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Feature Article 3

FEATURE ARTICLE

Kelly O’Dea, WVFC CFI av8trixcfi@gmail.com

 

Night Flying

I had dinner recently with another CFI and the topic of night flying came up. He said he absolutely avoids it unless it was to complete the necessary requirements for a private pilot student’s aeronautical experience. This was not the first time I heard these remarks from a well-seasoned veteran pilot. It is apparent within the GA community that there are those who do, those who don’t, and those who avoid it whenever possible. I’ve concluded it’s probably because of the fact that accidents at night are generally fatal. Full time flight instructors are certainly at a higher risk for catastrophe, so it’s understandable that the majority would like to mitigate the risk.


The vast majority of GA flying is done during the daytime and data concludes that less than 5% of GA hours are flown at night.


Flying at night presents a great list of challenges that every pilot should be ready for. First and foremost, would be the human factors which should be considered in the night flying process. The concept of ADM and risk management go hand in hand. They are systematic approaches that require fore-thought of the pilot in command. Physiological effects, however, can be potentially hazardous, especially when misunderstood.


The focus of this article is to re visit these human factors in order to prepare you for some of the affects you may encounter.


Night Vision:
We know through studying for the PPL that the rods are responsible for night vision and it is necessary to allow at least 30 minutes in low light conditions for those rods to work effectively. A secondary consideration is that the rods are peripherally stronger and the center of the eye which is normally used for focusing on targets during the day becomes weak and even blinded so the rods need time to adjust for off center focusing. The older the pilot, the longer time may be needed for this process to be complete and effective enough for clear vision. Whenever possible, try to conduct your preflight in natural light and give yourself some time on the ramp or in the dark cockpit to allow the eyes to adapt.


Illusions:
Auto-kinesis:
This occurs when a pilot stares at a fixed light source and the light appears to move about. This is more common in areas where there are few other lights in the vicinity. Be aware that the brain is attempting to make sense of this single light source. Don’t stress. The illusion is disconcerting, but is generally inconsequential. Blink your eyes and look away from the light, then try to re-focus on the area around the light instead of staring right at it.


Night Central Blind Spot:
Mentioned earlier here, the rods are responsible for periphery vision and the cones are inefficient at night. If you stare at a dim light source for too long, the source will disappear from view so it is important to keep the scan moving and don’t fixate on one light for too long.


Empty Field Myopia:
EFM happens when the eye is not encouraged to re-focus. This can happen when flying on cross country flights out of controlled airspace where there is little to no stimulation for the eyes to focus on. The most tragic scenario is CFIT. Keep your eyes re focusing on near and distant terrain features, highways, and inside the aircraft, to the wingtips, and back to the instruments. Don’t get lazy with the scan.


Black Hole Effect:
A common situation that develops when there is a long straight in approach over water or unlit terrain. All pilots need to be very aware of this hazard. The judging of one’s height on the final approach path can be exacerbated when lighting and terrain exists beyond the runway itself.  This causes the pilot to think they are high on the approach and therefore to steepen their descent and approach which can lead to potentially impacting terrain. Fly a normal distance traffic pattern and use the VASI or PAPI lights for reference to a safe glide path approach.


Fatigue:
Most GA pilots will conduct their night flying after a normal business day. It is important to be aware of your personal requirements for sleep and rest, as well as nourishment. Flying after work adds an element of fatigue that should heed awareness and self-evaluation of whether a flight should commence. If you’re hungry as well, you may be setting yourself up for a less than successful flight. It is important to perform the IMSAFE checklist and confirm you are fit to fly. My personal minimum for night flight training is a full night’s sleep and no more than 2 flights on that day. I want to be sharp and ready for a successful mission.


Hypoxia:
The FAA has concluded that hypoxic effects can be noticeable at 5000ft at night. In the average individual, night vision will be blurred and narrowed and dark adaptation will be affected. At 8000ft, studies have shown night vision to decrease by as much as 25% without supplemental oxygen. Few or no effects will be noticed during the day. You can purchase portable aviation oxygen canisters to carry for night flight and larger oxygen tanks for extended higher altitude flights and is always a good idea.


Hypothermia:
Without the warmth of the sun, it gets cold very quickly. Being too cold affects a person’s decision-making process and can bring on dangerous attitudes like “get there-itis” Ensure you are packed for comfort for the duration of your flight.

Night can be a wonderful time to fly. The air is typically calm, aircraft performance is better, and traffic is generally easier to see. Safe flights are of course possible with careful planning. Remember, currency does not mean proficiency, and legal does not necessarily mean safe. Reach out to your CFI for some refresher night training so you can feel confident flying at night.

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