Here is a good example:
F-35 Cockpit
With stealth, fully integrated avionics, advanced sensor fusion, and a dizzying array of interoperability and data-exchange requirements, the F-35 Joint Strike Fighter represents more revolution than evolution. Nowhere are the advances in this multirole combat fighter more starkly illustrated than in the cockpit.
What is
not there is what is most evident to pilots the first time they see the F-35 cockpit. Gone are the analog steam
gauge dials that populated the control panels of previous generations of fighter aircraft. In their place are large liquid-crystal touch-screen displays featuring color-coded symbology, pictographs, and digital information.
Changing the displays is only a matter of pressing a finger on different parts of the screen of the multi-function display, or MFD, to reconfigure or prioritize information or activate systems. The forest of toggle switches in previous fighter cockpits has been wiped clean from the F-35’s interior landscape, with most of their functions moved to the touch screen. A few switches still sprout here and there, but the overall cockpit ambience is one of simplicity and calm, almost to the point of aeronautical
feng shui.
Similarly, the cockpit of the F-22 Raptor offers a trio of glass displays. “Those displays represent a significant step toward the F-35 cockpit’s spare ambience and a departure from its steam-gauge predecessors,” notes Jon Beesley, the chief test pilot for the F-35. Beesley should know. As a veteran of advanced aircraft development programs, he served as a US Air Force test pilot on the F-117 stealth fighter and as a General Dynamics test pilot for the YF-22. Beesley was the fourth pilot to fly the YF-22 and second pilot to fly the F-22. “The F-22 prototype, the YF-22, had finger-on-glass controls as well,” Beesley notes. “We learned a lot from the experience with this technology on the prototype, which was not implemented in the production F-22.”
The F-22 Raptor is equipped with four reconfigurable liquid crystal displays — three 6.5 by 6.5 inches and one eight by eight inches — along with two non reconfigurable three- by four-inch up front displays. “They are a real advance from the past,” Beesley explains. “But the F-35 is the ultimate expression of the less-is-more sensibility.”
Beesley’s initial reaction to the F-35 cockpit is shared by many other seasoned pilots who see the cockpit for the first time. “Pilots are most impressed by the minimal number of hard switches in the F-35 cockpit,” he explains. “The most prominent portion of the cockpit is the eight- by twenty-inch LCD controlled primarily using finger-on-glass technology that has matured tremendously over the last several years. In the pursuit of easing pilot workload, advanced technology takes care of what pilots refer to as housekeeping chores.”
For example, finger-on-glass controls replace cockpit switches for selecting such functions as air refueling mode and flight control system tests. All radio, mission systems computers, and identification and navigation controls are on glass.
Beesley notes that the large eight- by twenty-inch multifunction display (created by combining two eight- by ten-inch displays) can be customized and divided into many different-sized screens through what he describes as an “elegant pilot-vehicle interface design.” By touching the screen, the pilot can select a pair of eight- by ten-inch window displays, or four five- by eight-inch windows, or any combination of window sizes to project information based on its importance at any given moment.
“This ability to control formats eases the interpretation of complex data,” adds Beesley. “The flexibility in display size and the diversity of data are not available in any other fighter aircraft.”
If one of the eight- by ten-inch screens fails, all information is automatically transferred to the other eight- by ten-inch screen. At the same time, this second screen remains fully customizable. “The missions for the F-35 can be some of the most complex fighter missions conceivable, varying from air superiority to close air support, to the destruction of enemy defense systems,” Beesley explains. “Well-thought-through pilot-vehicle interface makes the transition from one type of cockpit mission to another type of cockpit mission very natural, effectively reconfiguring the cockpit at the same time. Pilots adapt to the concept quickly.”
Rather than evolving the F-35 cockpit from previous designs, engineers decided to start with a clean sheet and base the cockpit’s architecture solely on the needs of the 21st-century fighter pilot. Instead of presenting the pilot with acres of gauges representing all systems and situations all the time, engineers gave priority to situational awareness and to ensuring the information — not just raw data—the pilot receives is the most pertinent for any given moment.
“The F-35 cockpit design is driven by the desire to return the pilot to the role of tactician,” says Mike Skaff, a former US Air Force F-16 pilot who serves as senior manager of the team designing the F-35 pilot-vehicle interface. “Modern fighters are amazingly complex. Monitoring the status of aircraft systems can divert a pilot’s attention from information more critical to the mission. The F-35 cockpit is designed to ensure that the pilot can focus on getting the job done without having to worry too much about other tasks.”
Beesley, whose résumé includes more than 5,000 hours of flying time in twenty different fighters, has already logged hundreds of hours in F-35 cockpit simulators. More recently, he is spending more time in the actual first F-35A test aircraft, known as AA-1, as its first flight approaches. The cockpit appearance of AA-1 is essentially the same as that of all subsequent F-35s. The handful of AA-1 features that won’t make it to production include a pair of electrical system emergency switches, an instrumentation control panel mounted in the center pedestal, and a small digital readout of tactical air navigation information required for AA-1’s unique communications, navigation, and IFF equipment.
“In past programs, controls unique to flight test, such as flutter excitation, control change evaluation, and flight test maneuvers, were selected through panels and switches,” continues Beesley. “On the F-35, these controls have all been incorporated into a display format that can be brought up on any of the LCD screens. We’ve incorporated numerous lessons learned from previous programs on the layout of these displays and on the operation of these flight test critical controls. We engage and terminate various modes using the controls on the hands-on throttle and stick, or HOTAS.”
The three F-35 variants share identical cockpits but with one functional difference. The conventional and carrier variants provide a button to drop and raise the arresting hook for carrier and emergency landings. The STOVL variant commands conversion into and out of the STOVL propulsion mode.
The engine throttle on the pilot’s left and the side stick on the pilot’s right are positioned to be compatible with the widest possible range of pilot shapes and sizes. The throttle is designed to give pilots the capability to vary the detents. It is also an active throttle, which means it provides feedback to the pilot as a function of flight envelope and flight mode. The side stick is also an active controller.
“Stick forces and deflections can be programmed in an active stick to allow either a slight increase or decrease in stick force while pulling g’s,” Beesley explains. “The real driver for an active stick was for vertical flying conditions on the F-35B, or STOVL, variant where we thought we would need light stick forces. In fact, we haven’t needed the feature so far. We have put detents in the STOVL stick. We use a soft stop detent to indicate the desired touchdown sink rate in the STOVL mode.
“The throttle uses the active controls to a greater degree,” Beesley continues. “The internal motors allow the throttle to be moved back automatically when the pilot has an auto throttle connected or in some of the STOVL modes allows the option to input soft stop detents and afterburner detents at will.”
One unique feature of this active throttle is that it does not have an engine cutoff position. It has, instead, a single toggle switch to cut the engine. The use of the active stick and throttle and a cutoff switch was introduced on the JSF demonstrator, the X-35.
Pilots have guided the F-35 cockpit design process from the very beginning to ensure the fighter’s front office is an efficient workspace that liberates the operator from unwanted distractions. “The design has been driven entirely by current and former military pilots from the US Air Force, Navy, and Marines as well as current and former military pilots from the United Kingdom, Canada, Denmark, Norway, the Netherlands, Italy, Turkey, and Australia,” Skaff says.
One of those military pilots providing direction is Lt. Col. Jeff Karnes, a Harrier pilot who is currently flying the F/A-18 Hornet for the US Marine Corps. He is a member of the exclusive fraternity that is both shaping and testing the F-35 cockpit. “The twenty- by eight-inch display provides expansive tactical workspace for manipulating the system and for segmenting down to twelve individual displays,” he says. “It places navigation, threat warning, target designation, and ordnance displays together for quick reference. The Joint Strike Fighter has been specifically designed to reduce pilot workload by minimizing cockpit switches, increasing system automation, and reducing displayed information to only critical items the pilot requires to complete current tasks. The active stick and throttle allows realtime control shaping to optimize feel and aircraft response as a function of current flight envelope and mode.”
Text and symbology on the MFD are color-coded to contrast clearly and sharply with the absolute black of the display screen background. Bob Russell, who manages simulations for the team integrating F-35 pilot systems, simplifies the significance of the colors. “In general, green indicates good or safe conditions, yellow indicates potential problems requiring pilot attention, and red indicates serious conditions demanding immediate pilot attention,” he says. “For example, text for advisories appears in green, cautions appear in yellow, and warnings appear in red.”
The same color codes apply to exterior objects, other aircraft, and phenomena detected by the F-35’s sensors. Symbols on the tactical display appear green if the aircraft’s sensors or off-board assets determine these objects are friendly. If unknown to the sensors, objects appear yellow. If identified as potential adversaries, objects appear red. “We also use blue and magenta, but sparingly,” adds Russell. “We use shades of gray to outline maps and to outline the aircraft planform shown on various subsystem formats, such as fuel, flight controls, and weapons. The symbols representing air and ground threats appear in different shapes that, along with the colors, enhance the pilot’s comprehension and situational awareness.”
Among the other cockpit features is voice activation of certain aircraft functions. “In the movie
Firefox, thought or voice control is used to command weapons,” Beesley says. “Finger activation, however, is much quicker than voice activation. Consequently, we do not use voice activation for tasks that demand split-second decisions. We use voice commands to take care of duties that normally require numerous inputs on a keypad, such as punching in navigation coordinates and changing radio frequencies and bingo fuel amounts. Voice is very effective for housekeeping chores.”
The F-35 cockpit also includes a simplified control system for the short takeoff/vertical landing variant and the ability to accommodate a spectrum of pilot physiques ranging from the light and short (about 100 pounds and four feet eleven inches tall) to heavy and tall (about 250 pounds and six feet five inches tall).
The F-35 cockpit is also the first in a production fighter to use a virtual head-up display that projects information onto the pilot’s helmet visor. The new system, called a helmet-mounted display, or HMD, was switched on in March for the first time in F-35 laboratories where it projected symbology onto the visor by way of the actual F-35 vehicle-management and display-management computers. The HMD provides HUD information as though pilots are looking through an actual HUD no matter in what direction they turn their heads.
“We have flown in the past with helmet-mounted sights, such as Joint Helmet-Mounted Cueing System, or JHMCS,” explains Beesley. “This system is used for off-axis symbology for tactical maneuvering. But because of higher latency, or lag times, these systems cannot be used to fly the airplane. This latency issue has been solved thanks to improvements in computer technology that allow very quick update rates needed for information associated with flying the airplane.”
With the virtual HUD, pilots can look in different directions to find key tactical and flight information in their line of sight. This off-axis capability, as it is called, increases lethality and survivability by allowing the pilot to target threats with head instead of aircraft motions. The HMD eliminates the cost and weight associated with traditional head-up displays and simplifies cockpit design.
“HMD advancements will improve both weapons’ aiming and target information that flows to the pilot,” Beesley says. “In the past, forward-looking infrared, or FLIR, imagery used for targeting was restricted to the narrow field of view of the head-up display or to the restrictions of a head-down display. With HMD, pilots can view the FLIR imagery in its true location, thereby greatly enhancing their awareness of the immediate environment.”
In addition to these advancements, the HMD allows night vision display capability both on-axis and off-axis using the F-35’s 360-degree array of infrared sensors, which is called a distributed aperture system. The sensors work in combination with night-camera technology.
While the F-35 cockpit has undergone evolution and iterative change during its development — including a switch from digital light projection technology to advanced liquid crystal displays — the baseline design is now essentially fixed. It is unlikely to undergo any further significant modifications. “The design will continue to be refined throughout the life of the F-35,” Skaff says, “but the actual layout and hardware will probably not change appreciably.”
“Any changes will lie primarily in pilot-vehicle interface improvements and in additional aircraft capabilities,” Beesley says. “One of the great areas for development is the use and operation of the HMD, because we are doing things with the helmet that have never been done before.”
Overall, the F-35 cockpit environment is a generation beyond those aircraft preceding it, with changes made not for technology’s sake but purely for the sake of mission success. “The significant difference is the F-35 cockpit’s flexibility,” says Beesley. “Complexity of missions, sensors used, weapons employed, and technology available have made this cockpit both necessary and possible.”
F-35 Cockpit « DarkGovernment
F-22 Raptor Cockpit
The F-22's cockpit is one of the very first "all-glass" cockpits for tactical fighters - there are no traditional round dial, standby or dedicated gauges. It accommodates the largest range of pilots (the central 99 percent of the Air Force pilot population) of any tactical aircraft. It is the first baseline "night vision goggle" compatible cockpit, and it has designed-in growth capability for helmet-mounted systems. The canopy is the largest piece of polycarbonate formed in the world with the largest Zone 1 (highest quality) optics for compatibility with helmet-mounted systems. While functionality is critical, the F-22's cockpit design also ensures pilot safety with an improved version of the proven ACES II ejection seat and a new pilot personal equipment and life support ensemble.
The F-22's cockpit represents a revolution over current "pilot offices", as it is designed to let the pilot operate as a tactician, not a sensor operator. Humans are good differentiators, but they are poor integrators. The F-22 cockpit lets the pilot do what humans do best, and it fully utilizes the power of the computer to do what it does best.
Using the power of the onboard computers, coupled with the extensive maintenance diagnostics built into the F-22 by the maintainers, that workload has been significantly reduced. The idea is to relieve pilots of the bulk of system manipulations associated with flying and allow them to do what a human does best - be a tactician.
Aircraft startup and taxi are excellent examples of harnessing the power of the computer to eliminate workload. There are only three steps to take the F-22 from cold metal and composites to full-up airplane ready for takeoff: The pilot places the battery switch 'on,' places the auxiliary power unit switch momentarily to 'start' and then places both throttles in 'idle.' The engines start sequentially right to left and the auxiliary power unit then shuts down. All subsystems and avionics are brought on line and built-in testing checks are made. Then the necessary navigation information is loaded and even the pilot's personal preferences for avionics configuration is read and the systems are tailored to those preferences. All of this happens automatically with no pilot actions other than the three steps. The airplane can be ready to taxi in less than 30 seconds after engine start.
Pilot/Vehicle Interface
The GEC-built Head-Up Display (HUD) offers a wide field of view (30 degrees horizontally by 25 degrees vertically) and serves as a primary flight instrument for the pilot. The F-22's HUD is approximately 4.5 inches tall and uses standardized symbology developed by the Air Force Instrument Flight Center. It does not present information in color, but the tactical symbol set is the same that is used on the F-22's head down displays (HDDs).
During F-22 canopy birdstrike tests, it was found that the HUD combiner glass would shatter the canopy. To solve this problem for EMD, the F-22 HUD will have a rubber buffer strip on it that will effectively shield the polycarbonate of the canopy when it flexes during a birdstrike from hitting the optical glass in the HUD and shattering. Design is also underway for a HUD that will collapse during a birdstrike, but would remain upright under all other conditions. Additionally, the team is investigating the possibility of having the HUD combiner glass laminated similar to household safety glass to preclude flying glass in the cockpit following birdstrike.
The Integrated Control Panel (ICP) is the primary means for manual pilot data entry for communications, navigation, and autopilot data. Located under the glareshield and HUD in center top of the instrument panel, this keypad entry system also has some double click functions, much like a computer mouse for rapid pilot access/use.
There are six liquid crystal display (LCD) panels in the cockpit. These present information in full color and are fully readable in direct sunlight. LCDs offer lower weight and less size than the cathode ray tube (CRT) displays used in most current aircraft. The lower power requirements also provide a reliability improvement over CRTs. The two Up-Front Displays (UFDs) measure 3"x4" in size and are located to the left and right of the ICP. The UFDs are used to display Integrated Caution/Advisory/Warning (ICAW) data, communications/navigation/identification (CNI) data and serve as the Stand-by Flight instrumentation Group and Fuel Quantity Indicator (SFG/FQI).
The Stand-by Flight Group is always in operation and, although it is presented on an LCD display, it shows the basic information (such as an artificial horizon) the pilot needs to fly the aircraft. The SFG is tied to the last source of power in the aircraft, so if everything else fails, the pilot will still be able to fly the aircraft.
The Primary Multi-Function Display (PMFD) is a 8"x8" color display that is located in the middle of the instrument panel, under the ICP. It is the pilot's principal display for aircraft navigation (including showing waypoints and route of flight) and Situation Assessment (SA) or a "God's-eye view" of the entire environment around (above, below, both sides, front and back) the aircraft.
Three Secondary Multi-Function Displays (SMFDs) are all 6.25" x 6.25" and two of them are located on either side of the PMFD on the instrument panel with the third underneath the PMFD between the pilot's knees. These are used for displaying tactical (both offensive and defensive) information as well as non-tactical information (such as checklists, subsystem status, engine thrust output, and stores management).
Integrated Caution, Advisory and Warning System (ICAW)
To reduce pilot workload in flight, the F-22 incorporates the uniquely designed integrated caution, advisory and warning system (ICAW). This system's messages normally appear on the 3-by-4 inch up-front display just below the glare shield. A total of 12 individual ICAW messages can appear at one time on the up-front display and additional ones can appear on sub pages of the display.
More than two years of detail design by pilots and engineers has gone into the filtering logic of the ICAW system and extensive testing of the system was done. In addition, the success of the Army's RAH-66 Comanche helicopter's ICAW system that uses a similar filtering approach gives the F-22 team confidence in the fundamental soundness of the design.
Two aspects of the ICAW display differentiate it from a traditional warning light panel. First, all ICAW fault messages are filtered to eliminate extraneous messages and tell the pilot specifically and succinctly what the problem is. For example, when an engine fails, the generator and hydraulic cautions normally associated with an engine being shutdown are suppressed, and the pilot is provided the specific problem in the form of an engine shutdown message.
The second is the electronic checklist. When an ICAW message occurs, the pilot depresses the checklist push button (called a bezel button) on the bottom of the UFD and the associated checklist appears on the left hand Secondary Multi-Function Display (SMFD). This function also provides access to non-emergency checklists for display to the pilot. In addition to the visual warning on the display, the aircraft has an audio system that alerts the pilot. A Caution is indicated only by the word "caution", while a Warning is announced with the specific problem - that is, "Warning. Engine Failure".
If multiple ICAWs occur, their associated checklists are selected by moving a pick box over the desired ICAW and depressing the checklist button. Associated checklists are automatically linked together so that if an engine failure occurs, the pilot will not only get the checklist for the engine failure procedure in-flight but also the single engine landing checklist. The pilot can also manually page through the checklists at any time from the main menu. This is particularly handy when helping a wing man work through an emergency.
Cockpit Display Symbology
The tactical information shown on the displays is all intuitive to the pilot-he can tell the situation around him by a glance at the screen. Enemy aircraft are shown as red triangles, friendly aircraft are green circles, unknown aircraft are shown as yellow squares, and wingmen are shown as blue F-22s. Surface-to-air missile sites are represented by pentagons (along with an indication of exactly what type missile it is) and its lethal range. In addition to shape and color, the symbols are further refined. A filled-in triangle means that the pilot has a missile firing-quality solution against the target, while an open triangle is not a firing-quality solution. The pilot has a cursor on each screen, and he can ask the aircraft's avionics system to retrieve more information. The system can determine to a 98% probability the target's type of aircraft. If the system can't make an identification to that degree, the aircraft is shown as an unknown.
Likewise, one of the original objectives for the F-22 was to increase the percentage of fighter pilots who make "kills".
The Inter/Intra Flight Data Link (IFDL) is one of the powerful tools that make all F-22s more capable. Each F-22 can be linked together to trade information without radio calls with each F-22s in a flight or between flight. Each pilot is then free to operate more autonomously because, for example, the leader can tell at a glance what his wing man's fuel state is, weapons remaining, and even the enemy aircraft targeted. Classical tactics based on visual "tally" (visual identification) and violent formation maneuvers that reduce the wing man to "hanging on" may have to be rethought in light of such capabilities.
Hands-On Throttle and Stick (HOTAS)
The F-22 features a side-stick controller (like an F-16) and two throttles that are the aircraft's primary flight controls. The GEC-built stick is located on the right console and there is a swing-out, adjustable arm rest. The stick is force sensitive and has a throw of only about one-quarter of an inch. The throttles are located on the left console. Both the stick and the throttles are high-use controls during air combat. To support pilot functional requirements, the grips include buttons and switches (that are both shape and texture coded) to control more than 60 different time-critical functions. These buttons are used for controlling the offensive (weapons targeting and release) and defensive systems (although some, like chaff and flares, can operate both automatically and manually) as well as display management.
Accommodations
Previous fighter cockpits were sized to accommodate the 5th percentile to 95th percentile pilots (a range of only 90%). The F-22 cockpit is sized to accommodate the 0.5 percentile to 99.5 percentile pilots (the body size of the central 99% of the Air Force pilot population) This represents the largest range of pilots accommodated by any tactical aircraft now in service. The rudder pedals are adjustable. The pilot has 15-degree over-the-nose visibility and excellent over-the-side and aft visibility as well.
Lighting
The cockpit interior lighting is fully Night Vision Goggle (NVG) compatible, as is the exterior lighting. The cockpit panels feature extended life, self-balancing, electroluminescent (EL) edge-lit panels with an integral life-limiting circuit that runs the lights at the correct power setting throughout their life. It starts at one-half power and gradually increases the power output to insure consistent panel light intensity over time. As a result, the cockpit always presents a well-balanced lighting system to the pilot (there is not a mottled look in the cockpit). The panels produce low amounts of heat and power and are very reliable. The aircraft also has integral position and anti-collision lights (including strobes) on the wings. The low voltage electroluminescent formation lights are located at critical positions for night flight operations on the aircraft (on the forward fuselage (both sides) under the chine, on the tip of the upper left and right wings, and on the outside of both vertical stabilizers. There are similar air refueling lights on the butterfly doors that cover the air refueling receptacle.
Life Support Ensemble
The F-22 life support system integrates all critical components of clothing, protective gear, and aircraft equipment necessary to sustain the pilot's life while flying the aircraft. In the past, these components had been designed and produced separately. The life support system components include:
- An on-board oxygen generation system (OBOGS) that supplies breathable air to the pilot.
- An integrated breathing regulator/anti-g valve (BRAG) that controls flow and pressure to the mask and pressure garments.
- A chemical/biological/cold-water immersion (CB/CWI) protection ensemble.
- An upper body counterpressure garment and a lower body anti-G garment acts a partial pressure suit at high altitudes.
- An air-cooling garment, which is also going to be used by pilots on the Army's RAH-66 Comanche helicopter provides thermal relief for the pilot.
- Helmet and helmet-mounted systems including C/B goggles and C/B hood; and the MBU-22/P breathing mask and hose system.
The Boeing-led life support development and its suppliers designed the life support system with the F-22's advanced performance capabilities in mind. The separate components of the life-support system must simultaneously meet pilot protection requirements established by the Air Force in the areas of higher altitude flight, acceleration, heat distress, cold water immersion, chemical and biological environments, fire, noise, and high-speed/high-altitude ejection. Escape-system tests have demonstrated that the life-support system will protect pilots when exposed to wind speeds of up to 600 knots. Current life-support systems are designed to provide protection only up to 450 knots.
The head mounted portions of the life-support system are approximately 30 percent lighter than existing systems, which improves mobility and endurance time for pilots. With its advanced design, the HGU-86/P helmet that will be used by F-22 pilots during EMD reduces the stresses on a pilot's neck by 20 percent during high-speed ejection compared to the current HGU-55/P helmets. The F-22 helmet fits more securely as the result of an ear cup tensioning device and is easily fitted to a pilot's head. The helmet provides improved passive noise protection and incorporates an Active Noise Reduction (ANR) system for superior pilot protection.
The chemical/biological/cold water immersion garment is to be worn by pilots when they fly over large bodies of cold water or into chemical/biological warfare situations. These garments meet or exceed Air Force requirements. During cold water immersion tests, the body temperature of test subjects wearing the garments fell no more than a fraction of a degree after sitting in nearly 32-degree Fahrenheit water for two hours. Current CWI suits allow body temperatures to drop below the minimum of 96.8 degrees F within an hour and a half. Normal body temperature is 98.6 degrees F. Other advantages of the F-22 life support system include its ability to fit a wider range of sizes and body shapes (the central 99% of the US Air Force pilot population).
On 15 May 2012, George Little, acting assistant secretary of defense for public affairs, said that Secretary of Defense Leon Panetta had ordered the Air Force to take additional steps to mitigate risks to F-22 pilots and expedite the installation of an automatic backup oxygen system in all of the planes. In addition, effective immediately, all F-22 flights will remain near potential landing locations to enable quick recovery and landing should a pilot encounter unanticipated physiological conditions during flight. Beginning in 2008, F-22 pilots began experiencing hypoxia-like symptoms when flying the aircraft. Subsequent attempts by the primary contractor Lockheed-Martin to fix to the problem were unsuccessful, and a supplementary filter reportedly introduced carbon particles into the oxygen system. On 24 July 2012, Defense Secretary Leon E. Panetta said he was satisfied the Air Force had identified the cause of hypoxia-like symptoms 12 F-22 pilots suffered, linking the incidents to a defect in the pilots' pressure garment vest. The use of the vest had been suspended in June 2012 as part of the investigation. The use of the supplementary filter initially installed to try and solve the problem was also discontinued. The Air Force was also looking at improving the oxygen delivery hose and its connections.
Canopy
The F-22's canopy is approximately 140 inches long, 45 inches wide, 27 inches tall, and weighs approximately 360 pounds. It is a rotate/translate design, which means that it comes down, slides forward, and locks in place with pins. It is a much more complex piece of equipment than it would appear to be.
The F-22 canopy's transparency (made by Sierracin) features the largest piece of monolithic polycarbonate material being formed today. It has no canopy bow and offers the pilot superior optics (Zone 1 quality) throughout (not just in the area near the HUD) and it offers the requisite stealth features.
The canopy is resistant to chemical/biological and environmental agents, and has been successfully tested to withstand the impact of a four-pound bird at 350 knots. It also protects the pilot from lightning strikes.
The 3/4" polycarbonate transparency is actually made of two 3/8" thick sheets that are heated and fusion bonded (the sheets actually meld to become a single-piece article) and then drape forged. The F-16's canopy, for comparison, is made up of laminated sheets. A laminated canopy generally offers better birdstrike protection, and because of the lower altitude where the F-16 operates, this is an advantage. However, lamination also adds weight as well as reduced optics.
There is no chance of a post-ejection canopy-seat-pilot collision as the canopy (with frame) weighs slightly more on one side than the other. When the canopy is jettisoned, the weight differential is enough to make it slice nearly ninety degrees to the right as it clears the aircraft.
In testing so far, the cockpit canopy has fallen far short of its service life requirement according to DOT&E.
ACES II Ejection Seat
The F-22 uses an improved version of the ACES II (Advanced Concept Ejection Seat) ejection seat that is used in nearly every other Air Force jet combat aircraft (F-16, F-117, F-15, A-10, B-1, B-2). The seat has a center mounted (between the pilot's legs) ejection control. The F-22 version of the McDonnell Douglas-built ACES II includes several improvements over the previous seat models. These improvements include:
- The addition of an active arm restraint system to eliminate arm flail injuries during high speed ejections.
- An improved fast-acting seat stabilization drogue parachute system to provide increased seat stability and safety for the pilot during high-speed ejections. The drogue is located behind the pilot's head, rather than in the back of the seat and is mortar-deployed.
- A new electronic seat and aircraft sequencing system that improves the timing of the various events that have to happen in order for the pilot to eject (initiation, canopy jettison, and seat catapult ignition).
- A larger oxygen bottle gives the ejecting pilot more breathing air to support ejection at higher altitudes (if required).
The F-22 ACES II ejection system utilizes the standard analog three-mode seat sequencer that automatically senses the seat speed and altitude, and then selects the proper mode for optimum seat performance and safe recovery of the pilot. Mode 1 is low speed, low altitude; Mode 2 is high speed, low altitude; and Mode 3 is high altitude.
F-22 Cockpit
