Some time ago when I was designing the approach radar module for the ATC simulator for HCAA, the spec was very clear that the limit had to be placed at 45 degrees. So I took it for granted and I didn't make any research of my own.

But very recently I had a discussion that made me wondering and I couldn't find any online documentation. I found Lnafziger's answer suggesting that

Controllers may issue a heading or a course direct to a fix between the IF and FAF at intercept angles not greater than 30 degrees for both conventional and RNAV instrument approaches

So I guess this is it for FAA airspace. But I would like to know if there are any EASA regulations or ICAO recommendations that impose 45 degrees in Europe.


2 Answers 2


45 degrees.

Aircraft vectored for final approach should be given a heading or a series of headings calculated to close with the final approach track. The final vector shall enable the aircraft to be established in level flight on the final approach track prior to intercepting the specified or nominal glide path if an MLS, ILS or radar approach is to be made, and should provide an intercept angle with the final approach track of 45 degrees or less.

ICAO Doc 4444 (PANS-ATM)

That said, we very often use a 30 degree intercept angle, even if we are allowed to go up to 45 degrees.


For completeness, in the USA it is not always 30 degrees; in fact the maximum is 45 degrees, but only for helicopters. The rules vary based on how far from the approach gate the aircraft will intercept the final approach course. The approach gate is an imaginary point one mile outside of the final approach fix, but at least five miles from the runway threshold. From the 7110.65 5-9-2a:

Distance from interception point to approach gate Maximum intercept angle
Less than 2 miles, or triple simultaneous approaches in use 20 degrees
2 miles or more 30 degrees (45 for helicopters)

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