Maintenance Simulators Gaining Military Acceptance

Returning from a mission in Iraq, the F/A-18 approaches the stern of the USS Nimitz, an aircraft carrier churning through the Persian Gulf. The warplane’s tires squeal as it drops to the deck, at a speed of 150 knots. As soon as she touches down, the pilot jams the throttle forward, so that she can take off again, just in case the tail hook doesn’t catch. When the tail hook does catch, the 50,000-pound warplane jerks to a stop in 340 feet.

It’s business as usual on a U.S. Navy carrier, as is featured in the engaging 10-hour PBS mini-series "Carrier." Our carriers which can project devastating U.S. air power practically anywhere on earth.

While "Carrier" chronicles the life stories of the young sailors on carriers, we have taken a look at how the Navy trains training of one segment of the carrier’s enlisted people — the military technicians who maintain the F/A-18s.

Maintaining Carrier-Based Warplanes

F/A-18s are some of the most powerful, versatile and deadly warplanes in the world, capable of both bombing and fighter missions. Supremely maneuverable and capable of speeds of more than Mach 1.7, the Thunderbirds use F/A 18s to perform at air shows.

Frequent combat missions, short landings, and catapult takeoffs are hard on carrier-based aircraft, as well as on the pilots. In fact, every morning, a search party assembles on the flight deck to clear the runways of metal parts and pieces.

Keeping high performance carrier-based combat aircraft ready to fly is among the most extreme aircraft maintenance challenges in the world. Especially in war time, there is only a small margin for error.

And who maintains these fearsome, expensive warplanes? Well, as with other jobs aboard the carrier, the people who perform the aircraft maintenance are mostly kids, just out of high school, who have about six months of training. Few of these trainees have worked on maintaining cars, much less on fighter-bombers that cost between $30 and $60 million per aircraft. As the "Carrier" series documents, many come from troubled backgrounds.

The Navy’s Mx Training

How does the Navy perform the amazing feat of training its young, enlisted people to do this exacting work?

One key is specialization. There are seven primary specialties, including aviation and weapons systems; aviation communication/navigation systems and wiring maintenance; propulsion system maintenance; structural and hydraulic system maintenance; and ordinance loading and unloading. And each technician specializes in maintaining either in the Legacy Hornet or the newer Superhornet version of the aircraft.

Another key is giving them training time on a computer simulator, the Simulated Aircraft Maintenance Trainer, or SAMT, with its sophisticated interactive graphics software.

The length of training varies according to specialty. For instance, training to maintain the Legacy Hornet requires the following number of days training:

• Structural and hydraulics — 89 days

• Propulsion system — 71 days

• Avionics and weapons systems — 185 days

• Communications and navigation maintenance — 149 days

• Ordinance loading — 65 days

After completing training, technicians typically work in the field for three years. About 90 percent of the technicians who re-enlist stay in the trade.

The training starts out with "A-school," which teaches basic aviation and troubleshooting theory. "A-school" resembles high school or college — students listen to lectures and powerpoint presentations and read books and manuals. Then, trainees move on to the simulator stage, training on SAMTs located in Oceana, Va. or Lemoore, Calif. Work on the simulators takes advantage of the recruits’ experience with computers and computer games. Ultimately, after the simulator training, the students complete their training on real airplanes.

Training Using Mx Simulators

The SAMT has two elements: a physical cockpit simulator and a virtual F/A-18 (including a virtual cockpit) displayed either on two 61-inch touch screens or a PC. The realistic virtual elements appear to be three dimensional. The trainer is interactive, like a video game. A student can engage in "natural navigation" by moving in virtual space. As the student moves in virtual space, he or she views the virtual cockpit or aircraft in three dimensions from the perspective of the point he or she has moved to.

American Systems Corp. developed the SAMT and delivered it to the Navy in 2006, while a small Orlando, Fla.-based training simulator firm called DiSTI subcontracted to provide the key interactive graphics software. The Finnish Air Force later bought an enhanced version of the SAMT to train its F/A-18 maintenance technicians.

The SAMT, which can train two mechanics at once, also has an instructor-led operator station. The instructor creates the maintenance situation, assigns tasks, and tracks the students’ responses. A second safety instructor also monitors the student’s actions to make sure he or she doesn’t do anything in cyberspace that would pose a danger to the student or other crew members in real life. The Navy has a repertoire of 451 canned SAMT exercises and can custom make any other situations it wants.

A student training to work on the Hornet typically spends 80 to 90 hours performing tasks on the SAMT. The student can sit in either the physical simulator SAMT cockpit or in the digital cockpit displayed on the computer screen, read its simulated instruments and manipulate its contents and controls in real time as he or she tries to diagnose the aircraft’s condition and complete maintenance tasks. The student can also "walk" around the virtual aircraft, open aircraft compartments, attach simulated test equipment, diagnose faults, remove and replace equipment and see how the SAMT’s virtual mechanical systems respond in real time. For instance, a student could open the nosecone and remove the components needed to take out the entire radar array.

The computer screens can also create multiple views of the aircraft, allowing the student to perform tasks that require simultaneous access to more than one area of the F/A-18.

Computer simulating training is also common for technicians servicing domestic aircraft. According to Damian Szigeti, engineering manager for American Systems, domestic fleets that use computer simulation training typically reduce their training costs by 30 to 60 percent.

Graphics of the SAMT

The sophisticated graphics software provided by DiSTI simulates the virtual cockpit, body, controls, the avionics, electrical, fuel, engines, flight control, hydraulic and armament systems of the F/A-18.

While the U.S. military has been using computer simulated training for years, DiSTI’s Chris Giordano contends that the graphics of the F/A-18 SAMT are more realistic than the graphics in other maintenance trainers used by the military. He says that other military training devices tend to be less sophisticated tools that simply contain hot points that bring up a photo or video clip, with interactivity limited to certain angles or views. On the other hand, the 3D interactivity with graphical elements generated through GL Studio is fully interactive and immersive.

The Navy, which has a policy of not endorsing products, refuses to comment on the relative efficacy of the SAMT or DiSTI’s training software. On the other hand, the fact that Lockheed Martin recently awarded DiSTI a subcontract to provide graphics software for the maintenance training simulator for the new F-35 program suggests that Lockheed Martin and the Defense Department prefer the F/A-18 SAMT’s graphics software to the products of its competitors.

Founded in 1994, DiSTI specializes in human-machine interface training simulation software. Headquartered in Orlando, Fla., the firm has 30 engineers and generated annual revenues of about $3 million in 2006. DiSTI has more than 400 customers, including global firms like Boeing, Raytheon, Lockheed Martin, Honeywell, BAE, Dassault, and Thales.

While DiSTI is well-known for providing simulation training software for both civilian and military training for pilots (e.g., instructor operator stations for the A-10 and F-16 cockpits), as well as training for military vehicle mechanics, the Navy’s F/A-18 SAMT was the first simulation product DiSTI designed to train aircraft maintenance technicians. Now, DiSTI’s software will train F-35 aircraft maintenance technicians, as well as the Navy’s F/A-18 technicians and the Finnish Air Force.

In the late 1990s, DiSTI’s GL Studio began developing an in-house computer simulation tool to perform military contracts. GL Studio is DiSTI’s flagship product for developing real time, three-dimensional human-to-machine interfaces for use in computer based training, maintenance and part task trainers and full mission simulators.

GL Studio generates code using OpenGL for graphics deployment (http://222.opengl.org/), an open graphics library that runs on every operating system. According to Giordano, OpenGL’s rich, real-time 3D interaction is ideal for developing training simulator software. OpenGL graphics are very efficient, according to Giordano; they draw quickly and can easily be managed from a programming standpoint.

Most of DiSTI’s competitors use DirectX for graphics deployment, which will only work on Windows-based systems. The GL Studio tool kit can generate human readable C++, Java and Safety Critical Embedded C++, while most of DiSTI’s competitors use proprietary scripting languages that people can’t read.

Today, according to Giordano, 3D simulation training products of DiSTI’s GL studio are everywhere. Major contractors use GL studio products to develop cockpit procedure trainers, instructor operator stations and maintenance training, prototyping detailed multi-functional display electronics. GL Studio products are even embedded into real avionics devices.

DiSTI’s Simulation Software

According to Giordano, GL Studio products have two main advantages over the simulation training software of DiSTI’s competitors: First, DiSTI’s GL Studio products are more versatile than other products; the software can be reused for other functions. Second, DiSTI’s software is more realistic and interactive than other products with canned or scripted animations.

DiSTI purposely designs GL Studio products to be versatile by building each component in its design file in a modular format so that the customer can easily reuse it. DiSTI calls these modules "Reusable Software Objects" or "RSOs."

For example, if the Navy developed another training program involving the landing gear of the F/A-18, it could use DiSTI’s maintenance trainer’s existing landing gear component, with all of the information about how the landing gear works already embedded in the object, for the new program.

GL Studio products are also versatile because people can read their source codes. Instead of getting "stove piped" by products with proprietary scripting languages, customers can integrate DiSTI products into any training simulation environment. In fact, according to Giordano, some customers integrate DiSTI GL tool kit products into competitor’s simulation environments.