The Horizon Air unauthorized takeoff in August 2018 exposed an uncomfortable truth for regulators and operators: insider access plus limited mental-health safeguards can produce catastrophic operational risk even when screening and background checks appear to be in place. The FBI concluded its investigation into the incident and determined the employee acted alone and that existing credentialing did not reveal an obvious motive. That post-incident reporting also made clear that routine airport vetting focuses on criminal background and identity checks rather than formal psychological screening.

Those facts create an obvious policy question. Should airlines and airport employers expand psychological screening beyond the narrow, periodic medical certification that applies to flightcrew, and if so how can that be done consistent with law, privacy, and operational realities? Any practical answer must start with the regulatory baseline that existed through mid-2023. In the European Union the Germanwings 2015 crash prompted a concrete regulatory response: by 2018 the EU adopted rules requiring airlines to provide pilot support programmes and to perform a psychological assessment of pilots before they commence employment. EASA and the European Commission framed this as both crew support and pre-employment assessment, with a transition timetable for implementation.

The United States took a different path. FAA doctrine emphasizes aeromedical oversight through Aviation Medical Examiners, pilot self‑reporting, targeted psychiatric or psychological evaluations when indicated, and voluntary peer support mechanisms. The FAA has expanded training for AMEs and encouraged peer support programmes, but it has not mandated a Europe‑style, universal pre‑employment psychometric regime for airline pilots. At the same time the FAA does maintain procedures to require psychiatric and psychological evaluations when the agency has information that raises concern about a certificated airman.

Legal limits in the U.S. matter. The Americans with Disabilities Act and EEOC guidance restrict medical inquiries and examinations before a conditional job offer. Post‑offer medical examinations are permitted, but any adverse decision based on those results must be job related and consistent with business necessity. That legal scaffolding means employers and regulators cannot freely deploy broad, invasive mental‑health testing for applicants without a clear legal justification tied to the essential functions and direct safety risks of the role. Implementation therefore requires careful design to avoid unlawful discrimination and to preserve confidentiality.

Operationally there are further constraints. Validated aviation assessments exist and are in use in selection contexts. Tools range from cognitive batteries such as CogScreen variants to personality inventories such as MMPI or NEO type instruments and structured interviews overseen by psychologists with aviation expertise. Those instruments can screen for certain risk factors and inform selection decisions, but they are blunt at predicting rare, low‑base‑rate acts such as deliberate sabotage or suicide carried out in an operational environment. Relying on testing alone creates a false sense of security. Any screening regime should therefore be layered with access control, monitoring of anomalous behaviour, peer reporting, and robust employee assistance programmes.

What a legally compliant, operationally credible policy package looks like

1) Targeted pre-offer and post-offer screening. For truly safety‑sensitive positions that require unescorted access to aircraft or aircraft controls, employers can use post‑offer medical and psychological examinations that are narrowly tailored and applied uniformly across the job category. The employer must document the job‑relatedness and business necessity of the tests and act consistently with ADA requirements. This is an appropriate point to require validated cognitive and personality screening administered or overseen by qualified aviation psychologists.

2) Expand who is covered. Screening for mental fitness cannot be limited to pilots if the risk vector includes ground staff, maintenance technicians, and other employees with cockpit or systems access. The Horizon case illustrates that non‑pilots with physical access can create serious risk. Coverage expansion should be risk‑based and tied to access privileges rather than job titles. Public policy should prioritize those with unsupervised access to aircraft, fueling systems, towing equipment, or jump seats.

3) Build robust support and rehabilitation pathways. Psychological assessment is not solely a gatekeeping tool. Regulators in Europe explicitly paired assessment mandates with access to support programmes. In practice an effective system must include confidential avenues for care, non‑punitive reporting pathways, return‑to‑work protocols, and monitored reintegration where needed. That reduces stigma and increases the likelihood that employees will seek help before a condition escalates.

4) Layer technical and physical controls. Screening must be complemented by strengthened access controls, two‑person rules where feasible, electronic logging of access, camera coverage of critical zones, and enhanced vetting for who may enter cockpits or jump seats. These technical mitigations reduce dependency on perfect human‑factor screening.

5) Safeguards for validity, privacy and oversight. Tests should be validated against aviation‑relevant populations, administered by qualified professionals, and limited in scope to minimize false positives and privacy invasion. Employers must maintain medical confidentiality and use results only for safety‑related decisions that meet ADA and other statutory standards. Regulatory oversight should require documentation and periodic audits of screening programmes.

6) Realistic communications with the flying public and workforce. Policymakers must avoid overselling screening as a panacea. Psychological tools reduce risk in measurable ways but cannot predict rare, improvised acts. Transparency about limits, combined with visible multilayered controls and support for workforce wellbeing, will preserve public trust while protecting legal rights.

Practical next steps for regulators and operators

  • Regulators should issue clear guidance on what constitutes a job‑related psychological assessment for different classes of personnel and provide acceptable means of compliance modeled on EASA’s approach. That guidance should spell out minimum qualifications for psychologists and standards for validation.

  • Employers should perform a risk mapping exercise to identify which roles require enhanced psychological assessment and which can be addressed through access controls and monitoring. Post‑offer psych evaluations should be the default for roles with unsupervised access to aircraft or primary controls.

  • Congress and oversight bodies should fund studies to validate screening batteries against aviation populations and to evaluate the effectiveness of support programmes and peer reporting in preventing serious insider events. Evidence will drive defensible policy that respects civil rights while addressing real vulnerabilities.

Conclusion

Horizon Air’s 2018 incident and the broader policy debate sparked by Germanwings show that aviation safety demands a balanced approach: one that strengthens psychological assessment where it is job related and necessary, protects employees’ rights under law, invests in validated assessment and support infrastructure, and layers non‑medical mitigations to reduce reliance on any single control. Policymakers should adopt targeted, evidence‑based screening for roles that truly matter to safety, protect confidentiality, and redouble investments in peer support and access control. No single measure will eliminate insider risk, but a legally sound, multilayered strategy will make the skies demonstrably safer.