Re: Only official instrument approaches authorised under FAR?

[Matt Barrow]

"Peter" > wrote in message
...
>
> FAR 91.175 (a) suggests that it is not permitted to carry out a
> descent in IMC except on an official published IAP.
>
> Any views on this?
>
> How would it differ if the entire procedure was done in Class G?
>
>
What would you use for terrain clearance, and what for separation from other
IFR aircraft?

[Roy Smith]

In article >,
Peter > wrote:

> FAR 91.175 (a) suggests that it is not permitted to carry out a
> descent in IMC except on an official published IAP.

It does more than suggest, it states it quite explicitly (for most of us,
neither of the exceptions are likely to apply):

"Unless otherwise authorized by the Administrator, when an instrument
letdown to a civil airport is necessary, each person operating an
aircraft, except a military aircraft of the United States, shall use a
standard instrument approach procedure prescribed for the airport in part
97 of this chapter."

> How would it differ if the entire procedure was done in Class G?

Not in the least. All IFR rules apply in class G except for the
requirement to obtain a clearance.

[Roy Smith]

"Matt Barrow" > wrote:
> What would you use for terrain clearance, and what for separation from other
> IFR aircraft?

SIAPs offer terrain clearance, which is why they are mandated.

Clearances are what offer separation from other aircraft, and are not
available in CGAS. In CGAS, IFR flights are afforded no separation
services from ATC.

[Steven P. McNicoll]

"Peter" > wrote in message
...
>
> FAR 91.175 (a) suggests that it is not permitted to carry out a
> descent in IMC except on an official published IAP.
>
> Any views on this?
>

FAR 91.175 (a) suggests nothing, it states, "Unless otherwise authorized by
the Administrator, when an instrument letdown to a civil airport is
necessary, each person operating an aircraft, except a military aircraft of
the United States, shall use a standard instrument approach procedure
prescribed for the airport in part 97 of this chapter."


>
> How would it differ if the entire procedure was done in Class G?
>

It wouldn't differ in any way, the regulation is not limited by class of
airspace.

[Matt Barrow]

"Roy Smith" > wrote in message
...
> "Matt Barrow" > wrote:
> > What would you use for terrain clearance, and what for separation from
other
> > IFR aircraft?
>
> SIAPs offer terrain clearance, which is why they are mandated.

He's talking about doing an approach without an official SIAP.

> Clearances are what offer separation from other aircraft, and are not
> available in CGAS. In CGAS, IFR flights are afforded no separation
> services from ATC.

Re-read his question.

[Paul Tomblin]

In a previous article, Peter > said:
>"Steven P. McNicoll" > wrote
>>FAR 91.175 (a) suggests nothing, it states, "Unless otherwise authorized by
>>the Administrator, when an instrument letdown to a civil airport is
>>necessary, each person operating an aircraft, except a military aircraft of
>>the United States, shall use a standard instrument approach procedure
>>prescribed for the airport in part 97 of this chapter."
>
>Does that mean that, on an IFR flight, one is not allowed to descend
>below the MOCA except on a published IAP?

It says "when an instrument letdown...is necessary" that you shall use an
instrument letdown. Isn't that sort of circular? It doesn't actually say
when an instrument letdown is necessary.


--
Paul Tomblin > http://xcski.com/blogs/pt/
"You must be smarter than this stick >---- to put a machine on the
Internet."

[Steven P. McNicoll]

"Peter" > wrote in message
...
>
> Does that mean that, on an IFR flight, one is not allowed to descend
> below the MOCA except on a published IAP?
>
> One could read 175 as saying that if an official IAP is provided, it
> must be used.
>

No, it means that unless otherwise authorized by the Administrator
nonmilitary aircraft of the United States operating under IFR are not
allowed to descend below the minimum IFR altitude when an instrument letdown
to a civil airport is necessary except on a published IAP.

[Jose]

> It says "when an instrument letdown...is necessary" that you shall use an
> instrument letdown. Isn't that sort of circular?

It doesn't quite say that... it's more like "when an instrument
letdown...is necessary to an airport... that you shall use =OUR=
instrument letdown to =THAT= airport." This looks like it precludes
shooting an approach to ABC and then slipping off to land at DEF, and it
certainly precludes home-grown approaches unless otherwise authorized by
the administrator.

Jose
r.a.misc snipped. I don't follow that group
--
He who laughs, lasts.
for Email, make the obvious change in the address.

[Steven P. McNicoll]

"Paul Tomblin" > wrote in message
...
>
> It says "when an instrument letdown...is necessary" that you shall use an
> instrument letdown. Isn't that sort of circular? It doesn't actually say
> when an instrument letdown is necessary.
>

An instrument letdown would be necessary whenever there's no way to descend
without one. Already at the MIA and still in IMC? Visual, contact, or
radar approach not an option? Looks like an instrument letdown is
necessary.

[Gary Drescher]

"Peter" > wrote in message
...
>
> "Steven P. McNicoll" > wrote
>
>>FAR 91.175 (a) suggests nothing, it states, "Unless otherwise authorized
>>by
>>the Administrator, when an instrument letdown to a civil airport is
>>necessary, each person operating an aircraft, except a military aircraft
>>of
>>the United States, shall use a standard instrument approach procedure
>>prescribed for the airport in part 97 of this chapter."
>
> Does that mean that, on an IFR flight, one is not allowed to descend
> below the MOCA except on a published IAP?

Correct, provided that an instrument letdown is necessary (ie, you're in
IMC).

> One could read 175 as saying that if an official IAP is provided, it
> must be used.

Can you explain how it could be read that way? You're proposing an exception
to the stated requirement--an exception in the event that no SIAP exists.
But no such exception is stated in the rule itself (it doesn't say, for
instance, "shall use an SIAP, *if any*"). Unfortunately, we can't
legitimately construe a rule to include an exception that we just make up
ourselves.

--Gary

[Steven P. McNicoll]

"Gary Drescher" > wrote in message
...
>
> Correct, provided that an instrument letdown is necessary (ie, you're in
> IMC).
>

What about a contact approach? One could even argue that a visual approach
can be flown in IMC since VFR cloud clearance requirements do not apply.

[Gary Drescher]

"Steven P. McNicoll" > wrote in message
. net...
>
> "Gary Drescher" > wrote in message
> ...
>>
>> Correct, provided that an instrument letdown is necessary (ie, you're in
>> IMC).
>>
>
> What about a contact approach? One could even argue that a visual
> approach can be flown in IMC since VFR cloud clearance requirements do not
> apply.

Good point.

[Roy Smith]

In article >,
"Gary Drescher" > wrote:

> "Steven P. McNicoll" > wrote in message
> . net...
> >
> > "Gary Drescher" > wrote in message
> > ...
> >>
> >> Correct, provided that an instrument letdown is necessary (ie, you're in
> >> IMC).
> >>
> >
> > What about a contact approach? One could even argue that a visual
> > approach can be flown in IMC since VFR cloud clearance requirements do not
> > apply.
>
> Good point.

No, bad point. Steven knows that neither a visual approach nor a contact
approach is legal in IMC. He's just being deliberately obfuscatory, as
usual.

[Steven P. McNicoll]

"Roy Smith" > wrote in message
...
>
> No, bad point. Steven knows that neither a visual approach nor a contact
> approach is legal in IMC. He's just being deliberately obfuscatory, as
> usual.
>

Please explain how they're illegal in IMC.

[Gary Drescher]

"Roy Smith" > wrote in message
...
> No, bad point. Steven knows that neither a visual approach nor a contact
> approach is legal in IMC.

A contact approach requires only 1sm visibility. That's certainly IMC in
class B, C, D, or E.

--Gary

[Roy Smith]

In article >,
"Gary Drescher" > wrote:

> "Roy Smith" > wrote in message
> ...
> > No, bad point. Steven knows that neither a visual approach nor a contact
> > approach is legal in IMC.
>
> A contact approach requires only 1sm visibility. That's certainly IMC in
> class B, C, D, or E.
>
> --Gary

Sigh. I knew I shouldn't have responded to that because we'd get into
something like this. By IMC I meant "in cloud".

[Steven P. McNicoll]

"Roy Smith" > wrote in message
...
>
> Sigh. I knew I shouldn't have responded to that because we'd get into
> something like this. By IMC I meant "in cloud".
>

Then you used the term incorrectly. IMC does not mean "in cloud", it means
"meteorological conditions expressed in terms of visibility, distance from
cloud, and ceiling less than the minima specified for visual meteorological
conditions."

[Julian Scarfe]

"Roy Smith" > wrote in message
...

> It does more than suggest, it states it quite explicitly (for most of us,
> neither of the exceptions are likely to apply):
>
> "Unless otherwise authorized by the Administrator, when an instrument
> letdown to a civil airport is necessary, each person operating an
> aircraft, except a military aircraft of the United States, shall use a
> standard instrument approach procedure prescribed for the airport in part
> 97 of this chapter."

So the next question, which I'll ask on Peter's behalf is...

Since Part 97 only prescribes approaches for airports within the US (and
presumably associated territories), how does an N-registered aircraft ever
fly an IAP in IMC outside the US?

Julian

[Steven P. McNicoll]

"Peter" > wrote in message
...
>
> This could be any of MEA, MOCA, MRA?
>

It couldn't be an MRA. An MRA is simply the lowest altitude at which an
intersection can be determined and should always be above the MEA/MOCA.


>
> Would the pilot be free to choose
> the lowest?
>

The pilot would comply with his clearance.

[Steven P. McNicoll]

"Julian Scarfe" > wrote in message
...
>
> So the next question, which I'll ask on Peter's behalf is...
>
> Since Part 97 only prescribes approaches for airports within the US (and
> presumably associated territories), how does an N-registered aircraft ever
> fly an IAP in IMC outside the US?
>

Probably by being otherwise authorized by the Administrator.

[Julian Scarfe]

> "Julian Scarfe" > wrote in message
> ...
>>
>> So the next question, which I'll ask on Peter's behalf is...
>>
>> Since Part 97 only prescribes approaches for airports within the US (and
>> presumably associated territories), how does an N-registered aircraft
>> ever fly an IAP in IMC outside the US?


"Steven P. McNicoll" > wrote in message
.net...
> Probably by being otherwise authorized by the Administrator.

So is there some sort of generic authorization, or is it authorized on a
case by case basis?

The latter seems unlikely. Do you really apply for such an authorization
every time you fly IFR to Canada?

Julian

[Roy Smith]

"Julian Scarfe" > wrote:

> So the next question, which I'll ask on Peter's behalf is...
>
> Since Part 97 only prescribes approaches for airports within the US (and
> presumably associated territories), how does an N-registered aircraft ever
> fly an IAP in IMC outside the US?

That's easy, this rule doesn't apply outside the US. Part 91.1 says:

"this part prescribes rules governing the operation of aircraft [...]
within the United States, including the waters within 3 nautical miles of
the U.S. coast."

[Steven P. McNicoll]

"Julian Scarfe" > wrote in message
...
>
> So is there some sort of generic authorization, or is it authorized on a
> case by case basis?
>

Probably neither.


>
> The latter seems unlikely. Do you really apply for such an authorization
> every time you fly IFR to Canada?
>

I've never flown IFR to Canada. Given that Part 91 only prescribes rules
governing the operation of aircraft within the United States, including the
waters within 3 nautical miles of the U.S. coast, I'd feel pretty silly
asking for such authorization if I had a notion to.

[Julian Scarfe]

> "Julian Scarfe" > wrote:
>
>> So the next question, which I'll ask on Peter's behalf is...
>>
>> Since Part 97 only prescribes approaches for airports within the US (and
>> presumably associated territories), how does an N-registered aircraft
>> ever
>> fly an IAP in IMC outside the US?

"Roy Smith" > wrote in message
...
> That's easy, this rule doesn't apply outside the US. Part 91.1 says:
>
> "this part prescribes rules governing the operation of aircraft [...]
> within the United States, including the waters within 3 nautical miles of
> the U.S. coast."

Ah. I'm getting confused with Parts 43 and 61, which clearly have to (and
do) apply extraterritorially. That will also satisfy Peter's original
question, which I think was looking at the applicability outside the US.

Julian

[Steven P. McNicoll]

"Julian Scarfe" > wrote in message
...
>
> Ah. I'm getting confused with Parts 43 and 61, which clearly have to (and
> do) apply extraterritorially. That will also satisfy Peter's original
> question, which I think was looking at the applicability outside the US.
>

What in Peter's original question suggested to you that he was looking at
the applicability outside the US?

[Julian Scarfe]

"Julian Scarfe" > wrote:
>
>> So the next question, which I'll ask on Peter's behalf is...
>>
>> Since Part 97 only prescribes approaches for airports within the US (and
>> presumably associated territories), how does an N-registered aircraft
>> ever
>> fly an IAP in IMC outside the US?

"Roy Smith" > wrote in message
...
> That's easy, this rule doesn't apply outside the US. Part 91.1 says:
>
> "this part prescribes rules governing the operation of aircraft [...]
> within the United States, including the waters within 3 nautical miles of
> the U.S. coast."

Now Peter has got me wondering about this.

The first bit that you snipped says:

" (a) Except as provided in paragraphs (b) and (c) of this section and
Secs. 91.701 and 91.703, this part prescribes rules governing the
operation of aircraft"

"Sec. 91.703 Operations of civil aircraft of U.S. registry outside of the
United States.

(a) Each person operating a civil aircraft of U.S. registry outside
of the United States shall--
....
(2) When within a foreign country, comply with the regulations
relating to the flight and maneuver of aircraft there in force;
(3) Except for Secs. 91.307(b), 91.309, 91.323, and 91.711, comply
with this part so far as it is not inconsistent with applicable
regulations of the foreign country where the aircraft is operated or
annex 2 of the Convention on International Civil Aviation; ..."

So what's the test for something being "inconsistent with applicable
regulations"? Many regulations work as prohibitions: if Part 91 prohibits
something and the regulations of the foreign country remain silent on the
issue (for example, the choice of instrument letdown), would the N-reg
aircraft still have to comply with Part 91?

Julian

[Gary Drescher]

"Julian Scarfe" > wrote in message
...
> "Sec. 91.703 Operations of civil aircraft of U.S. registry outside of the
> United States.
>
> (a) Each person operating a civil aircraft of U.S. registry outside
> of the United States shall--
> ...
> (2) When within a foreign country, comply with the regulations
> relating to the flight and maneuver of aircraft there in force;
> (3) Except for Secs. 91.307(b), 91.309, 91.323, and 91.711, comply
> with this part so far as it is not inconsistent with applicable
> regulations of the foreign country where the aircraft is operated or
> annex 2 of the Convention on International Civil Aviation; ..."
>
> So what's the test for something being "inconsistent with applicable
> regulations"? Many regulations work as prohibitions: if Part 91
> prohibits something and the regulations of the foreign country remain
> silent on the issue (for example, the choice of instrument letdown), would
> the N-reg aircraft still have to comply with Part 91?

Actually, *any* regulatory requirement on a pilot works as a prohibition
(that is, the pilot is prohibited from violating the requirement). So if
foreign regs were construed as "inconsistent" with a requirement simply by
virtue of their being silent (and thus not imposing the requirement
themselves), then 91.703a3 would be entirely superfluous--it would only
require compliance with US requirements that the foreign regs *also* impose,
and thus would merely reiterate 91.703a2. Since 91.703a3 presumably was not
intended to be superfluous, the only plausible interpretation is that when
the foreign regs are silent on a US requirement, the requirement is in force
for US aircraft.

--Gary

[Julian Scarfe]

"Gary Drescher" > wrote in message
...

> Actually, *any* regulatory requirement on a pilot works as a prohibition
> (that is, the pilot is prohibited from violating the requirement). So if
> foreign regs were construed as "inconsistent" with a requirement simply by
> virtue of their being silent (and thus not imposing the requirement
> themselves), then 91.703a3 would be entirely superfluous--it would only
> require compliance with US requirements that the foreign regs *also*
> impose, and thus would merely reiterate 91.703a2. Since 91.703a3
> presumably was not intended to be superfluous, the only plausible
> interpretation is that when the foreign regs are silent on a US
> requirement, the requirement is in force for US aircraft.

In which case I repose my question:

> "Unless otherwise authorized by the Administrator, when an instrument
> letdown to a civil airport is necessary, each person operating an
> aircraft, except a military aircraft of the United States, shall use a
> standard instrument approach procedure prescribed for the airport in part
> 97 of this chapter."

Since Part 97 only prescribes approaches for airports within the US (and
presumably associated territories), how does an N-registered aircraft ever
fly an IAP in IMC outside the US?

Julian

[Steven P. McNicoll]

"Peter" > wrote in message
...
>
> Julian knows I am in the UK, and also the return email address in my
> original post made this clear. I deliberately didn't say this in the
> original post because I didn't want to muddy the water (not sure if
> that's an American expression but you know what I mean :).
>

So what? Your question asked about FAR 91.175, which is applicable only in
the US.


>
> The other thing is that the internet isn't just the USA, and N-reg
> planes do fly outside the USA too :)
>

Yes, but they're not operating under FAR 91.175 when they're outside the US.

[Steven P. McNicoll]

"Julian Scarfe" > wrote in message
...
>
> In which case I repose my question:
>
>> "Unless otherwise authorized by the Administrator, when an instrument
>> letdown to a civil airport is necessary, each person operating an
>> aircraft, except a military aircraft of the United States, shall use a
>> standard instrument approach procedure prescribed for the airport in part
>> 97 of this chapter."
>
> Since Part 97 only prescribes approaches for airports within the US (and
> presumably associated territories), how does an N-registered aircraft ever
> fly an IAP in IMC outside the US?
>

By complying with the applicable rules of the country in which they're
operating, of course.

[Luke Scharf]

Steven P. McNicoll wrote:
> By complying with the applicable rules of the country in which they're
> operating, of course.

That's sane, reasonable, and my armchair-understanding of how everyone
does it.

But what do the regs say? Does ICAO weigh in?

-Luke

[[email protected]]

I haven't looked through the entire thread. Has anyone mentioned 91.177?
Once you achieve an en route altitude 91.177 is constant and mandatory except
for a Part 97 IAP or special IAP. (excepting a visual, contact, or
cancellation)

Roy Smith wrote:

> Peter > wrote:
> > One could read 175 as saying that if an official IAP is provided, it
> > must be used.
>
> I think one would need to be reading a different text than what I have
> available to come to that conclusion.
>
> The one I've got says, "each person [...] shall use a standard instrument
> approach procedure prescribed for the airport in part 97 of this chapter."
> I don't see anything in there that sounds like, "if one is provided".

[Paul Lynch]

Negative. Part 91 cannot be applied outside US territories. Not to long
ago the FAA attempted to violate an airline pilot for exceeding 250 KIAS in
a descent into the Miami area. He was off shore and outside the US
boundaries. Even though the aircraft was under US control, it was in
international airspace. The violation did not stick.


"Gary Drescher" > wrote in message
...
> "Julian Scarfe" > wrote in message
> ...
>> "Sec. 91.703 Operations of civil aircraft of U.S. registry outside of
>> the United States.
>>
>> (a) Each person operating a civil aircraft of U.S. registry outside
>> of the United States shall--
>> ...
>> (2) When within a foreign country, comply with the regulations
>> relating to the flight and maneuver of aircraft there in force;
>> (3) Except for Secs. 91.307(b), 91.309, 91.323, and 91.711, comply
>> with this part so far as it is not inconsistent with applicable
>> regulations of the foreign country where the aircraft is operated or
>> annex 2 of the Convention on International Civil Aviation; ..."
>>
>> So what's the test for something being "inconsistent with applicable
>> regulations"? Many regulations work as prohibitions: if Part 91
>> prohibits something and the regulations of the foreign country remain
>> silent on the issue (for example, the choice of instrument letdown),
>> would the N-reg aircraft still have to comply with Part 91?
>
> Actually, *any* regulatory requirement on a pilot works as a prohibition
> (that is, the pilot is prohibited from violating the requirement). So if
> foreign regs were construed as "inconsistent" with a requirement simply by
> virtue of their being silent (and thus not imposing the requirement
> themselves), then 91.703a3 would be entirely superfluous--it would only
> require compliance with US requirements that the foreign regs *also*
> impose, and thus would merely reiterate 91.703a2. Since 91.703a3
> presumably was not intended to be superfluous, the only plausible
> interpretation is that when the foreign regs are silent on a US
> requirement, the requirement is in force for US aircraft.
>
> --Gary
>
>