Thanks Dominican. We are a little more clearer now; because your opening question stated
"with regards to a landing of an MD83 in the wrong airport with the purpose of discussing messures of prevention...."
hence my question about what navigation systems are on the a/c. If you land at the wrong airport it might not be due to bad visual approaches.
The issue with visual approaches:
1. The pilots request it.
2. They must have the airfield and its surrounding terrain in sight, and ascertain their flight path to landing will remain clear of cloud and be such that they can keep the airfield/runway in sight at all times.
3. ATC is now no longer responsible for terrain or traffic avoidance.
So, if they ventured too far downwind ATC might advise/ask if they needed any help, or not. The crew had declared they had taken over responsibility for navigation and terrain avoidance. 320'/nm is 3 degrees, but that relates only to straight in finals. Much would depend if they were making a descending circuit via downwind, base and onto finals. They could then be descending at a steeper or flatter angle. It is all a matter of judgement and would depend on nav aids available, like DME or a Fix page in FMC. Mk.1 eyeball would be primary. However, if they were 7nm downwind it is almost certain they did not have the runway insight for turning base. It can be that some airfields have prescribed tracks to help guide you onto finals.
If the crew are flying a level downwind at circuit height, and correct speed, it should be easier to turn base and timing can be used to help. The airfield environment would be insight at all times, and the runway threshold would come back into view halfway round the turn onto base. If they were screaming downwind, then indeed, they need distance to slow down.
A little more detail of the incident would help us be helpful to you.
Last edited by RAT 5; 3rd Jun 2016 at 11:14.