Why do lnav approaches still exist?

[RobertGary1]

Are lnav approaches just old approaches that haven’t been converted to LP yet? Can’t imagine why you wouldn’t want increased sensitivity to the runway. 
 

-Robert 

[Niko182]

12 minutes ago, RobertGary1 said:

Are lnav approaches just old approaches that haven’t been converted to LP yet? Can’t imagine why you wouldn’t want increased sensitivity to the runway. 
 

-Robert 

Not everyone has WAAS.

[glafaille]

 

Many jet operators have complied with ADS-B with solutions that DO NOT involve a complete WAAS navigation lobotomy. 

A WAAS GPS might cost $10,000 installed for a small general aviation aircraft but for jet aircraft with multiple FMS systems you could be looking at $250,00 to $350,000 or more.  Is the ability to descend another 100 or 200 feet lower than what your current LNAV/VNAV system offers worth that expense?  Unless you frequently NEED that capability, the answer is often no, particularly for legacy jets worth under 3 million or so.   

Many jet operators find themselves frequenting airports with an ILS and are rarely, if ever inconvenienced by the lack of WAAS navigation.  Piston aircraft and turboprop aircraft on the other hand visit non ILS airports more frequently and can usually equip for WAAS for much less.

It’s all about the cost/benefit ratio, even on multi million dollar aircraft.

I often wonder how often the average general aviation aircraft owner really NEEDS the full capability of his WAAS GPS, in other words just how often is a single engine aircraft owner shooting REAL approaches in weather less than 400 and 1?  I’ll bet most never do, yet spent the money for the capability.