Odd missed approach instructions

[Paul Tomblin]

The published missed for the RNAV (GPS) RWY 04 at KROC says "Climb to 3000
direct CISON WP and via 098(degree) track to BREIT WP and hold". I'm
trying to think why they'd put in that "098 track" thing instead of just
saying "direct BRIET WP". The plan view makes it look like after crossing
CISON you'd have to fly about 135 degrees to intercept the 098 track
somewhere before BRIET. Are they trying to keep you clear of that 1030'
obstacle just north west of BREIT? I was reading it as if you had to be
at 3000' before you got to CISON, but I suppose you could read it that
you're still on your way up to 3000' on the way between CISON and BREIT?


--
Paul Tomblin > http://blog.xcski.com/
"Imagine if every Thursday your shoes exploded if you tied them the
usual way. This happens to us all the time with computers, and nobody
thinks of complaining." -- Jef Raskin, interviewed in Doctor Dobb's Journal

[Matt Barrow[_4_]]

"Paul Tomblin" > wrote in message
...
> The published missed for the RNAV (GPS) RWY 04 at KROC says "Climb to 3000
> direct CISON WP and via 098(degree) track to BREIT WP and hold". I'm
> trying to think why they'd put in that "098 track" thing instead of just
> saying "direct BRIET WP". The plan view makes it look like after crossing
> CISON you'd have to fly about 135 degrees to intercept the 098 track
> somewhere before BRIET. Are they trying to keep you clear of that 1030'
> obstacle just north west of BREIT? I was reading it as if you had to be
> at 3000' before you got to CISON, but I suppose you could read it that
> you're still on your way up to 3000' on the way between CISON and BREIT?
>
Probably right, but also, the more specific instructions they give, the less
you need to calc-on-the-fly during a MA.

[Paul Tomblin]

In a previous article, "Matt Barrow" > said:
>"Paul Tomblin" > wrote in message
...
>> The published missed for the RNAV (GPS) RWY 04 at KROC says "Climb to 3000
>> direct CISON WP and via 098(degree) track to BREIT WP and hold". I'm
>> trying to think why they'd put in that "098 track" thing instead of just
>> saying "direct BRIET WP". The plan view makes it look like after crossing
>> CISON you'd have to fly about 135 degrees to intercept the 098 track
>> somewhere before BRIET. Are they trying to keep you clear of that 1030'
>> obstacle just north west of BREIT? I was reading it as if you had to be
>> at 3000' before you got to CISON, but I suppose you could read it that
>> you're still on your way up to 3000' on the way between CISON and BREIT?
>>
>Probably right, but also, the more specific instructions they give, the less
>you need to calc-on-the-fly during a MA.

This is an RNAV (GPS) approach, so direct to the next waypoint is going to
involve considerably fewer calculations that trying to intercept a track.

Personally, I think whoever wrote that missed approach procedure forgot
that BREIT isn't an NDB any more.



--
Paul Tomblin > http://blog.xcski.com/
One item could not be deleted because it was missing.
-- Mac System 7.0b1 error message

[Ron Rosenfeld]

On Fri, 18 May 2007 17:49:00 +0000 (UTC), (Paul
Tomblin) wrote:

>The published missed for the RNAV (GPS) RWY 04 at KROC says "Climb to 3000
>direct CISON WP and via 098(degree) track to BREIT WP and hold". I'm
>trying to think why they'd put in that "098 track" thing instead of just
>saying "direct BRIET WP". The plan view makes it look like after crossing
>CISON you'd have to fly about 135 degrees to intercept the 098 track
>somewhere before BRIET. Are they trying to keep you clear of that 1030'
>obstacle just north west of BREIT? I was reading it as if you had to be
>at 3000' before you got to CISON, but I suppose you could read it that
>you're still on your way up to 3000' on the way between CISON and BREIT?

I agree that it is unusual, and I'm not certain of the appropriate wording
in this circumstance. However, the NACO chart calls for flying the 098°
track, whereas the JEPP chart call for flying a 118° track! Something is
really screwed up here.

Also, I believe you have misinterpreted a portion of the missed approach
procedure. Probably especially important in view of that tower NW of
CISON:

You write, "... after crossing CISON ...".

But CISON is depicted, on both the Jepp and the NACO charts, as a fly-by WP
and not as a fly-over WP. "Fly-by waypoints are used when an aircraft
should begin a turn to the next course prior to reaching the waypoint". So
you should not be "crossing CISON".
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Scott Skylane]

Ron Rosenfeld wrote:


> I agree that it is unusual, and I'm not certain of the appropriate wording
> in this circumstance. However, the NACO chart calls for flying the 098°
> track, whereas the JEPP chart call for flying a 118° track! Something is
> really screwed up here.
>
> Also, I believe you have misinterpreted a portion of the missed approach
> procedure. Probably especially important in view of that tower NW of
> CISON:
>
> You write, "... after crossing CISON ...".
>
> But CISON is depicted, on both the Jepp and the NACO charts, as a fly-by WP
> and not as a fly-over WP. "Fly-by waypoints are used when an aircraft
> should begin a turn to the next course prior to reaching the waypoint". So
> you should not be "crossing CISON".
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Yup!

The Jepp database supplied to our Universal FMS's definitely shows a 120
degree track from CISON to BREIT, and that CISON is fly past, so you
should begin your turn before the waypoint. NACO obviously goofed on
this one.

A double-take on the chart should alert you that 098 *cannot* take you
from CISON to BREIT, as 098 is the outbound heading of the hold, and is
clearly at a different angle than the CISON to BREIT leg.

Happy Flying!
Scott Skylane

[Ben Jackson]

On 2007-05-18, Paul Tomblin > wrote:
> This is an RNAV (GPS) approach, so direct to the next waypoint is going to
> involve considerably fewer calculations that trying to intercept a track.

Unless you just went missed due to GPS failure?

--
Ben Jackson AD7GD
>
http://www.ben.com/

[Paul Tomblin]

In a previous article, Ben Jackson > said:
>On 2007-05-18, Paul Tomblin > wrote:
>> This is an RNAV (GPS) approach, so direct to the next waypoint is going to
>> involve considerably fewer calculations that trying to intercept a track.
>
>Unless you just went missed due to GPS failure?

Like I said, BRIET (the missed approach fix) isn't an NDB any more, so in
the event of a GPS failure you wouldn't be able to fly the published
missed anyway.


--
Paul Tomblin > http://blog.xcski.com/
If killing them all to a man is not an option then you are better off to
simply leave them to slowly self destruct under their own incompetance.
-- Dag