Question to the Department for Transport:

To ask the Secretary of State for Transport, if she will review the evidential basis for the Colour Assessment Diagnosis test.

The UK Civil Aviation Authority (CAA) keeps the evidential basis for colour vision testing under regular review. The Colour Assessment and Diagnosis (CAD) test, developed with City University London, is currently the only advanced colour vision test accepted by the CAA because independent analysis has shown that it, along with anomaloscopes when used correctly, provides 100% sensitivity and specificity. The CAD test is also used by other aviation authorities including the United States’ Federal Aviation Authority, Australia’s Civil Aviation Safety Authority and the Civil Aviation Authority of New Zealand.

We recognise the importance of this issue for the pilot community and will continue to monitor emerging evidence and international practice carefully. International bodies, including the International Civil Aviation Organization (ICAO) and the European Union Aviation Safety Agency (EASA), are also actively examining developments in this area. EASA has commissioned a major research programme on colour vision in aviation, expected to conclude in 2026, which may inform future policy. The Government’s priority remains maintaining the high level of aviation safety expected in the UK.