How Does ATC Decide Which Approach to Give a Pilot for a Given Runway with Multiple Approaches?

[Devil07]

On a recent IFR flight I was cleared for 2 approaches at two different airports that I wasn't fully expecting and it got me to wonder how approach control decides what to give the pilot. Here are the two scenarios:

1. Flying into KLIT in the dark in a rainstorm I was cleared for the ILS, but I had already setup for RNAV 4L, and with the dark and the stormy weather it would have been unsafe to fumble around setting up for the ILS at that point, but controller didn't even miss a beat when I told them I was setup for RNAV and just cleared me for the RNAV instead. My guess is that I was given ILS because it had the lowest minimums? Or at international airports approach is used to giving "Cleared ILS"?

2. On a flight into an uncontrolled airport near New Orleans on my initial call to approach I specifically asked for RNAV, but controller cleared me for visual. There were no other aircraft IFR or VFR at the airport, only 1 VFR aircraft landed the whole time I was in the vicinity and that occurred about 10-15 minutes after I landed. I totally understand that ATC and give me visual approach, and that normally, it saves me time (and money) on my aircraft rental, but I'm just wondering what is reason from ATC perspective to give me a visual approach when I specifically asked for RNAV to a field with no other IFR traffic? Is it possible the controller forgot my request because I included it in the initial call up? Which was something like "approach, cessna 1234, level 8000, w/ airport automated weather, request RNAV 18, circling, full stop" is that too much for initial call to approach?

BTW: I got some amazing A+ service for ATC (Houston, Memphis, KLIT, NOLA) this weekend, thanks y'all!

 

[NovemberEcho]

At a controlled airport on the ATIS there should be an advertised approach in use. You can request any approach though and traffic permitting etc you should be able to get it no problem.

Thr guy who cleared tou for a visual when when you asked for a rnav probably just screwed up and forgot or didn’t hear you. Did he tell you what approach to expect?

 

[Devil07]

Thr guy who cleared tou for a visual when when you asked for a rnav probably just screwed up and forgot or didn’t hear you. Did he tell you what approach to expect?

That is what I was wondering, I didn't hear the controller say "expect" visual or anything, so I assumed I was getting the RNAV that I requested. (After listening to LiveATC I can tell controller had a lot of aircraft in the sector, which could also explain it--although in the past when I've requested an RNAV to the same airport and approach is busy they have told me, "expect visual"--thats what threw me off this time.)

LiveATC update: I was able to find the archive audio. My initial call to check on with approach (the long version listed above) went unanswered, but controller was really busy so I waited a minute, then checked on with shorter version "NOLA approach cessna 1234, leaving 5200 descending 5000", about 15 seconds later (controller was busy) came back with altimeter setting and asked for request, thats when I said where I was landing and requested RNAV18 circling approach. After hearing LiveATC I can tell there was a lot of radio traffic, the controller talked/responded to like 5 or 6 other aircraft before responding to my request over a minute later, but all they said was "....descend and maintain 2000". At this point I still assumed I was getting RNAV18. A few minutes later controller advised direction and distance of airport (i think it was like 15 miles so I couldn't see it yet in the dark), to which I responded "roger". Then a couple minutes later, controllers asked if I had the airport in sight, and when I said I did, I was approved for visual approach. I accepted the visual approach, thanked the controller and canceled IFR.