An official website of the United States government
Here's how you know
A .mil website belongs to an official U.S. Department of Defense organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

News | May 14, 2021

The Future Direct Air Support Center: Implementing Tactical Data Links to Enhance Combat Power

By Capt Earl Gerlach, USMC and Capt Aaron Falk, USMC Air Land Sea Application Center

Download PDF  →

Article Originally Published in Air Land Sea Bulletin 2017-02, August 2017


Common Aviation Command and Control System (CAC2S), Increment I, Phase II, is an aviation command and control system scheduled to be fielded to the to the direct air support center (DASC) from fiscal year 2018 through 2021. The system will be fielded to the rest of the Marine air command and control system (MACCS) on a similar timeline. This new system provides a common, expeditionary, modular and scalable system that enables data fusion throughout the Marine air ground task force (MAGTF). This article informs commanders and their staff, involved in every warfighting function, about the DASC’s new capabilities and employment options.

CAC2S is a hardware and software suite that enables the DASC to integrate existing information exchange systems such as Global Command and Control System (GCCS), Command and Control Personal Computer (C2PC), Integrated Broadcast Service (IBS), and Advanced Field Artillery Tactical Data System (AFATDS), using a Multi-source Correlator Tracker to fuse information onto a tactical display. CAC2S enables the DASC to execute the concept of digital interoperability, with organic assets and the joint force, through tactical data links (TDLs) such as radio frequency Link 16 and Joint Range Extension Application Protocol (JREAP). This fusion of data enables the DASC to see near-real-time air, surface, subsurface, land, and space tracks, and integrate modern C2 systems with legacy equipment to provide a true, common tactical picture. The addition of these enhanced capabilities will drive significant change across the DASC community and will improve the MACCS’ integration with the theater air-ground system (TAGS).

DASC Support to the MAGTF Commander

The DASC will soon have a plethora of exploitable capabilities that will create better synergy between the aviation combat element and ground combat element (GCE), ultimately increasing lethality and generating combat power for the MAGTF commander. CAC2S fuses the GCE’s current GCCS and AFATDS networks with a Link 16 capable system, which utilizes J-Series messages. AFATDS facilitates a GCE fires network utilizing K-Series variable message format messages. CAC2S can process J-Series, K-Series, and M-Series messages (Link 11 is primarily employed by the Navy and uses a 48-bit message compared to a Link 16 J-Series which uses a 75-bit message.[1] [2]

Harnessing these new capabilities will allow the use of TDLs to maximize the efficient use of aviation assets in support of the ground scheme of maneuver, thereby enhancing the effectiveness of the MAGTF. The increased speed and accuracy of the processing of immediate air support requests, with the advanced communication functions of digitally aided fire support, digitally aided close air support (CAS), and digital air control, make this a relevant and highly capable system for the MAGTF and its future battlespaces.

Figure 1.  Common Aviation Command and Control System, Increment I, Phase II, is the epitome of Digital Interoperability – Enabling the DASC to facilitate critical information exchange requirements over a variety of communications pathways.

Roles of the DASC

The defined DASC roles, as outlined in Marine Corps Reference Publication 3-20F.5, Direct Air Support Center Handbook, need to be discussed and refined. The following paragraphs describe how the DASC is an improved aviation command and control (AC2) agency through these new capabilities.

Immediate Air Support Requests Processing

The DASC processes immediate air support requests, including joint tactical air strike, assault support, and casualty evacuation requests. The process always begins with the requesting unit. Traditionally, a tactical air control party or air officer would request immediate air support via the battalion combat operations center. The request would be relayed up to an operator in the DASC, with vetting from the division fire support coordination center (FSCC) where the DASC is col-located. This is for mission number assignment, mission number verification, and aircraft sourcing data. CAC2S integrates AFATDS and Target Location, Designation, and Handoff System (commonly known as StrikeLink), on the host system. Thus, units can submit immediate air support requests, via K-Series messages to the DASC digitally. Even though StrikeLink will become obsolete in the coming years, the replacement, Target Handoff System, is interoperable with AFATDS, so this functionality will remain. As C2 becomes more and more digitalized, having this capability will improve timeliness and reduce the possibility for transcription errors. CAC2S will be able to receive requests, plot them to allow the operator to screen them for accuracy, and send mission assignment data back to the requesting unit.

Furthermore, if the selected aircraft is TDL capable, the DASC can exercise digital air control. The request can be transmitted directly from the DASC, to the aircraft via a J12.0 Mission Assignment and a J28.2 Residual Text message, concluding with a radio call confirming the pilot received the mission assignment. This is similar to StrikeLink operations. The aviator is required to acknowledge the received mission in flight. Simultaneously, the DASC can configure routing paths to forward the data to their senior agency, the tactical air command center, to ensure that situational awareness is maintained throughout the MACCS. By conducting this immediate air support request process via digital means, the aircraft and AC2 agency host systems can populate the request data with minimal user action. This speeds the process and limits operator interaction to confirming the accuracy of the information (the authors anticipate a “read back”, similar to that with close air support 9-Lines).[3]  This new tasking process, specifically for immediate air support requests, is an emerging joint tactic, technique and procedure (TTP) the authors believe will be the future of AC2 operations. The ability to quickly and accurately assign mission data to aircraft shortens the kill chain and provides rapid and accurate support to the requesting unit, thus, conserving limited aviation resources.

CAC2S gives the DASC a link to joint aviation assets. The DASC is the principal MACCS air control agency responsible for directing air operations that directly support ground forces.[4] In a joint or combined environment, C2 of aircraft creates unique challenges. This interoperable system will enable rapid submission of air support requests to joint, combined, coalition, adjacent, and senior AC2 agencies, such as the United States Air Force (USAF) air support operations center (ASOC) or their senior agency, the air operations center.[5] [6] The DASC will have the organic capability to see joint air assets’ locations, altitudes, and fuel and ordnance statuses via their precise participant location and identification (PPLI) and the associated J13.2 air platform and system status message. It will allow the DASC to receive sensor contacts from adjacent AC2 agencies. CAC2S also provides the capability to plug an AN/TPS-59 or AN/TPS-80 Ground/Air Task Oriented Radar (G/ATOR) directly into the system, providing real-time tracks, allowing the DASC to conduct better asset management and selection thereby, significantly, reducing the time to request ‘purple’ or joint aviation assets to provide aviation fire support for ground forces engaged with the enemy.

Integrating aircraft employment with Other Supporting Arms

CAC2S enhances the DASC’s capability to integrate aircraft employment with other supporting arms. TDLs provide DASC air controllers with accurate PPLI, along with the ability to transmit munition flight paths (also known as gun target lines), to aircraft in flight. CAC2S allows AC2 to integrate aviation assets in real time with supporting arms to maximize fire support and minimize airspace restrictions. This key tenet is outlined in Joint Publication (JP) 3-52, Joint Airspace Control, “Indirect fire systems are also airspace users and today range higher and farther than ever before. These increased user demands require an integrated airspace control system that facilitates mission accomplishment while reducing the possibility of unintended engagements against friendly, civil, and neutral aircraft.”[7] The DASC can accomplish this by digitally building and disseminating formal and informal airspace coordination areas (ACAs) to Link 16 participants. This facilitates a permissive fires environment where surface to surface indirect fires do not require coordination with AC2 agencies. While there may be risk involved in conducting this process entirely digitally, it can be enhanced through voice communications, or agreed to be conducted entirely digitally by the MAGTF commander and joint force commander. PPLI and sensor contact data will, ultimately, allow the DASC to more effectively integrate aircraft with munition flight paths using smaller informal ACAs than procedural means alone.

The DASC, col-located with the senior FSCC, can provide this air picture to its common tactical picture. This enhanced picture provides the air officer and fire support coordinator an accurate tool, resulting in quicker decision making. Furthermore, through a JREAP C (TCP/IP or UDP/IP, which is a secure internet connection), an air picture can be sent from the DASC to a regimental FSCC when a subordinate DASC agency is in direct support of them such as a CAC2S-equipped air support element. This further disseminates common situational awareness to lower levels of the ground combat element.

Manage Terminal Control Assets

The DASC community struggles with managing terminal control assets. According to doctrine, the DASC conducts this role by maintaining communications with the GCE and the supporting aircraft, via the tactical air control party (TACP), which is, according to doctrine, an extension of the MACCS. Managing terminal control assets enables the DASC to use these available assets for other, immediate, air support requests of higher precedence. However, dynamically re-tasking an aircraft that is already working with the GCE can be a difficult endeavor. Most Marine Corps aircraft have only two radios, therefore they cannot continuously monitor the DASC’s primary frequencies. With current systems, if the DASC wanted to re-task an aircraft under a TACP’s control to support another mission, the operators may have to contact the supported units’ air officer who would have to direct the aircraft back to the DASC’s primary frequency for coordination, or in the worst-case scenario, the DASC would be forced to transmit on the guard net, which is inefficient and potentially unsafe. The TDL capability that CAC2S provides is a viable solution to this difficult problem. The system will improve the DASC’s ability to manage assets that are in their assigned airspace but working in support of terminal controllers on the ground. Information such as battle damage assessments and in flight reports can be disseminated via TDL to the DASC. The DASC can reach out to aircraft (via J28.2 Residual Text Message) and re-task the aircraft, directly. This holds true even if the aircraft are in support of a TACP and not monitoring the DASC’s frequencies. This is possible because a J28.2 addressed to a specific aircraft, regardless of who the aircraft crew is talking to on the voice frequency, will still populate the aircrafts host system. This can enable the DASC to divert aircraft working with the TACP, with little required coordination. The time savings can save lives. Also, the DASC will be more efficient in multiplying the commander’s combat power.

Procedural Control of Aircraft in DASC Assigned Airspace

The procedural control of aircraft is a rapid, expeditionary, secure, and effective means of controlling airspace with limited communication required. However, the capabilities TDLs bring to the fight should not be ignored. The enhanced situational awareness air tracks bring to the DASC can produce many benefits; including shortened radio communications, minimized electronic signature, increased safety of flight for aircraft, more direct routing, and increased information exchange accuracy. Additionally, the DASC can maintain communications with various rotary-wing platforms through a radio frequency (RF) Link 16 network designed to support the relay function of Link 16, thus, vastly increasing the DASC’s RF Link 16 range. This can pose network design challenges if voice and imagery are being relayed, but this will be situationally dependent and determined by the joint force commander’s information exchange requirements.

The DASC will have the ability to see near-real time aircraft locations. This ensures the DASC’s air controllers can quickly see where aircraft are in an environment where it is impractical, or difficult, to manage and control airspace, simply, through procedural means. The ability to receive the radar feed from agencies like the Marine Corps’ tactical air operations center  or the USAF’s control and reporting center, (J3.2 air tracks and PPLIs directly from aircraft to the DASC’s RF Link 16 antenna), supports enhanced situational awareness to air controllers and senior decision makers alike. The DASC also will be able to fulfil more responsibility in a MACCS degradation plan, due to enhanced situational awareness enabled by CAC2S.

Figure 2. During Weapons and Tactics Instructor Course 2-16, Marines from Marine Air Support Squadron 1 and 3 participated in the Initial Operational Test and Evaluation of CAC2S, Increment I, Phase II.

Joint Operations

Modern warfare is almost always a joint endeavor. Combining the strengths of each component gives the joint force commander a unilateral capability. Through standardized joint doctrine and equipment sets, each Service component will be more prepared than ever to work with sister Services throughout a campaign. CAC2S provides the DASC, and, ultimately, the MACCS, a system that is complementary, compatible, and as capable as adjacent C2 agencies. While the specific TDL terminals will vary, the ability to process RF Link 16, and share it through JREAP connections, is the same. Not only will the DASC have a C2 system equal to or greater than other AC2 agencies such as the USAF ASOC or United States army air defense and airspace management cell, but because the DASC is col-located with the Marine Division and the senior FSCC, it will be an essential hub of information in the MAGTF area of operations. This area of operations integrates aviation, maneuver, fires, and intelligence data. This will not only keep the DASC relevant without a sensor, but will also allow rapid coordination with joint and organic aircraft, and surface fires synchronized with targetable intelligence provided through IBS.

Regularly, the Marine Corps operates as a part of a Navy-Marine Corps team (technically, this is not considered joint per JP-1).[8] The DASC will be better able to support amphibious landings and operations in support of a Marine expeditionary unit (MEU) and Navy amphibious ready group (ARG). The worldwide MEU and ARG rotation provides a, nearly, continuous presence in the Middle East. If landward control of aviation assets provided by a MEU/ARG is required for the geographic combatant commander, the MEU would be able to send a DASC element with an expeditionary CAC2S ashore to augment the already established airspace control system which, could provide positive control using their digital data links.[9]

CAC2S will enhance the MACCS as a whole, and allow a more effective and efficient C2 of joint air operations across the TAGS. The DASC will become a more flexible agency capable of operating within the MAGTF, alongside USAF AC2 agencies, or as a stand-alone AC2 agency, depending on the mission set.


            CAC2S, Increment I, Phase II, is the materiel future of the MACCS. The roles of the DASC are evolving based on new TTPs developed through enhanced capabilities. The community must notice and capture TTP as soon as CAC2S Phase II is fielded, improve understanding of TDLs in DASC operations, and redefine the role of the DASC in doctrine. There is a consensus in the AC2 community that the DASC needs to adapt to operate with improved technological advances to remain a relevant agency within the MACCS and TAGS. If leaders across the Marine Corps notice and act, the DASC will not only surpass expectations, but will become an AC2 agency capable of excelling in a digital interoperability environment, integrating with new technology such as the AN/TPS-80 G/ATOR radar system and the F-35 joint strike fighter to support the MAGTF commander on the modern battlefield.




[1] Military Standard 6016, Link 16.

[2] Military Standard 6011, Link 11.

[3] JP 3-09.3, Close Air Support, 25 November 2014.

[4] MCRP 3-20F.5, Direct Air Support Center Handbook, 15 November 2001.

[5] JP 3-30, Command and Control of Joint Air Operations, 10 February 2014.

[6] JP 3-52, Joint Airspace Control, 13 November 2014.

[7] Ibid.

[8] JP-1, Doctrine for the Armed Forces of the United States, 25 March 2013.

[9] JP 3-52, Joint Airspace Control, 13 November 2014.

Disclaimer. The opinions, conclusions, and recommendations expressed or implied within are those of the contributors and do not necessarily reflect the views of the Department of Defense or any other agency of the Federal Government.

Originally released on 01 August 2017 in Air Land Sea Bulletin 2017-02.