Defense Media Network

Interview with Frank W. Pace, President, Aircraft Systems Group, General Atomics Aeronautical Systems, Inc.

The UAS pioneer discusses unmanned heritage, unmanned future

Frank W. Pace is president, Aircraft Systems Group (ASG), General Atomics Aeronautical Systems, Inc. (GA-ASI). His group manufactures, supports, and operates a variety of proven and reliable remotely piloted aircraft systems for worldwide military and commercial applications. Pace spearheaded the conceptualization, development and delivery of Predator A and Predator B Reaper to the U.S. Air Force; Gray Eagle to the U.S. Army; Predator C Avenger; and is developing the Sea Avenger for Navy carrier operations. Prior to joining GA-ASI in 1991, Pace served as vice president and principal systems engineer for Leading Systems, Inc. There, he managed the Amber unmanned aerial vehicle (UAV) contract. Amber morphed into GNAT and GNAT into Predator, with a 40-hour flight endurance. Pace was inducted into the Hall of Fame for Engineering, Science and Technology in 2002. This honor recognizes his work in developing and promoting UAVs. He holds bachelor’s degrees from the University of California, Irvine in mathematics and computer science, and a master’s degree in computer science from UCLA.

Pace recently took time for a wide-ranging interview with Defense senior writer Clarence A. Robinson, Jr. His responses delve into today’s UAVs and future applications of unmanned aircraft.


Clarence A. Robinson, Jr.: You were at Leading Systems and then GA-ASI from the beginning. The Predator and its variants are a real success story. It seems the attitude has been “if you build it, they will come,” with the company designing and producing a medium-altitude long-endurance unmanned aerial platform with enormous growth potential, and then making it available to the government. Did this approach greatly reduce the development and production cycles and therefore costs?

Frank W. Pace: A lot of what happened was having the right system at the right time. We received the initial Predator contract in 1994 and made the aircraft available to the customer in 1995, flying it in theater 18 months after contract award. While Predator was successfully deployed and operational, little attention was directed at this unmanned platform until the September 2001 terrorist attacks. After 9/11, Predator demands and growth were explosive, as the company went from 500 to 5,000 employees, keeping pace with production orders. It almost immediately became obvious that Predator was the aircraft of choice for asymmetric warfare, doing what it does best – intelligence, surveillance and reconnaissance [ISR] in real-time. It also grew into other roles, but always with ISR functions foremost.


When General Atomics acquired Leading Systems and its Amber/GNAT aircraft, what did that entail in terms of people and aircraft? Also, Turkey had bought GNAT 750s. Had those aircraft already been delivered prior to the Leading Systems acquisition?

GA never really acquired Leading Systems. Instead, it acquired its assets – jigs, tooling, airframes – and brought over some 10 people from Leading Systems to form the nucleus of Aeronautical Systems. I was one of those people.

GA-ASI ended up with six GNAT 750s in various stages of build-up. Two UAVs were ready to fly and the others were in lesser levels of assembly, mostly fuselages without installed avionics or engines. The GNAT 750-45 became the Predator. The Turkish air force operated with six GNAT 750s and 16 improved GNAT variants, with some still in service.


The GNAT 750-45 that became Predator A and its larger, more powerful ground attack Predator B Reaper brother have matured as aerial platforms and figured prominently in headlines during combat operations in Iraq, Afghanistan, Pakistan, Bosnia, Serbia, Yemen, Libya, and Somalia. What are the cumulative flight hours for these vehicles?

Predators have flown more than 1.5 million flight hours as of late July 2011. Installing a satellite communications antenna initially atop a GNAT 750 and then into Predator’s nose really changed the whole ballgame, creating a true military revolution for remotely piloted vehicles.

UAVs could now loiter for days over a battlefield transmitting imagery, while controlled from thousands of miles away.


What lessons have been learned that may have led to some Predator modifications, if any?

Lessons learned are almost too many to tally. The Rotax 582 engine powered the GNAT 750. This is a 64-horsepower, two-stroke, two-cylinder, rotary intake valve, liquid-cooled, gear reduction-drive engine. It was initially designed for use on light sport and ultra light aircraft. We then installed the Rotax 912 engine in the GNAT 750. Predator also had the 912; however, it was not turbo charged. This engine uses air-cooled cylinders with water-cooled heads and a gearbox to reduce the engine’s relative high shaft speed to a lower speed for the propeller. Later, we installed the Rotax 914, a turbo-charged, four-cylinder, horizontally opposed aircraft engine with air-cooled cylinders and water-cooled cylinder heads. Installation of the 914 was the single biggest change we made, along with a much more efficient propeller. This system provided 3 kilowatts of power and was non-redundant. We now have a redundant system on Predator A that offers 5 kilowatts of power.

What other refinements took place in an emerging Predator platform?

Servo actuators, especially in the tail assembly, had to be replaced about every 100 flight hours. The servos are now up to 400 flight hours without replacement. The tail section was also modified, reducing vibration as the propeller went by. Less vibration also helped increase servo mean time between failures and thus flight hours. The mission readiness rate for the fleet is at 90 percent.


Have there been other significant changes to the unmanned aircraft system?

We have continually improved the ground control station [GCS] over time. Display screens have been added to better tie the aircrew in with the outside world while flying Predator, instead of only a narrow-view aircraft cockpit with instruments and sensor displays. In addition to the pilot, a sensor operator flies missions that enable the aircraft to fly up to 400 nautical miles and loiter over the target area for up to 14 hours before returning to base.

There are two versions of a new Predator cockpit. The Block 30 version will be available in about a year. This new cockpit will integrate displays and sensor systems into a vastly improved form, fit, and function, with modest human-machine interface improvements. A more advanced Block 50 version, to be fielded in 2014, will have an all-new graphical user interface, provide touch screens, surround situational awareness, new software, and state-of-the-art graphics.


Are you using the same logic for the ground control station as with the remotely piloted vehicle: you build it with huge growth potential knowing customers will come and buy it?

There is an element of that with the Block 30 GCS. GA-ASI built it up, showing it to customers, but without all the technical engineering drawings and specifications to take it into production. We built the prototype with our own money. We actually worked on the Block 50 for three years using internal research and development funds; however, the customer offers a lot of very helpful GCS input. We never intended to take it all the way to final product on our own. The first half of the Block 30 we funded ourselves. Approximately the first one-third of the Block 50 was completed with company funding.


How do these GCS improvements affect the use by the various services?

The Army operates the Gray Eagle GCS in a different manner. With their operational concept, the pilot, who is not necessarily a rated aviator, pushes a button to take off and a button to land. These functions are preprogrammed into the air vehicle. During flight, the GCS crew can either fly programmed waypoints or control the aircraft using the stick.

The Army uses a single design Gray Eagle GCS manufactured for GA-ASI by AAI, Hunt Valley, Md. The Air Force has all the options: Their aircrews either can use the stick and throttle or fly programmed waypoints. Typically, when engaging targets with weapons, the Air Force likes the flexibility of having positive control of the system rather than automated preprogrammed maneuvers.


What are major differences between the Army’s Gray Eagle version of Predator and Predators A and B?

In a competitive program, the Army selected Gray Eagle in August 2005. This UAV is more capable than the Predator A but less capable than Predator B Reaper. A $214 million system development and demonstration contract to GA-ASI set the stage for procurement of 11 Gray Eagle systems, each with 12 airplanes and five ground control stations.

Operational in 2009, the Army integrated the Hellfire missile system within a year, weaponizing four aircraft and deploying them to Afghanistan. Gray Eagle operates at more than 30 hours with speeds greater than 135 knots and up to 29,000 feet. A more reliable airplane, this UAV also uses heavy diesel fuel that can be found on the battlefield for use with Army vehicles, such as the High Mobility Multipurpose Wheeled Vehicle, as opposed to 100-octane aviation gas. The Predator A is 105 horsepower and the Gray Eagle engine generates 160 horsepower. The Gray Eagle carries four Hellfire missiles or 600 pounds of payload. Hellfire is the Army’s [munition] of choice.


How do the applications of the Army platform differ from the Air Force Predator/Reaper?

The aircraft is equipped with a synthetic aperture radar/ground moving target indicator. This long-range, long-dwell-time UAV is designed for operational control by Army field commanders. Its expansive mission set includes, but is not limited to, wide area ISR and improvised explosive device [IED] detection and defeat, close air support, communications relay, and weapons delivery missions. Gray Eagle is the largest size UAV that could be boxed and placed on a trailer for movement around the battlefield, meeting Army mobility requirements. The aircraft needs a runway but can take off and land from cleared roadways.


What is the production and delivery status of Gray Eagle?

GA-ASI is in the middle of building low-rate initial production aircraft. The first 17 UAVs were built under the original contract and another eight were procured. We have delivered almost 40 airplanes to the Army. As an aside, the Air Force has halted Predator A production and we are approximately a quarter of the way through the Predator B production run. The Air Force anticipates buying additional Reapers for another five years.


Is it true that the Army intends to operate Gray Eagle with non-rated personnel using a track ball system much like a video game rather than a stick and rudder arrangement? Please discuss in detail.

Army non-pilot personnel will fly the Gray Eagle. However, they receive extensive training, not only to fly the UAV and control sensors and weapon systems, but how to operate during an Instrument Flight Rules [IFR] environment to meet strict Federal Aviation Administration [FAA] standards. You can’t just take a soldier who carries a rifle and put him or her in the GCS to fly a Gray Eagle. The training is comprehensive.


Have Predator/Reapers been sold to allied nations that also operate the unmanned aerial systems as part of NATO forces in Afghanistan? If so, are there any changes to the flight vehicles to meet foreign requirements? How many hours have these aerial vehicles flown in combat?

Italy procured both Predator As and Bs and the United Kingdom operates only Predator Bs. Both nations are flying the aircraft in combat in Southwest Asia. State Department foreign military sales regulations have precluded deliveries to other nations. Tens of thousands of flight hours have been accumulated with Predator A and B by both Italy and England. A different radio was installed on Italy’s Predator.


Is it true that in Iraq a Predator armed with Stinger air defense missiles engaged an Iraqi MiG-25 in aerial combat, firing at the Foxbat? Please describe the engagement and the outcome.

This is accurate. There was some tit for tat going on in Iraq. Several days earlier, the Predator GCS crew spotted an Iraqi MiG aircraft in the area. Afterward, the Predator was armed with Stinger missiles, not an optimum weapon for air-to-air combat; however, they fit on the aircraft and could be launched in self-defense. We are pretty certain the Iraqi MiG-25 was detected before the Foxbat pilot saw the Predator. The problem is that the Stinger didn’t have sufficient range or closing speed and the Iraqi aircraft had much better missiles. The MiG-25 carries two radar-guided AA-6 Acrid and two infrared-guided R-40T missiles. We saw the missile coming and it struck the Predator A. If we had the Predator B and perhaps a better missile system, we believe we could handle our own in that scenario.

The Foxbat was still out of Stinger’s range when [the] Predator fired but we thought we would give it a try anyway. The whole engagement was recorded and has been studied for the enemy’s concept of operations and for lessons learned.

Predator can only carry 125 pounds on each of two hard points. However, the Predator B can carry a total of 3,000 pounds of weapons. A typical load for the Reaper is two 500-pound bombs and four Hellfire missiles. The B could accommodate radar-guided air-to-air missiles, if required. Nevertheless, extensive modifications would be necessary.


Amber/Predator at one point was to be designed for launch from a torpedo tube of a submarine. What changed this concept?

Amber, not Predator, was initially designed for launch in a canister from a box launcher to self-deploy, simultaneously providing many UAVs for ISR over wide areas of a battlefield. Batteries would fire Ambers from box launchers, filling the sky with 20 to 30 aircraft. This aerial platform also could be launched in a canister from a submarine’s torpedo tube. Amber’s design had provisions for a pivoting wing mounted on a pedestal atop the fuselage. The tail and propeller blades also folded to fit inside a canister. This was an early concept of a Defense Advanced Research Projects Agency [DARPA] program. This canister design was never flown. Predator is more like the GNAT 750, with wings mounted on the fuselage. There was never consideration of Predator being fired from a torpedo tube or box launcher.

Is it true that Predator, flying from a runway, conducted trials at sea with a submarine, scouting well ahead of the boat and relaying intelligence, surveillance, and reconnaissance information to a communications buoy tethered to the submarine?

Yes, we did some demonstrations working with a submarine. Communications transmissions went directly to the submarine’s mast-mounted antenna, not via a communications buoy.


With a new jet engine propulsion system and the Avenger/Sea Avenger name, will this aircraft assume missions such as fleet air defense, with an arresting-gear-capable maritime version, to protect carrier battle groups?

The Navy has a new competitive UAV class program. It keeps being delayed; however, we are expecting a request for proposal in early 2012. In the meanwhile, the Navy issued a Broad Agency Announcement and funded study contracts to four companies, each for $500,000. GA-ASI received a contract, along with Lockheed Martin, Northrop Grumman, and Boeing. These are likely to be the same competitors once the RFP [request for proposal] is issued.

The Sea Avenger requires a significant modification to the aircraft, not just making it arresting-gear capable. The g loads exerted on the aircraft for carrier flight-deck landing and takeoff make it a whole different situation. The underside of the aircraft must be beefed up. Once capable of carrier flight operations, the concept is for the Sea Avenger to fly ISR and air defense missions. The aircraft will likely need electronic countermeasures and stealth-like capabilities for survivability, much different than the UAVs we have delivered to this point.


What other changes were made in configuring the Avenger? Could it become an unmanned dog-fighting combat aircraft?

Our part of the fleet air defense mission could be to locate incoming hostile aircraft and alert the fleet. Other fighter aircraft would engage in dog fighting – those spotted on the carrier deck specifically designed for that mission. Dog-fighting UAVs are not likely until well into the future, with most of the agility and nimbleness designed into air-to-air missiles.


Naval Air Systems Command appears keen on developing an unmanned carrier-launched strike UAV. The Navy has always been prone to do business with contractors who have carrier aircraft design and production experience. Are you planning to add teammates?

GA-ASI is assembling a team. I cannot say yet who the team members might be since we are still in competition. We will have three or four major teammates and several minor ones. The major teammates will include companies that have been involved in developing carrier-based aircraft. We are studying carrier operations with a UAV and how this might affect onboard procedures. We have been involved in discussions with the Navy about ways to handle the UAV on the flight deck, whether to have the deck crew remotely steer the aircraft into position or use a tug to move it into place on the catapult, as an example. The longer the program RFP is delayed, the greater the challenge. A lot of testing is planned at Lakehurst, N.J., with the goal of having an operational aircraft by 2018.


The carrier-based UAV development and procurement looks to be the opposite of GA-ASI’s swift approach to designing and building unmanned aircraft. This program appears to be more mainstream procurement, which takes longer and drives the price up. Is that the case?

That is correct. Nonetheless, it’s nothing we don’t believe we can conquer on our own. The safety aspects of flying from a carrier deck preclude a lot of shortcuts. It is imperative that, in general, we make it safe to operate unmanned aircraft from a ship. This is especially the case when you must land an unmanned aircraft within several feet of sailors on the deck. You simply cannot shortchange a lot of the testing before operating on a carrier with all the people on the ship, particularly with other aircraft, weapons and refueling systems nearby. The flight-testing and safety aspects must be strictly incorporated.


Are there plans for in-flight refueling to integrate the persistence and flexibility of a UAV into a carrier air wing?

At one point, the Navy wanted to fly off the carrier with a UAV in-flight refueling capability for long-endurance missions. The overall requirement varied from something like 11 to 14 hours to 18 to 20 hours flight time. The requirement will probably be to operate without tanking; however, the Navy may still desire a tanking capability to meet mission needs.

Whatever is decided, our plan is to have Sea Avenger remain on station for 18 to 20 hours without being tanked. We believe this feature is really important for the Navy. Tanker aircraft are expensive and there are not a lot of them available to the fleet. They should remain available when they are needed for other priority missions with manned airplanes.


Are there other versions of the Predator in use by the Coast Guard and U.S. Customs and Border Protection? If so, what are the differences, if any, in the flight vehicles or sensor systems?

The Homeland Security applications and users are combined and we deliver Predator B aircraft to Customs and Border Protection. This version has been modified to carry an under-slung SeaVue surface search radar system. The UAV also is equipped with an Automatic Identification System [AIS] similar to Identification Friend or Foe [IFF], to interrogate ships and identify them as friendly, if indeed they are. If a vessel is pinged and doesn’t respond, either they are bad guys or their AIS system is broken. Either way, the boat must be checked out. There is also an added backup satellite data link, to better satisfy the FAA’s regulations when flying over U.S. territory. This aircraft uses two different types of satellite data links, but is not armed. It could, however, be armed, if required.

This article was first published in Defense: Fall 2011 Edition.


Clarence A. Robinson, Jr., is the author of Battleground High, a book in progress on...