Taking the Fright Out of Rotorcraft Night Flight
By Leah Murphy, FAA Safety Team Representative
For helicopter pilots, night flying can present a unique set of challenges with additional risks and threats to safety that must be mitigated. Threats such as reduced visibility, altered depth perception, and diminished spatial awareness all contribute to the complexity of operating at night. To ensure safety, helicopter pilots rely on various techniques such as utilizing celestial illumination, preplanning for off-airport landings, and taking precautions to avoid hazards.
Celestial illumination, the natural light provided by the moon and stars, plays a key role in enhancing visibility during night flights. On a clear, moonlit night, natural light can significantly aid a pilot’s ability to see terrain features, identify obstacles, and evaluate potential landing zones. The phase of the moon, cloud cover, and weather conditions all directly affect the amount of light available. During a full moon, there is more ambient light to support night vision, but during a new moon or overcast nights, pilots may encounter darker conditions that require additional caution.
For pilots flying without night vision goggles (NVGs), celestial illumination becomes even more critical. Monitoring lunar phases and weather forecasts before a night flight allows pilots to better anticipate the available light and plan accordingly. Flying in remote areas with little or no artificial light requires pilots to use the stars and moon to their advantage, helping them to maintain better spatial orientation in an otherwise dark environment.
Nighttime off-airport landings are particularly risky due to reduced visibility and limited ability to assess terrain. Pilots attempting off-airport landings at night should take extra precautions, such as performing an assessment of potential landing zones during the day, if possible. While daylight operations allow for a thorough visual inspection of a landing zone, nighttime operations depend more on preflight planning and careful approach techniques. The Helicopter Flying Handbook notes that pilots have a tendency to focus too much on the landing area and don’t pay enough attention to airspeed. If too much airspeed is lost, a vortex ring state condition may result. Unlike during daytime operations, it is difficult to judge the helicopter’s rate of closure using outside references at night. Pilots need to pay special attention to the airspeed indicator and maintain some form of forward airspeed until close to the ground.
Additional considerations for night flying include familiarization with obstructions along the route. The Helicopter Flying Handbook highlights that poor reflective surfaces, such as wires and small tree limbs, are difficult to detect. Pilots should always review the most current hazard maps with known wire locations before night flights.
Migrating birds pose an additional threat during night flights, especially during peak migration seasons in the spring and fall. Keep in mind that many bird species migrate at night to take advantage of cooler temperatures and to avoid daytime predators. Ninety percent of reported bird strikes occur at or below 3,000 feet above ground level. To mitigate this risk, pilots should review migration forecasts and adjust flight altitudes or routes when necessary. Understanding migration patterns and avoiding high-risk areas during peak times can significantly reduce the chance of encountering migrating birds, which can cause severe collision damage.
With mindful preparation and attention to night-specific challenges, helicopter pilots can navigate the complexities of night flying with greater safety and confidence. For more in-depth guidance on night operations, pilots can refer to the Helicopter Flying Handbook (Chapter 12), which provides comprehensive information on night vision techniques, landings, and managing unique nighttime hazards.
Leah Murphy is a dual-rated flight instructor and helicopter air ambulance pilot. She is also an FAA Safety Team Representative in Cleveland, Ohio.
