Garmin 530 WAAS?

"Stan Prevost" wrote:

But my question is how do they do it? The desired track in a hold is
not the pretty little racetrack pattern with two parallel sides and
two semicircles at each end, except in a no-wind situation.

An FMS does fly all holding patterns with two parallel sides and two semicircles. It corrects for the wind
by commanding the bank angle required to track the semicircle. This may be more or less than a
standard rate turn, depending on the wind.

Mike

"Stan Prevost" wrote:
The GPS box cannot do that without knowledge of the wind. A fancy FMS
which determines the wind correction from the autopilot can do that, but
how can a standalone GPS box, WAAS or not, do that?

Stan,

According to a Garmin rep I spoke to at NBAA, it can compensate if it is
connected to an airdata computer. Even the current 430/530 models can be
connected to an ADC, which allows them to display TAS and winds.

-Mike

Mike Adams wrote:


The 430/530 didn't provide hold guidance prior to the upgrade. The point he was trying to make is that
this feature is part of the same upgrade package, but not specifically related to WAAS. As Sam said, the
big-boy FMSs have provided hold and procedure turn guidance for years, using just VOR/DME or
DME/DME position updating.

So far as I know, although a lot of them used (and still do with the
older birds) DME/DME updating, none of them used VOR/DME updating...well
unless that was all that the system could see...and often it would just
stay with IRU position rather than use a bad solution.

Having said that, the method of flying track-guidance around a holding
pattern does not assure containment (at least in a jet at max holding
speed) unless the FAA holding patterns rules are followed (or the ICAO
rules).

Perhaps Garmin has been smarter than the big guys (they often are).

Stan Prevost wrote:


Mike


But my question is how do they do it? The desired track in a hold is not
the pretty little racetrack pattern with two parallel sides and two
semicircles at each end, except in a no-wind situation. The desired track
on the outbound leg is that which will put you in a position from which a
standard rate turn will roll you out on the inbound track That is why we
fly outbound with a multiple of the inbound wind correction.. The GPS box
cannot do that without knowledge of the wind. A fancy FMS which determines
the wind correction from the autopilot can do that, but how can a standalone
GPS box, WAAS or not, do that?



Standard rate turns become irrelevant if they do it right. Keep in
mind, it is standard rate turn or 30 degrees of bank, whichever is less.

So long as Garmin observes the inbound limit (in the case of timing) or
the outbound distance limit in the case of distance, and a pattern is
computed to roll out on course, inbound, they would have a compliant
pattern.

I can buy that, Mike. Given access to the air data, the machine can compute
an outbound track and turns to make it work out. But that was my point, the
box needs that data. Most of the GPS-equipped small airplanes have
standalone GPS boxes, no FMS, no ADC.

As Sam mentioned, increasing the bank angle to 30 degrees for the inbound
turn helps in some ways. For a small airplane holding at 90 kts, tracking
an outbound leg offset by 1 nm, and a 30 kt xwind, it just about works out,
IF the pilot knew he needed to use a 30 degree bank turn to inbound. I am a
bit reluctant to encourage pilots to use the higher roll rates associated
with those maneuvers in IMC, for physiological reasons.

I don't think my S-Tec 55 autopilot, without GPSS, could follow the
maneuver, anyway.

Stan


"Mike Murdock" wrote in message
...
"Stan Prevost" wrote:
The GPS box cannot do that without knowledge of the wind. A fancy FMS
which determines the wind correction from the autopilot can do that, but
how can a standalone GPS box, WAAS or not, do that?

Stan,

According to a Garmin rep I spoke to at NBAA, it can compensate if it is
connected to an airdata computer. Even the current 430/530 models can be
connected to an ADC, which allows them to display TAS and winds.

-Mike

Sam Spade wrote:
scott moore wrote:
Al G wrote:

Thanks to the certification and AML STC approval, owners of Garmin's
popular GNS 400/500 series panel-mount avionics will be able to
upgrade their products to meet the FAA's WAAS standards* without a
field approval**. These upgrades include 5 Hz position updates,
faster map redraws, fully coupled and guided procedure turns and
holding patterns, and increased XM weather content. Pilots will also
experience significantly enhanced functionality because of the WAAS
LPV, LNAV/VNAV, LNAV+V, and LNAV approach capabilities.


Coupled procedure turns and holds? Why is WAAS an enabling factor for
that?

I don't read where he said WAAS is the enabling factor for track-guided
procedure turns or holding patterns.

It wasn't able to do it without WAAS, now it is.

Stan Prevost wrote:
I can buy that, Mike. Given access to the air data, the machine can compute
an outbound track and turns to make it work out. But that was my point, the
box needs that data. Most of the GPS-equipped small airplanes have
standalone GPS boxes, no FMS, no ADC.

As Sam mentioned, increasing the bank angle to 30 degrees for the inbound
turn helps in some ways. For a small airplane holding at 90 kts, tracking
an outbound leg offset by 1 nm, and a 30 kt xwind, it just about works out,
IF the pilot knew he needed to use a 30 degree bank turn to inbound. I am a
bit reluctant to encourage pilots to use the higher roll rates associated
with those maneuvers in IMC, for physiological reasons.

I don't think my S-Tec 55 autopilot, without GPSS, could follow the
maneuver, anyway.


I guess the autopilot would track the turn better if it has roll
steering instead of CDI stearing. (Roll steering will be mandatory for
RF legs, which are coming along.)

I don't see any need for air data to make this work. It is a positive
course guidance oval, right? So, make the oval the correct dimensions
for containment in protected airspace. Then, the autopilot, flight
director, or hand-flying pilot will compensate for wind by simply
remaining on the yellow brick road.

scott moore wrote:

Sam Spade wrote:

scott moore wrote:

Al G wrote:

Thanks to the certification and AML STC approval, owners of Garmin's
popular GNS 400/500 series panel-mount avionics will be able to
upgrade their products to meet the FAA's WAAS standards* without a
field approval**. These upgrades include 5 Hz position updates,
faster map redraws, fully coupled and guided procedure turns and
holding patterns, and increased XM weather content. Pilots will also
experience significantly enhanced functionality because of the WAAS
LPV, LNAV/VNAV, LNAV+V, and LNAV approach capabilities.



Coupled procedure turns and holds? Why is WAAS an enabling factor for
that?


I don't read where he said WAAS is the enabling factor for
track-guided procedure turns or holding patterns.


It wasn't able to do it without WAAS, now it is.

And, after the upgrade it will be able to do holding patterns the
Garmin-improved way, even with WAAS is not available.

(Roll steering will be mandatory for RF legs, which are coming along.)

What are "radio frequency legs" (or did I mix up my TLAs again?)

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

Jose wrote:
(Roll steering will be mandatory for RF legs, which are coming along.)


What are "radio frequency legs" (or did I mix up my TLAs again?)

Jose

One of many ARINC-specified RNAV legs; radius-to-fix. A curved flight
path much, much more precise than an AF (arc-to-fix) leg used to overlay
a DME arc.

Palm Springs RNAV (RNP) Runway 13R is an application of RF legs. In the
not too distant future RF legs will be used for basic RNAV to get to
runway ends not posible with straight (TF, or track-to-fix) legs.