IFR minimums ?

[piperpilot12w]

What is the controlling factor for minimums on an approach - Ceiling, Visibility or both? I think it's visibility, but want to make sure.

How would you apply this to when you are preparing to do the approach. Does ceiling and visibility have to be above minimums to start the approach, or just visibility.

[BajtheJino]

Visibility.

[mojo6911]

Originally Posted by BajtheJino

Visibility.

Yup. If you are in the clouds at MDA, at the MAP, your visibility is going to be 0.

[piperpilot12w]

So if there was an approach that called for an MDA of 500 and 1/2 mi vis, and actual conditions were 400 ovc and 1 mi vis

I could attempt to do the approach because visibility is controlling, and in this case 1 mi is above the min, although when I get to the MDA of 500 I will probably be in the clouds and wont see anything.

Is that correct. I'm preparing for an interview

[Codyjp]

If you are part 91 you can do an approach even if it is reported at 0/0. you have to have flight conditions as determined by the pilot that is at or greater than what is required by the approach. That being said, shooting an approach when it is below minimums is probably only going to burn gas and time.

135, and 121 is another story.

[MidlifeFlyer]

Is this a trick question?

[piperpilot12w]

No tricks here.
Just trying to get a complete understanding of this in case I was asked a similar question in a 121 interview.

[mojo6911]

Originally Posted by piperpilot12w

No tricks here.
Just trying to get a complete understanding of this in case I was asked a similar question in a 121 interview.

For 121, if it is below weather mins, you cannot start the approach. If you are past the FAF and the weather drops below mins, you may continue the approach.

[ctab5060X]

Originally Posted by mojo6911

For 121, if it is below weather mins, you cannot start the approach. If you are past the FAF and the weather drops below mins, you may continue the approach.

Same for 135.

[skidz]

Originally Posted by piperpilot12w

What is the controlling factor for minimums on an approach - Ceiling, Visibility or both? I think it's visibility, but want to make sure.

How would you apply this to when you are preparing to do the approach. Does ceiling and visibility have to be above minimums to start the approach, or just visibility.

It's both. You can attempt the approach but once when you get to MAP and don't see the runway environment you got to go play somewhere else or try a different approach with lower minimums.

[ppilot]

Originally Posted by mojo6911

For 121, if it is below weather mins, you cannot start the approach. If you are past the FAF and the weather drops below mins, you may continue the approach.

Say the minimums on the plate are 500 ft/1 mile.

I THINK his question is 'is the weather below minimums if the ceiling is reported below 500 feet, or if the visibility is reported below 1 mile, or either?'

btw, the answer is 'if the visibility is reported below 1 mile.'

[MidlifeFlyer]

Originally Posted by ppilot

Say the minimums on the plate are 500 ft/1 mile.

I THINK his question is 'is the weather below minimums if the ceiling is reported below 500 feet, or if the visibility is reported below 1 mile, or either?'

btw, the answer is 'if the visibility is reported below 1 mile.'

Is it? So you're heading into, say Aspen, where the minimums are about 2000 AGL and 3 miles (http://naco.faa.gov/d-tpp/0804/05889LDE.PDF) . You are saying that if ASE is reporting, say a 500' ceiling and 20 miles visibility (not that unlikely), under 135 or 121, you would be allowed to begin the approach?

Do you have a source for that? I'm really just asking. I haven't had the need to look into that myself (despite reports to the contrary, FAA publications are =not= my bedside reading material of choice).

[Ian J]

Originally Posted by MidlifeFlyer

Is it? So you're heading into, say Aspen, where the minimums are about 2000 AGL and 3 miles (http://naco.faa.gov/d-tpp/0804/05889LDE.PDF) . You are saying that if ASE is reporting, say a 500' ceiling and 20 miles visibility (not that unlikely), under 135 or 121, you would be allowed to begin the approach?

Do you have a source for that? I'm really just asking. I haven't had the need to look into that myself (despite reports to the contrary, FAA publications are =not= my bedside reading material of choice).

Absolutely!

Under part 135 the reg is 135.225(a)(2).

The only time a ceiling comes into play when discussing minimums is when deciding if an alternate is needed or selecting an alternate.

[CRJ700]

Originally Posted by Ian J

Absolutely!

Under part 135 the reg is 135.225(a)(2).

The only time a ceiling comes into play when discussing minimums is when deciding if an alternate is needed or selecting an alternate.

This isn't the same for 121 too is it?

[Ian J]

I assume it is - I'm a 135 guy though so better one of them answers.

[ctab5060X]

Originally Posted by CRJ700

This isn't the same for 121 too is it?

Yeah it is...just can't quote the reg. Maybe someone else can post that much.

[MidlifeFlyer]

Originally Posted by Ian J

Absolutely!

Under part 135 the reg is 135.225(a)(2).

Wait, Ian. All 135.225(a)(2) says is

==============================
The latest weather report issued by that weather reporting facility indicates that weather conditions are at or above the authorized IFR landing minimums for that airport.
==============================

I know that reg. What I'm asking for is the source of the statement that "authorized IFR landing minimums" refers only to the visibility and not the ceiling.

Now, in 121 it's a bit different. 121.651(b) specifically talks about visibility:
==============================
Except as provided in paragraph (d) of this section, no pilot may continue an approach past the final approach fix, or where a final approach fix is not used, begin the final approach segment of an instrument approach procedure -
(1) At any airport, unless the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, issues a weather report for that airport; and
(2) At airports within the United States and its territories or at U.S. military airports, unless the latest weather report for that airport issued by the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, reports the visibility to be equal to or more than the visibility minimums prescribed for that procedure.
==============================

For 121, I can see that visibility controls. But where is it for 135?

[ppilot]

Originally Posted by MidlifeFlyer

Wait, Ian. All 135.225(a)(2) says is

==============================
The latest weather report issued by that weather reporting facility indicates that weather conditions are at or above the authorized IFR landing minimums for that airport.
==============================

I know that reg. What I'm asking for is the source of the statement that "authorized IFR landing minimums" refers only to the visibility and not the ceiling.

Now, in 121 it's a bit different. 121.651(b) specifically talks about visibility:
==============================
Except as provided in paragraph (d) of this section, no pilot may continue an approach past the final approach fix, or where a final approach fix is not used, begin the final approach segment of an instrument approach procedure -
(1) At any airport, unless the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, issues a weather report for that airport; and
(2) At airports within the United States and its territories or at U.S. military airports, unless the latest weather report for that airport issued by the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, reports the visibility to be equal to or more than the visibility minimums prescribed for that procedure.
==============================

For 121, I can see that visibility controls. But where is it for 135?

It's in 91. I don't have the rules in front of me right now, but I think it's in 91.175.

[mikecweb]

135 guys take a look at this.
http://www.ntsb.gov/alj/O_n_O/docs/AVIATION/4002.PDF
Obvisously the dawg in this story screwed up and this is pretty old but it's funny how things can be viewed in the court of law.

[MidlifeFlyer]

Originally Posted by ppilot

It's in 91. I don't have the rules in front of me right now, but I think it's in 91.175.

91.175(c) talks needing the required flight visibility in order to descend from the MDA or DA. But, that's not specific to 135 and, as mojo aptly put it

Yup. If you are in the clouds at MDA ... your visibility is going to be 0.

, so ceiling is pretty irrelevant at that point (that's why I asked why it was a trick question).

OTOH, there are specific rules on when you can start or continue an approach based on reported minimums for 135 and 121 ops (135.225 and 121.651 for example) that don't apply to Part 91 ops (where you can start down even if 0/0 is being reported), which is what I thought was being discussed

Two different questions.

[Ian J]

Good question, Mark. I'll hunt around for the source. (It's correct though, visibility that is. )

But let me ask you something: For whom is a ceiling a minimum for an approach? (And not talking alternates or anything here - talking who needs a reported ceiling to legally shoot an approach?)

Yup. If you are in the clouds at MDA ... your visibility is going to be 0.

Not true at all. Plenty of us on here have done approaches where the "ceiling" was below the MDA or DH. However, if the cloud/fog isn't very thick, or if it is night time and the approach lights are turned up bright, you can see right through at MDA or DH and have the required flight visibility to at least descend 100 feet below.

When we're talking RVR values for visibility, you're already in a cloud.

[MidlifeFlyer]

Originally Posted by mikecweb

135 guys take a look at this.
http://www.ntsb.gov/alj/O_n_O/docs/AVIATION/4002.PDF
Obvisously the dawg in this story screwed up and this is pretty old but it's funny how things can be viewed in the court of law.

Excellent!! You found the answer (although some would say the "court of law" is kind of an unnecessary complement to what goes on in administrative hearings).

For those without the patience to read it, it essentially says that, while the visibility on the IAP chart defines required minimum visibility, the MDA or DA does not define a minimum, but only the minimum descent altitude the pilot can go to before the visibility issue kicks in.IOW, the MDA is not a "weather condition" within the meaning of 135.225.

So, it appears the answer is indeed that visibility controls.

BTW, Mike, if you think that a case from 1993 is "pretty old" you must be "pretty young" And pretty smart to have turned this case up

[MidlifeFlyer]

Originally Posted by Ian J

Plenty of us on here have done approaches where the "ceiling" was below the MDA or DH. However, if the cloud/fog isn't very thick, or if it is night time and the approach lights are turned up bright, you can see right through at MDA or DH and have the required flight visibility to at least descend 100 feet below.

In addition, a ceiling can be broken, where you can reach MDA be above the ceiling an still meet the criteria to continue the approach.

That's why the NTSB's gymnastics in that case Mike found make sense.

[mikecweb]

Originally Posted by MidlifeFlyer

Excellent!! You found the answer (although some would say the "court of law" is kind of an unnecessary complement to what goes on in administrative hearings).

For those without the patience to read it, it essentially says that, while the visibility on the IAP chart defines required minimum visibility, the MDA or DA does not define a minimum, but only the minimum descent altitude the pilot can go to before the visibility issue kicks in.IOW, the MDA is not a "weather condition" within the meaning of 135.225.

So, it appears the answer is indeed that visibility controls.

BTW, Mike, if you think that a case from 1993 is "pretty old" you must be "pretty young" And pretty smart to have turned this case up

Lets just say I was single digits when that report came out. I found it awhile back when researching random accidents involving 135 freight. I think it is very important for those who think regualtions are vague to help pilots out. Vague regulations and grey areas can bite you too.

Also include that the NTSB, which wrote this particular document, clearly disputes what both the FAA and judge seem to rule out of nowhere that ceilings are included in the "landing minimums". They called for the FAA to clarify their stance and to my understanding, correct me if I'm wrong, they haven't.

[MidlifeFlyer]

Originally Posted by mikecweb

Also include that the NTSB, which wrote this particular document, clearly disputes what both the FAA and judge seem to rule out of nowhere that ceilings are included in the "landing minimums". They called for the FAA to clarify their stance and to my understanding, correct me if I'm wrong, they haven't.

Not as far as I know. I just did a quick search into the NTSB online database and this appears to be the only 135.225(a) case there.

I have a sense that part of the dressing down of the FAA is a little turf war going on. Notice how the NTSB treats the FAA's attempt to force it's ceiling interpretation:

==============================
While deference to the Administrator's validly adopted interpretations of the Federal Aviation Regulations is now explicitly required by statute, such deference cannot be readily accorded in the context of a hastily developed record that is sustained solely by argument of counsel. This is particularly so where the interpretation advanced is unsupported by citation of practice, precedent, or explicit documentation, and where it entails consequences not only for respondent, but for the aviation community generally
==============================

Unfortunately (for us), the NTSB ultimately loses this battle. You may have heard of the case - it's the one where a 121 captain mistakenly thought an ATC instruction was for him. He even read it back and was not corrected (he was stepped on). In the enforcement action, the FAA argues that the pilot was responsible for the failure to comply with the ATC instructions, and that the misunderstanding and failure of the readback to get it corrected did not excuse the violation. The NTSB thought this was ridiculous and overturned the FAA in language very similar to the language in the Krachun case you pointed to. If you're interested, check out http://ntsb.gov/alj/alj/O_n_O/docs/aviation/4670.PDF

This time, though, the FAA appealed to the US Court of Appeals, where, in a famous decision, FAA v. NTSB and Merrell,, 190 F.3d 571 (DC Cir 1999), the Court reversed the NTSB and upheld the FAA's interpretation:

==============================
The NTSB's refusal to defer to the FAA on this question of regulatory interpretation and air safety policy was error. The FAA is not required to promulgate interpretations through rulemaking or the issuance of policy guidances, but may instead do so through litigation before the NTSB. **** The fact that this mode of regulatory interpretation necessarily is advanced through the "litigation statements" of counsel does not relieve the NTSB of its statutory obligation to accord it due deference
==============================