The Role of Sector Command Ii/Makassar in Countering Aerial Threats Via Indonesia's Archipelagic Sea Lanes (Alki) Ii and Iii

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Bogor– Sector II/Makassar Command Faces Rising Air Threats in ALKI II and III. A recent study by Janner Halomoan Silalahi, Suwito, and Rudi Sutanto from The Republic of Defense University was published in the Contemporary Journal of Applied Sciences (CJAS), Vol. 4 No. 2 (February 2026).

A new study by Janner Halomoan Silalahi, Suwito, and Rudi Sutanto from The Republic of Defense University highlights the critical role of Sector II/Makassar Command in countering increasingly complex aerial threats across these vital corridors.

ALKI II and III: Strategic but Vulnerable Airspace

ALKI II and III are internationally recognized transit corridors that allow foreign ships and aircraft to pass through Indonesian waters and airspace under regulated conditions. These routes cut across central and eastern Indonesia and border the airspaces of Malaysia, the Philippines, Timor-Leste, Australia, and the U.S.-administered Palau region.

With tensions rising in the South China Sea and increased military deployments by major powers—including the United States and China—flight frequency through these corridors has intensified.

According to monitoring data shown in Figure 4 (page 176) of the study, 129 unscheduled military flights passed through ALKI III in 2023 alone. Aircraft types recorded include C-17, F-22, B-52, F-16, KC-135, and reconnaissance platforms such as the R-135. The C-17 accounted for 44 detections, while KC-135 aircraft reached 33 detections.

This growing activity underscores the strategic importance of Sector II/Makassar Command in safeguarding national airspace.

The Strategic Role of Sector II/Makassar Command

Sector II/Makassar Command operates within Indonesia’s layered air defense concept, or “defense in depth.” Its responsibilities include:

• Detecting and identifying aerial threats
• Monitoring international flight corridors
• Coordinating interception operations
• Supporting law enforcement in airspace violations

The study emphasizes that the effectiveness of this role depends heavily on the performance of radar-based Intelligence, Surveillance, and Reconnaissance (ISR) systems.

Radar ISR: The Backbone of Air Defense

Military radar systems in Sector II/Makassar currently include legacy platforms such as:

• Plessey AWS II
• Plessey AR-15
• Plessey AR-325 Commander
• Thomson TRS 2215/R

As shown in Table 1 (page 178), many of these radars were manufactured between 1961 and 1992, with maximum ranges between 120 and 250 nautical miles. Some systems still rely on magnetron tube transmitters with limited power output.

Intelligence Role

Radar systems gather critical intelligence on suspicious air activity. However, due to outdated technology, Primary Surveillance Radar (PSR) detection ranges fall below 200 nautical miles in some installations, limiting early detection beyond the Exclusive Economic Zone (EEZ).

The study warns that aging systems reduce the ability to respond to modern threats, including stealth aircraft and hypersonic weapons.

Surveillance Role

Radar systems are expected to operate 24 hours a day. Yet in Sector II/Makassar, most radars operate only 12–18 hours daily to prevent damage caused by outdated components.

Given that the monitored Flight Information Region (FIR) spans more than 5.19 million square kilometers, this limited operational window creates surveillance gaps.

According to the study, radar downtime ranged from 276 to 456 hours per month due to aging equipment and spare part shortages.

Reconnaissance Role

Reconnaissance supports early detection across three defense layers:

1. Outer Air Defense Area (EEZ zone)
2. Main Air Defense Area (ADIZ boundary)
3. Inner Air Defense Area (vital national object protection)

However, as explained on pages 180–181, existing radar systems can only effectively detect threats within the inner defense layer (118–240 nautical miles), leaving outer defense coverage insufficient.

Meanwhile, neighboring countries are deploying advanced Over-The-Horizon Radar (OTHR) systems with ranges up to 3,000 kilometers, including Australia’s Tacmor OTHR system illustrated in Figure 7 (page 181).

This technological gap poses strategic risks to Indonesia’s early warning capability.

Rising Geopolitical Risks

The study connects radar limitations with escalating regional tensions:

• Increased US and allied military flights through ALKI II and III
• Deployment of aircraft carriers and nuclear submarines in surrounding waters
• Development of hypersonic missile systems by China, Russia, and the United States

Hypersonic weapons are particularly concerning due to their high speed and maneuverability, making them difficult for conventional radar systems to detect.

Indonesia’s geographical position places it within the operational radius of multiple regional power projection systems.

Short-Term and Long-Term Solutions

Short-Term Measures

Sector II/Makassar has signed a Letter of Operation Coordination Agreement (LOCA) with Makassar Air Traffic Services Center (MATSC) AirNav Indonesia.

Through this cooperation:

• Data from 10 civilian radar installations are integrated
• Military-Civil Coordination (MCC) personnel are stationed at MATSC
• Civil radar coverage up to 250 nautical miles supports ISR functions

This integration strengthens early detection and correlation processes.

Long-Term Modernization Strategy

The study recommends:

1️⃣ Procurement of modern active radar systems with improved amplification and Mode-S ADS-B capability
2️⃣ Acquisition of passive radar systems to counter stealth aircraft
3️⃣ Deployment of Over-The-Horizon Radar (OTHR) with coverage up to 2,700 km
4️⃣ Software modernization aligned with national air defense doctrine

Passive radar, in particular, is highlighted as effective against stealth aircraft by detecting electromagnetic emissions rather than relying solely on reflected signals.

Conclusion: Modernization Is No Longer Optional

The study concludes that Sector II/Makassar Command plays a strategic role in protecting Indonesia’s airspace sovereignty in ALKI II and III. However, aging radar technology significantly reduces early detection capability and operational readiness.

Without modernization, Indonesia risks falling behind regional defense developments.

To ensure 24/7 air defense readiness, the researchers emphasize:

• National radar modernization programs
• Strengthened research and development
• Greater defense industry independence
• Integration of advanced ISR technologies

As geopolitical tensions continue to intensify in the Asia-Pacific, the ability to detect, monitor, and respond to aerial threats will determine Indonesia’s capacity to safeguard its sovereignty.

Author Profiles

• Janner Halomoan Silalahi-  Universitas Republik Pertahanan
• Suwito-  Universitas Republik Pertahanan
• Rudi Sutanto- Universitas Republik Pertahanan

Research Source

Silalahi, J. H., Suwito, & Sutanto, R. (2026). The Role of Sector Command II/Makassar in Countering Aerial Threats Via Indonesia's Archipelagic Sea Lanes (ALKI) II and III. Contemporary Journal of Applied Sciences (CJAS), Vol. 4 No. 2, 169–188.

DOI: https://doi.org/10.55927/cjas.v4i2.135

URL: https://ntlformosapublisher.org/index.php/cjas