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Dear Captain Lim,
First I would like to thank you for being so kind, investing your time and sharing your knowledge and experience on your wonderful website, helping so many of your readers with various questions, contributing to overcoming the fears and scientifically giving answers to various technical questions, what was recently almost impossible, and many would have wished to get in contact with a qualified pilot and explore marvelous science of flying as well as alleviate their fears. Now you have given us all the real touch with aviation and flying, and I must praise you for your good work!
Loving the flying very much and mostly playing a simulator when not really flying, I hope you will get some time to answer my questions.
1. I was talking to a friend of mine about today*s airplanes and the safety statistics, and he confronted me with an interesting fact. Namely, it*s been said that the flying is 21 times safer than riding a car, and much safer than riding a train. And he says he uses his car, like many other people, every day, and also trains depart much more often than airplanes, and he travels by airplane once every six months, and that this fact doesn*t correspond to general statistics on air safety. Can you help me elaborate this?
2. The general landing speed of a B737 is lower than that of a B777, concerning their weight and size. But why do we see those bigger airplanes such as B777 moving much slower in the air on final and when landing, slower than B737 or smaller airplanes?
3. What is the Landing Altitude?
4. What is the usual vertical speed, or correct one, when landing, after crossing the runway*s threshold and just before touchdown? And where is the difference in vertical speeds in a soft, normal and hard landing?
Thank you in advance for your answers!
Nex
Vienna, Austria.
Hi Nex,
1. I have answered many FAQ on air safety. Please review the air safety topics. There are many skeptics on how air safety is measured. In the end, I think, it becomes a very subjective issue ? most fearful flyers continue to reject the figures whereas the general confident air travelers are happy with the statistics.
2. It is true that the landing speed of the Boeing 777 is faster than the Boeing 737. Why we see bigger airplanes moving much slower in the air on final and when landing than smaller airplanes is a question of perception and size of the moving object. A good analogy is to compare the sensation of speed when on a motorboat and an ocean liner. Both may be moving at the same speed ? but if you were on the ocean liner, you felt you were hardly moving!
3. Landing altitude is the height of the runway elevation. If you were landing on Runway 29 at Vienna airport, the landing altitude is 600 feet.
4. When you are carrying out an approach, the rule of thumb to stay on a normal profile is five times the grounds speed. For instance, if your ground speed (not true air speed!) were 150 knots, your rate of descent (vertical speed) should be around (5 X 150) = 750 feet per minute.
However, when you are about to touch down, your vertical speed must be progressively reduced as you start to flare ? something like 300 to 400 feet per minute. In fact, on a visual manual landing, you no longer look at the instruments, but feel with the so-called ?seat on your pants? to achieve a soft landing.
If you were doing an auto landing, the computer will automatically sense the landing altitude (on a Boeing 777, it is about 25 feet above the runway), retard the thrust levers, flare and comes to a soft landing. It is difficult for me to quote a specific rate of descent to achieve a soft, normal or hard landing. It is all through experience and you should be able to experiment it on your own MSFS (normally, the feel would not be the same as a real plane). Obviously, anything greater than what I have quoted above would give you a hard landing! Try it out yourself!
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