Flight Bomb Threats: Is a Hoax an Offence Under the Montreal Convention?

Introduction

Flight bomb threats disrupted commercial aviation across Europe in early November 2026, forcing aircraft to divert, triggering emergency security procedures, and raising questions about criminal liability. Among the incidents was the diversion of an Aer Lingus flight traveling from Dublin to Rome to a French military air base on November 5. Although several earlier warnings proved unfounded, the events raised a legal question: can someone commit an international aviation offense by falsely claiming that a bomb is aboard an aircraft?

Under the 1971 Montreal Convention, a knowingly false bomb threat can constitute an offense even when no explosive device exists. Article 1(1)(e) prohibits the intentional communication of information known to be false when that communication endangers the safety of an aircraft in flight. The provision does not require an explosion, injury, or physical damage. It does, however, require a causal connection between the false information and danger to the aircraft (Montreal Convention, 1971, art. 1(1)(e)).

The distinction becomes significant when a warning causes a precautionary diversion. Aircraft crews must respond seriously to potentially credible security threats, and their decisions may involve emergency landings, changes in flight plans, and coordination with authorities in several countries. Whether those measures establish endangerment under the Convention depends on the circumstances. The treaty does not expressly define the degree of danger required, and the available judicial and institutional authorities do not establish a single evidentiary test applicable to every diversion.

National criminal laws may also punish fabricated aviation warnings under provisions broader than those of the Montreal Convention. Where a suspect, aircraft, and affected authorities are located in different countries, jurisdiction and extradition rules determine how criminal proceedings may be pursued. A separate question of state responsibility could arise if reliable evidence established governmental involvement, although no such attribution has been established for the November 2026 incidents.

1. The European Flight Bomb Threats of November 2026

Commercial flights operating across Europe received multiple bomb threats during the first days of November 2026. The warnings affected aircraft operated by airlines including Aer Lingus, Ryanair, LOT Polish Airlines, Scandinavian Airlines, Wizz Air, and Finnair. Authorities responded through aircraft searches, precautionary diversions, and heightened security procedures. Some aircraft received military escorts, while others continued to their intended destinations under security arrangements.

On November 3, seven passenger flights were reported to have received bomb alerts. The affected services included flights operating to destinations in Poland, Italy, Spain, and Bulgaria. A LOT Polish Airlines flight from London Heathrow to Warsaw diverted to Warsaw-Modlin Airport, while a Scandinavian Airlines service from Copenhagen landed at Warsaw Chopin Airport and underwent security checks. Ryanair and Wizz Air flights were also affected.

The warnings prompted temporary airport disruptions and searches of aircraft, passengers, baggage, and cargo. Authorities reported finding no explosive devices in the incidents investigated that day. British officials described the warnings as malicious hoaxes, although investigators had not established whether the different communications originated from a common source, according to Reuters and Associated Press reporting published on November 3, 2026.

The incidents continued on November 5. Aer Lingus flight EI402, an Airbus A320 operating from Dublin to Rome, diverted to the French military air base at Évreux in Normandy following a bomb warning. The office of French Prime Minister Sébastien Lecornu confirmed the diversion. The aircraft landed safely, with 151 passengers and six crew members reported safe, while military explosive-ordnance specialists examined the aircraft (Reuters, 5 November 2026; Associated Press, 5 November 2026).

The Aer Lingus incident illustrates the international dimension of an aviation-security emergency. A commercial aircraft operating between Ireland and Italy landed in France following a warning received during its journey. The diversion involved aviation and security authorities outside the original itinerary. Such circumstances may engage several countries' legal interests, although the aircraft's route and the nationality of its airline operator do not alone identify every state possessing criminal jurisdiction.

The absence of explosives in the earlier incidents does not establish that every sender knowingly fabricated a threat. That conclusion requires evidence concerning the communication and the person's knowledge at the time. The publicly reported investigations had not identified those responsible for the November 2026 sequence or established that the warnings were coordinated. Nor had the incidents been attributed to any government.

2. The Criminal Offence Under the 1971 Montreal Convention

The Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation was adopted in Montreal on September 23, 1971, and entered into force on January 26, 1973. It establishes an international framework for suppressing specified acts threatening civil aviation through national criminal legislation and cooperation between contracting states.

Article 1 identifies the prohibited conduct. It includes violence against persons aboard aircraft, destruction or damage to aircraft, interference with air navigation facilities, and the communication of knowingly false information that endangers aircraft safety. Article 1(2) also addresses attempts and accomplice liability, while Article 3 requires contracting states to make the specified offenses punishable by severe penalties (Montreal Convention, 1971, arts. 1–3).

The Convention does not create an international criminal court. It requires contracting states to establish offenses and criminal jurisdiction under defined circumstances, with prosecutions conducted through competent national authorities. Individual liability depends on the applicable domestic legislation and the prosecution's ability to establish the relevant elements of the offense.

The 1971 instrument must be distinguished from the Montreal Convention of 1999, which governs aspects of international carriage by air. The later Montreal Convention addresses matters including carrier liability for specified passenger, baggage, and cargo claims. The present legal question concerns the 1971 aviation-security treaty and its provisions dealing with unlawful interference with civil aviation.

2.1 False Information, Knowledge, and Intent

Article 1(1)(e) establishes an offense where a person unlawfully and intentionally communicates information known to be false, thereby endangering the safety of an aircraft in flight. The wording contains separate requirements concerning the communication, the sender's knowledge, and its consequences. A prosecution must establish more than the existence of an alarming message or the fact that a security warning subsequently proved inaccurate.

The knowledge requirement distinguishes a deliberate hoax from an incorrect report made in genuine belief that a threat exists. A passenger who reports suspicious circumstances in good faith does not satisfy the provision merely because investigators later determine that no explosive device was present. Someone who knowingly invents a bomb warning and intentionally communicates it may satisfy the mental element, provided the remaining legal requirements are established.

The Convention does not prescribe a particular method of communication. A fabricated warning delivered by telephone, email, or another means may fall within Article 1(1)(e). Nor does the provision require the message to be transmitted directly to a pilot. Information communicated to an airline, airport authority, or air traffic service may ultimately affect an aircraft through established operational channels.

These distinctions are particularly relevant to remotely communicated threats, where the sender may never approach an airport or board an aircraft. Investigators may need to establish the message's origin, its content, the circumstances of transmission, and evidence demonstrating the sender's knowledge. Proof of deliberate fabrication remains legally distinct from proof that the communication endangered aircraft safety.

2.2 When an Aircraft Is Legally Considered in Flight

The Montreal Convention defines an aircraft in flight more broadly than the ordinary meaning of being airborne. Under Article 2(a), the relevant period begins when all external doors have been closed following embarkation and ends when a door is opened for disembarkation. In the case of a forced landing, the period continues until competent authorities assume responsibility for the aircraft and the persons and property aboard (Montreal Convention, 1971, art. 2(a)).

An aircraft may consequently be considered in flight while preparing for departure after boarding, even before takeoff. Similarly, an aircraft that has landed may remain within the treaty-defined period until the relevant external door is opened. This definition reflects the fact that safety risks may arise during operational phases when an aircraft is not physically airborne.

Article 2(b) separately defines an aircraft in service. That period generally begins with preflight preparations by ground personnel or crew and continues until 24 hours after landing, while encompassing the entire period legally classified as flight. The distinction is significant because different offenses in Article 1 use the expressions in flight and in service.

A bomb warning concerning an aircraft before boarding does not automatically satisfy the requirement that its safety be endangered in flight. The applicable legal analysis must account for the aircraft's operational status, the timing and effects of the communication, and the particular offense alleged. Domestic legislation may also provide separate criminal offenses concerning false alerts outside the Convention's defined flight period.

2.3 The Convention's Territorial Scope

Article 4 establishes conditions governing the Convention's application. For the false-information offense, Article 4(2) generally requires a connection extending beyond the aircraft's state of registration. This condition is satisfied where the aircraft's actual or intended place of departure or landing is outside the state of registration, or where the offense occurs in another state.

The provision applies irrespective of whether a flight is formally characterized as international or domestic. For a flight departing Ireland and intended to land in Italy, at least one of those locations necessarily lies outside the territory of any single state of registration. The Dublin–Rome route consequently satisfies the international connection specified in Article 4(2)(a).

Article 4(3) provides an additional basis of application where the offender or alleged offender is found in a state other than the aircraft's state of registration. The Convention also includes special provisions concerning jointly operated or internationally registered aircraft and offenses involving air navigation facilities.

These application rules must be distinguished from Article 5, which specifies the circumstances in which contracting states must establish criminal jurisdiction. An offense may fall within the Convention's scope without every country connected to the flight automatically acquiring jurisdiction under each treaty provision.

Article 4(1) excludes aircraft used in military, customs, or police services. This classification concerns the aircraft's function rather than the type of airport where it lands. A civilian commercial aircraft diverted to a military air base during a security emergency does not become a military aircraft merely because military personnel or facilities assist with its landing and inspection.

3. Does a Precautionary Diversion Amount to Endangerment?

The central difficulty in applying Article 1(1)(e) concerns the meaning of endangerment. The provision criminalizes knowingly false information when its communication endangers an aircraft in flight. It does not expressly state that every false warning becomes a completed treaty offense whenever an airline activates emergency procedures, interrupts a scheduled flight, or orders a precautionary diversion.

The wording differs from other offenses listed in Article 1, several of which expressly refer to conduct likely to endanger aircraft safety. Article 1(1)(e) instead requires that the false communication thereby endanger the aircraft. This difference supports treating the existence of danger as a separate legal question. It does not establish that an accident, physical injury, or independently documented mechanical hazard is always necessary.

The provision must be interpreted according to the ordinary meaning of its terms, their context, and the treaty's object and purpose. These principles are reflected in Articles 31 and 32 of the Vienna Convention on the Law of Treaties. The Montreal Convention seeks to protect civil aviation against unlawful interference, but its protective purpose must be considered alongside the particular language establishing criminal liability.

The treaty does not define the degree of danger necessary to satisfy Article 1(1)(e). Its application may involve both the risks generated by the false information and the effect of that information on operational decisions. The available institutional findings and domestic judicial decisions illustrate different factual circumstances, but they do not establish a single internationally binding evidentiary threshold.

A precautionary diversion may be powerful evidence that the warning affected the aircraft's operation. Its criminal significance nevertheless depends on the circumstances in which the decision was taken and the safety consequences of the communication. The existence of operational disruption and the existence of danger are closely related questions, but they should not be treated as legally identical in every case.

3.1 Emergency Diversions and Aircraft Safety

A false bomb warning may require flight crews to make consequential operational decisions under uncertainty. Those decisions can involve changing routes, selecting alternate airports, coordinating with air traffic controllers, and preparing for an unscheduled landing. The circumstances of the flight, including weather, fuel reserves, airport suitability, and surrounding air traffic, may influence the risks associated with those measures.

A precautionary diversion does not invariably expose an aircraft to the same degree of danger. An orderly diversion to an appropriate airport may be completed without any identifiable operational hazard beyond the uncertainty that prompted the response. Other circumstances may involve more serious consequences, particularly where false information manipulates safety-critical decisions or interferes with the normal exercise of professional judgment.

The fact that an aircraft lands safely does not necessarily establish that no endangerment occurred. Exposure to danger can exist without ultimately producing an accident. Conversely, the seriousness with which authorities treat a warning does not independently resolve whether the requirements of Article 1(1)(e) have been established.

The legal inquiry must consider the nature of the communication, the circumstances in which it was received, the operational response, and the causal relationship between the false information and aircraft safety. The provision permits a finding of criminal liability where those elements are established, but it does not authorize a presumption of guilt merely because established security procedures were followed.

3.2 ICAO's Findings on Ryanair Flight FR4978

The diversion of Ryanair flight FR4978 in Belarusian airspace on May 23, 2021, provides a significant example of deliberately false information being used to interfere with civil aviation. The aircraft was traveling from Athens to Vilnius when Belarusian air traffic authorities communicated a bomb threat. It subsequently landed in Minsk, where Belarusian authorities detained opposition journalist Roman Pratasevich and Sofia Sapega.

The International Civil Aviation Organization investigated the incident through a fact-finding team. Its investigation considered communications between air traffic controllers and the flight crew, information concerning the alleged bomb warning, and evidence obtained from those involved in the events.

On July 18, 2022, the ICAO Council completed its consideration of the investigation. In its public statement of July 19, the Council concluded that the bomb threat had been deliberately false and had endangered the aircraft's safety. It also found that the threat had been communicated to the crew on instructions from senior Belarusian government officials (ICAO Council, 2022).

The Council condemned Belarus's conduct as unlawful interference with civil aviation. It reiterated the relevance of the Montreal Convention's prohibition concerning knowingly false information that endangers an aircraft in flight. The Council's findings were subsequently endorsed by the ICAO Assembly in Resolution A41-1, adopted in October 2022.

These conclusions were supported by evidence of official involvement in the aircraft's diversion. The European Union's General Court also addressed that evidence in Belaeronavigatsia v Council, Case T-536/21, judgment of February 15, 2023. In reviewing EU restrictive measures, the Court considered the evidence that officials of the Belarusian air navigation service had knowingly participated in an operation intended to divert the aircraft for reasons unrelated to aviation safety.

The General Court's proceedings concerned the legality of EU restrictive measures, not the criminal conviction of an individual under Article 1(1)(e). Similarly, the ICAO Council's determination was an institutional finding rather than a criminal judgment establishing a universal judicial test for endangerment.

The FR4978 incident demonstrates that a deliberately fabricated threat can endanger an aircraft through the manipulation of aviation communications and operational decisions. Its circumstances, particularly the involvement of senior state officials and air traffic services, distinguish it from a routine diversion ordered in response to a warning whose origin and credibility remain under investigation.

3.3 The French Court of Cassation's 1987 Judgment

A judgment of the French Court of Cassation delivered on February 24, 1987, illustrates why the existence of a false warning and its effects on aircraft safety may require separate legal assessments. The case arose from a telephone call made on May 25, 1983, to Air Inter following an argument with an airline employee.

The defendant falsely claimed that a bomb had been placed aboard an aircraft preparing to depart for Paris. The warning triggered immediate security procedures. The aircraft, whose external doors had already been closed, was moved to a remote position, passengers disembarked, and baggage was inspected.

The lower court convicted the defendant under former Article 462-1 of the French Penal Code, which punished knowingly false information compromising the safety of an aircraft in flight. The Court of Cassation found that the lower court had not sufficiently established how the aircraft's safety had been compromised by the communication (Cour de cassation, Criminal Chamber, 24 February 1987, No. 84-94.308).

The Court nevertheless dismissed the appeal. The established conduct satisfied a separate offense under former Article 308-1, which punished knowingly false information intended to create belief in a serious attack against persons or property. The six-month suspended sentence was legally justified under that alternative provision.

The judgment interpreted French criminal legislation then in force, rather than determining the meaning of Article 1(1)(e) as a matter of international treaty law. It cannot be treated as a binding interpretation of the Montreal Convention for other states.

Its significance lies in the reasoning required to distinguish a false warning from an aviation-endangerment offense. The decision shows that a documented security response does not necessarily establish every element of a particular national offense. It does not resolve the separate question of what degree of danger satisfies Article 1(1)(e) under all circumstances.

4. National Criminal Liability for False Bomb Threats

The Montreal Convention establishes obligations for contracting states, but criminal proceedings against individuals are ordinarily governed by national legislation. Domestic statutes determine the precise elements of offenses, available penalties, procedural requirements, and jurisdictional conditions. Their provisions may extend beyond the Convention, particularly where legislatures criminalize conduct likely to endanger an aircraft rather than requiring proof that endangerment actually occurred.

Ireland provides a significant example. Section 3(1)(e) of the Air Navigation and Transport Act 1975, as amended, criminalizes the unlawful and intentional communication of information known to be false where that communication endangers, or is likely to endanger, the safety of an aircraft in flight. The inclusion of likely endangerment broadens the statutory formulation beyond the language of Article 1(1)(e) of the Montreal Convention (Air Navigation and Transport Act, 1975, s. 3(1)(e)).

The Irish legislation provides severe penalties. Under Section 6(1), an offense under Section 3 is punishable, following conviction on indictment, by imprisonment for life or a shorter term considered appropriate by the court. Section 6(2) prohibits suspension of a sentence imposed under that provision. Life imprisonment represents the statutory maximum rather than a sentence automatically imposed whenever a fabricated warning is communicated.

The seriousness of the penalty does not dispense with the need to establish the offense's elements. A prosecution under Section 3(1)(e) must still prove the relevant communication, the accused person's knowledge that the information was false, and the required connection with aircraft safety. The presence of likely endangerment in the statutory language affects the substantive test but does not eliminate the prosecution's evidentiary burden.

French law provides a different approach to false warnings. Article 322-14 of the French Penal Code punishes the communication or disclosure of false information intended to create belief that destruction, damage, or deterioration dangerous to persons will occur or has occurred. It also punishes false information creating belief in a disaster and capable of provoking unnecessary intervention by emergency services. The prescribed penalties are two years' imprisonment and a €30,000 fine (Code pénal, art. 322-14).

These provisions permit criminal liability to be considered independently of whether the particular aviation-endangerment elements associated with the Montreal Convention have been established. Their application nevertheless depends on the conduct satisfying the specific statutory requirements. The fact that an aircraft lands in France following a warning does not, without more, establish the liability of an unidentified sender under French criminal law.

The United Kingdom's Aviation Security Act 1982 adopts another formulation. Section 3(3) criminalizes intentionally communicating information that is materially false, misleading, or deceptive where the communication endangers or is likely to endanger aircraft safety in flight. Section 3(4) provides specified defenses, including reasonable belief in the truth of the information and certain communications made in good faith during lawful professional duties (Aviation Security Act, 1982, s. 3).

These national differences affect the classification and prosecution of fabricated aviation threats. Conduct that does not satisfy the precise endangerment requirement of Article 1(1)(e) may nevertheless constitute a domestic offense under a broader provision or a separate false-alert law. The applicable jurisdictional rules must also be established, particularly where threats originate outside the state whose aircraft or aviation services are affected. Such questions form part of the wider law governing extraterritorial jurisdiction in international law.

5. Which State Can Prosecute an International Bomb Threat?

A false bomb threat may involve several countries without occurring entirely within any one jurisdiction. An aircraft may be registered in one state, operated by an airline established in another, and traveling between two further countries. The sender may be located elsewhere, while the resulting security response occurs in another state's airspace or territory.

The diversion of Aer Lingus flight EI402 illustrates these overlapping connections. The aircraft departed Ireland for Italy but landed in France following a bomb alert. Ireland, Italy, and France were connected to the operation, although their respective jurisdictional positions cannot be determined simply from the aircraft's itinerary. Aircraft registration, the location of the alleged offense, and the identity and whereabouts of any suspect remain legally significant.

International criminal jurisdiction does not follow automatically from a state's involvement in an aviation incident. A country may have responsibility for coordinating an emergency response without necessarily possessing every jurisdictional basis contemplated by the Montreal Convention. Conversely, a state may have criminal jurisdiction over an offense even when the aircraft never enters its territory.

A further distinction concerns jurisdiction and enforcement. The authority to prescribe criminal law or adjudicate an offense does not independently authorize officials to arrest a suspect or seize evidence within another country's territory. Those separate forms of authority are addressed by the broader principles of jurisdiction in international law, together with applicable rules of international cooperation.

5.1 Criminal Jurisdiction Under Article 5(1)

Article 5(1) of the Montreal Convention requires contracting states to establish jurisdiction over specified offenses through four jurisdictional connections. The first concerns offenses committed within a state's territory. The second concerns offenses committed against or on board aircraft registered in that state. These grounds reflect territorial jurisdiction and the legal significance of aircraft registration (Montreal Convention, 1971, art. 5(1)).

The third ground applies where an aircraft on board which an offense was committed lands in a state's territory with the alleged offender still aboard. Both the location of the offense and the offender's continued presence aboard are relevant to this provision. It cannot be applied automatically to a remotely communicated bomb threat merely because the affected aircraft lands in another country.

The fourth ground concerns offenses committed against or on board aircraft leased without crew to a lessee whose principal place of business, or qualifying permanent residence, is located in the state asserting jurisdiction. This provision accounts for aviation arrangements in which the operator's connection with a state differs from the aircraft's registration.

These bases may overlap. The Convention does not establish a general rule granting exclusive criminal jurisdiction to the country where an aircraft makes an emergency landing. Nor does it treat the nationality of the airline operator as interchangeable with aircraft registration.

A prosecution concerning a remotely communicated warning may require identifying where the communication occurred and whether its transmission or consequences establish a recognized territorial connection under applicable law. The precise legal classification depends on the offense alleged and the jurisdictional rules of the state concerned.

5.2 The Jurisdictional Limitation in Article 5(2)

Article 5(2) establishes an additional jurisdictional obligation where an alleged offender is present within a contracting state's territory and that state does not extradite the person to a state possessing jurisdiction under Article 5(1). Its language, however, is narrower than the general offense provisions of Article 1.

The additional requirement expressly covers offenses under Article 1(1)(a)–(c), together with attempts and accomplice liability relating to those offenses. It does not expressly include Article 1(1)(e), concerning knowingly false information that endangers an aircraft in flight (Montreal Convention, 1971, art. 5(2)).

This omission limits the jurisdictional obligation established by Article 5(2). It would be inaccurate to interpret the provision as expressly requiring every contracting state to establish presence-based jurisdiction over all false aviation bomb threats, irrespective of any other jurisdictional connection.

Article 5(3) preserves criminal jurisdiction exercised in accordance with national law. A state may possess additional jurisdiction over conduct falling within the Convention where its domestic legislation provides a lawful basis. The Convention's mandatory jurisdictional provisions and the jurisdiction actually available under national law must consequently be distinguished.

The limitation also creates an interpretive question when Article 5(2) is considered alongside Article 7, which contains the Convention's broader obligation concerning extradition or submission for prosecution. The relationship between those provisions affects how contracting states may address an alleged false-information offender found outside the countries most directly connected to the aircraft.

6. Extradition, Prosecution, and International Cooperation

The Montreal Convention establishes mechanisms intended to prevent alleged aviation offenders from escaping legal proceedings merely because their conduct involves several countries. These mechanisms concern preliminary inquiries, custody, extradition, submission for prosecution, and assistance between national authorities. Their operation depends on the treaty's requirements and the domestic law governing the particular proceedings.

Article 7 provides that a contracting state in whose territory an alleged offender is found must, if it does not extradite that person, submit the case to its competent authorities for the purpose of prosecution. This obligation is commonly described as aut dedere aut judicare, or extradite or prosecute. The provision applies irrespective of whether the offense was committed within the state's territory (Montreal Convention, 1971, art. 7).

The obligation to submit a case does not require the authorities to obtain a conviction. Article 7 directs competent national authorities to make their decision in the same manner as for an ordinary offense of a serious nature under that state's law. Prosecutorial decisions remain subject to the applicable legal standards, including the sufficiency of evidence and procedural requirements.

The relationship between Articles 5(2) and 7 requires careful interpretation. Article 7 employs broad language concerning alleged offenders found in a contracting state's territory, while Article 5(2) expressly limits its additional jurisdictional requirement to specified offenses that do not include Article 1(1)(e).

The difference cannot be disregarded by treating Article 7 as though it automatically amended Article 5(2). Nor does the narrower jurisdictional provision eliminate the separate language of Article 7. The Convention does not expressly resolve every consequence of this asymmetry for a false-information offense. Domestic jurisdictional legislation remains significant in determining how a particular prosecution may proceed.

Article 8 establishes arrangements concerning extradition. It requires offenses covered by the Convention to be treated as extraditable under relevant treaties between contracting states. Where a requested state ordinarily requires an extradition treaty but has none with the requesting state, Article 8(2) permits the Montreal Convention itself to serve as the legal basis for extradition.

That possibility remains subject to the other conditions imposed by the law of the requested state. The Convention does not establish an unconditional entitlement to surrender a suspect regardless of applicable procedural requirements or legal protections. The distinction between international extradition obligations and domestic surrender procedures is central to extradition in international law.

Article 6 addresses preliminary inquiries and measures concerning an alleged offender's presence. Where the relevant circumstances warrant such measures, the state concerned must act in accordance with its law and undertake a preliminary inquiry. The provision also establishes notification obligations and safeguards concerning communication with representatives of the detained person's state of nationality.

The Convention additionally requires cooperation in obtaining information and pursuing criminal proceedings. Article 11 obliges contracting states to afford extensive mutual assistance, subject to the law of the requested state. Articles 12 and 13 concern the communication of information between states and reporting to the International Civil Aviation Organization.

These provisions may be important where a threatening communication is transmitted from one country but affects an aircraft operating elsewhere. Investigators may need assistance in identifying the sender, securing communication records, obtaining witness evidence, and reconstructing operational decisions. None of these steps can be presumed to establish criminal liability before the relevant evidence has been assessed.

Article 10(2) addresses a separate consequence of unlawful interference with civil aviation. Where a flight has been delayed or interrupted because of an offense covered by Article 1, a contracting state in whose territory the aircraft, passengers, or crew are present must facilitate continuation of the passengers' and crew's journey as soon as practicable. It must also return the aircraft and cargo without delay to those lawfully entitled to possession.

The obligation is particularly relevant to international diversions, but its application depends on the disruption resulting from commission of a covered offense. It does not automatically arise merely because authorities investigate an alert that has not been established as criminal conduct under Article 1.

7. The 2010 Beijing Convention and False Aviation Threats

The Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation was adopted in Beijing on September 10, 2010, and entered into force on July 1, 2018. It represents a later development in international aviation-security law, extending the range of prohibited conduct and revising several jurisdictional and cooperation arrangements associated with the earlier Montreal Convention.

The Beijing Convention retains the knowingly false-information offense in Article 1(1)(e). Its language continues to require that the communication endanger the safety of an aircraft in flight. The later treaty consequently does not eliminate the legal question concerning the relationship between a fabricated warning, operational disruption, and endangerment (Beijing Convention, 2010, art. 1(1)(e)).

The jurisdictional provisions contain more substantial differences. Article 8(1)(e) requires states parties to establish jurisdiction over covered offenses committed by their nationals. Article 8(2) permits additional jurisdiction in specified circumstances involving offenses committed against nationals or by stateless persons habitually resident within the state's territory.

Article 8(3) is particularly significant for false bomb threats. It requires states parties to establish jurisdiction over offenses under Article 1 when an alleged offender is present in their territory and is not extradited to a state possessing jurisdiction under the applicable provisions of Article 8. Unlike Article 5(2) of the 1971 Montreal Convention, this additional requirement does not exclude the knowingly false-information offense (Beijing Convention, 2010, art. 8(3)).

The distinction strengthens the jurisdictional arrangements between states bound by the Beijing Convention. It does not remove the need to prove that the communication was intentionally made, that its sender knew the information was false, or that the required endangerment occurred.

The two conventions also differ in their application between states. Article 24 of the Beijing Convention provides that it prevails over the 1971 Montreal Convention and the 1988 supplementary protocol concerning violence at airports as between states parties to the later instrument. It does not terminate the operation of the 1971 Convention between states that have not become parties to the Beijing Convention.

Treaty participation is consequently decisive. The International Civil Aviation Organization's updated 2026 depositary record identifies 60 parties to the Beijing Convention, including France, but does not list Ireland or Italy as parties. France became bound by the Convention when it entered into force on July 1, 2018. The instrument cannot be presumed to govern the treaty relationships of all three countries merely because the Aer Lingus aircraft landed in French territory (ICAO, 2026).

France's participation may be relevant to its jurisdictional obligations under the Beijing Convention where the necessary legal conditions are satisfied. It does not establish, without further facts, that French authorities possess jurisdiction under every provision of that instrument over the unidentified sender of a remotely communicated threat.

The Beijing Convention illustrates how international aviation-security law has expanded the grounds on which states must establish criminal jurisdiction while preserving the essential requirements of the false-information offense. The applicable treaty, jurisdictional connections, and domestic implementation must be identified separately in each case.

8. State Responsibility if Government Involvement Is Established

Individual criminal responsibility for a false bomb threat must be distinguished from the international responsibility of a state. A person who deliberately communicates false information may face prosecution under applicable national law. A separate question arises where the conduct is attributable to public officials or persons acting under state instructions, direction, or control.

The general rules of state responsibility in international law require conduct attributable to the state and a breach of an international obligation binding upon it. These elements appear in Article 2 of the International Law Commission's 2001 Articles on Responsibility of States for Internationally Wrongful Acts. The Articles are not a treaty, although important provisions reflect customary international law and have been relied upon by international courts (ILC, 2001, art. 2).

Attribution depends on the relationship between the relevant conduct and the state. Article 4 addresses conduct of state organs, while Article 5 concerns persons or entities exercising governmental authority. Article 8 covers conduct undertaken on a state's instructions or under its direction or control. The applicable rule must be assessed against evidence demonstrating the necessary legal connection.

The fact that a government might benefit politically from disruption does not independently establish attribution. Nor does the origin of an electronic message or the location of communications infrastructure automatically demonstrate that the relevant state directed or controlled the conduct.

The FR4978 incident illustrates the importance of specific evidence. ICAO's 2022 findings identified senior Belarusian officials as having instructed the communication of a deliberately false bomb warning to the aircraft. The ICAO Council condemned the resulting unlawful interference and addressed its inconsistency with Article 4 of the Chicago Convention.

Article 4 of the Chicago Convention requires contracting states not to use civil aviation for purposes inconsistent with the Convention's aims. The ICAO Assembly subsequently endorsed the Council's determination that Belarus's conduct in the FR4978 incident amounted to a flagrant and serious violation of that provision (ICAO Assembly, 2022, Resolution A41-1).

The legal findings concerning FR4978 cannot be transferred to unrelated incidents. If reliable evidence eventually established state involvement in deliberate aviation bomb threats, the relevant legal analysis would need to identify the attributable conduct and the international obligation allegedly breached. The rules governing state responsibility do not create a presumption that repeated threats are governmental operations.

Disputes between contracting states concerning the interpretation or application of the 1971 Montreal Convention may also engage Article 14. That provision establishes a conditional procedure involving negotiation, arbitration, and potential referral to the International Court of Justice. Its application depends on the specified procedural conditions and any relevant reservation excluding the compulsory dispute-settlement mechanism.

Article 14 concerns disputes between states, not the criminal prosecution of individuals accused of communicating false warnings. Its relevance would arise only where an identifiable interstate dispute concerned obligations under the Convention.

The November 2026 European flight bomb threats have not been attributed to a government on the publicly established evidence. Their timing, geographic distribution, and operational effects do not provide a sufficient basis for identifying a responsible state. The immediate legal questions concern the communications themselves, their effect on aircraft safety, and the national and international mechanisms available to investigate any resulting offenses.

Conclusion

A deliberately fabricated bomb warning can constitute an offense under Article 1(1)(e) of the 1971 Montreal Convention even when no explosive device is found aboard an aircraft. The provision requires intentional communication of information known to be false and resulting endangerment of an aircraft in flight. An explosion, injury, or accident is unnecessary, but the treaty does not expressly treat every precautionary diversion as conclusive proof of endangerment.

The legal assessment depends on the circumstances of the communication and its demonstrated consequences for aircraft safety. ICAO's findings concerning Ryanair flight FR4978 establish that a fabricated warning can amount to unlawful interference involving endangerment, while the French Court of Cassation's 1987 judgment illustrates the separate evidentiary requirements that may arise under domestic aviation-endangerment legislation. Neither authority supplies a universal criminal-law test applicable to every bomb alert.

National legislation may impose liability under broader provisions, including offenses concerning likely endangerment or false information intended to provoke emergency responses. International jurisdiction, extradition, prosecution, and cooperation obligations operate through the Montreal Convention and, between states bound by it, the later Beijing Convention.

The European incidents of November 2026 demonstrate how a communication that ultimately proves unfounded can disrupt international civil aviation across several jurisdictions. They do not establish that every reported threat satisfies the Montreal Convention's criminal definition, nor do they establish common authorship or governmental responsibility. Criminal liability depends on the applicable law and evidence, with a decisive distinction between an unfounded warning, a knowingly fabricated communication, and conduct that endangers aircraft safety within the meaning of the relevant offense.

References

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