Why Some Carriers Fly Restricted FIRs and Others Do Not
For any FIR with active advisories or restrictions — Russian-controlled airspace, OIIX (Tehran), ORBB (Baghdad), OYSC (Sanaa), OAKX (Kabul) — published flight-track data shows that some carriers continue to operate while others avoid the FIR entirely. The pattern reflects layered structural factors rather than a single operator decision.
The Five Layers of Routing Decision
State of registry
The operator\'s state of registry sets the baseline. Russian-airspace prohibitions apply to EU, US, Canadian, and UK-registered operators (and were reciprocally adopted by Russia for those carriers). Operators registered elsewhere are not subject to those rules. Similarly, FAA SFARs (e.g. SFAR 117 covering OIIX) bind US-registered operators globally; they do not bind, for example, an Emirati or Singaporean carrier.
Home authority interpretation of advisories
EASA CZIBs are advisory for EU-registered operators, but each EU member-state CAA can convert them into binding national instructions for carriers under its registry. As a result, a CZIB covering the same FIR may be operationally binding for a German-registered operator but advisory for a Spanish-registered operator, depending on each CAA\'s implementation. Non-EU carriers follow their own national authority\'s guidance, which may be lighter or stricter than the EASA position.
Insurance terms
Hull war and liability insurance is priced and structured per region of operation. An operator may face premium increases, deductible changes, or specific underwriter conditions for FIRs with active advisories. Where the regulator does not prohibit operation but insurance economics make the route unviable, the operator may still avoid the FIR. Insurance terms are typically reviewed at annual renewals, with intermediate adjustments possible after material safety events.
Internal Safety Management System (SMS)
Each operator runs an SMS that includes route-level hazard identification and management. The SMS produces operator-specific decisions on whether to operate a given FIR, at what altitude, with what crew familiarisation, and with what real-time monitoring. Two operators under the same regulator and with similar insurance terms can reach different SMS conclusions for the same FIR; both can be defensible within the regulatory framework.
Route economics and bilateral agreements
Even where an operator could legally operate a FIR, the route\'s yield versus the cost of overflight fees, fuel burn, crew duty, and capacity must support the schedule. Where the route is marginal, an operator may suspend service rather than absorb additional costs. Bilateral air-service agreements between states can also include specific corridor terms that materially affect economics. Carriers with long-standing bilateral arrangements may retain access that newer or differently-aligned operators do not have.
Why Different Operators Reach Different Conclusions
A common observation is that operators registered in different jurisdictions, or even within the same jurisdiction, make different decisions on the same FIR. Examples that illustrate the layering:
- Russian airspace overflight is operationally available to many Asian carriers (subject to bilateral terms) but not to EU/US/Canadian/UK carriers (binding home-authority prohibition).
- Iranian airspace (OIIX) is binding-prohibited for US carriers under SFAR 117 but advisory under EASA CZIB 2026-02-R1 for EU operators; operator-by-operator decisions differ within the EU.
- Iraqi airspace (ORBB) is binding-prohibited for US carriers under SFAR 77 with carve-outs for Erbil ORER and Sulaymaniyah ORSU; EU operators apply EASA CZIB guidance and internal SMS.
- Afghan overflight (OAKX) is conducted by a narrow set of regional and Asian operators under specific arrangements; major Western carriers continue to avoid OAKX.
In each case, the differences are driven by the layered framework above, not by any single operator\'s view of the underlying conditions.
Related
Restricted FIR Operations — Frequently Asked Questions
Common search queries answered with current status, FIR codes, and source citations.
- Why can some airlines fly through Russian airspace while others cannot?
- The decision is governed primarily by the operator's state of registry. The Russian airspace ban (and the reciprocal bans by EU, US, Canada, and the United Kingdom) applies to operators registered in those jurisdictions. Carriers registered elsewhere — for example, Chinese or Gulf operators — are not subject to those bans and may continue to overfly Russian airspace within the constraints of their own home authorities and bilateral agreements.
- Is it the airline's choice or a regulator's decision?
- It is layered. The home regulator (e.g. FAA for US-registered operators, EASA member-state CAAs for EU operators) sets binding constraints. Within those constraints, the operator makes its own decision based on its safety management system, insurance terms, route economics, and corporate policy. Two carriers under the same regulator can therefore make different operational choices for the same FIR.
- What role does insurance play?
- Hull war and liability insurance terms vary materially by region. Carriers operating in or near restricted FIRs may face higher premiums, additional exclusions, or specific underwriter requirements. An operator may decide that the insurance economics make a route unviable even where the regulator does not prohibit it. Public reporting from Lloyd's market and aviation insurance trade press tracks these dynamics.
- Why do operators differ on FIRs covered by an EASA CZIB?
- EASA Conflict Zone Information Bulletins are advisory by default for EU-registered operators. Each EU member-state national aviation authority can convert advisory CZIBs into binding national instructions for their registered operators. Where the CZIB remains advisory, individual operators apply their internal safety management system to decide whether to operate, at what altitude, with what frequency, and under what monitoring. Outcomes therefore vary across operators registered in different EU member states.
- Do bilateral air-service agreements matter?
- Yes. Overflight rights are formalised in bilateral or multilateral air-service agreements between states. A carrier's ability to overfly a particular FIR depends on whether such an agreement is in effect and what conditions it specifies. Some carriers retain corridor access through long-standing agreements that other operators do not have. Bilateral arrangements can also include specific carve-outs for restricted FIRs.
- Where can I see which carriers fly through which restricted FIRs?
- Public flight-tracking platforms (Flightradar24, FlightAware, ADS-B Exchange) show real-time and historical flight tracks. Industry trade publications (FlightGlobal, Reuters, Bloomberg Aviation) regularly publish analysis of carrier-by-carrier overflight choices. EUROCONTROL Aviation Trends publications include aggregated flow data. FlySafe maintains FIR-level briefings rather than carrier-specific routing data; for individual carrier choices, consult flight-tracking tools.
FlySafe provides automated computation of numerical indices from publicly available data. Operational routing decisions rest with individual operators in compliance with their home-authority requirements. Indices and explanations are educational and do not constitute operational advice. See Terms of Service.