Reserve altitude

Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

On Thursday, May 25, 2017 at 4:00:44 PM UTC-7, wrote:
Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

Dennis

If you set your Alt Res [ft] at 1000'. The Arrival will say 0' when you have final glide to the target selected. You will arrive at 1000' above the target point selected assuming nothing changes on the glide.

If arrival says 1000' you will arrive 2000' above the target point. The Alt Res + 1000'.

Richard
www.craggyaero.com

On Thursday, May 25, 2017 at 4:44:36 PM UTC-7, Richard Pfiffner wrote:
On Thursday, May 25, 2017 at 4:00:44 PM UTC-7, wrote:
Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

Dennis

If you set your Alt Res [ft] at 1000'. The Arrival will say 0' when you have final glide to the target selected. You will arrive at 1000' above the target point selected assuming nothing changes on the glide.

If arrival says 1000' you will arrive 2000' above the target point. The Alt Res + 1000'.

Richard
www.craggyaero.com

Richard
With all due respect,just maybe my ignorance, the Oudie 2 manual says quote; "All final glide calculations are subject to correction of the altitude reserve. If this value is greater than 0,
then your arrival altitude to the waypoint will be this much above the altitude of the waypoint elevation
from the waypoint database (this may not be its actual altitude, so use at own risk, needless to say)."
So.... soI'm confused ?

On Thursday, May 25, 2017 at 6:15:58 PM UTC-7, 6PK wrote:
On Thursday, May 25, 2017 at 4:44:36 PM UTC-7, Richard Pfiffner wrote:
On Thursday, May 25, 2017 at 4:00:44 PM UTC-7, wrote:
Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

Dennis

If you set your Alt Res [ft] at 1000'. The Arrival will say 0' when you have final glide to the target selected. You will arrive at 1000' above the target point selected assuming nothing changes on the glide.

If arrival says 1000' you will arrive 2000' above the target point. The Alt Res + 1000'.

Richard
www.craggyaero.com

Richard
With all due respect,just maybe my ignorance, the Oudie 2 manual says quote; "All final glide calculations are subject to correction of the altitude reserve. If this value is greater than 0,
then your arrival altitude to the waypoint will be this much above the altitude of the waypoint elevation
from the waypoint database (this may not be its actual altitude, so use at own risk, needless to say)."
So.... soI'm confused ?


Then you should check every waypoint in the data base you use. It is contingent on the pilot to use a correct waypoint database. In my experience airports altitudes on the worldwide turnpoint exchange in the USA are correct.

If arrival is 0 and your Alt Res is 1000 then you will arrive 1000 above your target if the altitude of the target is correct.

I was relating how the program works not if the database you use is correct.


Richard

On Thursday, May 25, 2017 at 7:00:44 PM UTC-4, wrote:
Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

Hi Dennis,

The better way to do this is set the reserve altitude to zero and let the device report estimated arrival height. Then do that PIC thing and make appropriate decisions. Targeting an arrival at Post Mills (and many other places) at an arbitrary 1000 agl from 20 miles out is going to lead to problems.

best,
Evan / T8

On Thursday, May 25, 2017 at 7:00:44 PM UTC-4, wrote:
Just double checking my understanding of the see you mobile, (Oudie) reserve altitude correction.

If I set my reserve at 1000' and my target field is at 700' and my "Arrival Altitude" says 2700' ... does that mean I will arrive at 3700' essentially 2000 above the ground?

Dennis DC

Thank you all. I just wanted to double check the logic. Yes Evan I think you are right in keeping the information unfiltered is ultimately the way to go.

Dennis DC

Hi Evan -

Would you please expand a bit on why you think it is better to set reserve altitude to zero?

Thanks!

Lou

On Friday, May 26, 2017 at 8:46:28 AM UTC-4, MNLou wrote:
Hi Evan -

Would you please expand a bit on why you think it is better to set reserve altitude to zero?

Thanks!

Lou

Uh, sure. This is a semi-religious issue, so opinions will vary. Here's my $0.02 on a rainy day:

Conditions vary. Airport environments vary. I happen to fly in a region of the world (Northern New England) that features a lot of terrain that runs between poorly landable and completely unlandable, and weather than runs from benign to a crash-waiting-to-happen. While my environment is more challenging than many, yours isn't uniform, either.

So, the basic point is: there is no one standard reserve height that is appropriate in all situations. You as PIC need to be making decisions based on environment, current conditions & anything else that affects safety of flight. The computer is your assistant, not your decision maker.

For example: At my home airport (also DC's home airport) our traffic pattern is high due to surrounding terrain and your final glide ought to be padded well beyond this because there is simply no safe place to land other than the airport for a radius of about 5 miles (and then only one or two places, not necessarily where you want them!). Furthermore, the "safe" (that is, landable) route into my home airport follows a river valley which often features a) valley winds and b) subsiding air. I'm usually looking for 1500' over an MC 2.0 (kts) final glide from 25 out, based on the airport elevation. When I was learning to fly XC here, it was more like 2000 over.

This is total overkill at a million flat lands airports.

The obvious, simple solution is to set your flight computer to report estimated arrival height at any destination without any reserve, then do the PIC decision making thing. For old Cambridge gear, that's trivial. For ClearNav, there's one gotcha involved (easily handled, set the purple amoeba to zero and the red one to 1000 agl), for SN-10, you have to build yourself a whole new database with fake-news airport elevations (yes, people really do this, I've watched).

Go fast, make good decisions, land safe!

best,
Evan Ludeman / T8

I agree with Evan.

But why not get the guys at LXNav, Naviter,
LXNavigation, to call it arrival "height" and reserve
"height" if you must have it? Which imho is what it is
displayed, and this more precise terminology might
remove at least one source of confusion.

While you're at it, Waypoints have Elevation, perhaps.



At 14:08 26 May 2017, Tango Eight wrote:
On Friday, May 26, 2017 at 8:46:28 AM UTC-4, MNLou
wrote:
Hi Evan -=20
=20
Would you please expand a bit on why you think it is
better to set
reserv=
e altitude to zero?
=20
Thanks!
=20
Lou

Uh, sure. This is a semi-religious issue, so opinions will
vary. Here's
m=
y $0.02 on a rainy day:

Conditions vary. Airport environments vary. I happen
to fly in a region
o=
f the world (Northern New England) that features a lot
of terrain that
runs=
between poorly landable and completely unlandable,
and weather than runs
f=
rom benign to a crash-waiting-to-happen. While my
environment is more
chal=
lenging than many, yours isn't uniform, either.

So, the basic point is: there is no one standard reserve
height that is
app=
ropriate in all situations. You as PIC need to be making
decisions based
o=
n environment, current conditions & anything else that
affects safety of
fl=
ight. The computer is your assistant, not your decision
maker.

For example: At my home airport (also DC's home
airport) our traffic
patter=
n is high due to surrounding terrain and your final glide
ought to be
padde=
d well beyond this because there is simply no safe
place to land other
than=
the airport for a radius of about 5 miles (and then only
one or two
places=
, not necessarily where you want them!). Furthermore,
the "safe" (that
is,=
landable) route into my home airport follows a river
valley which often
fe=
atures a) valley winds and b) subsiding air. I'm usually
looking for
1500'=
over an MC 2.0 (kts) final glide from 25 out, based on
the airport
elevati=
on. When I was learning to fly XC here, it was more
like 2000 over.=20

This is total overkill at a million flat lands airports.=20

The obvious, simple solution is to set your flight
computer to report
estim=
ated arrival height at any destination without any
reserve, then do the
PIC=
decision making thing. For old Cambridge gear, that's
trivial. For
Clear=
Nav, there's one gotcha involved (easily handled, set
the purple amoeba to
=
zero and the red one to 1000 agl), for SN-10, you have
to build yourself a
=
whole new database with fake-news airport elevations
(yes, people really
do=
this, I've watched).

Go fast, make good decisions, land safe!

best,
Evan Ludeman / T8

I also set reserve to zero. Remembering which reserve altitude is set for the glide to turnpoint, glide to alternates, glide to finish, and the two amoebas (clearnav) is too much for me. So I set them all to zero. If I want to arrive at 1000', I don't proceed unless it says 1000' (plus a decent macCready). The one exception is the finish -- if it's a contest finish and the arrival height is 1000' MSL, then I set that to 1000' MSL, which is the logical equivalent of zero.

John Cochrane BB