Aerial maneuvers: upgrades will keep F-15's, F-16's in combat for two more decades.

Boeing's F-15 Eagle and Lockheed Martin's F-16 Fighting Falcon are dueling, if not in the sky, then in the marketplace. Both companies are actively selling their jet fighters at home and abroad.

To keep the legacy fleets flying for another 20 years, the Defense Department and the fighters' overseas customers have a long list of upgrades in the works. Despite the arrival of the F-22 Raptor and the development of the F-35 joint strike fighter, production of the older fighters continues.

"They're so far up the production curve that building them is pretty cost effective," said Richard Aboulafia, an analyst with the Teal Group. "They come with attractive price tags and modern systems."

For the F-15, upgrades are divided into two categories, one set for the A through D models built in the 1970s and early 1980s, and a second for the F-15E Strike Eagle introduced in the late 1980s, said George Spencer, director of the U.S. Air Force's F-15 Systems Group.

"Our whole objective is to keep the Eagle viable past 2025," Spencer said at an Institute for Defense and Government Advancement conference. There are currently 224 Eagles in the U.S. fleet. "We look at what we can afford, as well as what's going to give us the most bang for the buck," he added.

Upgrades to the aircraft's sensor arrays top the list, he said.

The active electronically scanned array (AESA) is replacing the APG-70 radar. AESA allows a pilot to track and target multiple targets.

Advanced processors will replace on-board computers. The tenfold increase in computing power will help pave the way for the F-15E to drop a new weapon now in development by the U.S. Air Force, the small diameter bomb. Further computer upgrades will be added in 2009 and 2012.

"We need that speed and memory in order to make this happen," Spencer said, adding that "AESA gives us a significant amount of lethality." The goal is to "put bombs on targets faster."

The upgraded computers will allow the F-15 to integrate new weapons systems more efficiently, and "that's going to be a significant cost advantage for us," Spencer said.

The Eagle can carry almost every type of ordnance, totaling 23,000 pounds on each aircraft. It can carry three GBU-28, 5,000-pound bunker busters and will be capable of loading 28 small-diameter bombs. This kind of flexibility makes the F-15 special, Spencer said.

The program receives between $300 million to $400 million per year to spend on upgrades, a figure that has been stable over the years, Spencer said.

A projected enhancement for the F-15 in the next two decades is an improved capability to shoot mobile targets. "They're not going to sit there and let us shoot them. They're going to be moving around on us," Spencer said. The question is, "what can we do to defeat those mobile targets?"

As for the older models, Spencer said he expects the Defense Department to retire some of the A through D series aircraft with some of the Cs moving to National Guard units. Upgrades to these early series aircraft will include new computer and cockpit displays.

The joint helmet mounted cueing system, built by Vision Systems International LLC is being installed in C through D models. The display gives pilots a greatly expanded view of their target areas. "As they say, 'first shot, first kill,'" Spencer said.

Also on the wish list is a better radar system, one that will enable all-weather targeting. It would increase the F-15'S range in air-to-air and air-to-ground modes, Spencer said.

The Air Force is also exploring ways to transfer sensor data through its Link 16 airborne network. Demonstrations have already been carried out, he said. The "sensors forward" concept calls for an F-15 to gather imagery and send it to an air operations center where it can be fed to others. "That will give our combatant commanders a great ability to understand what's going on in the battlefield, and then make decisions on what they want to target."

In a Defense Advanced Research Projects Agency-led demonstration, an F-15 passed streaming video to the Pentagon through Voice over Internet Protocol, and ground operators were able to communicate directly with pilots.

The Air Force has also demonstrated the ability to take control of an unmanned aerial vehicle from an F-15, Spencer said.

Both the F-15 and the F-16 upgrades feature the Sniper XR (extended range) advanced targeting pod. Reviews for the system, selected as the third generation of targeting pods for jet fighters, have been glowing, said Col. Scott Jansson, commander of the F-16 systems group.

"The pilots just couldn't say enough about the significant capabilities Sniper brought to the fight," Jansson said. The pods contain sensors and video cameras that relay data to the pilot's cockpit display screen, and in turn, boost their ability to launch smart munitions, especially under adverse weather conditions.

Another pod, called Litening, has been fielded on the Block 30 models and will soon be mounted under Block 40s. They're "being used over Iraq to help coordinate targets with forces on the ground," Jansson said.

The F-15E Strike Eagle will be the first aircraft to drop the small-diameter bomb, which was designed to operate from a range of 60 nautical miles and to hit its surveyed target within an average of four feet. Operational tests will begin by the middle of this year. The F-16 is scheduled to add the bomb to its arsenal in 2012, Jansson said.

Like the F-15, the Air Force and Boeing intend to keep the later models of the F-16 flying into the mid 2020s or beyond.

"Even though we're legacy platform, there's a lot of investment still going on with the F-16, because the F-16 is going to remain a critical part of the USAF infrastructure way beyond 2020," Jansson said. Avionics upgrades will make the aircraft more lethal and survivable, he added.

The AN/ASQ-213 high-speed anti-radiation missile (HARM) targeting system pod has joined the Sniper, giving the Fighting Falcon the ability to suppress surface-to-air missiles. The smart targeting and identification via networked geo-location (STING) upgrade to the HARM system will be fielded in April 2007.

Even with the STING upgrade, there are still weather-related limitations to suppressing enemy air defenses, Jansson said. A synthetic-aperture radar, to be fielded in September 2009 on the Block 50 aircraft, will give air-to-air and air-to-ground modes auto-target recognition and cueing ability. It will feature a 2-foot by 1-foot point targeting resolution capability and an increased range.

Link 16 will be used hand-in-hand with HTS-STING to provide precise target location. "It will really enhance our ability to destroy, rather than just suppress, enemy air defenses," Jansson said.

Aboulafia said these advanced sensors and targeting pods have rejuvenated both aircraft. The flexibility to mount different weapons and improvements to turbine technology cannot be ignored either. Their engines have evolved from 19,000 to 30,000 pounds of thrust during the past two decades, he noted. "That's a lot of power."

Fighters' Foreign Customers Add to Mix

While it's well known that foreign buyers of the F-15 and F-16 jet fighters are helping to keep the production lines open, some of these customers are also helping boost the development of the aircraft, according to managers of the two programs.

"It's still surprising to a lot of folks that ... we have a very active production line" at Lockheed Martin, said Col. Scott Jansson commander of the Air Force's F-16 Systems Group.

There is a backlog of 150 aircraft being built for foreign customers as of November, he said. Twenty-two countries fly the F-16, with Chile and Poland expected to join their ranks this year. He anticipates a market for another 200 to 300 aircraft.

"It used to be said that the sun doesn't set on the British Empire, now it can be said that the sun doesn't set on the worldwide F-16 fleet," Jansson said.

Improvements have been made to the F-16 radar-known as the (v) 9-with the help of Greece and Israel. The two countries paid for the radar's development and have fielded it on 100 aircraft. The U.S. Air Force in turn is making some additional modifications to its (v) 9s, Jansson said.

The United Arab Emirates has been active in the development of the Block 60 version of the aircraft. It can collect a $3 million per aircraft royalty on every unit Lockheed Martin sells to a non-U.S. buyer.

"[These countries] have been able to take advantage of development and investments that the U.S. and other countries have made ... We've just got to turn it around for a change and we appreciate the help," Jansson said.

George Spencer, director of the U.S. Air Force F-15 systems group, said Boeing and its foreign customers have similar synergies.

"We take that into account what others are doing--our international partners--as well as the F-18 and F-35 programs," Spencer said.

The foreign customers are Japan, Israel, South Korea and Saudi Arabia. Singapore announced in December that it will become the sixth country to fly the aircraft, placing an order of 12 F-15SGs, with an option for another eight. The order is expected to keep the production line open until 2008, and possibly 2010.

As for how long Boeing and Lockheed Martin can keep their respective lines open, Richard Aboulafia, an analyst for the Teal Group, said it is hard to see a future past the end of the decade.

The F-15 might get a boost from a follow-on order of 20 to 40 from South Korea, he said. "Beyond that, there are probably not a whole lot of prospects."

The F-16's future is murkier. Orders begin to run thin after the next couple of years, he said. It will come down to potential orders from India, Pakistan and follow-on buys from other customers.

"The key thing from Lockheed's perspective is to stay in the export fighter business until the [joint strike fighter] starts getting built in quantity."