FlySafe was not operational during this event. This analysis reconstructs publicly available signals — to demonstrate how predictive airspace intelligence could have provided advance warning.
Sudan Civil War Airspace Closure
April 2023 — Full FIR Shutdown in Active Conflict
On April 15, 2023, fighting erupted between the Sudanese Armed Forces and the Rapid Support Forces in Khartoum. Within hours, the airport was a battlefield. Military aircraft were using the runway. Civilian staff fled. The HSSS (Khartoum FIR) closed to all civil aviation. Three years later, it remains closed. In October 2024, a cargo aircraft was lost over North Darfur — confirming that even non-combatant aviation faces lethal risk in Sudanese airspace.
What Happened
On April 15, 2023, armed clashes erupted between Sudan's Sudanese Armed Forces (SAF) and the paramilitary Rapid Support Forces (RSF) across Khartoum. Within hours, Khartoum International Airport (HSSS) — the primary international gateway for Sudan and a key transit node for Africa — was overrun by military forces. Civilian aircraft parked on the apron were damaged and rendered inoperable in the fighting. Civil aviation ceased entirely. The Khartoum FIR (HSSS) was shut down to all civil traffic, triggering a cascade of regulatory and operational responses that continues to this day.
EASA issued a Conflict Zone Information Bulletin (CZIB) for Sudan, and Safe Airspace assigned Sudan its most severe designation: Level 1 — Do Not Fly. What began as an acute crisis rapidly became one of the longest-running FIR closures in recent African aviation history, with the airspace remaining closed to scheduled civil traffic for over three years. A cargo aircraft lost over North Darfur in October 2024 confirmed that the threat environment had not diminished — it had expanded geographically.
- —HSSS FIR open to civil aviation
- —Khartoum International handling scheduled international flights
- —Europe–East Africa routes transiting Sudanese airspace normally
- —Political tension elevated but no active combat
- —Diplomatic framework (Jeddah talks) still nominally active
- —HSSS FIR fully closed to civil aviation
- —Khartoum airport overrun, civilian aircraft damaged beyond repair on apron
- —EASA CZIB issued; Safe Airspace Level 1 designation active
- —Europe–East Africa routes rerouted via HAAA (Ethiopia) or HCSM (Somalia)
- —Cargo aircraft lost over North Darfur, Oct 2024
Warning Signs
The April 2023 collapse of Sudanese airspace did not emerge without warning. An 18-month trail of political, military, and institutional signals — each individually noteworthy, collectively alarming — preceded the outbreak of open warfare. For operators and flight planners tracking the right data sources, the Sudan FIR was not an unexpected emergency. It was a predictable consequence of an accelerating crisis.
October 25, 2021: General Abdel Fattah al-Burhan dissolved the transitional government and declared a state of emergency. Power transferred entirely to the SAF. Historical precedent shows that military political transition removing civilian oversight represent the highest-tier precursor to airspace instability — every contested military power transition introduces armed faction risk into the operational environment.
Throughout late 2022 and early 2023, public disputes between SAF commander Burhan and RSF commander Mohamed Hamdan Dagalo (Hemedti) intensified around the proposed integration of RSF forces into the regular military. This structural dispute — over command, timeline, and force size — created a documented, publicised pathway to armed confrontation. By March 2023, OpsGroup sources flagged the deteriorating civil-military relationship as an active airspace risk factor.
In the days and weeks before April 15, both SAF and RSF forces positioned assets in and around Khartoum, including near the international airport perimeter. Unverified reports of RSF units occupying strategic infrastructure preceded the outbreak by at least 72 hours. Airport proximity to armed faction positioning is a direct airspace integrity threat that NOTAM systems alone cannot capture.
The Framework Agreement signed in December 2022 — intended to return Sudan to civilian rule — stalled repeatedly on the question of RSF integration. By early April 2023, international mediators including the African Union and IGAD publicly acknowledged the talks were at an impasse. When diplomatic frameworks that are explicitly designed to prevent violence collapse without replacement, the risk of uncontrolled armed confrontation increases sharply.
Sudan sits at the intersection of the Horn of Africa, the Sahel, and the Red Sea corridor — a uniquely congested risk zone. Both Ethiopia (HAAA) and Somalia (HCSM) — the primary reroute options for HSSS-avoiding traffic — carry their own elevated conflict risk profiles. HAAA had experienced Tigray conflict overflight concerns through 2022, and HCSM remains categorised as high-risk. A closure of HSSS was therefore not just a local event but a regional airspace stress test.
Timeline
SAF General al-Burhan dissolves Sudan's transitional government in a military political transition. Prime Minister Hamdok placed under house arrest. International community condemns the action. First concrete precursor to full state breakdown — civilian aviation oversight authority begins to weaken under military administration.
Framework Agreement negotiations over RSF-SAF military integration stall. Hemedti refuses terms that would subordinate RSF to SAF command within two years. Both forces begin positioning assets in Khartoum. International mediators from the AU, IGAD, and UN publicly flag rising risk of armed confrontation. OpsGroup raises Sudan as an elevated airspace monitoring zone.
Final diplomatic deadline passes without agreement. RSF forces reported moving into positions near Khartoum International Airport and the SAF General Command HQ. Multiple embassies in Khartoum issue travel advisories. Tension in the capital at breaking point — commercial aviation continues but with elevated operational caution.
Fighting erupts simultaneously across Khartoum between SAF and RSF at approximately 09:00 local time. Khartoum International Airport (HSSS) is overrun by military forces within hours. Civilian aircraft on the apron — including commercial jets from multiple operators — are damaged and rendered inoperable by gunfire and explosions. Air traffic control ceases operations. HSSS FIR declared closed to civil aviation. Evacuation flights suspended.
EASA issues Conflict Zone Information Bulletin (CZIB) for Sudan, advising European operators to avoid Sudanese airspace. Safe Airspace publishes Level 1 designation — the most severe rating, equivalent to "Do Not Fly." Airlines across Europe, the Middle East, and Africa reroute Europe–East Africa flights away from HSSS, adding significant track distance via HAAA (Addis Ababa FIR) or, where operationally acceptable, HCSM (Mogadishu FIR).
International community organises evacuation of foreign nationals via Wadi Seidna military airbase north of Khartoum — the only viable alternative airfield. Evacuation flights coordinated by the US, UK, France, Saudi Arabia, and others operate under military escort conditions. No commercial civil aviation resumes. Ceasefire attempts repeatedly fail.
A cargo aircraft is lost over North Darfur — the western region of Sudan where RSF control is near-total. The incident confirms that man-portable air defence systems (man-portable systems) or equivalent ground-based threats are actively deployed across multiple Sudanese regions, extending the threat envelope well beyond Khartoum. EASA CZIB and Safe Airspace Level 1 remain in force.
HSSS FIR remains closed to civil aviation. No timeline for resumption of commercial operations. Sudan's airspace closure has exceeded three years in duration, placing it among the longest-running conflict-driven FIR shutdowns in modern aviation history alongside Ukrainian (UKBV) and Libyan (HLLL) closures. Europe–East Africa routing continues to absorb significant detour penalties.
Aviation Impact
The Sudan closure is not a contained regional incident. It represents a systemic stress on the Africa–Europe–Asia routing network that has compounded over three years. With HSSS unavailable and alternative FIRs (HAAA, HCSM) themselves carrying elevated risk profiles, operators planning equatorial Africa routes now face a permanently degraded airspace environment with no near-term resolution.
HSSS has been closed to civil aviation since April 15, 2023 — over three years of continuous closure with no resumption date. One of the longest conflict-driven FIR shutdowns in recent history, alongside Ukraine (UKBV) and Libya (HLLL).
Sudan holds the highest risk designation on the Safe Airspace scale — "Do Not Fly" — continuously since April 2023. EASA CZIB has been active for the same period, making Sudan one of the most clearly and consistently flagged no-fly zones in current international aviation guidance.
A cargo aircraft was lost over North Darfur in October 2024, confirming the presence of operational air-to-ground regional military systems across the conflict area — not limited to Khartoum. This event validated the Level 1 designation and demonstrated that the threat envelope extends across the country's full geography.
Europe–East Africa traffic displaced from HSSS must transit HAAA (Addis Ababa FIR, Ethiopia) or HCSM (Mogadishu FIR, Somalia) — both of which carry their own active conflict risk assessments. Sudan's closure created a regional airspace problem: no clean alternative exists for the affected corridors.
Aircraft damaged beyond repair on apron. Multiple civilian aircraft — commercial jets parked at Khartoum International — were damaged or rendered inoperable during the fighting. The airport itself became a battle site within the first hours of conflict, a scenario that airport security planning rarely models and that creates unrecoverable loss of operational assets.
Evacuation operations constrained. With HSSS overrun, all civilian evacuation coordination shifted to Wadi Seidna military airbase — a facility not designed for high-volume civil operations. International military and government aircraft operated the evacuation under significant coordination complexity and risk.
Africa routing network degraded. The loss of HSSS as a transit FIR for Europe–East Africa routes added meaningful track miles to hundreds of weekly flight sectors. Carriers operating routes from Europe to Ethiopia, Kenya, Tanzania, and beyond absorbed fuel cost increases and schedule margin reductions that persist across the closure period.
Regulatory response immediate and sustained. Unlike some conflict zones where regulatory guidance lags events, EASA's CZIB issuance was rapid and has been maintained without interruption. This demonstrates the international regulatory appetite for sustained, durable designation of high-risk zones when the threat evidence is unambiguous.
Takeaway
The Sudan case is a textbook illustration of why pre-event political risk monitoring is not optional for flight operations departments. The HSSS closure on April 15, 2023 was not a surprise — it was the terminal outcome of an 18-month visible deterioration. Every signal was documented, publicised, and assessable through open-source and specialist intelligence channels. What separated operators who were prepared from those who were not was whether they were systematically aggregating that signal into operational decision frameworks before the guns started firing.
The specific failure mode here is one of category blindness: NOTAM monitoring and AIP watching — the standard tools of flight operations — are designed to capture declared airspace changes, not to predict undeclared conflicts. They are reactive by design. Sudan's airspace was technically open, with valid NOTAMs and active ATC, until the moment it was physically overrun. No NOTAM system may have flagged the risk 30 days earlier. Only a cross-domain intelligence approach — tracking political, military, and diplomatic signals — may have provided meaningful lead time.
The October 2024 cargo loss event over North Darfur adds a secondary lesson: conflict-zone threats are dynamic and geographically mobile. An operator who had judged Sudan to be a "Khartoum problem" and assumed peripheral areas might eventually reopen for cargo or charter operations received a lethal correction. Airspace risk assessment must account for the full territorial footprint of an armed conflict, not just its initial epicentre.
This retrospective analysis examines signals present in public data before the event. It is provided for educational context only and does not claim predictive capability for future events.
A retrospective analysis suggests FlySafe's indices may have indicated Sudan as an elevated airspace concern from October 2021 onward — the moment of the SAF political transition. The RSF–SAF integration dispute, tracked through open diplomatic and military sources, may have triggered progressive risk score escalation through Q1 2023. By early April 2023, as troop positioning near Khartoum International became reportable, FlySafe's HSSS FIR risk rating may have reached its highest tier — prompting route planning recommendations to avoid Sudanese airspace before the first shot was fired on April 15.
Coup detected → Sudan political risk flag raised. HSSS added to elevated monitoring list.
RSF–SAF talks collapse → Risk score escalates to HIGH. Reroute advisory issued to subscribers.
Troop movement near HSSS detected → CRITICAL alert. Immediate avoidance recommendation issued — 72 hours before closure.
Sudan also illustrates the importance of ongoing monitoring, not just pre-event alerting. Three years into the closure, with a cargo aircraft brought down in Darfur in October 2024, the risk environment has not resolved — it has evolved. FlySafe's continuous threat tracking ensures that operators do not drift back toward risk-normalisation for conflicts that are still active, simply because the initial emergency coverage has faded from news cycles.
Sources
- — OpsGroup — Military Coup Sudan: Airspace Closed — operational bulletin covering the April 15, 2023 FIR closure and ongoing status
- — EASA — Conflict Zone Information Bulletin (CZIB) for Sudan — issued April 2023, active and maintained through present
- — Safe Airspace — Sudan Conflict Zone Status — Level 1 (Do Not Fly) designation and ongoing risk assessment updates
- — Arab News — Sudan conflict aviation impact reporting — coverage of regional rerouting, evacuation operations, and airport seizure
- — BBC News / Al Jazeera — Sudan internal conflict timeline and conflict reporting — contemporaneous coverage of April 2023 outbreak, subsequent escalation, and October 2024 aircraft loss event
This is a retrospective analysis of publicly documented events. FlySafe's prediction system was not operational during this event. All information is sourced from public records, aviation authority publications, airline statements, and open data.