Night-Vision Goggles in Helicopter Operations: Potential Contribution to Spatial Disorientation and Operational Implications

Introduction: Night vision goggles (NVGs) extend the capability of helicopter crews to conduct night operations, but they do not reproduce daytime vision and may alter the visual conditions in which spatial disorientation (SD) develops. A historical helicopter study reported an approximately five-fold higher SD-related accident rate during night-vision device (NVD) operations than during daytime flight. This review examines how NVG/an night vision imaging system characteristics, degraded visual environments (DVE) and crew-system interactions may contribute to the development or delayed recognition of SD, and identifies practical safety barriers for helicopter operations. Method: This purposive narrative review integrates peer-reviewed aviation-medicine and human-factors literature with a structured analysis of seven publicly documented helicopter accidents or serious incidents involving NVG/NVD operations. The case analysis distinguishes official investigation findings from the author’s interpretation and maps case evidence onto recurrent perceptual, cognitive and operational mechanisms. Results: Across the seven cases, recurrent patterns involved low-contrast or featureless scenes, loss or degradation of visual references, blooming or incompatible lighting, delayed transition to instruments and attentional or crew-monitoring failures. Five proposed conceptual operational pathways summarise how these conditions may converge on SD. Conclusions: The principal hazard is not NVG use per se, but continued reliance on a partially reliable external image that may omit a stable horizon, surface texture, optical flow or valid depth cues. Mitigation therefore depends on predefined visual-reference minima and abort criteria, early transition to instruments, compatible lighting, radar-altimeter and flight-parameter monitoring, realistic DVE training, and assertive crew coordination.