As the U.S. Air Force (USAF) works toward developing assets like the Northrop Grumman B-21 Raider, the next T-X trainer, and possibly a new close air support aircraft, testing continues on a quieter project: parachutes. The 418th Flight Test Squadron (418 FLTS) at Edwards Air Force Base, CA, is currently assessing a new parachute for the Advanced Concept Ejection Seat II (ACES II) that will improve safety and expand the acceptable personal weight range of aircrew.
About 43% of ejection-related injuries occur during the landing phase, and the new GR7000 parachute is designed to provide a slower rate of descent and oscillation than the C-9 canopy currently used with the ACES II system. Multiple USAF Safety Investigation Boards highlighted the need for ACES II improvements which led to Congressional interest in ejection seat improvements in 2014. USAF statistics show that about 10% of ACES II ejections have been outside of the originally cleared weight range—with four deaths occurring outside of that range. The testing is part of the USAF Materiel Command ACES II Safety and Sustainability Improvement Program (SSIP).
The ACES II SSIP has been ongoing for many years; however, since the initial fielding of the ACES II system in 1978, the USAF has only made two significant changes affecting ejection seat safety. The first change was expanding the allowable aircrew weight—originally 140 to 211 lb—to 103 to 245 lb without ejection seat upgrades.
“Another significant change affecting the safety of the ACES II was the introduction of helmet-mounted devices, particularly the nuclear flash blindness goggles used by B-2A Spirit aircrew. The combination of larger allowable aircrew anthropometric range, and the added head-born weight of the helmet-mounted devices, increased the risk of having an unsafe ejection,” said Daniel Bush, 418 FLTS ACES II SSIP Project Flight Test Engineer. Modifications were made to the Northrop Grumman B-2 version of the ACES II in regard to the helmet mounted devices.
Over several weeks in June, GR7000 parachute testing consisted of 10 dummy drops, 20 live-person jumps, and five drops using a crosswind deployment cylindrical test vehicle, which looks similar to an inert bomb. The tests were conducted out of a Short SC.7 Skyvan from Skydive Perris of Perris, CA. The USAF has previously used Skyvans for live jumps, dummy drops, and airdrops. The test plane has an anchor cable with a winch on the right side of the aircraft cargo hold and bench seats for parachutists and passengers running down both sides.
According to the 418 FLTS ACES II SSIP project pilot, Maj. Duncan Reed, the Skyvan is able to meet test requirements to climb and level off between 16,000 and 17,000 ft median sea level and trim to between 90 and 100 knot-indicated airspeed, which is required for the cylindrical test vehicle drops.
“Key performance values for this test are airspeed, altitude, rate of descent, and canopy structural integrity. Riser loads and acceleration data also will be collected and analyzed,” said Dean Van Oosterhout, 418 FLTS ACES II SSIP Project Engineer.
“The overall test objective is to demonstrate the strength of the GR7000 parachute at worst-case ejection (situations), high-altitude Mode 1 deployment and evaluate the steady-state descent characteristics of the GR7000 parachute,” said Alice White, 418th FLTS ACES II SSIP Project Manager.
This particular test of the GR7000 is being conducted on the B-2 Spirit version of the ACES II, but data could be applied for all ACES II systems currently using the C-9 canopy.
The ACES II is manufactured by United Technologies Aerospace Systems (UTAS). The ACES II brought standardization to USAF ejection seats—with it being used in the Fairchild Republic A-10 Thunderbolt II, McDonnell Douglas F-15 Eagle, General Dynamics F-16 Fighting Falcon, Lockheed Martin F-22 Raptor, Rockwell B-1 Lancer, Northrop Grumman B-2 Spirit, and formerly on the Lockheed F-117 Nighthawk. The standardization reduced maintenance and training costs as maintainers and pilots (generally) only have to train on one type of ejection seat.
Furthermore, the ACES II is the lowest life-cycle cost, third-generation seat according to 2013 figures. This is in part because the USAF owns the rights to the seat which allows for competitive procurement of maintenance, repair, and service life extension parts and programs for the 5000 ACES II units currently in-service. Since its fielding, the ACES II has saved more than 630 lives.
The potential incorporation of the GR7000 parachute into the ACES II system comes only two years after UTAS demonstrated its ACES 5 system at the 2015 Dubai Airshow. The upgraded ACES 5 model also features the GR7000 parachute to reduce descent rate and oscillation.Continue reading »