The Modernized ‘Herc’

By James W. Ramsey | July 1, 2000
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It first flew nearly a half century ago, in 1954, yet its new cockpit could make the pilots of modern fighters and bizjets near green with envy. Lockheed Martin has transformed the versatile C-130 Hercules tactical transport with an ultra-modern, two-crewmember, glass cockpit and avionics suite.

Now designated the C-130J, the modernized workhorse has been operational with the UK’s Royal Air Force since last February. Lockheed Martin has delivered more than 50 C-130Js to the UK, Australia, and to the U.S. Air Force, Marine Corps and Air National Guard. Forty more aircraft are on order, including 22 for the Italian Air Force. Other potential customers include Denmark and Kuwait.

C-130Js are being delivered to the RAF (where they are designated Hercules C. Mk 5) at the rate of one every three weeks until the full contingent of 25 aircraft are on the ramp at RAF Lyneham, the Royal Air Force Strike Command’s main Hercules operating base near London. In addition to 10 standard-length C-130Js, the RAF, launch customer for the J model, will be receiving 15 of the stretched C-130J-30s, which is a capacious 15-feet (4.57 meters) longer. RAF has an option to buy an additional 25 new-model Hercules to replace the remainder of its older C-130 fleet.

The U.S. has 35 aircraft on contract, including the standard transport and other C-130J variants. USAF has a stated requirement for at least 168 aircraft over the next several years, according to Lockheed Martin.

New Cockpit

The C-130J’s cockpit includes dual Flight Dynamics head-up displays (HUDs), four 8-by-11-inch (20.3-by-28-cm) color liquid crystal displays (LCDs), dual mission computers, and GPS/inertial navigation (GPS/INS). Its Mil-Std 1553B databus architecture provides high-speed data communications and integrates avionics and other systems.

Such automation allows the J-model to be operated by two pilots; it eliminates the need for a flight engineer and navigator, while increasing mission effectiveness. In fact, Lockheed Martin maintains that the central mission computer can automatically secure a failed engine. And, among other missions enhanced by the new cockpit is all-weather airdrop capability.

The HUDs are certified by the Federal Aviation Administration (FAA) as the C-130J’s primary flight displays, an industry first, according to Arlen Rens, C-130J pilot at Lockheed Martin’s Aeronautical Systems Division, in Marietta, Ga. Why obtain FAA certification? Rens explains that the aircraft was developed as a private venture, not by the Air Force, so civil certification was required in lieu of military qualification.

Where most aircraft would have their panel-mounted primary display, the C-130J presents either a digital moving map or radar–in either weather or ground-mapping mode. Next to this screen would be one that usually shows engine instruments. The third of four Avionics Displays Corp. vertical screens on the J-model can depict aircraft systems, such as hydraulic or fuel, or be used for ground map or radar. The copilot can choose whatever display he wants on the fourth LCD.

Splitting Displays

The radar display from the aircraft’s Northrop Grumman Modar 4000 radar can be split. "I am at 200 feet and want the ground mapping mode on the pilot’s side, but down in Ecuador, we are having lots of thunderstorms, so the copilot can be on the weather mode," says Rens, offering a split-mode scenario. "We get both displays out of one radar at one time."

The weather radar also provides wind- shear warning, giving an aural alert in the headset and visual warning on the HUD. The Honeywell navigation system combines a GPS receiver with a ring laser gyro, inertial nav system. It’s accuracy can be measured in inches. Rens reports that on a nonstop flight from Hawaii to Atlanta, accuracy at shutdown was less than half a foot error.

The C-130J has an enhanced traffic alert and collision avoidance system (TCAS), which was once made by Honeywell, but because of the manufacturer’s merger with AlliedSignal, was sold to L-3 Communications (see Avionics Magazine, May 2000, page 10). It provides both advisory and resolution for traffic avoidance that can be called up on the head-down navigation display.

Plus, the J-model’s Doppler-based radar can go into a "skin paint" air-to-air mode, similar to that of a fighter, "painting a potential intruder as a primary target," Rens adds.

Rapid advances in LCD technology are expected to give the C-130J systems a healthy 8,400 hours mean time between failure (MTBF) rate. With an average military aircraft-utilization rate of 500 to 600 hours yearly, the systems would not require replacement for 14 years.

In Full Control

Mounted on the glare shield below the HUD are the five 2.5-by-4 inch (6.35-by-10.2-cm) control display units. They allow the pilot not flying the aircraft to control all the displays–staying head up–and to select whatever the pilot chooses.

"If I’m sitting in the right seat, and the pilot wants this nav system, I can feed him that," Rens explains. "By pressing buttons I can select which display I want to manipulate and then do it. The display will show up on his HUD or whatever LCD he wants it on.

"On the center display unit is the com nav breaker panel," the Lockheed pilot adds. "I can tune all communications or navigation radios, and, more importantly–a first–I can open or close any circuit breaker."

Rens maintains the C-130J is a step ahead of any other transport aircraft, attributing this in part to Lockheed Martin’s experience in designing and building advanced aircraft such as the F-16 and F-22. Systems developed for advanced fighters are benefiting the C-130J, he maintains.

Development of the C-130J cockpit began in the early 1990s, leading to the aircraft’s first flight in April 1995. The modernized "Herc" was developed as a software-driven aircraft with continuous software upgrades for increased reliability and reduced pilot workload, says Rens.

As contrasted with other modern aircraft, such as the USAF’s C-17 Globemaster airlifter and Boeing’s 777 commercial airliner, the C-130J has two mission computers instead of three, and they operate synchronously, Rens explains. If one fails, the other is already up and running; no noticeable change exists except for an advisory to the crew that one computer has failed. On the C-17 and triple-7, the two most comparable computer readings are used, and the third reading is dropped. This indicates which computer may be faulty, and it causes a noticeable but only slight change of heading.

Precision Approach

For the U.S. Air Force, a system is being developed to provide a precision approach capability wholly from on-board avionics. It is said to offer instrument landing system (ILS)-like accuracy. Called IPRA (independent precision radar approach), this capability will allow the C-130J to land in marginal weather conditions at airfields without sophisticated ground landing systems. By providing latitude and longitude of the intended touchdown zone, the mission computer can fly the aircraft down to Category II minimums (100-foot altitude, 1/4-mile visibility) without ground radio equipment.

The C-130J is also night vision goggle (NVG) compatible. And, like the C-17 strategic airlifter, the new Herc has a SKE (station keeping equipment) automated formation positioning system. Using the HUD for guidance and engaging the autothrottles, the system helps to automatically position and maintain the aircraft in formation, eliminating much of the pilot’s workload.

The J-model also features an integrated diagnostics system (IDS) that monitors 7,300 system test points and displays. It notes advisories, cautions or warnings, and is accessed after landing via the computer screens on the aircraft’s glareshield. The IDS records and tells maintenance technicians everything that occurred to the airplane systems during flight and helps determine what support action to take.

The Diversified Herc

Lockheed Martin admits to being late in delivering some aircraft, but points out that unlike the C-17, whose only customer to date is the USAF, the C-130J has seven customers all requiring different equipment. While the United States uses Rockwell Collins radios, the RAF version has Marconi radios made in the UK. The Italian version uses Elmer combined U/VHF multiband radios, and its integrated defense system includes missile warning, radar warning, and laser warning. The Italian variant also will be the first C-130J "receiver tanker," with the ability to refuel other aircraft, as well as be refueled itself, in flight.

C-130J missions range from those of the traditional tactical airlift C-130J transports being delivered to the Maryland Air National Guard at Baltimore’s Martin State Airport to the WC-130J hurricane hunter–which has already been used at Keesler AFB, Miss.–and the KC-10J aerial tankers for the Marine Corps. C-130EC versions are being delivered without special mission equipment, which will be provided after delivery from Lockheed Martin’s Skunkworks.

All of these missions represent a heavy workload for an airframe that is nearly a half-century old.

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