GPS approaches being so trivially easy to establish and maintain, are there any/many US airports with instrument approaches which do not have at least one RNAV approach?
Very interesting question! I analysed my current navigation database*1 (AIRAC 2205), filtered for US airports with instrument approaches and grouped them into 3 categories:
- airports with radio based approaches, but without RNAV/RNP approaches
- airports with RNAV/RNP approaches, but without radio based approaches
- airports with both
The result is shown here:
Only 25 airports (1.8%) have a radio based approach, but no RNAV/RNP available. The list is here:
K2K7, KAVX, KBAD, KC03, KCOF, KDYS, KHIF, KINW, KIPL, KLSV, KLUF, KLZD, KMCC, KMIB, KMMT, KMUO, KMXF, KNQI, KNRB, KOLS, KRCA, KSOA, KSSC, KVBG, KVNY
How does this compare to the rest of the world?
As you can see, the percentage of airports without RNAV/RNP is much higher in the rest of the world. In particular, European*2 airports still rely much more on radio based approaches (28.6% have radio only). The global average is 18.2% for radio based only.
*1 My database does not contain all airports in the US, usually only the ones with instrument approaches available, but there is no guarantee for completeness.
*2 For European airports, I filtered for those airports with ICAO airport codes starting with E or L, which covers most of Europe.
According to the May 2022 TERPS catalog. FAA Digital Procedures Website
There are over 3,000 airports in the U.S. national airspace with a RNAV approach comprising over 7,000 RNAV (GPS), RNAV (RNP) and GPS approaches.
There are 33 airports without any RNAV (GPS), RNAV (RNP) or GPS approaches.
Number of airports without RNAV approaches by state
TX with 7
OH with 4
CA and SC with 3
AZ and UT with 2
AK, AL, CT, FL, ID, IL, LA, MN, NV, OR, SD and WI with 1
List of airports:
12G; 1X1; 2P7; 44C; 4I9; 56D; BAD; C16; COF; DYS; F14; F41; HIF; LSV; LUF; LZD; MCC; MGG; MMT; MUO; MXF; NOG; NQI; P19; PHH; RCA; S12; SSC; U69; VBG; VDZ; VNY; WEA
On the opposite end, there are 1,406 airports with only RNAV (GPS) or GPS approaches.
Yes, there are airports without RNAV approaches. They are very common; as another answer pointed out, there are fewer than 7000 RNAV approaches spread over 19,400 airports in the NAS, and they are certainly not spread evenly. If you browse Skyvector you will see any number of examples without even trying.
As far as larger public-use airports, KMCC (McClellan Airfield, Sacramento, CA) is an example. At the time of writing, it only has ILS and VOR/DME approaches. Others nearby include KVNY (Van Nuys, CA) and KLSV (Nellis AFB).
Why? Presumably they'll get around to it eventually. Designing an approach isn't "trivially easy". It takes considerable work on the part of the FAA to design a new approach.
(Just as a reference: As of 2016, an extremely basic RNAV approach with one line of minima starts at $10,000 - not including annual maintenance costs. Which may be cheaper than whatever it's replacing... but just to show that there's non-trivial work involved.)
According to this FAA site FAA Airport Categories:
There are approximately 14,400 private-use (closed to the public) and 5,000 public-use (open to the public) airports, heliports, and seaplane bases.
According to this FAA site Instrument Flight Procedures (IFP) Inventory Summary:
There are (as of 5/19/2022) 6956 RNAV approaches, of which 69 are categorized as GPS approaches (stand-alone), 6468 categorized as RNAV (GPS) approaches, and 419 categorized as RNAV (RNP) approaches.
I'm unable to find the number of airports that do not have at least one RNAV approach. But, as you have suggested, with the expansive use of GPS/RNAV technology available for the development of Instrument Approach procedures (IAPs), the number of airports that have these IAPs is likely significant.