Angier,
This could be the start of an interesting discussion.
If one primarily flies VFR, TCAS is perhaps more valuable than WAAS (in
an FAA approved IFR approach and sole-source navigation box).
If one flies more than occasionally under IFR, the WAAS equipment ranks
at the top of the list. "Why?" You might ask. Well.......
1. Sole source navigation devices are usable in non-radar environments -
such as during terrain challenged aviating above piles of granite. This
also pertains to IFR flights in VFR conditions.
2. There are more GPS approaches with vertical guidance than ILS
approaches here in the US and with minimums almost as good as ILS.
This virtually eliminates the need to perform risky circle-to-land
procedures. It also opens up more airports (GPS only) to choose from in
nasty weather flying (more and better located alternates). There are
more GPS approaches added continuously at no cost to the Stimulus Plan nor
added jobs.
3. TCAS is less valuable because of ATC traffic separation when
flying under IFR rules (or even flight following, conditions
permitting).
You would have to pry my WAAS device (in my case, a 430W) from my cold
dead hands before I would give it up. GPSS navigation (laterally coupled
to auto pilot) and approach vertical guidance is a beautiful thing to
behold. In general, GPS approaches consist of three 5-mile-long
legs (most often in a T configuration). IAF to AF = get to correct altitude
and approach speed. AF to FAF = Stabilize approach, check
everything twice, hand hovering on gear switch. FAF to RWY (or missed) =
descend on VNAV glide slope, shut off AP at DA, make perfect landing.
OR, one button-push for guidance thru missed approach procedure. The GPS
approaches are so similar that even minimal practice raises one's confidence
in a successful outcome during their use, personal limitations, lack of ice
build up and all other things considered.
However, my cheap Monroy traffic alerter (TCAS like, approximate distance
and altitude difference, no azimuth) usually wakes me up once or twice on
long VFR trips (no flight plan or following) with a
screaming TRAFFIC NEARBY! and it has saved me from one
sure midair, if not more (details released upon any request).
You are right to consider disabling TCAS in an airport
environment as it can be most distracting (unless is has non-critical traffic
suppression).
Scott
Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL
(KARR)
Pilot not TSO'd, Certificated score only >
70%.