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General Aviation Night Flying Guidance

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Article Information
Category: General General
Content source: SKYbrary About SKYbrary
Content control: EUROCONTROL EUROCONTROL

Description

This article provides generic guidance on flying at night for General Aviation pilots. For further information, see the references at the bottom of this articles under Further Reading and follow the links within the text to more detailed information.

Before you go Flying

Ensure you are fully rested before flying during a normal sleep pattern. Fatigue can have a significant impact on the safety of night flying. Avoid heavy meals which may affect your alertness.

Flight Planning

  • NOTAMs. When reviewing NOTAMs, consider what the implication of information will be for flying at night. For example, consider the impact on the conduct of the flight if airfield lighting is inoperative (e.g. VASIS) or if taxiways are closed.
  • Weather Forecast. Pay attention to anything which could lead to rapid deterioration in visibility whilst flying enroute or on approach to land. The risk of VFR flight into IMC is increased at night. Pay particular attention to the trend in Dew Point and surface temperature difference which is an indication of potential for ground fog.
  • Route Planning and Navigation. What might be a good turning point on a VFR day is not necessarily suitable at night. Consider distinctive, well lit, highway junctions or bridges, larger towns, unique islands and headlands. Back these up with bearings and distances from radio navigation aids - never rely completely on GPS. When marking maps, use ink that is comparable with the aircraft lighting - the use of red light in the cockpit helps to preserve night vision but makes certain colours of ink difficult to see.

Pre-flight Inspection

Take extra care with the pre-flight external check as, during the hours of darkness, it may not be so easy to spot things which are out of place, leaking or damaged. A torch to shine some light into the shadows is essential for a proper inspection.

Visual Illusions

Spend some time reminding yourself of the various types of visual illusion and how to avoid them. Ask other pilots what typical illusions they have experienced on the route you intend to fly.

Because there may be fewer visual cues and references (e.g. the horizon and other line features), spatial disorientation is more likely when flying at night e.g.

  • Somatogravic and Somatogyral Illusions - Somatogravic and Somatogyral illusions are the two most common forms of vestibular or ‘false sensation’ illusion which may be encountered when no clear horizon is present and flying wholly or partly by visual external reference is attempted.
  • Runway Visual Perspective - The Runway Visual Perspective may give rise to a visual illusion that may result in landing short of the runway, hard landing or runway overrun, but may also cause spatial disorientation and loss of control.
  • Autokinetic Effect - when staring at a single point of light against a dark background it can appear to move on its own. This is what is happening when a star or planet is misidentified as an aircraft. To avoid this maintain a normal scan pattern.
  • False Horizon - A false horizon can occur when the natural horizon is obscured or not readily apparent. It can be generated by confusing bright stars or city lights or while flying toward the shore of an ocean or large lake. Because of the relative darkness of the water, the lights along the shoreline can be mistaken for stars in the sky.

A good way to avoid night illusions is to fly to and from airports with Visual Approach Slope Indicator (VASI) or approach lighting systems.

Use of Flight Instruments

If you intend to fly at night and even if the weather is clear, an instrument rating improves your chances of a safe trip.

The use of flight instruments in conjunction with visual references enhances safety and reduces the risk of visual illusions e.g. use of Vertical Speed Indicator (VSI) to ensure a positive rate of climb when taking off into a "black hole" or the use of Attitude Indicator to supplement a marginally visible horizon reference.

Terrain Avoidance

Even though there may be unlimited visibility and not be a cloud in the sky, obstacles and terrain may not be that easy to see, especially if there is little cultural lighting (towns etc.) and no moonlight. Adjust the cockpit lighting to improve your night vision and reduce reflections.

Take note of the Maximum Elevation Figures (MEF) on your map - flying above the MEF will help ensure obstacle and terrain clearance.

Top Tip to Save your Life

  • If you have been able to see ground lights while flying enroute or descending at night, and then they disappear, consider pulling up immediately. You may have encountered a dark ridge or hilltop which lies in your flight path!

Related Articles

Further Reading

FAA

EUROCONTROL Guidance Notes for GA pilots

UK CAA