Every F/A-22 Raptor begins as an aluminum bulkhead loaded into a fixture at one end of a u-shaped production line in Marietta, Georgia. The assembly clock starts ticking at 8200, the numerical designation of the first forward fuselage assembly station. The station designations count down to position 1 as the aircraft transforms from raw metal into a fully functioning F/A -22.
Changing Mindsets
The F/A-22 assembly line is being transformed as F/A-22 manufacturing ramps up from eleven aircraft in 2003 to nineteen in 2004 and up to a maximum of thirty-two beginning in 2007. "To paraphrase Winston Churchill, we are not at the beginning of the end for the program, but at the end of the beginning," says Terry Leek, deputy vice president for F/A-22 production and material operations at Marietta. "Production requires a different mindset from development," Leek continues. "In development, I can tell mechanics I need to change something and they can make it work. In production, we have to develop a process for addressing the change in subsequent and existing aircraft. That process must be both efficient and repetitive. We have to specify every task within the production process in detail. We have to make sure everything comes together at the right time and at the right place."
Increasing the rate can also highlight inefficiencies in any production line, especially one as sophisticated as the F/A-22 line. "We were focused on shaking down the tooling when we were working at lower production rates," notes Mike Packer, the director of F/A-22 manufacturing in Marietta. "We have to standardize the assembly process to improve efficiency. We've pressed over the last year and a half to fill up every position on the line. Maintaining a throughput on a strict cadence reveals obstacles to production."
That throughput, for 2004, equates to one F/A-22 rolling out of the factory every 9.6 days. One complete aircraft rolling out makes room for all the ones in work to roll up one position. Ideally, every position on the entire line moves to this ten-day drumbeat.
As the drumbeat increases over the coming years, employees have to work smarter. "We have to become more efficient since we can get only so many people to work around an assembly," says Mark McDonald, senior manager of production affordability. "We become more efficient by minimizing design changes and by listening to the mechanics assembling the airplane. Working smarter can mean reorganizing work flows, designing a new tool to simplify a task, or adding a run station on the flight line."
Many of the recent changes are paying off. "We had as many as six midsections waiting to be mated a year ago," says Charles Baggett, director of major assembly. "Now when a midsection is shipped from Fort Worth, it arrives just in time for fuselage mate. The overall span time from loading the first bulkhead to moving out the door was sixteen months for Ship 29, which was rolled out of final assembly in 2004. That goes down to one year for Ship 52, which will roll out of final assembly in 2005. So, the span goes down significantly in the coming year."
Exacting Tolerances
F/A-22 assembly takes place in the southwest corner of the large B-1 manufacturing building in Marietta. B-1 encompasses 3.5 million square feet, of which the Raptor assembly area occupies 240,000 square feet. The F/A-22 production area is physically divided into two parallel lines, forward fuselage assembly and final assembly.
The overall production tasks assigned to Marietta can be traced back to the original three-company teaming agreement for the Advanced Tactical Fighter. That agreement cut the aircraft into sections, with Boeing building the wings and aft section in Seattle, Washington; General Dynamics (now Lockheed Martin Aeronautics Company) in Fort Worth building the midsection; and Lockheed (now also Lockheed Martin Aeronautics Company) building the forward fuselage, performing final assembly, and conducting flight tests in Marietta.
Both the forward fuselage and final assembly lines have split-level stations. Upper and lower decks allow crews of mechanics to work above and below assemblies simultaneously. Supplemental lighting, reflected by shiny white epoxy-painted floors, keeps the work areas well illuminated. The line is relatively quiet thanks to a recently installed utility tunnel that brings power, compressed air, water, and hydraulic fluid to the line. Assemblies move from one station to the next on rail systems for much of the line. Workers use laser theodolites and mechanical alignment tools at various locations to verify tolerances measured to one-thousandth of an inch in some cases.
"Interchangeability drives a lot of our tolerance requirements," explains David Trawinski, director of production engineering for F/A-22. "Maintainers in the field have to be able to replace one panel with another panel and not worry about trimming the new panel to fit. Low-observable requirements drive some of these tolerances as well."
Trawinski is in charge of making rapid engineering changes on the production line. "I deal with discrepancies on the line," he says. "For example, if someone trims a part too much, say by thirty-thousandths of an inch, we have to figure out if it can still be used. We disposition the part quickly to keep the line moving. We also take immediate corrective actions so we don't repeat mistakes."
Engineering support centers located next to the production line minimize the time needed to disposition the discrepancies and take corrective actions. The centers, called waffle houses because their picture windows and rectangular shape resemble local restaurants of the same name, were put in about two years ago to get support functions as close to the line as possible.
"Engineering, quality assurance, and material support are within an arm's reach of the mechanics," Trawinski adds. "As the line matures, we replace engineers with more direct shop floor support personnel."
Portable computer terminals scattered throughout the production line provide updated drawings as well as digital work instructions. Mechanics can pull up the latest detailed drawings and assembly instructions with step-by-step illustrations. "Space limitations don't allow us to go up into a tank to show someone how to do a job," notes Steve Ansley, a supervisor on the final assembly line. "So, we use work instructions with photographs that show fastener installations, drill-outs, pressure checks, sealant applications, and tube installations. Quite a bit of work goes on inside a fuel tank, so these instructions must be very detailed."
Beginning: Forward Fuselage
The forward fuselage of the Raptor takes shape on the left half of the U-shaped production line, beginning with the wheel well and forward fuel tank assembly in Station 8200 and ending with forward fuselage functional checks in Station 6000. The entire process takes about 100 workdays.The forward fuselage begins as two separate structures, the wheel well/fuel tank assembly and the forward structure that will eventually contain the cockpit. The forward structure is built up on two stations of a short, perpendicular feeder line. It is then slid on tracks onto a turntable that pivots ninety degrees to line it up parallel with the wheel well/fuel tank assembly. The sections are mated in Station 8000. Holes for access doors, panels, and skins are drilled in the mate fixture before the forward fuselage assembly is moved down the rest of the line as a single unit.
Inlet diverter skins, cockpit side skins, substructure for the cockpit deck, seatback rails and brackets, warm air manifold, and other major components are installed next (Station 7000). The internal structure of the forward assembly then receives a coat of white epoxy paint before it moves to the last station on the forward fuselage assembly line.
At Station 6000, mechanics install the cockpit center console, avionics racks, and the console assembly, which includes wire harnesses that connect the cockpit console and displays to all of the aircraft systems. Wiring, fiber optics, tubing, switches, brackets, panels, hoses, ducts, and decals are installed. Functional tests are conducted on fiber optics and the emergency landing gear system. The cockpit is tested for pressure leaks as well.
Before heading to the final assembly line, the forward fuselage is thoroughly inspected and cleaned. It is then loaded in a fixture called a rotisserie and rotated to remove any foreign objects left over from the assembly process. The move to the final assembly line is the first done by overhead crane. Crane moves are kept to a minimum to ensure the structural integrity of the assembly.
Middle: Body Mate
The three major fuselage sections come together in Station 5000, which consists of four sequential positions. The aft sections and midsections, delivered to the line from Seattle and Fort Worth, respectively, are painted in Marietta before they arrive at the final assembly line on a flatbed truck. The forward fuselage is loaded by overhead crane onto a precision fixture called a skate. The skate slides forward on rails, allowing space for the aft section and midsection to be loaded behind onto their own skates.
More than seventy-five operations are completed in the first position. The most critical of these involves the precise alignment of the aft and midsection. Laser targets on the wing attachment points or lugs on both the aft and midsection provide alignment data to a computer. Mechanics use computer software to send signals to eight motors under each section to ensure the wing attachment lugs on each section are aligned to each other within thousandths of an inch. Once aligned, more than 750 holes are drilled in the frames, bulkheads, and other structure to join the aft and midsection. The forward section is aligned to the midsection and approximately 1,000 more holes are drilled to join it to the midsection.
The entire assembly slides to the second of four positions, where the sections are separated. All of the holes are deburred and cleaned. The sections are then mated with sealant and all fasteners are installed. The next critical operation is drilling out six undersized wing attachment holes on each side of the midsection to precise tolerances within ten to fifteen one-thousandths of an inch. In this second position, the wiring and tubing are run between the sections and attached at the prescribed locations.
Once in the third position, attachment points are drilled for the vertical stabilizers (manufactured in Meridian, Mississippi), horizontal stabilators (built in Marietta, but which will soon be made by Vought in Texas), the inlet assemblies (built in Marietta), the landing gear (supplied by BFGoodrich), and control surface edges (made by Lockheed Martin in Palmdale, California). Holes are also drilled for chevron skin panels that cover the aft/mid and mid/forward interfaces. The environmental control system is tested. Wiring connections are checked. Tubing and fuel tanks are pressure tested.
The majority of the drilling and fastening is complete when the assembly reaches the fourth position in Station 5000. The remaining work consists of sealing and pressure testing fuel tanks. The final operations involve completing the remaining functional tests for the environmental control system and cleaning the entire assembly and inspecting it for foreign object debris, or FOD.
"Many of the 300 or so mechanics we have on the final assembly line came from commercial airlines," Ansley says. "We have a lot of mechanics from Delta, United, and Northwest. Most of them have excellent mechanical backgrounds. Airline mechanics are more familiar with the tolerances than someone who, say, came from a sheet metal shop. They have an understanding of blueprints, metal work, the tools involved, and the terminologies we use. We're also seeing more experience with composite materials from commercial airline mechanics. All of this experience simplifies training."
Jerry Worley is one of the veteran mechanics on the line. He has worked on the C-141, C-5, and C-130 since coming to Lockheed Martin in Marietta in 1983. He worked on the L-1011, B-1 bomber, and the Space Shuttle in California before that. "I've been everywhere in the Marietta facility from the flight line to final assembly," he says. "The F/A-22 is the most different and difficult aircraft I have ever worked on. That's what makes it so much fun. I don't come in every day and drill the same old holes. The job is never boring.
"The various materials, the alloys and composites, keep the work interesting," Worley continues. "The airplane doesn't have flat areas. Every surface is angled or contoured. That affects the drilling process. The working spaces are very compact. We have to be careful with fiber-optic lines. Every operation is precise. We can't tolerate one sloppy hole on that aircraft." Raptor mechanics take a personal role in making production schedules and achieving quality goals. They track their own work on large charts next to the production line, signing off specific tasks as they are completed. Locations of toolboxes and drill motors are the result of employee suggestions. Mechanics have input into jig designs and tooling setups. Even toolbox arrangements are based on requirements developed by mechanics.
End: Final Assembly
From the last position in the body mate station, the F/A-22 rises tailfree and wingless with the help of an overhead crane. The incomplete Raptor, clad in patchwork shades of primer yellow, green, and tan, lands a few yards away on a fixture called a tri-dolly, a one-piece movable fixture that attaches to the fuselage at three points. The next time the aircraft leaves the ground, it will be propelled by a pair of Pratt & Whitney F119 engines. The Raptor is now about seven positions and fewer than 100 workdays away from rolling out of the factory.
Any visitor to the Raptor production line, and to the final assembly area in particular, will leave with an increased sensitivity to FOD. Twenty minutes before the end of every shift, mechanics and management crawl on the jet on their hands and knees searching for FOD with mirrors and flashlights. Others sweep and vacuum the work spaces. Areas designated FOD-critical require those entering to abide by a FOD dress code—no jewelry and nothing but clothing allowed above the waist.
Loran Bodnar manages the first five positions of the final assembly area (Positions 8 through 4). "I practically live out on the floor trying to make that mechanic's life a little easier. I'm getting the right people out there to answer his questions. We keep busy every day improving the quality of the jet and its assembly process."
The Raptor spends most of its time in Bodnar's domain getting all of its flight control surfaces installed and working. The landing gear is the first major component installed after body mate. The wings and vertical stabilizers go on next. They are followed by the horizontal stabilators, and control surface edges. The ailerons, flaperons, and rudders complete the installation of the control surfaces.
"We install the surfaces and route the hydraulics to them," says Bodnar, who brought his F-16 production experience to Marietta a few years ago. "We complete all the hydraulic system connections that have to be made after body mate," he explains. "We swing the gears for the first time. The aircraft leaves Position 6 on its own landing gear." Pre-power tests are started in Position 5, where the inlets, aft boom edge, wingtip edge, wing stub edge, and the leading edge flaps are installed. In Position 4, the inlet and diverter lip edges, antennas, and main and side weapon bay doors are installed. At this point, all the actuators and hydraulics are working and the jet has full electrical power.
The Pratt & Whitney F119 engines and the Northrop Grumman AN/APG-77 radar are installed in Position 3. "We get very heavy into functional testing in Position 2," notes Scott Eads, who manages the final three positions on the line. "We install all of the avionics. We load software. We test each system individually. We turn everything on. We fire everything up from the radar to the electronic warfare system—all at the same time. We play war games with the airplane on the assembly line. We make sure that everything is good to go."
Once the system checks are complete, open panels are closed before the Raptor moves to the final assembly position. Most of the compartments, which will not be opened again before the airplane is delivered, require an okay from a government inspector before the panel is installed. The canopy and radome are the last major components installed before the Raptor rolls off the assembly line. The ACES III ejection seat is the very last major component, and it is installed on the flight line.The last position is dedicated to the inspection process. "Quality assurance teams are involved throughout the assembly process," notes Janet Nash, director of quality for the F/A-22. "A government acceptance team in Marietta also participates in inspections throughout the final assembly line and on the flight line. Air Combat Command has a full-time staff here. All of these inspectors are checking holes, measuring locations, and checking paint thickness and surface finishes. Many of these inspection items were established as part of the design process. The lists have been refined as we gain experience with production."
Once company inspectors have scrutinized the aircraft in Position 1, the Raptor is officially released to a team of government inspectors. "Ten to fifteen government inspectors crawl all over the airplane," notes Eads. "They write up everything they find. Our goal is for them to find nothing wrong with the airplane. We average only ten to twenty write-ups per aircraft and nearly all of these are relatively minor. We've never had an airplane rejected. Fixing all the write-ups for a given aircraft has never required more than two hours."
To The Flight Line
Newly minted Raptors are towed out of the factory to the south side of Lockheed Martin facilities in Marietta. A yellow line marks most of the route, which cuts across Dobbins ARB. The first stop is a fuel tank flushing facility. The fuel system is flushed ten to twenty times with JP-8 through a range of filters, from coarse to fine. "The process once required more than 100 flushes to get a fuel system completely clean," says Nash. "We managed to reduce that to about thirty flushes by changing the cleaning process for the fuel tanks here on the assembly line. We implemented those same procedures for fuel tanks assembled in Fort Worth and Seattle."
Once the fuel system is deemed spotless, the Raptor is loaded with fresh fuel and towed to an engine run station. The aircraft is tied down and the engines are cycled for roughly an hour from idle through afterburner. The auxiliary power unit is tested here as well. The Raptor is now ready to fly.
The first two or three flights of every Raptor are typically company test flights. The first flight, which focuses on basic airframe systems, lasts a little over an hour. The flight profile takes the Raptor in and out of afterburner to a top speed of Mach 1.5 and to a maximum altitude of 50,000 feet. It includes pressurization checks, a military power, or nonafterburner, climb to 30,000 feet, aerial refueling checks, auxiliary power starts, engine airstarts, engine transients at various altitudes, landing gear warning checks, and instrument landing system tests.
The second flight focuses on avionics, including autopilot, weapons, communication, navigation, identification, and electronic warfare systems. The Raptor is kept to about 20,000 feet on this flight profile. While the aircraft is not taken to supersonic speeds, it is flown at high angles of attack. The test pilot also performs symmetry, g-limiter, and trim checks.
Once all the company flight tests are passed, the Raptor goes through an extensive final coating process. Its stealthy properties are verified in an anechoic chamber. The airplane is then handed over to a government test pilot for two or three more flight tests with profiles similar to those flown by company test pilots. Once these tests are passed, the government formally accepts the airplane. An Air Force pilot from the receiving base flies the Raptor to its new home.
Customer Confidence
The current production run for the F/A-22 is somewhere between 250 and 300 aircraft, depending on who is doing the cost projections. "We can affect our own destiny on the overall production number," says Mike Packer. "We help the cause by being more efficient and producing higher-quality aircraft at lower cost."
Seventy percent of the material, parts, and components come from outside Lockheed Martin, so Packer and his team can generate only a certain amount of savings directly. "But we can identify a lot more by virtue of being the prime contractor," he says. "Suppliers have to gear up their production to support our 9.6-day move rate as well. We are also looking at multiyear procurement approaches that afford suppliers more stability, which in turn lowers prices."
Aside from economic considerations, the Air Force continues to express its confidence in the program. "From the secretary of the Air Force, the chief of staff, and the general officers who are accepting the hardware down to the pilots and maintainers who are using the hardware, all are communicating their satisfaction to us and to our supply base," Packer says. "This builds confidence in the program."
"Every time a Raptor rolls out the door, word comes down the line," says Worley. "Seeing a new one fly for the first time still attracts a crowd. Every time I see a tail number in a photograph, I recall working on that particular aircraft. People care about the program and we all want to do a good job."
Eric Hehs is the editor of Code One.
