Departure Procedure jStumper Question

[[email protected]]

Take a look at Salmon Idaho KSMN, Ahehu 1 RNAV Dept (Obstacle). I
realize few aircraft are equipped to fly this, however;

1. Notice the "at 200 kt" requirement for some waypoints. Is this
TAS, GS, or IAS? And a reference please if you know of one.

2. Why is the stipulation "at" instead of "at or below"?

Stan

[Newps]

Looking at the chart on the AOPA website nowhere is there a speed
listed. If a speed were listed it would be IAS.




wrote:
> Take a look at Salmon Idaho KSMN, Ahehu 1 RNAV Dept (Obstacle). I
> realize few aircraft are equipped to fly this, however;
>
> 1. Notice the "at 200 kt" requirement for some waypoints. Is this
> TAS, GS, or IAS? And a reference please if you know of one.
>
> 2. Why is the stipulation "at" instead of "at or below"?
>
> Stan

[B[_2_]]

You have to check the NOTAMs, too:

08/014 - AHEHU ONE DEPARTURE (RNAV) (OBSTACLE) NOTE: DO NOT EXCEED
200 KIAS UNTIL FIPFE AND FANID WIE UNTIL UFN

Newps wrote:
> Looking at the chart on the AOPA website nowhere is there a speed
> listed. If a speed were listed it would be IAS.
>

[B[_2_]]

Jeppesen didn't do quite a bad job of charting it as NACO.

It's at or below 200 knots and the authority is the departure criteria
the FAA uses.

wrote:

> Take a look at Salmon Idaho KSMN, Ahehu 1 RNAV Dept (Obstacle). I
> realize few aircraft are equipped to fly this, however;
>
> 1. Notice the "at 200 kt" requirement for some waypoints. Is this
> TAS, GS, or IAS? And a reference please if you know of one.
>
> 2. Why is the stipulation "at" instead of "at or below"?
>
> Stan

[[email protected]]

On Tue, 18 Sep 2007 12:19:29 -0700, B > wrote:

>It's at or below 200 knots and the authority is the departure criteria
>the FAA uses.
>
wrote:
>
>> Take a look at Salmon Idaho KSMN, Ahehu 1 RNAV Dept (Obstacle). I
>> realize few aircraft are equipped to fly this, however;
>>
>> 1. Notice the "at 200 kt" requirement for some waypoints. Is this
>> TAS, GS, or IAS? And a reference please if you know of one.
>>
>> 2. Why is the stipulation "at" instead of "at or below"?
>>
>> Stan
Thanks b. For lurkers, the Jepp chart does indeed say "at 200 kt".
The reference that I was looking for is the FAR or AIM that tells the
pilots whether the charted speed is supposed to be TAS, GS, or IAS. I
realize the notam clarifies that it is IAS, but without it, how does a
pilot know? Stan

[B[_2_]]

The AIM tells you that ATC assigns speeds in terms of IAS.

It also tells you that the speed for procedure turns is in terms of IAS.

Although Part 97 and the AIM are silent on whether Approach Categories
are IAS, TAS, or ground speed, how could they possibly be anything other
than IAS?

What about the speed limits on STAR charts?

wrote:

>
> Thanks b. For lurkers, the Jepp chart does indeed say "at 200 kt".
> The reference that I was looking for is the FAR or AIM that tells the
> pilots whether the charted speed is supposed to be TAS, GS, or IAS. I
> realize the notam clarifies that it is IAS, but without it, how does a
> pilot know? Stan

[Mark Hansen]

On 09/20/07 05:52, B wrote:
> The AIM tells you that ATC assigns speeds in terms of IAS.
>
> It also tells you that the speed for procedure turns is in terms of IAS.
>
> Although Part 97 and the AIM are silent on whether Approach Categories
> are IAS, TAS, or ground speed, how could they possibly be anything other
> than IAS?

I'm not sure sure Part 97 is silent on the issue. It says that the categories
are based on the "speed of VREF, if specified, or if VREF is not specified,
1.3 Vso at the maximum certificated landing weight".

VREF and Vso are IAS references, aren't they?

>
> What about the speed limits on STAR charts?
>

--
Mark Hansen, PP-ASEL, Instrument Airplane, USUA Ultralight Pilot
Cal Aggie Flying Farmers
Sacramento, CA

[B[_2_]]

Mark Hansen wrote:

>>
>>Although Part 97 and the AIM are silent on whether Approach Categories
>>are IAS, TAS, or ground speed, how could they possibly be anything other
>>than IAS?
>
>
> I'm not sure sure Part 97 is silent on the issue. It says that the categories
> are based on the "speed of VREF, if specified, or if VREF is not specified,
> 1.3 Vso at the maximum certificated landing weight".
>
> VREF and Vso are IAS references, aren't they?

So it would seem. ;-)

[[email protected]]

On Thu, 20 Sep 2007 05:52:54 -0700, B > wrote:

>The AIM tells you that ATC assigns speeds in terms of IAS.
>
>It also tells you that the speed for procedure turns is in terms of IAS.
>

>
>What about the speed limits on STAR charts?
>
All good points, and from others too. However I wasn't asking about
atc speeds. and the speed for procedure turns is not on the chart,
although I'm not arguing about that aim specified limit.

My query was about speeds listed on jeppessen charts. And I see
approach categories are referenced to IAS as a poster has noted. But
on the same chart where approach category minimums are stated, there
is also often a descent from faf chart that is noted as in GS. Now
sure, it's easy for "experts" say of course it's GS, (as noted on the
chart) since distance and time cannot equal IAS, so that's obvious.

But look at the case of the departure in the initial thread. The same
argument "that's obvious" can be made for GS, since the obstacle
clearance is based on a specified turn radius plus safety factor, and
clearly GS determines radius assuming a constant bank angle and not
IAS. Remember there is no annotation on the dept (jepp chart) on
whether it's ias tas or GS. And for the sake of this argument let's
not consider the notam (which specifies ias) in this hypothetical
case.

Are there other speeds on charts where it is not specified whether it
is IAS TAS or GS?

[Mark Hansen]

On 09/21/07 11:28, wrote:
> On Thu, 20 Sep 2007 05:52:54 -0700, B > wrote:
>
>>The AIM tells you that ATC assigns speeds in terms of IAS.
>>
>>It also tells you that the speed for procedure turns is in terms of IAS.
>>
>
>>
>>What about the speed limits on STAR charts?
>>
> All good points, and from others too. However I wasn't asking about
> atc speeds. and the speed for procedure turns is not on the chart,
> although I'm not arguing about that aim specified limit.
>
> My query was about speeds listed on jeppessen charts. And I see
> approach categories are referenced to IAS as a poster has noted. But
> on the same chart where approach category minimums are stated, there
> is also often a descent from faf chart that is noted as in GS. Now
> sure, it's easy for "experts" say of course it's GS, (as noted on the
> chart) since distance and time cannot equal IAS, so that's obvious.
>
> But look at the case of the departure in the initial thread. The same
> argument "that's obvious" can be made for GS, since the obstacle
> clearance is based on a specified turn radius plus safety factor, and
> clearly GS determines radius assuming a constant bank angle and not
> IAS. Remember there is no annotation on the dept (jepp chart) on
> whether it's ias tas or GS. And for the sake of this argument let's
> not consider the notam (which specifies ias) in this hypothetical
> case.

Well, I didn't see the Jepp chart in question, so I may be off here,
but from the discussion, I was under the impression that the annotation
on the chart was a speed restriction, which is different than a climb
gradient minimum.

When the ODPs need you to climb at a certain gradient, they don't give
you a speed at all - they give you the climb gradient. The pilot is
supposed to convert that into a climb rate based on actual GS.

So ... if the chart is telling you that you must be doing at or at/below
a speed at a certain point, I would interpret that as IAS.

>
> Are there other speeds on charts where it is not specified whether it
> is IAS TAS or GS?



--
Mark Hansen, PP-ASEL, Instrument Airplane, USUA Ultralight Pilot
Cal Aggie Flying Farmers
Sacramento, CA

[B[_2_]]

The FAA has charted TAS in a few cases, but that is no longer policy.
Example, KBUR ILS 8 missed approach text.

As far as taking into account adverse winds for turns, holding patterns,
and such, the TERPS criteria has wind assumptions built into them Some
of the assumptions are not very good, but that's the ballgame.

They are getting better with this, though, as RNAV criteria evolves.

wrote:

>
> Are there other speeds on charts where it is not specified whether it
> is IAS TAS or GS?