Same altitude crossing paths

So what would happen here, both at 32,000 and will be close to crossing paths at the same time. Obviously in IF it’s up to the pilot to climb or descend, presuming their not asleep haha
But in real life would this be the centre controllers job?
Or who’s responsible to identify these two aircraft as a possible collision?


They have a system that detects possible dangerous situations and alerts the ATC. Even if the controller doesn’t do anything the TCAS system from the aircraft will talk to each other and command the pilots to climb or descent.


In real life, it would be ATC, then TCAS if it’s still not detected. In IF, it’s the pilots responsibility to look at the map and check surrounding planes, those in danger of collision turn amber then red.


Ok thanks, forgot about the TCAS for some reason


A general guideline is to set your cruising altitude based on your heading.

If your heading is on the west side of the compass, you go even. East side, odd. Not that as you get higher the separation rules are greater so some going west are odd. But for the most part from what I’ve seen flight planning websites will give you a proper altitude for the heading.

Also note that there are many different reference images out there.

For example…

… taken from another post


In OP’s case, both planes are flying West so they could potentially be on the same flight level as prescribed by the rule you mentioned, thus the question.


Very interesting, never knew that before, I’ll definitely start using that! But what if you’re going exactly South or exactly North?

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This is the way it’s done in most countries. In some cases, in countries where most airways are in a north-south layout eg Portugal, Spain, Italy(not sure about this) and France, they use odd thousand when heading south and even thousands when heading north.

Eg A flight heading from LFPG-LPPT would cruise at FL390 while the return cruises at FL380.

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The Chart put up by @Chris_S is very handy and accurate; and it answers you question.

If you are going exactly North, then you are going 360, which means you should be on an odd flight level.
If you are going exactly South, then you are going 180, which means you should be on an even flight level.

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Thanks for clearing that up, didn’t see that bit

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In a case such as this where they could both be at even altitudes they controller would recognize the conflict and provide a vector, often as little as 10° to ensure one or the other passes behind the converging traffic. You might also receive a climb to the next appropriate even altitude, or in some cases simply 1,000ft above or below, only to be returned to your original altitude once the conflict no longer exists.


What altitude do you cruise at if there is a segment of your flight where your headingkeeps on crossingthe east-west boundary (eg. this happens usually when leaving south out of China through Hong Kong)

Hey Tyler thanks that’s explains it more
But would it be more common for ATC to vector one aircraft behind the other and to climb 1000ft instead of descend, only asking because I was thinking of the wake turbulence falling from the crossing aircraft if the aircraft going behind was to descend instead of climb

If a Super or Heavy is involved that would certainly be taken into account, though the book describes WT extended to 1,000ft below as well for the separation standard, not just in trail of a larger aircraft. Lots of tools to build the separation you need! 🙂


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