Departure/Enroute RAIM

A chart change notice (and a similar Jeppesen briefing bulletin) were
sent to all subscribers in the past few weeks setting forth the new Type
A or B requirements for RNAV OPDs, SIDs, and RNAV routes.

The practical aspect for light aircraft equipped with either TSO 129 or
146 boxes is that a terminal RAIM check must not be accomplished before
using an RNAV ODP. And, if the aircraft can get into the low flight
levels and use a Q Route, then a predictive RAIM check must be made.

This is all dependent upon whether any of the GPS birds are inoperative,
the determination of which places a significant new burden on the light
aircraft IFR pilot using IFR GPS.

AOPA just issued a bulletin on the subject, which I feel really glosses
over the issues raised by all of this.

http://www.aopa.org/whatsnew/newsite...50901rnav.html

These requirements became effective yesterday.

Does anyone know how to do a predictive RAIM check with a 129 box? What
is required for using an RNAV ODP, a perdictive RAIM check or an actual
terminal RAIM check at departure time? How is a terminal RAIM check
accomplished (as opposed to an approach RAIM check, which is easy to do,
but perhaps overly restrictive).

Anyone understand this stuff? I know I am confused.

I suppose most non-commercial operators will be able to just press on
and just fly the ODP. No doubt it will be just as safe post-Sept 1st as
it was before. But, eventually some inspector, designee, or CFI-I doing
an ICC is going to make an applicant do a rug dance over this new stuff.

In article , wrote:
AOPA just issued a bulletin on the subject, which I feel really glosses
over the issues raised by all of this.

http://www.aopa.org/whatsnew/newsite...50901rnav.html

Thanks for posting this. It's the first I've ever heard of any of this!

Reading over the AOPA writeup, I see some problems already. They say:

First off, to use any of the new RNAV procedures, you must have a TSO
C-129 or C-146 certified GPS (panel mount, IFR certified for en route
and approach operations) or certain kinds of FMS (flight management
system) equipment, and a current database.

The CNX-80/GNS-480 (perhaps unique among IFR units?) does not require that
you have a current database. It only requires that you have verified the
accuracy of the waypoint data (presumably by comparison to a current
chart). I can't imagine that this has changed any.

It also seems odd that an RNAV SID should be treated any differently from
any other departure procedure. If the plate says, "Track outbound on the
315 bearing from the XYZ NDB until reaching 1800 feet", why should the
rules change if they take that procedure and wrap it up in a named SID?
The terrain is the same either way.

Roy Smith wrote:

Thanks for posting this. It's the first I've ever heard of any of this!

Jeppesen had a Briefing Bulletin, but it is clear as mud.



Reading over the AOPA writeup, I see some problems already. They say:

First off, to use any of the new RNAV procedures, you must have a TSO
C-129 or C-146 certified GPS (panel mount, IFR certified for en route
and approach operations) or certain kinds of FMS (flight management
system) equipment, and a current database.

The CNX-80/GNS-480 (perhaps unique among IFR units?) does not require that
you have a current database. It only requires that you have verified the
accuracy of the waypoint data (presumably by comparison to a current
chart). I can't imagine that this has changed any.

Your box is certainly an usual exception to the database requirement.



It also seems odd that an RNAV SID should be treated any differently from
any other departure procedure. If the plate says, "Track outbound on the
315 bearing from the XYZ NDB until reaching 1800 feet", why should the
rules change if they take that procedure and wrap it up in a named SID?
The terrain is the same either way.

I am far more concerned about RNAV ODPs at non-radar airports.

The Type A and Type B stuff is a tortured response to all the airliners that
don't have GPS and thus use DME/DME postioning to update their FMS position.

On Fri, 02 Sep 2005 05:56:12 -0700, wrote:

The practical aspect for light aircraft equipped with either TSO 129 or
146 boxes is that a terminal RAIM check must not be accomplished before
using an RNAV ODP.

According to the AOPA article, RAIM check's need NOT be done for a TSO 146
box unless there is a WAAS outage.

"Of course, if you have the latest IFR GPS navigation system, a Wide Area
Augmentation System (WAAS) receiver, no RAIM checks are needed. Just make
sure no WAAS notams are published, and you're good to go."


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

That is correct, but few folks have WAAS 146 boxes and no biz jet or air
carrier has WAAS. WAAS doesn't travel well for intercontinental jet aircraft.

Ron Rosenfeld wrote:

On Fri, 02 Sep 2005 05:56:12 -0700, wrote:

The practical aspect for light aircraft equipped with either TSO 129 or
146 boxes is that a terminal RAIM check must not be accomplished before
using an RNAV ODP.

According to the AOPA article, RAIM check's need NOT be done for a TSO 146
box unless there is a WAAS outage.

"Of course, if you have the latest IFR GPS navigation system, a Wide Area
Augmentation System (WAAS) receiver, no RAIM checks are needed. Just make
sure no WAAS notams are published, and you're good to go."

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Fri, 02 Sep 2005 11:42:49 -0700, wrote:

That is correct, but few folks have WAAS 146 boxes and no biz jet or air
carrier has WAAS.

I'm not sure of the relevance of this comment to my statement.

1. The fact that most folk may not have WAAS 146 box still means that the
RAIM stuff is not applicable to the 146a boxes.

2. Not only do the biz jet or air carriers not have WAAS, but it is my
understanding that very few have GPS. Hence they would not be doing RAIM
to assure their RNP accuracy in any event.

3. The lack of intercontinental coverage is not really an issue for most
as the procedures are being enacted in US airspace, aren't they?




Ron Rosenfeld wrote:

On Fri, 02 Sep 2005 05:56:12 -0700, wrote:

The practical aspect for light aircraft equipped with either TSO 129 or
146 boxes is that a terminal RAIM check must not be accomplished before
using an RNAV ODP.

According to the AOPA article, RAIM check's need NOT be done for a TSO 146
box unless there is a WAAS outage.

"Of course, if you have the latest IFR GPS navigation system, a Wide Area
Augmentation System (WAAS) receiver, no RAIM checks are needed. Just make
sure no WAAS notams are published, and you're good to go."

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron Rosenfeld wrote:

On Fri, 02 Sep 2005 11:42:49 -0700, wrote:

That is correct, but few folks have WAAS 146 boxes and no biz jet or air
carrier has WAAS.

I'm not sure of the relevance of this comment to my statement.

The relevance is that most users with GPS, light aircraft, biz jet, or air
carrier cannot exercise the WAAS option.



1. The fact that most folk may not have WAAS 146 box still means that the
RAIM stuff is not applicable to the 146a boxes.

2. Not only do the biz jet or air carriers not have WAAS, but it is my
understanding that very few have GPS. Hence they would not be doing RAIM
to assure their RNP accuracy in any event.

The vast majority of the business jet fleet has GPS as a sensor in it FMS sensor
array. The percentage is smaller in the air carrier fleet.



3. The lack of intercontinental coverage is not really an issue for most
as the procedures are being enacted in US airspace, aren't they?

My point was that even the latest and greatest jets do not have WAAS because it
does not travel well. There is no point in equipping that type of aircraft for
something that is only useful in this country. Baro VNAV, GPS, and IRUs work all
over the world.

On Fri, 02 Sep 2005 13:09:11 -0700, wrote:

The relevance is that most users with GPS, light aircraft, biz jet, or air
carrier cannot exercise the WAAS option.

OK, but my comment was solely related to the WAAS boxes.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron Rosenfeld wrote:

On Fri, 02 Sep 2005 13:09:11 -0700, wrote:

The relevance is that most users with GPS, light aircraft, biz jet, or air
carrier cannot exercise the WAAS option.

OK, but my comment was solely related to the WAAS boxes.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

And, ok, you responded to my comment about the situation that changed a whole
lot yesterday and affects the majority of the GPS-using community; i.e.,
TSO-C129 panel mounts and the high-end FMS/LNAV suites. I don't believe you
started a new thread. ;-)

On Fri, 02 Sep 2005 14:53:18 -0700, wrote:



Ron Rosenfeld wrote:

On Fri, 02 Sep 2005 13:09:11 -0700, wrote:

The relevance is that most users with GPS, light aircraft, biz jet, or air
carrier cannot exercise the WAAS option.

OK, but my comment was solely related to the WAAS boxes.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

And, ok, you responded to my comment about the situation that changed a whole
lot yesterday and affects the majority of the GPS-using community; i.e.,
TSO-C129 panel mounts and the high-end FMS/LNAV suites. I don't believe you
started a new thread. ;-)


You are correct that I did not start a new thread. I did not feel it was
warranted when I was correcting your statement about RAIM being required
for TSO 146a boxes.

At least that's what I thought I was doing. However, what you actually
wrote was:

"The practical aspect for light aircraft equipped with either TSO 129 or
146 boxes is that a terminal RAIM check must not be accomplished before
using an RNAV ODP".

I thought you had made a typo -- "RAIM check must not be accomplished..."
should have read "RAIM check must NOW be accomplished..." and that was what
I was responding to.

If it was a typo, then your statement about the 146 boxes was incorrect; if
it was not a typo, then your statement about the 129 boxes was incorrect.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)