Supporting the fleet


Mark Ayton overviews the adversarial services provided to the US Navy fleet by Vertex Aerospace with its fleet of specialised Learjets

Headquartered at Newport News-Williamsburg International Airport, Virginia, Vertex Flight International operates a fleet of 12 Learjet aircraft. On contract with the US Navy to provide electronic warfare and target towing services, the company operates from three locations in support of the Atlantic and Pacific fleets. Based on the Atlantic shores, the Newport News facility serves aircraft carriers, amphibious assault ships, destroyers, frigates and naval air forces based at the gigantic Norfolk Naval Base, and other units homeported or home-stationed in Florida. To serve the Pacific fleet, Vertex Flight International maintains three-aircraft detachments at Naval Air Station North Island, California and Marine Corps Air Station Kaneohe Bay, Hawaii.

Aircraft, aircrew and pods

Each of the company’s Learjets is heavily modified and Vertex holds supplemental type certificates issued by the Federal Aviation Administration for the modifications, the biggest of which are the under wing hard points used to carry pods and payloads.

Aircraft are equipped with a special mission power system to power all types of pods and payloads, an array of antennas for use with customer-supplied pods and payloads, and internally racks used to carry a customer’s equipment. Internal wiring, jacks and plug-ins are all standard though a variety of wiring is installed out to the hard points to provide the correct MIL-STD connection to pods and payloads.

All aircraft in the Vertex fleet are either standard Learjet 35 or Learjet 36 models, some of which are configured for long range flights across the Pacific with higher fuel capacity.

In order to carry the necessary jamming pods supplied by the US Navy, and other customers, the company’s Learjets are modified with under wing hard points each capable of carrying payloads weighing up to 1,000lb (454kg). Typical pods carried are the AST-6, AST-9, standard ALQ-167, and the P5 TCTS.

The AST-6 is an active emitter threat simulation pod that replicates the latest and most complex anti-ship missile systems operating in bands H, I and J bands using the UPT-2A RESS or radar emission simulating set. The RESS simulates progressive stages of a threat by executing stored programmes called scenarios; a sequence of commands for the specific radio frequency, radio frequency pulse repetition frequency rate, and radio frequency pulse widths as the designated threat.

The AST-9 is an airborne radar and anti-ship cruise missile system simulator pod, which uses high power traveling wave tube and magnetron transmitters.

The ALQ-167 is an airborne electronic attack threat simulation pod that replicates current and projected jammer systems operating in bands B through J using diff erent modules of the ULQ-21 countermeasures set, which operate a given frequency range and generate noise and deception signals. In addition, the Learjets can and often do carry Cubic P5 Tactical Combat Training System pods used for real time weapon simulations and live monitoring functions, to provide real-time air-to-air, air-to-ground and surface-to-air combat training missions.

Vertex undertakes most aircraft modifications in house but uses a contractor company that specialises in avionics to undertake the bigger mods, simply because its maintenance department has its hands full conducting the ongoing maintenance of its fleet of 12 aircraft. According to Eric Theisen the company’s mechanics do a fantastic job which is borne out by a 95% mission capability rate.

Flight deck crew comprises two; a pilot in command and second-in-command. Eric Theisen said the company has a mix of former military and civilian pilots. He said: “The former military pilots served with either the Navy, Marine Corps or Air Force while the company’s civilian pilots have grown up with the company and learnt the trade with us. Acquiring that type of experience takes time, so when we hire a new pilot they usually start out in the right seat as the second-incommand until they have acquired enough time and experience to figure out all of the different missions we conduct before they upgrade to pilot in command.”

Banner towing missions also require a tow operator on board, usually a mechanic qualified for the mission. When flying research, development and test-missions customers usually require operators to be on board to control the equipment or systems installed.


According to Vertex Flight International’s special programmes manager, Eric Theisen, the company provides jamming services, including red air adversary electronic warfare when the Learjets jam blue air aircraft as they fly from the outlying borders of the airspace. Another specific role is air intercept controller training for trainee E-2 Hawkeye radar operators during the graduation exercise for their course with Carrier Airborne Early Warning Squadron 120 (VAW-120) based at Chambers Field, Norfolk, the E-2 fleet replacement squadron.

Eric Theisen said Vertex launches four Learjets, two assigned to blue air and two to red air, to provide the Hawkeye crew with a variety of presentations for the students to control during the final graduation sortie, this is a cheaper alternative than using F/A-18 Super Hornets for the same role.

In support of the surface fleet, Vertex Learjets carry an under wing reeling machine from which one of two types of targets are towed for ships to shoot at. One, the MRT- 2000 is used during live fire exercises trailed 13,000 feet behind the Learjet for targeting by the ship’s close in weapon system in a scripted and safe setup. The ship’s fire control team tries to shoot off the target from the cable in what Eric Theisen describes as deadly accurate shots. He said: “We also trail targets at 22,000 feet for the big guns.”

All firing exercises are scheduled by either one of the Navy’s three Fleet Area Control and Surveillance Facilities at Virginia Capes, Virginia, San Diego, California and its detachment at Pearl Harbor, Hawaii.

Theisen said: “Individual ship scheduling is rigorous, driven by range time, such that we know when we have to fly, though we remain quite flexible and usually require about 24 hours of notice if the customer needs something different.

Other missions flown in support of ship training are long range track exercises using AST-9 pods to simulate different threats against the ship. Theisen explained: “We fly multiple low-level passes from the ship’s radar horizon simulating different threats against its radars and systems. This is a standard training work-up requirement for ships assigned to all carrier strike groups and expeditionary strike groups prior to deployment.”

As previously mentioned, Vertex Learjets also support training of naval air forces towing banners on a 2,000-foot long cable as a target for fighter aircraft to shoot at. Explaining the process, Theisen said: “We set up in one of a variety of different patterns according to what the fighter squadron requires, and usually get eight jets across one banner in the required range time before we have to return to base. We drop the banner at the base so the unit can see how many times the pilots hit the banner and score the shots.”

Worldwide ops

Vertex deploy worldwide in support of its US Navy and Department of Defense customers. For example, Australia for Exercise Talisman Sabre every other year, Andersen Air Force Base, Guam for Exercise RIMPAC and Alaska for Northern Edge. Occasionally the Vertex Learjets deploy to places in support of the Naval Research Laboratory, such as an exercise staged in Norway during 2017. Eric Theisen said regular deployments are made to Jacksonville, Florida in support of ships working in the area, and previously to Tyndall Air Force Base, Florida to tow banners for the US Air Force and US Navy squadrons participating in Air Combat Command’s Weapon System Evaluation Program. Banner towing remains the company’s primary line of business with the Air Force.

Vertex hold worldwide landing permits with the Department of Defense to land at any of its bases no matter which service, in addition to other NATO bases.

Despite the company’s contractual commitment to the Navy which requires a certain number of aircraft to be assigned each day, and given its 12 aircraft fleet, if the schedule permits, work is undertaken for other customers, particularly for research test and development with organisations such as the MIT Lincoln laboratory, the Georgia Tech research institute and the Naval Research Lab.

Eric Theisen said the company regularly undertakes new roles in support of the Navy. He said: “We recently started a communications relay role for shore stations to be able to talk to ships further out to sea.

This involves positioning a Learjet between the shore station and the ships when the aircraft conducts communications relay.

The objective, now proven, enables both/ all agencies to accomplish a lot more thanks thanks too clearer and more concise communications.”

Surface ship targets

Targets used by surface ships to shoot at are towed on either a 13,000ft (2.4 mile) or 22,000ft (4.1 mile) cable.

Clear and concise communications with the ship are essential so establishing communications with the ship is the Learjet crew’s first priority before the exercise starts.

Explaining, Eric Theisen said: “Once we start, we stream the target which we can only do in the restricted airspace allocated to us as set out for this particular gun exercise conducted by the ship. Once the target is streamed from the reel, the Learjet crew sets up and flies a pattern, either in front of the bow or behind the stern of the ship. The Learjet crew asks the speed, course and surface wind details from the ship, details they use to determine how far in front or behind the ship they need to fly so the target can reach a notional basket in front or behind the ship for shooting. The basket is about 500 feet above the water and about 1,000 feet off the bow or the stern of the ship.”

Eric Theisen reckons the Vertex aircrew pretty much hit the basket every time even though the target is 5 miles behind the aeroplane and is affected by the wind. He said: “It’s a very scripted exercise. We advise the ship when we are doing a tracking pass which is a cold pass during which the ship does not fire or shoot. Once the ship has performed a couple of successful tracking runs we then make a hot or firing run for which we give the ship details of when to fire and in what direction. We pass in front or behind the ship and will not give them clearance to fire until we are way past the ship such that they can fire behind us at the target. Firing varies depending on the ship, it can comprise a series of big shells.”

Hitting the target with a large round, even though they are radar guided, is good shooting. The ship fires its big guns first before starting the CWIS (close-in weapon system) which is very accurate and tends to shoot the target off every time.

Customer variety

Vertex serves a range of customers who lease an aircraft to conduct research, development and test of a new system. Such customers can be US government agencies, federally funded research institutes or defence companies.

Eric Theisen explained that Vertex mechanics help the customer set up the system or systems inside the aircraft and then conduct a test programme with them. He said: “The customer usually has operators in the back to operate the specific equipment using our aeroplane to fly a specific profile as required. Our pilots are familiar with attaining specific air speeds, altitudes and headings required by the test cards.”

Some customers use antennas as fitted on the aircraft for the test, some customers wish to use their own pod, which is fine provided it’s a type on our supplemental test certificate so that we can carry it and that the customer operators can operate it from the inside.

If a customer wishes to use a bespoke pod, a blueprint design, we undertake preliminary discussions and direct them on the art of the possible and advise them to try to source a pod type that is on our supplemental test certificate. However, it that customer wants to use an off the wall pod then we must go through the entire supplemental test certificate process with the Federal Aviation Administration to gain approval for its use on the Learjet. That represents a lot of time and paperwork such that if a customer needs something doing quickly and has to use an off the wall pod, generally we cannot support that. That said, we own a couple of AST- 6 shape pods that are empty and for rent by customers. Last summer we flew a test campaign with a rented pod.

In the past we conducted some experiments for NASA with an aerosol sensor installed within a tip tank, but much of our ongoing testing is focused on new jamming techniques for diff erent government and federally-funded laboratories.

Northern Edge 2019

Vertex deployed three Learjets to Eielson Air Force Base, Alaska to participate in US Indo-Pacific Command’s Exercise Northern Edge. The company was contracted by both Naval Air Systems Command and the Naval Research Laboratory for two purposes. Initially, one crew and aircraft operated from Elmendorf Air Force Base and worked with the USS Theodore Roosevelt Carrier Strike Group. That single aircraft carried an experimental system funded by the Naval Research Laboratory to provide a threat against the ship underway in the Gulf of Alaska.

The second purpose was to provide red force adversary services against the blue force operating in the JPARC with two aircraft carrying a variety of diff erent jamming pods provided by the US government.

Eric Theisen said: “We flew 56 sorties with the three aircraft which provided the customers with a lot of good training. The Learjet can remain airborne for a long time which meant our aircraft can, if required, cover a couple of diff erent vul periods, so the customer was happy with our ability to provide jamming against the blue force for extended periods.

The jamming provided by Vertex Learjets was undertaken in concert with EA-18G Growlers assigned to Electronic Attack Squadron 134 (VAQ-134) ‘Garudas’ cobased for the exercise at Eielson, and part of the red force.

Explaining how the Vertex Learjets were fully integrated into the exercise, Eric Theisen said: “We attended the morning briefing with all of the participants, after which we went to the separate red force briefing where we received our specific assignments for the mission ahead. Our pilots have a formation qualification allowing them to fly standard tactical formations such as a basic closing echelon formation or indeed a trial formation. Sometimes we flew a two ship, sometimes a single ship under the control of the red force AWACS dubbed Baron.

“We worked in conjunction with ATAC’s Hunters on the red force and we were supplementing the military fighters assigned to the red force which was presenting an adversary threat laydown against the blue force which was receiving the training. For Vertex this involved throwing beeps and squeaks at the red force to disturb and disrupt using new electronic warfare and electronic attack systems funded and provided by the US Navy.

AIR International asked Eric Theisen how Vertex was able to operate the Navy’s new systems being part of the fight in a big exercise, given that as contractors the aircrew are not experts in the systems carried? He replied: “The electronic warfare and electronic attack systems used for the experiments are run by Navy operators in the back of the jet while under development. Once that type of pod becomes operational the systems are miniaturised and housed in a pod. The Navy provided us with a mini control box and a cheat sheet so we can select diff erent modes of operation which ranged from light to heavy jamming and the diff erent threats it could simulate. Even though our pilots are not experts in electronic warfare we had enough information on board to provide the required threat level of jamming as specified by the customer. We are thoroughly briefed on what the new systems do, what it is going against, and all crew members have the appropriate clearances.

F/A-18 Super Hornets and EA-18G Growlers assigned to developmental and operational test squadrons based at Naval Air Weapons Station China Lake flew from Elmendorf as part of the blue force faced the new systems in operation on board the Vertex Learjets. The China Lake aircrews will have conducted tactical evaluations of the systems their Super Hornet and Growlers were fitted with against the threatening beeps and squeaks presented by the Learjets.

All of the Learjets were fitted with data recorders for recording all responses from the new systems in operation. That data is used for debriefing the blue force aircrews so they learned how they performed in the fight, and post exercise for detailed analysis of the systems performance.

Air Test and Evaluation Squadron 20 (VX-20), the E-2D Advanced Hawkeye developmental test squadron based at Naval Air Station Patuxent River, Maryland sent three aircraft to Elmendorf for Northern Edge. This Navy test squadron is a regular customer of Vertex acting as targets or towing targets to enable the E-2D crew to evaluate the aircraft’s systems and calibrate each new system configuration set for among many systems the APY-9 active electronically scanned array radar, and developmental test phases as the E-2D moves from fully networked combat operations capability under Increment 1 to information dominance under the forthcoming Increment 2; transformational capabilities in the Battle Management, Command and Control (BMC2) and Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) concepts.

Use of the Learjets in Northern Edge represent a very cost eff ective means of providing a red air adversarial aircraft because the Learjet is probably the cheapest type to operate. By contracting Vertex to provide adversarial electronic warfare and electronic attack service, Naval Air Systems Command and the Naval Research Laboratory save the US government quite a bit of money for a 95% mission capability rate. AI