When I saw the question “How safe is flying at night” asked on a forum recently it made me think.
Flying at night is extremely safe for commercial flights these days. This is due to all of the aids available both inside the cockpit and on the ground. In fact, there is hardly any difference between flying at night or during the day.
It is certainly very safe so why do people feel apprehensive about it? Perhaps it is just a lack of knowledge. Knowing what aids are available to a pilot to “see in the dark” might help …..
Driving at night
Most people don’t think twice about driving themselves, or being driven by someone else, at night.
The only aid that drivers have to drive safely are their eyes. At night, vision is greatly impaired compared to driving in the daytime. The other drivers on the road are also in the same position of course. Added to that, some may be drunk or reckless too, so also present a hazard to you.
Yet, despite all this, 99.99% of journeys by car are completed safely at night.
Flying at night
Although many short flights are flown during daylight, most long haul flights will include a certain amount of night flying. This is particularly true when flying west to east as the days are effectively shortened. I have traveled from London to New Zealand and flown through two nights on that journey before reaching Auckland.
One factor which actually makes flying at night safer than during the day is that generally there are less aircraft in the sky at night so less aircraft to avoid.
So how do pilots fly at night? What aids do modern pilots have in addition to their eyes?
1. Air Traffic Control
Aircraft are constantly monitored by a network of air traffic control centers all along their route. They are able to do this using sophisticated radar that not only shows where aircraft are but also at what height they are flying. Air traffic controllers use this information to give instructions to pilots to ensure adequate separation from other aircraft and also route information.
On international flights aircraft are passed from one country’s ATC to another when they approach a border.
As well as the air traffic controllers on the ground having radar, all modern aircraft are also equipped with onboard radar.
Aircraft radar is very sophisticated as not only does it show where other aircraft are but it now incorporates a computer controlled TCAS (Traffic Collision Avoidance System). This system warns the pilot of any possibility of collisions and even tells him what to do to avoid a collision which may be to climb or descend.
Two aircraft equipped with this system that are on a collision course actually communicate with each other and decide which should climb and which should descend before informing the pilots. As well as avoiding collisions with other aircraft these systems also advise of potential collisions with with mountains etc.
Aircraft radar can also incorporate weather displays to allow a pilot to avoid flying through storms or other weather fronts.
3. Navigation Systems
In the earlier days of long range flying, aircraft navigated at night using a combination of dead reckoning and astro-navigation (navigation using the stars). Yes, some aircraft actually had a nautical sextant mounted in the roof of the cockpit that the navigator used to determine the position of the aircraft, after some complicated calculations.
Nowadays things are rather different. Modern aircraft have computerized navigation systems which use, among other things, GPS to know precisely where they are.
A pre-planned route can be entered into the navigation computer so the autopilot follows the route precisely. Pilots can alter the route if instructed to do so by air traffic control or to avoid weather problems.
4. Landing aids
To assist with finding their way on to the runway at night, or in cloud, there is a system used throughout the world called the ILS (Instrument Landing System). This incorporates two radio waves, called the localizor and the glideslope. The localizor sends out a signal out along the center line of the runway. The glideslope sends out a signal at a particular angle from the end of the runway.
First the pilot flies on a heading that he/she knows will cross the center line of the runway, some distance away. As the aircraft approaches the localizer an indicator starts to move on a cockpit display and the pilot starts to turn towards the runway. When the indicator is centered the pilot knows he/she is lined up with the runway.
Then the pilot starts to descend until the glideslope indicator starts to move. Again, once this indicator is centered the aircraft is flying down the glideslope (the preferred approach angle to the runway). Provided both indicators are in the middle the aircraft will reach the middle of the end of the runway, even if the pilot can’t see a thing out of the cockpit window.
5. Mark 1 eyeballs
Of course, as well as all the other aids, just like the driver, a pilot still has his eyes to assist with flying at night. Using those eyes he can see other aircraft in the sky because of their lights. These include red and green lights. Red lights on the tip of the left (port) wing and green on the tip of the right (starboard) wing.
The reason for this is that it is possible to tell if another aircraft is heading towards or away from you.
- If you see the two lights and the green is to the left and the red to the right then the aircraft is flying towards you.
- If you see the two lights and the red is to the left and the green to the right then the aircraft is flying away from you.
Simple but effective and the same system used by ships. Interestingly, this is one of the main reasons why people who are color blind cannot become pilots.
Flashing white strobe lights are also carried on the tail and underneath to make the aircraft easier to spot.
I hope I didn’t make this explanation of how safe is flying at night too complicated. Please feel free to let me know in the comments.
You may also be interested in my article on How to get over your fear of flying (with a free ebook) and How safe is flying in turbulence?