IFR GPS question

[Robert M. Gary]

A couple questions...
1) Does a GNS-430 have DME built in? i.e. If I don't upgrade the GPS DB
can I still fly a VORDME approach off the 430's VOR? (I'm trying to
decide if I should keep my DME)
2) What is really the requirement to install an IFR GPS? What rule
(FAR) actually prohibits an A&P from approving a 430 for approaches?

-Robert

[Jose[_1_]]

> 1) Does a GNS-430 have DME built in?

Sort of. It reports the straight line (not slant range) distance to the
next fix. This can legally be substituted for the DME on an approach
(if the GPS is IFR approach certified). There may be an exception for
DME arcs similar to the exception for substituting for NDB during NDB
approaches.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Thomas Borchert]

Robert,


> 1) Does a GNS-430 have DME built in? i.e. If I don't upgrade the GPS DB
> can I still fly a VORDME approach off the 430's VOR? (I'm trying to
> decide if I should keep my DME)

No, it doesn't have a DME built-in. However, if the DME is a waypoint in
the database (not the airport the DME is at, but the DME itself, which is
the case for most, if not all), then you can legally substitute the GPS
distance readout for the DME. You should still be able to fly a VOR
approach with the 430 without a database, but obviously not a VORDME, if
you substitute the DME in the way described above, since the DME part
would depend on the database.

--
Thomas Borchert (EDDH)

[bsalai]

Robert M. Gary wrote:
> A couple questions...
> 1) Does a GNS-430 have DME built in? i.e. If I don't upgrade the GPS DB
> can I still fly a VORDME approach off the 430's VOR? (I'm trying to
> decide if I should keep my DME)

There is a slight advantage to keeping your DME, and ADF if you have
one. If you need an alternate, and the alternate only has non GPS
approaches that need either a DME, or ADF, then you can't legally use
the alternate unless you have the necessary equipment in addition to
your GPS.

At least that's how I understand it.

Brad

[Robert M. Gary]

Thomas Borchert wrote:
> Robert,
>
>
> > 1) Does a GNS-430 have DME built in? i.e. If I don't upgrade the GPS DB
> > can I still fly a VORDME approach off the 430's VOR? (I'm trying to
> > decide if I should keep my DME)
>
> No, it doesn't have a DME built-in. However, if the DME is a waypoint in
> the database (not the airport the DME is at, but the DME itself, which is
> the case for most, if not all), then you can legally substitute the GPS
> distance readout for the DME. You should still be able to fly a VOR
> approach with the 430 without a database, but obviously not a VORDME, if
> you substitute the DME in the way described above, since the DME part
> would depend on the database.

That was my fear. I don't plan on keep the DB up to date all the time
and I still need to be able to fly VORDME approaches. I guess I'll need
to keep my King DME. I assume I can slave it off the 430's nav.

-Robert

[Jose[_1_]]

> ...then you can't legally use the alternate

Not quite. You can't file that airport as an alternate if you need the
GPS to get in there. However, once you actually =need= an alternate,
that restriction goes away. It's a restriction on filing, not on flying.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Newps]

Robert M. Gary wrote:
> Thomas Borchert wrote:
>
>>Robert,
>>
>>
>>
>>>1) Does a GNS-430 have DME built in? i.e. If I don't upgrade the GPS DB
>>>can I still fly a VORDME approach off the 430's VOR? (I'm trying to
>>>decide if I should keep my DME)
>>
>>No, it doesn't have a DME built-in. However, if the DME is a waypoint in
>>the database (not the airport the DME is at, but the DME itself, which is
>>the case for most, if not all), then you can legally substitute the GPS
>>distance readout for the DME. You should still be able to fly a VOR
>>approach with the 430 without a database, but obviously not a VORDME, if
>>you substitute the DME in the way described above, since the DME part
>>would depend on the database.
>
>
> That was my fear. I don't plan on keep the DB up to date all the time
> and I still need to be able to fly VORDME approaches. I guess I'll need
> to keep my King DME. I assume I can slave it off the 430's nav.



It is not necessary to have a current database for a VOR/DME approach as
long as you verify that the data you do have is correct. So you're good
to go with a 430.

[Thomas Borchert]

Robert,

> I assume I can slave it off the 430's nav.
>

Shouldn't be a problem.

--
Thomas Borchert (EDDH)

[Neil Gould]

Recently, Jose > posted:

>> ...then you can't legally use the alternate
>
> Not quite. You can't file that airport as an alternate if you need
> the GPS to get in there. However, once you actually =need= an
> alternate, that restriction goes away. It's a restriction on filing,
> not on flying.
>
Well, *all* restrictions go away in an emergency, so that doesn't really
address the root of the problem. The reason why you can't file such an
alternate is that you don't have the minimum information required to
safely fly that approach. So in the case where the OP needs to maintain
that capablility to fly VORDME approaches it would be a questionable move
to eliminate it by removing equipment that he already has installed.

Neil

[Jose[_1_]]

> Well, *all* restrictions go away in an emergency, so that doesn't really
> address the root of the problem.

Diverting to your alternate is not an emergency, nonetheless, you are
permitted, once in the air, to divert to any airport you want, with any
approach you want (that you can fly). The point of the filing
regulation is to ensure that you carry enough =fuel= to fly to an
alternate that doesn't require your GPS.

It's a fuel on board for flight planning thing, that's all. Once in the
air, it goes away, emergency or no.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Newps]

Neil Gould wrote:

>
> Well, *all* restrictions go away in an emergency

Yes, but irrelavant to the discussion.


, so that doesn't really
> address the root of the problem.



You missed the root of the problem completely.







The reason why you can't file such an
> alternate is that you don't have the minimum information required to
> safely fly that approach.




No, that's not why. As a matter of fact you do have all the
information. The reg is there to provide redundancy.

[Neil Gould]

Recently, Newps > posted:

> Neil Gould wrote:
>
> The reason why you can't file such an
>> alternate is that you don't have the minimum information required to
>> safely fly that approach.
>
> No, that's not why. As a matter of fact you do have all the
> information. The reg is there to provide redundancy.
>
Oh? The question Robert asked was whether he could legally fly VORDME
approaches if he removed his DME after installing the 430. I thought
Thomas Borchert gave a very good reply, which seemed clear to me. I'm sure
that my IFR training, which is not very deep, may lack some practical
point about this, as I don't see how a reg that requires you to specify
the equipment on board could allow one to file an alternate that requires
equipment that you don't have. If I have that wrong, I would appreciate
your clearing it up for me.

Neil

[Ron Natalie]

Robert M. Gary wrote:

> That was my fear. I don't plan on keep the DB up to date all the time
> and I still need to be able to fly VORDME approaches. I guess I'll need
> to keep my King DME. I assume I can slave it off the 430's nav.
>

Probably can. I have a 480 and it is driving my King DME.

[Ron Natalie]

Jose wrote:
>> ...then you can't legally use the alternate
>
> Not quite. You can't file that airport as an alternate if you need the
> GPS to get in there. However, once you actually =need= an alternate,
> that restriction goes away. It's a restriction on filing, not on flying.
>
> Jose
An "alternate" only exists for filing purposes. After that you're
just changing your destination. The minimums, equipment requirements,
etc... are the same.

[Ron Natalie]

Neil Gould wrote:
> Recently, Jose > posted:
>
>>> ...then you can't legally use the alternate
>> Not quite. You can't file that airport as an alternate if you need
>> the GPS to get in there. However, once you actually =need= an
>> alternate, that restriction goes away. It's a restriction on filing,
>> not on flying.
>>
> Well, *all* restrictions go away in an emergency,

Going to an alternate isn't an emergency.