I’m happy to see there’s some interest in this thread. I’ll try to answer everyone’s questions, but between wanting to give inteligent, thoughtful answers and having a life to conduct I probably won’t be able to answer instantly. So please be patient, I’ll eventually get to everyone.
Hmm… to answer that I’m first going to introduce a little terminology and some definitions (don’t panic - I’ll make it quick and painless)
Flight plan- this is actually sort of obvious, in that it’s what you plan to do with your aircraft. However, there’s more than one type of flight plan, which I’ll get to later. I will point out, however, that it is very rare that the flight conforms excactly to plan.
ATC - Air Traffic Control
Clearance - this is what we pilots call the permissions, instructions, and so forth we get from ATC. So, if ATC gives you permission to enter a particular airspace, we say you are cleared to enter it, and if you do so you have obeyed your clearance. If you file a flight plan, ATC may tell you “cleared as filed”, or they may give you a different clearance to follow.
VFR - Visual Flight Rules. This is when your primary navigation is by eyesight, looking out of the cockpit. Everybody can fly VFR.
IFR - Instrument Flight Rules. This is when your primary navigation is by instruments, and you must file an official flight plan and fly with clearance from ATC. In order to legally fly IFR, you require an IFR rating, which requires additional training and testing beyond the basic private pilot license.
Now I can answer your questions. If I’m flying VFR and I stay out of airspace around busy airports where I require a clearance from ATC in order to enter the area, I don’t have to file a flight plan with anyone, and I don’t have to get a clearance, and I don’t have to even talk to ATC. I just get into my airplane and go where I want to, weather permitting. Just like I can get into my car and drive wherever I want to without getting permission. Given the wide-open spaces and vast rural areas in the United States that exist between cities, that’s a lot of territory.
I will also add that this is a characteristic of the United States - other countries may have far more stringent rules and requirements. Some countries have no general aviation at all.
All that said, it is in my best interests to plan my flight thoroughly beforehand, particularly if I am going any distance. And I certainly have the option to file what is know as a VFR flight plan with Flight Service. But that’s not a request to go somewhere, that’s mostly a mechanism where, if I am overdue to arrive somewhere, they have some clue where to send the search parties. While I am filing such a thing with flight service they will also inform me if there are special airspace restrictions or other things I should be aware along my intended route. One memorable Saturday afternoon I was planning to fly from Gary, Indiana over Joilet, Illinois, then further north to Aurora. Well, while talking to Flight Service the briefer informed me of a hot air balloon festival along my route and two amateur rocket clubs that had launch permission to 5,000 feet in two different locations, and then he started talking about skydive operations… at which point I decided that maybe I wanted a route with a little less activity in my path. So there can be real benefits to filing a flight plan, or just talking to Flight Services, even if it’s not required.
[small disclaimer for the pilots: I will simplify the following so we don’t get bogged down in regulations. I want the non-pilots to stay interested, not fall asleep
)
Now, let’s say I did want to fly over the city of Chicago to, say Palwaukee airport with is just north of the big city. Well… I have to pass by Midway and O’Hare, two VERY busy airports along the way. If I pass within a certain distance of those airports I have to talk with ATC. That’s what’s meant by controlled airspace, it’s under air traffic control (more or less - like I said, I don’t want to get too bogged down here). So, I would dial in the proper radio frequency and say something like “Midway, Cessna 2273J, request permission to transit your airspace south to north”. Most of the time they’ll say something like “Cessna 73J, radar contact, squawk 1234 and maintain heading and altitude” The “squawk” bit means tune my transponder to that frequency (this helps them keep track of me) and the rest means “keep going as you are”. But sometimes they’ll need to steer you around other traffic, or they’ll ask you to change altitude. Sometimes they’ll ask you to call them when you pass a certain landmark. Sometimes they’ll say “Do not enter”, which means just that. In which case you have the option of circling outside their airspace, waiting for permission, or you have to go around. And that’s about all there is to that, other than doing what they ask you to do.
Unless, of course, that might result in something unsafe. A pilot always has both the right and the duty to avoid accidents. So if the controller ever tells you to something unsafe, you say “can not comply”. But don’t do that unless you really have to.
Which brings me to two more terms. If a controller gives you a command and barks “EXPEDITE!” into the microphone it means do it now before someone gets hurt. If a pilot says “MAYDAY” then it means I have a serious emergency and I need help before someone gets hurt, at which point ATC will fall over themselves trying to get traffic out of your way and render any assistance they can. Needless to say, neither term should be used lightly.
Anyhow, continuing on our journey, as I approach Palwaukee, I’ll have to talk to their control tower. And that’s much the same as befoe: “Palwaukee Tower, Cessna 2273J, request permission to land” and they’ll usually come back with “73J, you are cleared for runway 34” Sometimes they’ll tell you you’re second or third in line for the runway. But I don’t need to call ahead (an exception will be dealt with later in this, another mega-post). A public-use airport is just that, public, and if you show up they’ll try their best to accomodate you as rapidly as possible. Now, if I did fly into, say, Midway, they might make me wait to squeeze me in between the jet traffic, but I have as much right to be there (at least in theory) as the airlines. On the other hand, I don’t like sharing airspace with passenger jets - it’s somewhat like riding a skateboard down the freeway. Your vehicle is very much outclassed by the heavier traffic. Which is why most of us small guys prefer small airports the big boys don’t use, or mid-size airports where they’re used to a mix of traffic.
Now, for a very busy airport it might be wise to call ahead, even if it’s not necessary, especially if you want to store your airplane in a hangar overnight - they might run out of hangar room, in which case your airplane stays outside. Some airports charge “tie-down” fees for storing your airplane, and you’ll want to know about ahead of time. Some have landing fees. Some don’t. So really, a phone call before you take off might be prudent, especially going into a large airport. For a really small airport, you might want to make that phone to ask if they have fuel to sell, or if they have anyone on premsis on, say, a Sunday morning in case you need something. Many airplanes have a phone line with a recording on it giving you current weather, which is very handy to know as well. One time when I flew into Fort Wayne - which is sort of like Midway as far as airspace classification, regulations go, and also has big jet traffic - I called ahead to ask when their heavy traffic times were and delibrately planned to arrive at a time other than rush hour. (I still wound up behind an F-14 and in front of a 737. Oh well, I tried…) There’s no penalty for calling for information, and frequently some real benefit.
Airports always seem quite willing to find someplace to put your airplane. Small planes like I fly can be parked on grass or dirt, so if they run out of hangar space and pavement they’ll park you on the front lawn of the terminal building if they have to. When they grounded everyone on 9/11/01 a LOT of airplanes wound up parked on grass, but room was found for everyone.
O’Hare International - which is about as busy as an airport can get - still allows small general aviation airplanes. I knew a couple flight instructors who used to fly a Cessna 150 into O’Hare around once a year, apparently for yucks and to put “ORD” in their logbooks. They usually did this around 2 am, so as not to tick off ATC too much - during a peak time they last thing ATC is going to want to see is a C150 (a very slow plane) knocking on their door to be let in among the Big Boy Jets. It would really mess up their traffic flow, and they might even be able to get away with telling you to go elsewhere if things were that busy. They might suggest your little airplane might be comfortable at, say, Waukegan, Palwaukee, or Schaumberg rather than O’Hare. But if they can accomodate you they are obligated to do so.
Is all that a hassle? Well… some people think so and never fly into airports with towers or over big cities. Me, if I have a reason to go to a place like that I do so - if you plan your flight thoroughly it’s about as much hassle as taking the correct exit off the freeway on a long trip. If you haven’t flown into a place like that for awhile it’s usually no big deal to find someone to double-check your plans, or help you rehearse a little for the radio calls you’ll need to make if it makes you feel a little more confident.
The relationship between ATC and pilots isn’t adversarial (usually - we can all name exceptions) but more collaborative. For instance, at the towered airport nearest to me (which is not very busy) they’re usually quite accomodating. So, if an instructor wants to bring a student there the tower will let the instructor decide if he wants the student to make a full stop landing, or go-around, or land and take off again immediately. A pilot can request a particular runway, rather than waiting to be assinged one. Although traffic patterns normally require all turns to be to the left, you can request a right-hand pattern and if traffic is VERY light ATC might set you up for that - with the caution that if several other planes show up the tower might have to warn you off until they land. So really, it’s more requests and negotiation than commands and orders. The busier things are the more commanding ATC becomes - but it’s their job to put safety ahead of your convenience in that case.
And that’s the story on VFR flight. IFR flight is a little different, and I don’t have an IFR rating so I’m not really entirely conversant with the procedures (IFR pilots feel free to jump in and clarify things). The big difference with IFR is that your under the direction of ATC at all times during the flight. You must file a flight plan - in this case, it’s not a directive for search and rescue (well, you hope not!) but more a reservation for time and attention from ATC. At an airport with a tower, they’ll tell you when to take off, what direction to go, and so forth. You can take off IFR from an airport without a tower, but in that case ATC gives you a “window” of about 5-10 minutes (if I recall correctly) during which you must take off - and on a busy day that “window” might be 1/2 an hour, 40 minutes, or more after your initial call. If you miss that window, you have to cancel the first plan, file again, and go back to the end of the line. So, once in awhile, you can see pilots running through the airport building and charging out to their airplanes to meet that deadline. Anyhow, once you’re high enough to appear on radar, you call ATC and let them know you’re there, and they direct you from there.
As I think I mentioned earlier, you can’t legally fly IFR without an IFR rating. Aside from legalities, to attempt to do so would be extremely foolish, and quite likely fatal. VFR pilots are given minimal training in IFR flight, but it’s ONLY for emergency purposes, to get out of a bad situation.
A pilot flying IFR is expected to follow ATC instructions exactly and promptly. The pilot can request a change, or ATC can impose a change, but nothing is done on a whim. A pilot can also ask to cancel his IFR clearance - he might do so if he flies out of bad weather into a clear, sunny location, for example - in which case he reverts to VFR flight. Or, if weather deteriorates unexpectedly while the pilot is aloft he can request an IFR clearance from the air, but I gather they really would prefer you to avoid those situations whenever possible.
Now, there are situations where a pilot might be required to call ahead. What I said about controlled airspace assumes you’re in a conventional GA airplane with transponder and radio - but there are airplanes without transponders. There are even airplanes without radios. If such an airplane wants to fly to an airport where such equipment is normally required, they will have to ask permission first.
A real life example: A group of ultralight pilots and homebuilt aircraft enthusiasts wanted to fly into an event at Meigs Field in Chicago (obviously, this was back before Mayor Daley backhoed the runway). Now, ultralights are normally forbidden to enter controlled airspace at all, and a homebuilt without transponder or radio is barred from the airspace above Chicago. But these guys wanted to make an exception. So they wrote to the FAA in advance (a couple months in advance) and said they wanted an exception made and what did they have to do to get permission. The FAA said they had to describe the number and sorts of aircraft, at least one licensed pilot had to be in charge of the group, and that person had to have a working radio. They had to give the FAA an exact description of their planned flight path over the city, and indicate where, if an emergency landing was required, they could land. They had to take off from a particular airport, and travel as a group. The person with the radio had to maintain contact with ATC the whole way.
Well, they complied with the requests, submitted all required information, and received a letter from the FAA granting them permission. On the appointed day they gathered at the designated airport. They called the ATC facility they had been told to call and told them they were taking off, how many were in the group, and their expected arrival time. And they flew to Meigs, landed, and basically repeated the exercise to return home.
A deaf pilot, who can’t use the radio, would have to do something similar prior to flying to an airport with a tower - contact ATC ahead of time, let them know he won’t talk to them over the air (in case you’re wondering, towers have “light-guns” that allow them to visually signal airplanes without working radios), and receive a time frame in which he has permission to arrive.
The other time a VFR pilot would require permission ahead of time is when crossing an international border. In such a case, you have to call ahead of time to let them know you’re coming and when you expect to arrive. You also much file an international flight plan prior to take off.