CAT II Minimums on a CAT I Approach

[Giwi]

I've heard that some pilots have the authority to descend to CAT II
minimums (RA100) on CAT I intstrument approaches. If this is true,
then how is the CAT I approach altered? Is the DH simply lowered?
Seems like this would result in steeper approach angles to make it
work out right. Alternately it seems possible that the DH is lowered
farther along the inbound course...but wouldn't this make it more
difficult to transition out of the cockppit and land?

[Ryan Ferguson]

Yes, a recent edition of IFR Magazine covered this topic. It was news to
me as well.

Basically you can apply for Cat II authorization at Cat II runways with
'standard' avionics equipment (i.e. your normal GA spamcan) and a waiver
for Cat II authorization on Cat I approaches. FAR 91.193 is the reg that
states the FAA may grant authorization to 'small aircraft' for deviation
from 91.189, 91.191, and 91.205(f).

The authorization and/or waiver only applies to a certain pilot in a
certain aircraft. There are some slightly different currency
requirements, and gaining the authorization/waiver requires a flight
check in the specific aircraft for which the authorization/waiver is
sought.

The flight check is done with a fed onboard and uses the instrument
rating PTS, but always includes at least a two-engine ILS to Cat II
minimums and a single-engine ILS with a single-engine missed approach.

I find the whole thing quite intriguing, really.

-Ryan
CFI/MEI/CFI-H

Giwi wrote:

> I've heard that some pilots have the authority to descend to CAT II
> minimums (RA100) on CAT I intstrument approaches. If this is true,
> then how is the CAT I approach altered? Is the DH simply lowered?
> Seems like this would result in steeper approach angles to make it
> work out right. Alternately it seems possible that the DH is lowered
> farther along the inbound course...but wouldn't this make it more
> difficult to transition out of the cockppit and land?

[Robert Moore]

(Giwi) wrote
> I've heard that some pilots have the authority to descend to CAT
> II minimums (RA100) on CAT I intstrument approaches. If this is
> true, then how is the CAT I approach altered? Is the DH simply
> lowered? Seems like this would result in steeper approach angles
> to make it work out right. Alternately it seems possible that
> the DH is lowered farther along the inbound course...but
> wouldn't this make it more difficult to transition out of the
> cockppit and land?

Yes, the decision height is simply lowered. There is no
difference in the glideslope angle and touchdown point in
any of the ILS approaches for the same runway.
Part 121 aircarriers have a somewhat different definition
for CAT I approaches than the standard 200-1/2 that most
pilots understand CAT I to mean. This is spelled-out in
the aircarrier's FAA OPSPECS and usually limits the CAT I
pilots to 250-3/4 unless specific training requirements are
meet. These training requirements include handflying an ILS
to what ammounts to CAT II minimums (100-1/4). This flying
an ILS to CAT II minimums inorder to achieve CAT I approval
may be the source of the original question.

Bob Moore
ATP B-727 B-707
PanAm (retired 1991)

[[email protected]]

Giwi wrote:

> I've heard that some pilots have the authority to descend to CAT II
> minimums (RA100) on CAT I intstrument approaches. If this is true,
> then how is the CAT I approach altered? Is the DH simply lowered?
> Seems like this would result in steeper approach angles to make it
> work out right. Alternately it seems possible that the DH is lowered
> farther along the inbound course...but wouldn't this make it more
> difficult to transition out of the cockppit and land?

This authorization has been around some 30 years. It is limited to ILS
ground installations that meet CAT II performance requirements, but do
not have TDZ or CL. As I recall, it is limited to Category A aircraft.

Having said that, why do you think the geometry would be any different
for a CAT II DA/H? it is on the same G/S, just lower and closer-in than
the CAT I DA/H point.

[Ron Natalie]

"Giwi" > wrote in message m...
> I've heard that some pilots have the authority to descend to CAT II
> minimums (RA100) on CAT I intstrument approaches. If this is true,
> then how is the CAT I approach altered?

Not that I am aware of. What I am aware of is there is a procedure to
for pilots and the aircraft to get approved for CAT II approaches with
exemptions for some of the requirements (radar alt etc...). Requires
a check ride and is good only for the pilot/aircraft it's demonstrated in.

[Michael P. McCullough]

This may also apply to aircraft operated witha HUD or the new EVS system
installed on Gulfstreams. Some Part 91 operators of transport category jets
(business jets) have been granted CAT II minimums on CAT I approaches after
receiving approval and VERY specific training.


"Ron Natalie" > wrote in message
m...
>
> "Giwi" > wrote in message
m...
> > I've heard that some pilots have the authority to descend to CAT II
> > minimums (RA100) on CAT I intstrument approaches. If this is true,
> > then how is the CAT I approach altered?
>
> Not that I am aware of. What I am aware of is there is a procedure to
> for pilots and the aircraft to get approved for CAT II approaches with
> exemptions for some of the requirements (radar alt etc...). Requires
> a check ride and is good only for the pilot/aircraft it's demonstrated in.
>
>
>

[Ron Rosenfeld]

On Wed, 23 Jul 2003 18:19:46 GMT, Ryan Ferguson > wrote:

>Basically you can apply for Cat II authorization at Cat II runways with
>'standard' avionics equipment (i.e. your normal GA spamcan) and a waiver
>for Cat II authorization on Cat I approaches. FAR 91.193 is the reg that
>states the FAA may grant authorization to 'small aircraft' for deviation
>from 91.189, 91.191, and 91.205(f).

The FAA has granted authorization to both Part 91 and Part 125 operators to
use less than standard minimums on CAT I ILS's. A few years ago, when I
went through the CAT II authorization process in my Mooney, my recollection
was that this was not possible for my a/c. If I recall correctly, the
issue was that the various waivers were authorized to be issued for my
performance of CAT II approaches at CAT II runways. However, there was no
similar waiver authority to allow special CAT I minimums with the equipment
I had in my a/c.

>
>The authorization and/or waiver only applies to a certain pilot in a
>certain aircraft. There are some slightly different currency
>requirements, and gaining the authorization/waiver requires a flight
>check in the specific aircraft for which the authorization/waiver is
>sought.
>
>The flight check is done with a fed onboard and uses the instrument
>rating PTS, but always includes at least a two-engine ILS to Cat II
>minimums and a single-engine ILS with a single-engine missed approach.

Before you even go flying, the Fed's also do an inspection of the aircraft
to ensure that all the equipment requirements are met.

At least in a single engine a/c, the minimum required flight check consists
of only two approaches -- one to a full-stop; one to a missed approach with
a DH of 100' AGL. Of course, the FAA examiner is always looking at you for
attitude and general flying ability anyway. In a multi-engine approach,
there is a requirement to do a single engine missed approach with the
critical engine set at idle or zero thrust before reaching the middle
marker.


In addition, the standard for flying the approach is no more than 1/4 scale
deflection of either LOC or GP needles. That may be more rigorous than the
Instrument PTS, but I don't have that information handy.

>
> I find the whole thing quite intriguing, really.

It was an interesting experience.


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

[Richard Kaplan]

"Ron Rosenfeld" > wrote in message
...

> use less than standard minimums on CAT I ILS's. A few years ago, when I
> went through the CAT II authorization process in my Mooney, my
recollection

Just curious.. .did you do this as a training exercise or because you
intended to use these privileges?

Do you keep the privileges up?

Did you ever actually land when weather was less than Cat I minimums?


--
Richard Kaplan, CFII

www.flyimc.com

[Ryan Ferguson]

Ron Rosenfeld wrote:

> The FAA has granted authorization to both Part 91 and Part 125 operators to
> use less than standard minimums on CAT I ILS's. A few years ago, when I
> went through the CAT II authorization process in my Mooney, my recollection
> was that this was not possible for my a/c. If I recall correctly, the
> issue was that the various waivers were authorized to be issued for my
> performance of CAT II approaches at CAT II runways. However, there was no
> similar waiver authority to allow special CAT I minimums with the equipment
> I had in my a/c.

Very interesting. So if I understand this correctly (and maybe I don't,)
you're saying that you obtained authorization for CAT II approaches, but no
waiver for CAT I minimums with the equipment on-board your Mooney? If so,
which required equipment were you lacking?


> Before you even go flying, the Fed's also do an inspection of the aircraft
> to ensure that all the equipment requirements are met.

What are the equipment requirements?


> In addition, the standard for flying the approach is no more than 1/4 scale
> deflection of either LOC or GP needles. That may be more rigorous than the
> Instrument PTS, but I don't have that information handy.

It is... the instrument rating PTS allows no more than 3/4 scale deflection on
the final approach segment of the ILS.

> It was an interesting experience.

Like Richard, I am curious as to why you decided to do this and what, if any
utility you've gained from the Cat II authorization you were granted. I've
tossed the idea of pursuing this around for a little bit - mainly just for the
challenge and learning experience.

-Ryan

[Ron Rosenfeld]

On Thu, 24 Jul 2003 03:23:38 GMT, "Richard Kaplan" >
wrote:

>Just curious.. .did you do this as a training exercise or because you
>intended to use these privileges?

Both -- I was looking for a challenge. It certainly made flying a CAT I
approach a piece of cake.

>
>Do you keep the privileges up?

I did for a number of years when I was based at ASH. I haven't in the past
few years since being based at EPM

>
>Did you ever actually land when weather was less than Cat I minimums?

Just once. But more importantly, I was able to depart BGR on a flight to
BOS when BOS was closed to a/c unless they were authorized for an RVR of
1200.



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

[Ron Rosenfeld]

On Thu, 24 Jul 2003 04:03:16 GMT, Ryan Ferguson > wrote:


>
>Very interesting. So if I understand this correctly (and maybe I don't,)
>you're saying that you obtained authorization for CAT II approaches, but no
>waiver for CAT I minimums with the equipment on-board your Mooney? If so,
>which required equipment were you lacking?

You understand correctly. Required equipment includes an autopilot
approach coupler, HUD or FD system that provides guidance to DH. While
this stuff is also "required" for CAT II operations, one can obtain a
waiver for a CAT A a/c under Part 91. There is no similar authority to
obtain a waiver for special Cat I minima.

>
>
>> Before you even go flying, the Fed's also do an inspection of the aircraft
>> to ensure that all the equipment requirements are met.
>
>What are the equipment requirements?

Unfortunately, it's not easy for me to do a cut and paste because of the
columns in the pdf document. But you can find 8700.1 on the FAA web site.
Look in Volume 2 Chapter 59 and that info is there. Any well-equipped GA
a/c should probably qualify. On my airplane, I had to add an alternate
static air source. I also had to adjust the rigging of my flaps as the a/c
tended to turn enough to one side that I had difficulty flying that last
100'. I never noticed it flying CAT I approaches.

>
>
>> In addition, the standard for flying the approach is no more than 1/4 scale
>> deflection of either LOC or GP needles. That may be more rigorous than the
>> Instrument PTS, but I don't have that information handy.
>
>It is... the instrument rating PTS allows no more than 3/4 scale deflection on
>the final approach segment of the ILS.
>
>> It was an interesting experience.
>
>Like Richard, I am curious as to why you decided to do this and what, if any
>utility you've gained from the Cat II authorization you were granted. I've
>tossed the idea of pursuing this around for a little bit - mainly just for the
>challenge and learning experience.
>

For me it was mostly the challenge and learning experience. But it did
give me additional confidence, skill and some added utility.


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

[[email protected]]

"Michael P. McCullough" wrote:

> This may also apply to aircraft operated witha HUD or the new EVS system
> installed on Gulfstreams. Some Part 91 operators of transport category jets
> (business jets) have been granted CAT II minimums on CAT I approaches after
> receiving approval and VERY specific training.

That is a whole new set of authorizations issued in the past few months and only
for the real EVS, not the computed stuff.