are fitted with Martin-Baker US18E ejection seats which have commonality with the F-35 ejection seat and are based on the US16E.
The Martin-Baker Mk14 ejection seat, more commonly known as SJU17A and Navy Aircrew Common Ejection Seat (NACES), is currently in service in the Boeing F/A-18 and T-45 Goshawk. The NACES was developed to take aircrew safety and survival to a higher level of control. Used in the F/A-18, and T-45, the NACES is the most advanced seat used in the United States Navy inventory which uses a digital electronic sequencer along with airspeed sensors and electrically-fired systems on the seat to allow for five separate modes of operation. Version differences include mainly seat bucket shape, headrest and canopy breaker configuration, and other changes to accommodate the various cockpit requirements.
Beyond the computer controlled firing sequence, it uses the same basic frame from the Mk10 series of seats including the tubular seat adjustment rails which allow for easy disassembly. The drogue gun has been replaced with a rocket-deployed system that moves the drogue parachute from the headrest to the large tubular structure on the top of the main beam assembly. With the addition of the electronic sequencer, the scissor shackle has been eliminated.
The main recovery parachute is housed in the headrest and deployed by a rocket located on the left main beam assembly. The sequencer computer module fits under the headrest above the shoulder harness. The sequencer is actuated by dual thermal batteries which are in turn actuated by hot gas from the duel initiators located under the seat firing handle at the front of the seat bucket.
In 2022, the U.S. Navy discovered an issue affecting cartridge actuated devices (CAD) which deploy a parachute when the pilot pulls the ejection handle, in some of its fixed-wing aircraft including the F/A-18B/C/D Hornet, F/A-18E/F Super Hornet, E/A-18G Growler, and T-45C Goshawk training and F-5N Tiger II adversary aircraft.
After being notified of a potential defect by the supplier, Martin-Baker, the U.S. Navy team used validated radiography procedures to scan on-hand inventory to verify each item was properly manufactured before sending to the fleet to replace existing CADs. Cleared replacement parts were shipped to several fleet maintenance centres and in less than 45 days.
The Secretaries of the U.S. Navy and USAF are required to provide semi-annual reports to Congress on the status of ejection seats in use, thanks to a provision included in the 2022 National Defense Authorization Act. Specifically, the services must detail how many ejection seats have a waiver that allows them to remain in use, even if repairs or replacement parts are necessary. The measure followed the 2020 death of USAF pilot 1st Lt. David Schmitz, who suffered an ejection seat malfunction during an F-16 mishap.
At the same time the USAF Air Education and Training Command temporarily grounded two potentially impacted trainer fleets, the T-6A Texan IIs and T-38C Talons, some 300 aircraft in total, due to concern over defective cartridges.
ACES
Apart from Martin Baker, the only other Western company making ejection seats for high performance fighter and training aircraft is Collins Aerospace which manufactures the ACES ejection seats. Introduced in 1978, there are currently 6,000 ACES II seats in service on various aircraft, including the USAF’s A-10, F-15, F-16, F-22, B-1 and B-2 fleets, as well as all F-15s and F-16s worldwide. The seat was introduced in 1978. In 2020, Collins Aerospace was awarded a $700 million firm-fixed-price contract for the delta qualification, production and fielding of a next generation ejection seat (NGES) for various USAF aircraft including the new Boeing/Saab T-7 Red Hawk advanced trainer.
The T-7′s digital design process and advanced manufacturing techniques have been highlighted by Boeing as a potential model for designing and building next generation aircraft faster and with fewer risks and defects. However, problems, including concerns over the aircraft’s new ACES 5 ejection seats and other emergency egress systems, have slowed progress.
The T-7 was designed to accommodate pilots with a wider range of body types and heights, as well as both male and female pilots. In the past USAF aircraft and their cockpits were designed with fitting only men in mind, and women frequently found it difficult to receive clearance to fly;with tests showing that the T-7′s emergency escape system could be dangerous for some pilots. In 2021 the USAF admitted that tests found some ejecting pilots could be at a high risk of concussions, unsafe acceleration when parachutes open, or losing their visor at high speeds. Since than, the USAF and Boeing stated that minor adjustments to the ACES 5 seat have increased safety and reduced the risk to pilots.
However, ;the new T-7A pilot training jet won’t be ready for initial operations until 2028, documents show, putting the programme another year behind schedule.
Originally, the T-7A was supposed to be ready for initial operations in 2024 but testing revealed continuing problems with the aircraft’s ejection seat that have pushed the in-service date back to the second quarter of fiscal 2028, according to budget justification documents submitted with the 2025 budget issued in March 2024.
The Air Force Life Cycle Management Center’s Mobility and Training Aircraft Directorate has successfully tested the ACES 5 escape system drogue chute that will go on the T-7A aircraft.
“We’re testing a possible new use of the ejection seat drogue chute,” said Dr. Dan Mountjoy, T-7A Crew Systems Lead Engineer with the directorate’s T-7A Program Office. “The ejection seat configuration we’re going to be using on the T-7A has not been used on any other platform or for the full anthropometric range of occupants. It’s going to need to safely eject pilots that weigh between 103 and 245 pounds.”
Historically, the drogue chute was designed to slow the ejection seat and occupant down after an ejection at speeds above 250 knots and before the personnel parachute is deployed. Working closely with the ACES 5 developer, Collins Aerospace, and the T-7A Prime contractor Boeing, the programme office needed to gather important data at speeds below 250kts and ensure the system will properly operate and supply the necessary drag to improve stability during the slower speed ejections. Four tests were accomplished at Hurricane Mesa Test Facility in Utah in November 2023.
Joe Rich, Air Vehicle Branch, Flight Systems Lead Engineer for the programme office said, “The adaptation of an existing test sled and existing drogue chute assets allowed the programme to collect the data needed in a very dynamic environment of constantly changing airspeeds during test runs. This allowed for cost savings and proof of theory for possible use of the drogue chute in slower speed ejections.”
The T-7A programme has also gathered an extensive amount of amass properties information and aerodynamic wind tunnel data of the ACES 5 family of seats with the aid of the 711th Human Performance Wing at Wright Patterson Air Force Base and the 716th Test Squadron, Arnold Engineering Development Complex at Arnold Air Force Base, Tennessee. All the testing and data collection will go into an update to the modelling software for the ejection seat performance.
The next phase of testing accomplished a fully integrated dynamic sled test in February 2024 at Holloman Air Force Base, New Mexico to gather more information needed to confirm any system updates before the implementation and resumption of its qualification programme. All the data collected is being used to determine the necessary changes that need to be made to make the T-7A escape system safe for all body types and sizes, thus meeting the USAF’s mandate to accommodate a larger range of pilots.
The importance of the success of the ACES 5 system will make way for its adoption for the new B-21 and the manned element of the USAF’s Next-Generation Air Dominance (NGAD) programme to to deliver a 6th-generation fighter to replace the F-22 Raptor.
The Eurofighter Typhoon is fitted with the Mk16A NXG ejection seat and Martin Baker is part of the UK team developing the RAF’s next generation fighter aircraft, Tempest. Working alongside Martin Baker, a team of BAE Systems engineers has led ejection seat trials, using a rocket-propelled sled travelling at speeds of more than 434kts. Alongside Martin Baker and BAE Systems, the team behind the crew escape system includes experts from GKN for canopy design, Hamble Aerospace for detonator cords, and rig manufacturers EDM, as well as specialists from the Royal Air Force’s Rapid Capabilities Office (RCO) and scientists from the Ministry of Defence.
Crashworthy Seats
Martin-Baker also manufactures what it calls ‘crashworthy’ seats for helicopters and fixed-wing transport aircraft. Its Multi-Functional Operators Seat (MFOS) offers 360º rotation with locking at intermediate positions. There is an option to add sideways seat movement in installations where a floor overlay pallet is used for seat integration. The lightweight MFOS is Army qualified to the requirements of AS8049/a Type B but with an increased occupant size and weight ranges now specified for military products.
Martin-Baker’s Troop and Gunner seats were designed and developed to meet the new improved crash requirements of the Sikorsky UH-60M Blackhawk using Martin-Baker’s patented energy attenuation technology.
Both seats are designed and tested to MIL-S-85510 using the latest military standards for occupant size and weight. The troop seat is qualified for fore and aft facing installations. The gunner seat is qualified for side facing installations. Both seats incorporate a fold-up sitting platform with a sitting sling. The gunner seat is fitted with three acceleration sensing MA-16 type inertia reels and a stand-up harness that allows the user 48 inches of webbing payout to manoeuvre around the cabin.
Since 1958, the German company AUTOFLUG has been performing repair and maintenance for Martin-Baker ejection seats in Germany as well as manufacturing components under licence. AUTOFLUG‘s troop seats for soldiers and parachutists offer high protection at minimum weight and with maximum installation and removal flexibility. Extensive tests have shown that the troop seats meet the highest crash safety, flammability and sustainability standards.
Its safety seats for pilots and crew members of military helicopters feature a low weight, while complying with military crash safety requirements. Seats can be provided with ballistic protection, if required. To ensure maximum flexibility AUTOFLUG currently develops modular seat concepts enabling the extension of standard seats, which include a foldable headrest, weapon supports or splinter protection.
Building on its legacy brand, Simula, BAE Systems is providing innovative, life-saving products to the rotorcraft market. Since introduction of the first successful military crashworthy crew seat in the UH-60 Black Hawk in 1977, BAE Systems has been a pioneer in aerospace crash safety and combat survivability, manufacturing military folding troop seats to FAA- certified lightweight helicopter crew and passenger seats. The S7000 seats are crashworthy and include armoured options for military crew seating applications. The S5000 line of crashworthy seats features lightweight designs for crew seating applications.
With many available options, the S5000 seats are easily adaptable to any platform. BAE Systems Mission Adaptable Crew Seat (MACS) features vertical and horizontal adjustment, seat back and pan cushions support for comfort. It is fitted with 5-point restraint with dual-action rot buckle and inertial reel, a fixed headrest and is night vision goggle (NVG) compatible. An optional armoured seat features the quick installation or removal of armour panels without tools, and advanced lightweight armour materials provide ballistic protection against .50 cal projectiles.
by David Oliver
