I’m often asked how I can see where I’m going in the dark or in cloud. Quite often fearful flyers are under the impression that if it’s a clear day I can see where I’m going and navigate accordingly. This isn’t unreasonable … it’s what we do in a car every day.
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why instrument flying was called blind flying. In the beginning flying …. go to premium for more
Unfortunately because of the forces involved and the way the human body is built (see here) it’s not possible to fly a plane in cloud without something to show which way is up …. Premium … however, you lowered the nose and the plane slowed down you knew you were upside down.
… an instrument was designed that could detect sideways movement and it worked like this … see fear of flying Premium
All very strange … but it’s always the same … it will always do the same thing … (It’s called gyroscopic precession) and the quicker you move the wheel, the more the wheel will precess (wobble).
and that’s exactly why early blind flying was called limited panel … because by comparison a full panel has an instrument that draws a picture for you, showing whether you’re level with the horizon (which you can’t see when you’re in cloud) and gives you height speed and position all on the one instrument. And it tells you when to operate the flaps and all sorts besides. Wasn’t like that in my day.
Following on from the main paragraph, a modern flight system certainly makes it a whole lot easier to fly to Paris in cloud, because instead of ‘working it out’ you can see a visual representation of the outside world. In addition a full panel will have an instrument that shows how fast you’re going up or down …not speed, but the rate at which you’re changing height.
And this is very useful when approaching an airfield runway because if you come down at about 600 feet every minute when you’re flying at 120 mph, then you know you’re coming down at the correct angle. (That’s an approximate figure but at this stage in your flying career it’s ok). Premium on-line fear of flying course covers this and much more.
In a plane when you’re a passenger you have no instruments to tell you which way is up. So it’s possible, and quite normal for you to feel perfectly level when the plane is in fact turning and similarly to imagine you’re turning when you’re flying perfectly level.
And it gets worse than this because … as I’m sure you know can mislead you into thinking that just after take-off when the power is reduced … that you’re going down!
This is a very, very basic explanation of how we ‘feel’ in a plane.
I want now to move on to the advantages of the modern instruments because I shall finish this article by saying that the Flight Management system can be connected to the autopilot and the whole flight can be managed through one system… and whilst it could be described as flying blind it is not a reflection of what is really happening.
Earlier I spoke of the bicycle wheel and it’s funny wobbling properties … that is a very basic form of gyro and the way we can get information from a gyro is to hold it in place with springs so that instead of moving, we can measure the force in the spring and work out what it would have done if it hadn’t been restrained.
Well it’s very easy to turn that force into electricity and measure the voltage or current or whatever it is we can measure and determine what the gyro would have done if it wasn’t held in place by magnets … or some other electrical force, and so we go on getting more and more sophisticated until we have a completely automatic …
Where is all this leading us? Towards a wonderful safety feature that is on all modern aircraft. see Premium for more help
What we can do now is show the pilots which way the numbers are moving without him having to watch them. In other words if the speed of the plane is reducing … the electronics can measure how quickly it’s changing AND then show a pointer saying ” if you carry on like this for another 15 seconds the speed (or height, or anything else) will be this much”.
After this it goes from strength to strength because you can build in warnings that say “with the flaps in this position, your maximum speed is this much and your minimum speed is that much.” And this provides a perfect back up and warning in case the pilot and his/her co-pilot didn’t spot it!
The designer can even get the thing to make warning noises if it’s an important enough event, like approaching the stall or exceeding the speed limit for the ‘configuration’.
But why should we stop at this level, because … see premium for more details
Why not show when the plane can climb higher or even where it should start its descent towards the destination airport. Why not include information about what the auto pilot is doing? Actually we need to limit the amount of information that we give the pilot in case all this help overloads him/her.
Hey I’ve just had an idea. Rather than allow the autopilot to do what we tell it to do like change direction or height, why don’t we connect it to the system that is providing all this information, especially if we can programme the route into it.
You’re not surprised that we actually do exactly that. Indeed we start the flight by programming all this information into what is unsurprisingly called the Flight Management Computer. And this determines where and how the aircraft flies the route that we select. And we’ll have another safety measure here; the routes are agreed by Air Traffic Control … and they are updated monthly.
We have moved a long way from the notion of ‘blind flying’ to a fully integrated flight management system that greatly enhances flight safety.
And that is what the original question implied; that blind flying is unsafe.
I shall finish this article by saying that the Flight Management system can be … see premium for more information and help