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Reading up on the old Hong Kong airport Kai Tak, I'm left with the question as to why the planes didn't land from the sea?

I know that takeoff was done towards the sea, but is there any reason that you couldn't land from the same direction you take off? Or is this less feasible due to traffic?

It otherwise seems to me that largely congested airport areas could (have) benefitted from bi-directional use of the runways. And I don't think wind direction could have made much of an impact for Kowloon, given the mountains and skyscrapers everywhere.

This question seem to suggest that landing and takeoff in/from the same direction is not standard in aviation, but with very limited details.

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    $\begingroup$ The issue is wind, you always (usually) want to take off or land into the wind. So yes, you always (usually again) want to take off/land in the same direction. I'm not sure why you would say it isn't standard, it is very much standard. $\endgroup$ – Ron Beyer Apr 13 '17 at 20:36
  • $\begingroup$ I meant landing from west and takeoff towards west, rather than takeoff towards east (as an example). $\endgroup$ – Claus Jørgensen Apr 13 '17 at 20:38
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    $\begingroup$ you want to face in the same direction for both takeoff and landing, because the effect of the wind is the same. if the wind comes always from the sea, you will takeoff/land always facing the sea, as also the answer you link says. $\endgroup$ – Federico Apr 13 '17 at 20:48
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    $\begingroup$ Why do you think wind direction wouldn't have "made much of an impact?" The mountains and buildings may have had an effect on the wind, but there were still winds, often fairly strong ones, and they often favored Runway 13. $\endgroup$ – Zach Lipton Apr 13 '17 at 20:51
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    $\begingroup$ I don't know what you are asking. Take offs and landings were carried out on runway 31 too. $\endgroup$ – Simon Apr 13 '17 at 22:22
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Reading up on the old Hong Kong airport Kai Tak, I'm left with the question as to why the planes didn't land from the sea?

It's a small point, but Kai Tak was not next to the open sea but rather alongside Victoria Harbor. Most of the rwy 31 final approach was over the harbor but with mountainous terrain on either side. The rwy 13 final approach was over Hong Kong island, then Victoria Harbor, then Kowloon.

Both rwy 13 and rwy 31 were used for takeoffs and landings depending on the wind, and winds in Hong Kong were often strong right down to ground/water level. Generally the prevailing winds favored rwy 13. By that I mean that when tracking the runway just before touchdown or when taking off you would have a headwind component. However, because most of the time there was a crosswind, it often meant that when approaching for landing but before you made the 47 degree right turn from the IGS course to short final, you had a tailwind component.

Both runways could be very turbulent. If ceiling and visibility were poor, that always meant a rwy 13 approach, at least that was my experience. The worst turbulence, though, was in severe clear conditions to rwy 31 when the wind was coming off the Chinese mainland.

I have a blog item about operating into Kai Tak on my website. You can look at it here.

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Here is an overly simplified diagram of the operations around a runway:

enter image description here
(Source: Quora)

As you can see, aircraft land and take off in the same direction. This is to keep the aircraft into the wind.

Related: Why is tailwind during final approach and landing so dangerous? Much of the same argument goes for taking off too. Taking off with a tailwind you need to have a faster ground roll to get the same airspeed to take off. This increases the time on the ground and uses up valuable runway in case of an abort.

The other problem as you hinted at is traffic. Pointing aircraft taking off at aircraft landing requires a much greater distance between the two so the outbound aircraft can turn to avoid the inbound aircraft. When you are closing at high speed (usually above 400kts), the separation requirements are used up pretty quickly and you need to space them out farther. It's also like playing chicken with hundreds of passengers, not something you want to do.

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