In remote areas that have no radar (oceanic airspace, etc.) how is aircraft separation maintained so that airplanes don't get too close?
What do areas that normally have radar do when there is a sudden radar outage? There are airplanes going everywhere, not necessarily on standard airways, and a lot of them are being given radar vectors. What happens when the screens go dark?
For oceanic airspace, flights proceed along specified tracks and altitudes specified in their filed flight plan. From there, once they leave radar-controlled airspace, radio reports are made to ATC, who ensure that aircraft are appropriately separated if a flight needs to change its track or altitude. See the wiki article the North Atlantic tracks, which give a good overview on the track system. Specifically:
Prior to departure, airline flight dispatchers/flight operations officers will determine the best track based on destination, aircraft weight, aircraft type, prevailing winds and Air Traffic Control route charges. The aircraft will then contact the Oceanic Center controller before entering oceanic airspace and request the track giving the estimated time of arrival at the entry point. The Oceanic Controllers then calculate the required separation distances between aircraft and issue clearances to the pilots. It may be that the track is not available at that altitude or time so an alternate track or altitude will be assigned. Planes cannot change assigned course or altitude without permission.
Contingency plans exist within the North Atlantic Track system to account for any operational issues that occur. For example, if an aircraft can no longer maintain the speed or altitude it was assigned, the aircraft can move off the track route and fly parallel to its track, but well away from other aircraft. Also, pilots on North Atlantic Tracks are required to inform air traffic control of any deviations in altitude or speed necessitated by avoiding weather, such as thunderstorms or turbulence.
I'm going to leave the "what happens when things break" to someone else.
When the screens go dark ATC breaks out the flight progress strips (and possibly the shrimp boats or other airplane-substitutes to lay on a map & push around) and uses brain power to substitute for the computer and radar. Check out one of my favorite "Say Again?" columns over on AvWeb which talks a little bit about it (and you can find lots more if you browse the archives).
Broadly, there's a few implications to non-radar operations - both routine and "when stuff breaks" - most of which are concessions to safety. The one most pilots will feel, and the biggest safety item, is that "random RNAV routes can only be approved in a radar environment" (you'll find that gem in the AIM, but the translation is this: "GPS Direct? YOU NO CAN HAS!").
To facilitate separation in a non-radar environment the controllers are going to chuck you (and every other IFR flight) on airways, at standard IFR altitudes, quite probably with a specified airspeed, and they're going to route you navaid-to-navaid.
The idea here is simple: "You gotta put them together to keep them apart": By ensuring all flights are on known airways, at known altitudes, and at known speeds controllers have a good idea of who is where in their airspace. They will supplement this mental picture by asking pilots to report crossing certain fixes (intersections/radials), so that they know exactly where that flight is when they make their report (which will help them account for winds aloft, and give them an idea of what the flight's ground speed is in addition to the airspeed they're asking them to fly).
All of the above provides IFR-to-IFR separation, which is what the controller is concerned with. IFR-to-VFR separation (which is normally supplemented by radar) becomes the responsibility of the pilots ("See and Avoid") - this means it's largely a factor of altitude (that 500-foot difference between IFR and VFR cruising altitudes and those cloud clearance requirements should start to seem pretty important right about now).
ATC aircraft separation is built upon the assumption of no radar by way position reports. At compulsory reporting points (black triangle on enroute charts), an IFR aircraft (unless radar identified) is required to report (see 5-3-2 of the AIM):
(d) Altitude or flight level (include actual altitude or flight level when operating on a clearance specifying VFR-on-top);
(e) Type of flight plan (not required in IFR position reports made directly to ARTCCs or approach control);
(f) ETA and name of next reporting point;
(g) The name only of the next succeeding reporting point along the route of flight; and
(h) Pertinent remarks.
ATC uses the position and ETA to keep aircraft separated. Most of the US is covered by radar, but remote parts of Alaska and oceanic still use position reports. If ATC radar is not functioning (rare), then the system reverts to position reports.
Moving forward, ADS-B allows aircraft to self broadcast its position. A network of ground and satellite ADS-B receivers can build up a picture of the traffic.
In remote areas that have no radar (oceanic airspace, etc.) how is aircraft separation maintained so that airplanes don't get too close? What do areas that normally have radar do when there is a sudden radar outage? There are airplanes going everywhere, not necessarily on standard airways, and a lot of them are being given radar vectors. What happens when the screens go dark?
Primary target: An aircraft not reporting mode-C, the only thing the controller has is the return on the radar. When a controller reports a primary target as traffic to other aircraft, the controller does not have the altitude of the target. Given this, I conclude that ATC radar does not have the altitude (angle-up) to the target, and only provides azimuth. So then without the altitude, how... miles out. However, if the target is at 15,000ft, the proper position would be 9.5 miles out. Since the difference is so small, does the radar just put the target at 10 miles, and the FAA separation
In class D and E airspace, there is no separation between IFR and VFR traffic. However, most airspace in the United States below 18,500 feet MSL is class E airspace, which is exactly where non-pressurized aircraft cruise when flying IFR. My question is not about regulation (that's perfectly clear: no separation between IFR/VFR) but I'm curious to learn how safe it actually is when cruising... to the regulations the pilot is still responsible for seeing and avoiding other VFR traffic. Are there any accident statistics on this? I have read hundreds of accident reports over the last few years and I
Provided an aircraft with a fly-by-wire system, there are basically two possible choices when it comes deciding how to let the pilots interface with it: rate control / attitude hold: a deflection... translate to a deflection of the surfaces, mimicking the "old" mechanical control setup. It is my understanding that this is the design choice of Boeing in its new aircrafts. I do not wish to discuss how Airbus and Boeing made their design decisions, but rather see if there has been performed a study on what interface is preferred by pilots, eventually differentiating among private/commercial pilots
there might be some radio interference or static from such as large aircraft behind them? Are there every any issues when refueling aircraft do this sort of thing? What is the resolution of radar? Would one...I just finished reading an interesting post where the author suggests that the missing Malaysian Airlines flight 370 could have 'hidden' under the cover of Singapore Airlines flight 68 to fly to a covert airstrip. I've read multiple thrillers where submarines have hidden behind the acoustic signal of large cargo vessels to mask their sound over sonar arrays, and this (at least in the book
I was looking through my virtual radar logs one of the days and found this "glitchy" ADS-B behavior. I am almost 100% sure that this is not due to my antenna or setup since two independent different radars confirmed this weird behavior from FlightRadar24. Also A/C before and after this one did not exhibit this behavior. Does anybody have any thoughts as to what may be happening??? Why... of occurrence is approximately: 3/16/2014 6:09pm CST I have also verified FlightAware is ALSO showing the same weird glitch. See below "yellow" highlighted airplane: Same A/C from FlightRadar24
or is there any guidance to say when the report is required? I.e. is it anytime that we get an RA (even if we visually have the aircraft in sight), only if we actually respond to an RA, or is it if the two airplanes get within a certain distance from each other? When a report is required, how do we report it and what information is required? Is there a form that needs to be filled out? ... Transportation Safety Board (NTSB) office when: ... (10) Airborne Collision and Avoidance System (ACAS) resolution advisories issued either: (i) When an aircraft is being operated
I was looking through my ADSB Virtual Radar outputs couple days ago and saw a weird re-route for one of the aircraft that looked out of place. Can one of the pilots/ATC guys pitch in to help me understand what may have caused this A/C to do this? Is this "normal"? I would expect if this was a wake turbulence from A/C ahead they would have just asked the rerouting A/C to just slow down? Tail #: N39463
Based on the reading I've been doing of FAA's Next Generation Air Traffic Control (NextGen) plans, I've been wondering if and how radar systems will continue to be used for ATC as NextGen rolls out? Questions include: Is it correct to assert that radar coverage will effectively become a less precise, backup only, data feed? I am suggesting this because my understanding (which could easily be incorrect) is that ADS-B will mandated for most (everyone?) and so aircraft will be actively reporting their precise position without the need for a radar track. Will existing radar coverage eventually
Due west of KLAS and Death Valley are a large number of MOAs and Restricted areas. On the sectional and terminal area charts, there are thin magenta lines snaking over some of the mountain tops. What do those lines represent? They don't seem to be a mode C veil of any sort, and the legend doesn't otherwise mention a thin magenta line without spikes.