Mark Ayton spoke with members of Lockheed Martin’s T-50A team from Greenville, South Carolina, about its supersonic T-50A trainer aircraft and its applicability to the US Air Force T-X programme
MILITARY LOCKHEED MARTIN T-50A
Right now, the US Department of Defense is in the process of selecting a new jet trainer aircraft for the US Air Force, after which it will sign a multi-billion-dollar contract for 350 aircraft. Three contenders are in: Boeing’s BTX-1, Lockheed Martin’s T-50A and Leonardo DRS’ T-100.
Requirements for the new jet trainer family of systems is extensive and includes six essential aspects: an all-aspect pilot, instructor and maintainer training capability; sustainment in terms of operational and materiel availability for aircraft; sustained g parameters of the aircraft; an ability to enter and be managed on networks and to effectively exchange information; the ability to conduct the most fuel-demanding advanced pilot training syllabus directed sorties with sufficient fuel payload and fuel-burn rate; and a groundbased training system. This issue also contains a feature about the Boeing BTX-1 titled ‘Stadium Seating’ found on pages 80-83.
Breaking some of the aspects down into a little more detail, the sustainment requirement is specified as operational aircraft availability greater than 80%, and materiel aircraft availability greater than 76%, both measured over 20,000 fleet hours.
In terms performance, the US Air Force criteria for sustaining g throughout the manoeuvre (deemed steady state flight) when the aircraft is in its standard configuration, carrying 80% of its fuel maximum internal fuel payload on a standard day with a pressure altitude of 15,000ft at an airspeed no greater than Mach 0.9 and specific excess power no greater than 200ft/sec, is 7.5G or more.
A big component of the T-X family of systems is the ground-based training system (GBTS). The off cial US Air Force requirement is straight forward: the ability to display objects accurately and to replicate aircraft performance accurately to enable positive transference of skill sets from the GBTS to the aircraft. This specification is split between visual acuity and performance fidelity. Visual acuity must include accurate and relative aircraft sizing, shape, features, angle off, aspect angle and closure rates of 9,000ft (2,750m) for the weapon system trainer and 6,000ft (1,825m) for the operational flight trainer. Performance fidelity for the weapon system trainer and the operational flight trainer must adequately replicate the aircraft’s performance, cockpit controls, switches and avionics systems to allow accurate instruction in the GBTS and reflect training in the aircraft.
The requirement for a training capability is defined such that core personnel – pilots, GBTS operators and maintainers – will be trained with the T-X family of systems to proficiency levels relevant to the Air Education and Training Command (AETC) syllabuses for its Specialised Undergraduate Pilot Training, Pilot Instructor Training and Introduction to Fighter Fundamentals programmes, as well as associated maintenance directives.
Additional system requirements are far more numerous and the more interesting ones are explained below.
Aircraft manoeuvrability is essential performance criteria for any fast jet aircraft, for T-X the US Air Force wants its new trainer capable of withstanding the following parameters with the aircraft in standard configuration, carrying 50% of its internal fuel payload, at an airspeed up to Mach 0.9, at a 15,000ft pressure altitude.
- Instantaneous G
- G-onset rate greater than 6G/second
- Instantaneous turn rate with less than or equal to a 3,000ft (910m) turn radius
- Sustaining a turn rate less than or equal to a 4,500ft (1,370m) turn radius in level flight
- The ability to fly with level one handling qualities to a positive angle-of-attack greater than the subsonic angle-of-attack at zero lift
The T-X family of systems must provide situation awareness indicators and switches to support simulated employment of gun, infrared and radar-guided missiles, GPS/INSguided munitions, general-purpose bombs and laser-guided bombs. Missile employment must be simulated with high off -boresight and off -boresight capability, and a pilot-selectable lead computing optical sight and/or enhanced envelope gun sight. Air-to-surface weapon employment must be simulated with the use of a constantly computed impact point and a similar mode for employing the gun, and a constantly computed release point.
Even though T-X is a procurement competition for a jet trainer aircraft, the airframe must have a datalink capability between aircraft with the ability to integrate live, virtual and construct assets, and to instruct tactical datalink employment using an unclassified real or simulated datalink. The datalink’s connectivity must provide local area, near real-time data exchange between the weapon system trainer, the operational flight trainer and the unit training device components of the GBTS. Data exchange between the GBTS components and the aircraft is defined as line-of-sight within 100 nautical miles.
Connectivity refers to the ability of various GBTS devices to connect via ethernet, datalink, wireless or direct connection to each other to enable training missions to be conducted virtually, as a flight for formation and intercepts.
A modular open system architecture (MOSA) will be used for all kinds of reasons including maintainability, interoperability and long-term supportability. Cited as a flexible architecture design, MOSA is designed to accommodate new and changing technology and requirements, and to support rapid and affordable incremental technology insertion.
One important aspect of any aircraft is its cockpit and the displays and ergonomics used to aid the pilot and crew. In the case of the T-X, both cockpits must feature a large area display that provides the same functionality and information front and aft.
The instructor pilot will normally fly in the aft cockpit and teach the student pilot in the front cockpit, but the aircraft can be flown from either cockpit to include all actions necessary to recover the aircraft without relying on front-seat occupant assistance. However, for instructor pilot upgrade training, the qualified instructor sits in the forward cockpit and the instructor undergoing upgrade is seated aft. Therefore, both cockpit configurations must optimise the ability to provide instruction in accordance with syllabuses for AETC’s Specialised Undergraduate Pilot Training, Pilot Instructor Training, and Introduction to Fighter Fundamentals programmes.
T-X must also provide the ability to fly the aircraft tactically without the need to reference cockpit console information using front and aft cockpit head-up displays suitable for all advanced pilot training flying tasks.
The family of systems must have scenario input capability for pre-planned and real-time tactical scenario injects for the aircraft by either aircrew position, and those for a virtual air traffic control environment for the GBTS at both the cockpit and console.
Other capabilities include an external carriage capability with a MIL-STD-1760 compatible aircraft/store electrical interface to accommodate either a weapons systems support pod or a travel pod.
The T-X family of systems must also provide the ability to conduct aerial refuelling training in the simulator for day and night lighting conditions, including full visual display; the aircraft must have the capability to accept installation of an aerial refuelling receptacle without significant structural modifications or the need to move or redesign other systems or subsystems.
Son of a Golden Eagle
What about Lockheed Martin’s contender, the T-50A? The aircraft was specifically developed as a trainer to replace the T-38 Talon in the Republic of Korea Air Force. Development was undertaken in partnership with Korea Aerospace Industries. With a future US Air Force trainer requirement on the horizon (the T-50 was developed in the late 1990s), Lockheed Martin made a smart moving in its involvement with the T-50, a ready-to-go option for what today is known as T-X.
The T-50’s design shares about 70% design, component and parts commonality with the F-16. Lockheed Martin’s T-50 chief test pilot Mark Ward, a former F-16 pilot himself, says the company took all of the best parts of the F-16, looked at them in relation to the training mission and identified which ones should be translated to a trainer aircraft. Ward gave some examples: “The F-16 uses a hydrazinebased emergency power system. Hydrazine is a high-maintenance [substance] and a little more problematic with fuels, so you don’t want to have to deal with it in the training mission in which jets are turning every day, so we did away with the system. The T-50 has a basic auxiliary power unit system that does the job of the old EPU system, and we have also tied that with a thermal battery. Both systems are highly reliable and require little or no maintenance, which helps to drive the total cost down and reliability up.”
Another example is the F-16’s side stick controller. This is a force sensor, so it moves hardly at all, but it senses force. After lots of studies of F-22 and F-35 operations, Lockheed Martin engineers noticed that if they used a displacement stick, still a side stick controller, but with more sensitivity to motion that senses displacement instead of force, the pilot has a better flying experience. Lockheed Martin’s studies revealed that pilots are able to control the jet better and like the feel of it better. Mark Ward said Lockheed Martin has used full displacement stick systems in the T-50 to give the aeroplane a more natural feel than the F-16.
Ward’s third example is the landing gear. He said: “The F-16’s landing gear is relatively short and stiff, and while the aircraft is easy to land, it tends to bounce down the runway, which is not what we want in a trainer aircraft; we want to teach with an aeroplane that has more basic landing characteristics than the F-16. So, the T-50’s landing gear is a different design, one that allows the pilot to either set the aircraft down firmly at a sink rate as high as 13ft/sec [a carrier landing sink rate], but the landing gear absorbs the load without a bounce, or grease it on to the runway when the aeroplane just settles nicely and doesn’t bounce. The redesign on the landing gear makes a huge difference in providing a good solid trainer as required for training a student.”
For his final example, Ward cited the GE F404 engine, the same variant used by the F-18 Hornet, with millions of hours of flight time on the design. He said the T-50 team, which includes GE Aviation, added a dual FADEC system that allows the pilot to move the throttle carefree “anywhere, anytime”, similar in form and functionality to the engine control systems fitted in the F-22 Raptor and the F-35 Lightning II, and many fourthgeneration aircraft, too.
Cockpit and display
Discussing pilot expectations of a modern aircraft, Ward said the T-50 team identified the need for a large touchscreen cockpit display to the exact dimensions as the screen fitted in the F-35. He said: “The screen is laid out in a similar format to an F-35, but uses slightly different portals: a blend between those used in the F-16 and those in the F-35. Consequently, the screen provides a flexible layout that can be configured to look like an F-16 or an F-22 or an F-35 cockpit display.”
“Both systems are highly reliable and require little or no maintenance, which helps to drive the total cost down and reliability up.” Lockheed Martin’s T-50 chief test pilot, Mark Ward
AIR International asked Mark Ward whether the T-50’s cockpit was too complicated for student pilots. He replied: “Well, you would think so, but based on my experience as an instructor on T-38s, an old design with lots of cockpit switches, all of which have to be instructed upon telling the student the positions of each switch, those are very complicated tuitions. As well as the complicated tuition, as the instructor in the aft seat, I can’t really see what the student is doing with the switches. By contrast, in the T-50 everything is on the displays, so as the instructor I can see every single thing the student does on his display. So is that really more complicated? Not really. From an instructor’s viewpoint we have simplified the cockpit and given the instructor the ability to view the front cockpit, see what is happening and catch any mistake before one happens.”
The two cockpits are linked and allow the instructor to use menus to set-up a training scenario without interfering with the student or without the student knowing what is being done. Ward explained: “If during advanced training the instructor wants to set up a scenario in which he or she does not want the student to know where the threat aircraft are coming from, the cockpits can be easily decoupled. The instructor can work on the aft display and the important information shows up on the front cockpit, but the actual presentation, the pages and the menus being used do not show. Then when the instructor is done with that event the cockpits can be relink so the student’s actions can once again be observed. This capability also allows the instructor to present the student with unexpected problems.”
Ward said that in the early phases of flight training before the student really understands the whole concept of flying, coupled cockpits enable the instructor to watch and monitor the student and coach them through the event. Once a student is more experienced such that the instructor is less concerned about the individual’s ability to fly and control the aircraft, more challenges will be presented to the student without any advanced warning. By decoupling the two cockpits, the instructor can make the set-up in the aft cockpit, and the student will see the presentation in the front, but will not see the set-up in advance.
AIR International asked Mark Ward what the T-50 gives the student and the instructor that they do not have with the T-38.
Ward noted the really neat thing about the T-50 is that it has been designed to fly extremely smoothly and has more than adequate power, but at the same time it is very easy to fly. He said: “What do I mean by that? When a student pilot has no experience of flying jets, they are just learning the entire time. They climb in the front seat, the instructor is in the back seat: it’s a whole new experience. A student will never use the T-38’s afterburner throughout their entire pilot training course. Why? Because afterburner is not required, and when you only fly the aircraft between idle and mil power, it’s wonderful; it has enough power that you do not get in dangerous situations. However, student flying often involves flying close to the ground, and if the student makes an error with his power, that requires the instructor to slam both throttles to full afterburner and hang on for dear life and hope the aeroplane accelerates before we hit the runway.”
In the T-50, idle to mil power provides just the right amount of power that you don’t get into difficulty. If the student does something silly, the instructor can push the throttle to mil and have adequate power to very quickly recover from the situation without ever getting into that cliff [scenario]. There are a lot of cliffs and we’ve taken them out.
“So, what is the T-50’s afterburner for? Well, the Republic of Korea Air Force introduces each student to afterburner even though no phase of the course requires that and is all conducted in idle to mil power. Once a student graduates to the advanced phase in the T-50, they can then use the extra power afforded by afterburner to learn how to fight with the aircraft, understand what afterburner gives them, what fuel consumption rates are and really push performance way up. Lockheed Martin believes keeping the afterburnerequipped engine on the T-50 is important, because it enables the aircraft to conduct the full gamut of training: basic and advanced.”
The T-50’s performance allows it to conduct other missions outside of advanced pilot training, the most likely being used as an adversary fighter in the classic aggressor role. By 2030, the US Air Force has forecast an annual requirement for 130,000 individual aggressor sorties to support its F-35 fleet. As a consequence of that requirement, the Air Force is already citing T-X aggressor as a solution. That means use of the aircraft type selected for the forthcoming T-X programme as a dedicated adversary aircraft in what would certainly require a new and bigger aggressor force. The T-50’s manoeuvrability, an aerial refuelling capability, its datalink system which would enable threat presentations to be placed on the network, extended to the classified Link 16 network if a MIDS terminal is carried, and even high-end threat if a radar system is also fitted, make the jet a perfect type for the aggressor role.
One of the proposed changes to advanced pilot training with the T-X family of systems is downsizing, which is a reference to changing the shape of where a student flies the hours during their entire training programme. Under AETC’s current advanced pilot training programmes, a student completes a year of pilot training, half of which is flown in the T-38. For students selected to fly fighter aircraft, a three-month introduction to fighter fundamentals course follows, and then six to nine months at a type-specific formal training unit. The six to nine months spent at the formal training unit is a very expensive phase of a pilot’s flying training programme, because it involves flying a fourth or fifth-generation aircraft, and it cause wear and tear on aircraft that are combat assets. In the future, once T-X and downsizing is in effect, the introduction to fighter fundamentals course will probably extend beyond three months, possibly as long as nine months, and the formal training unit phase may be reduced to a three-month programme. The number of hours flown by each student is also likely to change, given the capability of today’s and future simulators where some flight hours will be off oaded.
The step-up in trainer aircraft quality afforded by the type chosen for T-X will also have a significant effect. Today there is very little to compare a 1960 model T-38C Talon with a 2018 model F-35A Lightning II. The advent of T-X will afford graduate pilots a level of performance and capability that will make their transition into an advanced fighter quicker.
AIR International asked Mark Ward what he believes the T-50 can do for a student in specialised undergraduate pilot training and introduction to fighter fundamentals programmes. He said:
“That’s a big question. In basic training, during which a student learns the basic skills, how to land, fly in weather, using the instruments, in a T-50 the student will do so with a modern cockpit display and will become very comfortable with his or her interaction with a touchscreen display.
“Once a student moves into introduction to fighter fundamentals with the T-50, the performance to manoeuvre, dog fight and how to fly different formations required for tactical operations will be a world away from the current T-38. A student will be able to use the datalink, fly datalink formation, conduct [simulated] radar operations, all in a progressive. They will learn how to manoeuvre and use the aircraft’s systems and capabilities, including aerial refuelling. However, once the student is done with the IFF [introduction to fighter fundamentals] phase, they will require a much shorter transition into a fighter, because he will have a good understanding of the tactical requirements such as datalink formation and the positions required for air-to-air engagements and air-to-ground strikes based on the tactics instruction given in the T-X trainer.”
Background on T-X
Bill Looney is a retired US Air Force General, a former F-15 Eagle pilot, and a former commander of AETC. Discussing some of the early thinking behind the T-X programme, he explained how, during his tenure as commander of AETC, apparent the need for a new jet trainer was given the shortcomings of the Talon in training pilots for the F-22 Raptor and the F-35 Lightning II.
He said: “The T-38 is a great aeroplane, but it’s been around since the early 1960s and was built primarily to train pilots for, what were then, third-generation fighters, and has since trained pilots destined for fourthgeneration fighters, but trying to apply it to fifth-generation pilot training is just too hard. It is lacking in its ability to pull g. Only 5g is available; we require 8.5 to 9g. The avionics are not up to speed, and digital and connectivity capabilities are not there. Nor is it able to do aerial refuelling [and] it does not have a radar or a targeting pod, so it was very apparent to all of us at AETC that the time had come to get serious about replacing it with a new trainer aircraft. Work began on that concept [now dubbed T-X] in the 2006 to 2007 timeframe.”
Based on his command experience at AETC, Gen Looney said the US Air Force wants an aircraft that is capable of manoeuvring in high G flight scenarios, one that is network centric with an all-glass cockpit, and equipped with simulated radar and targeting pod systems, with a virtual capability that links to simulators, and a constructive element in which targets can be virtually embedded into a live, virtual and constructive scenario.
Part of the T-X family of systems requirement is a ground-based element that according to Gen Looney, “creates a realistic environment to the point where it can off oad some of the sorties currently flown in aircraft into simulators to save money and time”.
The General said that the T-X family of systems must fill 16 training gaps identified by AETC between the current standard of graduate pilots and what’s required to meet the demands of pilots selected to fly fifthgeneration fighters:
An ability to maintain high energy manoeuvring
An ability to simulate a network with a datalink with the added ability to simulate a radar and a targeting pod
A glass cockpit, with a configurable touchscreen display to enable replication of displays fitted to existing fighters like the F-15, F-16, F-22 and F-35; a requirement to make the transition to any one fighter type easier for the graduate pilot
A very realistic GBTS that includes tabletstyle computers loaded with apps featuring all of the academic component of the pilot training syllabus, a throttle and side skip for plug-and-play, with a laptop or computer upon which to practise the next day’s sortie, all in addition to simulators
AIR International asked General Looney for his view on the prospect of a future T-X aggressor and the applicability of the T-50 to the role. Explaining the history of the US Air Force aggressor force, General Looney believes there is an appreciation by the US Air Force of the value that adversary training brings to fighter squadrons. As a former F-15 Eagle pilot who benefited from aggressor training during his career, he hopes funding will one day be found to create a new aggressor force. He said: “The natural follow-on for that would use of the T-X aircraft. Although the T-X programme is focused solely on pilot training, I believe there is an understanding by the US Air Force, and certainly by industry, that more orders can be placed, and the T-X aircraft can very easily transition into adversary mode with little or no modification whatsoever. It might require, for example, an actual radar fitted, so it can present a more credible air-to-air threat, but other than that, I can’t think of any other modification that would be required.
“If – and it’s a big if – the Air Force has the opportunity to form an aggressive force, it will all depend on whether they have the resources and the budget to do so. There are, of course, a lot of advantages to that, because the Air Force would have complete control over the entity, and an opportunity for follow-on training for proficiency. When pilots finish an F-22 or F-35 tour, their next assignment could be an aggressor pilot, which is what the Air Force previously did with F-15 and F-16 pilots when the F-5 aggressor force operating. Pilots served as an aggressor pilot for three or four years, during which time they accumulated hundreds of hours of flying time and became exposed to building their craft and expertise before returning to an F-22 or F-35 tour, so it was a really nice flow.”
Lockheed Martin claims the T-50A will create better pilots in less time for lower costs. The company cites the Republic of Korea Air Force, the original operator of the T-50 trainer, which has reduced the number of flights required in its KF- 16 operational conversion course to only nine sorties. Better pilots, according to the company, are created because the T-50 training system enables student pilots to focus their airmanship skills on improved aero performance, digital flight controls and fly-by-wire, with next-generation air traffic management systems, while operating from an anthropometrically designed fifthgeneration cockpit.
Lockheed Martin’s T-50A is not the same T-50 as operated by the Republic of Korea Air Force, but a configuration based on the FA-50 fighter variant, the most capable version of the T-50 series built to date, albeit without the combat systems fitted.
In February 2016, Lockheed Martin announced its plan to off er the T-50A in the T-X competition based on evaluation of clean-sheet alternatives, which according to company off cials posed prohibitive risks to the programme’s cost and schedule requirements. Should Lockheed Martin be selected as winner of the T-X competition, the company plans to build all 350 aircraft at a final assembly and checkout facility in Greenville, South Carolina. The facility and its operations centre were opened in August 2016. T-50 flight operations started from the Greenville facility in November 2016.
Lockheed Martin is partnered with Korea Aerospace Industries, General Electric and numerous subsystem suppliers for the design and production of T-50A.
“In a T-50 the student will learn with a modern cockpit display and will become very comfortable with his or her interaction with a touchscreen display.” Lockheed Martin’s T-50 chief test pilot, Mark Ward