What Is MSL in Aviation?
Pilots · 5 min read
MSL stands for Mean Sea Level, a measurement of altitude that is used by pilots for both aircraft and drones.
Flying at night may increase the utility of a general aviation aircraft if it is used for work. At night, the airflow may be finer, the weather more pleasant, and breezes may fade away as the sun goes down. There is generally less traffic, less radio conversation, and less brightness to struggle with, and the scanning of equipment may be easier.
As the smog of the day clears, visibility typically increases, and the illumination of buildings and runways occasionally shines up, making them easier to identify. Instead of flying over vast stretches of uninhabited countryside at night, pilots may take a route that passes through more airports in case an emergency landing is necessary.
Part 1 of Title 14 of the Code of Federal Regulations (14 CFR) defines a number of terms related to night flights.
First and foremost, it is vital to understand the FAA’s night flight requirements. The word “night” obtains its first significant meaning. The interval between true sunset and actual sunrise. Nightfall, on the other hand, does not happen quickly. During the duration of darkness, pilots may fly under ordinary daytime VFR flight conditions.
The interval between formal sunset and 30 minutes past dusk, or 30 minutes prior to dawn, is known as “civil twilight.” There is enough sunlight to see clearly during this time, depending on the weather. The only provision of the FAR is that airplanes have positioning lights on from dusk to dawn.
If situations demand it, such as while taxiing on the ramp or flying in instrument weather conditions where the beacon or flashing might create confusion, the revolving beacon must also be turned on.
The period between the conclusion of evening civil twilight, which is 30 minutes following sunset, and the start of dawn civil twilight is referred to as “night” by pilots; that is, 30 minutes before official sunrise.
Night operations need pilots to be contemporary in order to transport passengers between the completion of evening civil twilight and the start of dawn civil twilight.
You’ll need an instrument rating, an instrument-equipped aircraft, 1-mile visibility, the ability to stay clear of clouds, and special VFR permission from air traffic control to receive a special VFR approval at night. First and foremost, contrary to FAR 91.157, there are 3-time intervals you must be aware of in order to fully comprehend the FAA’s night regulations.
Positioning indicators must be turned on and anti-collision lights too on an airplane. In the transition from evening civil dusk to dawn, civil twilight pilots may record night flying time, and the aircraft must be prepared for night flight from 1 hour after dusk to 1 hour before dawn. The pilot must be night landing authorized to transport people.
To carry passengers within 1 hour after dusk and 1 hour before s, pilots must consider making three takeoffs and three landings in the prior 90 days within 1 hour after sunset and 1 hour before dawn, in accordance with FAR 61.57 (b). This is called night currency. The FAA in the United States demands pilots to maintain night currency.
Night VFR flights necessitate both safety and electric equipment:
Required safety equipment
Required electrical equipment
The essential instruments and equipment are necessary for IFR flight:
Although human vision really cannot perform as well at night as the eyes of nocturnal animals, night vision may be considerably enhanced by using the eyes appropriately and understanding their limits. Low light situations, such as at night, cause vision impairments due to the anatomy of the eye. As a result, it’s critical to comprehend the eye’s structure and how lack of light affects its operation.
The rear of the eye, or retina, has an abundance of light-sensitive nerves known as “cones” and “rods,” which concentrate all pictures. Such nerves attach to the neurons of the optic nerve, which provide instructions to the brain directly.
The rods and cones work in the daytime and moonlight, but in the absence of normal light, the rods are nearly solely responsible for night vision. In the daytime, staring immediately at an item is the best method to view it, but at night, the night blind spot is a blind zone in the middle of the field of sight. It’s possible that an item in this area will go undetected.
As the range between the eye and the subject rises, so does the development of this blind spot. It is more beneficial to use a search process to allow off-center observation of the item. To strengthen their night mode, pilots must intentionally rehearse this screening routine. A significant feature of night vision is the eye’s adaptability to darkness.
It is impossible to see anything in a dim environment unless the eyes grow accustomed to the darkness. The cones acclimatize to the dim light after about 5 to 10 minutes, and the eyes become roughly 100 times more sensitive to light than they were before entering the darkened place. The rods take approximately 30 minutes to acclimate to the dark, but once they do, they are 100,000 times more sensitive to sunlight than they were in the lit environment.
Until the eyes adjust to the brightness, sudden blindness induced by an abnormally strong light may create hallucinations or flickering shadows. These optical illusions are created by the mind and reflected by the eye. As a result, things are misjudged or erroneously identified, such as slanted clouds being mistaken for the horizon or inhabited regions for a landing strip.
Vertigo is a dizzying and unbalanced sensation that can cause or exacerbate illusions. The hallucinations appear to be quite genuine, and pilots of all levels of experience and ability are susceptible. The best defense for night flying is to recognize that the mind and sight may sneak up on pilots.
Since most general aviation pilots fly at the end of a normal day, they should be conscious of their own sleeping and resting needs. Before taking each trip, pilots should go over the checklist and make sure they are well-rested and fed. Flights should be avoided after a hectic day.
Fatigue is caused by insufficient rest and disrupted biological cycles. These considerations are critical for pilots who work night shifts on the ground or in the air. To decrease the emergence and consequences of tiredness, airline pilots should adapt their schedules and routines to enable proper sleep and rest, and also keep a good nutrition intake to sustain overall health and avoid dehydration. This may imply postponing or arranging activities in order to prioritize sleep and recuperation.
At night, because vision is particularly sensitive to diminished oxygen, a prudent rule is to use supplemental oxygen when flying above 6,000 feet MSL. So, when you fly at high altitudes, supplemental oxygen is the only solution.
This means that pilots flying at night at critical flight level should be fully conscious of the effects of hypoxia, and other factors which make slight oxygen deprivation more unsafe, such as lack of sleep, tiredness, nutritional deficiencies, and dehydration, should be minimized and monitored as much as possible.
Hypothermia is a medical problem caused by the human body losing heat more quickly than it can create it, resulting in a severely low body temperature. The normal body temperature is just below 37 degrees Celsius, or 98.6 Fahrenheit. If the human body temperature drops below 95 °F or 35 °C, you have hypothermia.
It may get quite chilly very rapidly without the sunlight. Always have enough clothes on onboard to protect both the pilots and the passengers from hypothermia. A cold can influence a person’s judgment mechanism.
One of the finest times to fly is at night. At night, the gusts fall down, reducing aerodynamic turbulence, especially above mountains and valleys. Severe storms also diminish at night, which improves safety in storm-prone areas.
Flying at night is one of the most enjoyable experiences. The breezes drop down, and the thermal turbulence fades away, offering a clear sky and a comfortable journey compared to daytime flying. According to data acquired, night flights account for around 10% of all general aviation accidents but 30% of deaths.
Most pilots consider it simpler to fly at night than during the day because of the lower traffic levels and the cooler winds that occur at night. Less drag on the wings allows for a smoother, turbulence-free flight. Due to weather concerns, it allows pilots to fly safely at night.
Pilots don’t have any better night vision than anyone else. Pilots nearly always rely on their equipment and flight computers when flying at night. Pilots utilize lighted streets, runway lights, and taxiway lights when flying VFR. Cockpit lighting should be adequate for pilots to monitor equipment and controls, pilots may even use night-vision goggles.