When you fly into somewhere like San Diego or New York, you fly right over the city and are basically directly next to skyscrapers. But when you fly into somewhere like Austin or New Orleans, you’re flying over flatlands. How do pilots know clearance for certain areas, does ground control tell them how best to land or does that not matter?
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Note that for commercial flights, *other* than landing and take-off, if they’re ever anywhere near the top of a building, something has gone horribly horribly wrong already.
For take-off and landing, commercial flights follow well-known approaches that have reasonable clearance. Planes are expected to follow certain *glide slopes*, typically around a 3° angle downwards towards the runway. There are several tools to help them, including [PAPI lights](https://global.discourse-cdn.com/infiniteflight/original/1X/4e5ee137d8fbd687cc38f0f76ec4e13f028c1440.gif) which show different colors depending whether you’re too high or too low, and ILS, or Instrument Landing Systems, which use overlapping radio signals to guide the autopilot down.
There are established “minimums” where the plane *must* be on a “stabilized approach” by a certain height above the ground, typically 1000ft but can be as high as 2000-3000 depending on the conditions and instructions from ATC. “Stabilized” means the plane is at a constant rate of descent, with a constant speed, so it stays on that 3° slope, and has “captured” the ILS – meaning, the system is tuned into the radio signal and knows where the plane is…if the pilot did NOTHING, the plane should go right where it’s supposed to go without any more input, other than very small corrections.
If the plane is not stabilized by that height, they must initiate a go-around. They abandon the attempt to land, they throttle back up, fly over the runway, and go around to try again. As long as the plane is even remotely within that glide slope, there shouldn’t be any buildings anywhere near them.
For private flights using Visual Flight Rules, or VFR, there’s a lot less equipment but the procedure for take-off and landing are similar. There is probably some kind of indicator like PAPI lights for the pilot to follow down, and they practice a *lot* so that even without an indicator, they know what kind of glide slope they need to capture and how to do it. VFR pilots often don’t have any help from ATC – there are plenty of non-towered airports and the pilots just have to pay attention and land according to their own discretion and training.
Every airport has [charts, diagrams, and additional information](https://skyvector.com/airport/ATL/Hartsfield-Jackson-Atlanta-International-Airport) which pilots have to know how to read. These charts will include the runway length, standard approach direction, and even notes about things like trees or buildings that are nearish the airport. None of them should be close enough to be a serious hazard for a normal landing or take-off, but the pilots may still want to know they’re there *just in case*, and can plan their maneuvers accordingly. Like, if you know you’re taking off at your max weight and there’s no wind to help you, you’d know that you’re going to climb pretty slowly so, hey, maybe let’s *not* take off on the runway with tall trees in that direction *just to be safe*.
There are even *more* charts that show the best, recommended, or required approaches. Like, if you’re coming into this airport, you *must* follow this line. This doesn’t just help avoid buildings, it helps keep planes organized and prevent them from hitting each other, almost like lanes on a highway.
For just flying around, like I said commercial flights should never be remotely close to anything on the ground. Private pilots flying VFR *usually* won’t be flying that low, but they might be. It’s up to the pilot to plan their route and look at the charts. The charts will have symbols showing tall landmarks, both to help the pilots avoid hitting them, but also to help them navigate because they are, well, *landmarks*. VFR pilots have a lot of tools to help them figure out where they are, but typically not GPS so having something really obvious to let you know where you are is useful. It’s also up to the VFR pilot to pay attention to what they’re doing and avoid running into stuff. VFR pilots are not allowed to fly without being able to see a good distance all around them. They can’t fly into or through clouds. They should be able to see everything in front of them, so avoiding stuff on the ground *should* be as easy as seeing it and not running into it. The only time they would be at risk is from doing something that *requires* them to be extremely close, like doing crop dusting. And yeah, they just need to be good pilots and really pay attention to avoid running into anything.
A private pilot flying IFR – instrument flight rules – are allowed to fly when they can’t see, since they’re trained to use their instruments to navigate. However, they should know better than to ever put themselves into a position where they’re at risk of hitting something close to the ground while they can’t see anything. They probably don’t have any kind of radar, so they need to just be aware that, based on what their altimeter says, they’re close to the ground and either they better know that there’s nothing tall around, or they need to get away from the ground.
Source: Currently taking online courses for private pilot ground school to hopefully get a private pilot certificate soon.
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