121 wx to shoot approach prior to final fix

[Eric]

I have been told one thing and heard another. I read 121.651, and I still have questions.

Any help on the following scenarios will be appreciated. Assume this flying is done under part 121

1. Prior to final approach fix, you get atis and it reports 3/4 mile vis, ceiling 100 feet. You are going to fly an ILS. The approach requires 1/2 mile vis and has a 200' dh. Can you start the approach.

2. How about same scenario above, but the reported wx is 1/4 mile vis, ceiling 300 feet?

3. How about a non-precision approach. Plate calls for 1 mile and 500' mda. Wx reports 2 miles vis and a 300 foot ceiling?

4. Same non precision with wx reported as 1/2 mile, 700' ceiling.


I think answers to these questions will help clear up my 'visiblity is controlling' conundrum. Do you start the approach based on visibility, ceiling, or both.

Thanks

 

[vclean]

Yes, no, yes, no.

Approach visibility determines if you may continue past the FAF.

 

[falcon20driver]

Yep, visibility is the only minimum required.

 

[ThomasR]

I have been told one thing and heard another. I read 121.651, and I still have questions.

Any help on the following scenarios will be appreciated. Assume this flying is done under part 121

1. Prior to final approach fix, you get atis and it reports 3/4 mile vis, ceiling 100 feet. You are going to fly an ILS. The approach requires 1/2 mile vis and has a 200' dh. Can you start the approach.

2. How about same scenario above, but the reported wx is 1/4 mile vis, ceiling 300 feet?

3. How about a non-precision approach. Plate calls for 1 mile and 500' mda. Wx reports 2 miles vis and a 300 foot ceiling?

4. Same non precision with wx reported as 1/2 mile, 700' ceiling.

I think answers to these questions will help clear up my 'visiblity is controlling' conundrum. Do you start the approach based on visibility, ceiling, or both.

Thanks

Hope I am not confusing this too much:

1) No
2) Yes
3) No
4) No

You can bust Vis only on precision to MDA

 

[falcon20driver]

Hope I am not confusing this too much:

1) No
2) Yes
3) No
4) No

You can bust Vis only on precision to MDA

I think you got a couple of those answers bassackwards ThomasR.

#1 is Yes

#2 in No

#3 is Yes I believe, I've only flown 135 and I'm pretty sure visibility is all that is required to begin any approach, I'm going to check that one.

#4 is NO

 

[bafanguy]

Falcon20 is correct. Viz is all that controls and RVR controls ( rather than prev.viz) if that is what is reported. It gets a bit more complicated re circling approaches and receiving below mins viz report AFTER entering the final approach segment. A lot fo this stuff is spelled out in Ops Specs and FAR 121, as you mentioned.

 

[Zulu]

Here's the applicable portion (bold added):

121.651.......

(b) 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—............

(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.

Notice that it says nothing about ceiling, precision vs. nonprecision, straight-in vs. circling, etc. As far as FAR 121 is concerned, ceiling in irrelevant and visibility rules for beginning an approach. Note that the company ops specs can (and probably will) be more restrictive.

So, by 121 only, my answers would be:
(1) Yes (meets visibility minimums)
(2) No (doesn't meet visibility minimums)
(3) Yes (meets visibility minimums)
(4) No (doesn't meet visibility minimums)

 

[bafanguy]

Part 121 doesn't mention a ceiling, but our Ops Specs have ceiling requirement for circling. We require "ceiling- 1000 feet or the published CatD/highest speed HAA, whichever is higher". This undoubtedly varies with companies. It can get a bit complicated when you start talking approach legalities. It's a pretty interesting subject, though.

 

[typhoonpilot]

Just as an aside, some Non-Precision approaches say " ceiling required " on them. Somebody got an example ?

TP

 

[COEX-FO]

Number 2 is No if CAT I and YES if CAT II.

COEX is now CAT II and 100/RVR1200 you are good to go!

It's fun, did it a few times to mins!

 

[Lindy]

Sometimes ceiling is controlling as well as visibility -- pursuant to OPS SPECS and a High Mins Captain.


However, I believe your question was presuming that the Captain had the requisite 100 Hours in make/model.

 

[bafanguy]

COEX-FO,


One has to be careful about these approach legalities. If I'm reading the question correctly,the original question said the approach "required" 1/2 viz. This means it's a CAT 1 ILS. So 1/4 mile reported viz is no-go. CAT 2 is a separate animal legality-wise and there are a bunch more hoops to jump to be legal...CAT 3 is even more so. It's a fun subject to kick around.

 

[Eric]

Thanks guys. I was told a couple of things. I'm glad to see that I interpreted the regulation correctly. I was told by someone that on an ILS all you needed was vis but on a non-precision you needed both ceiling and vis to start the approach.

 

[Singlecoil]

All you need is vis period. On a non-precision you know you may not break out, but there are plenty of times when the ceiling is broken or the clouds are right over the AWOS, but not the runway where you will see enough to land.

 

[bafanguy]

Typhoonpilot's Question....

TP,

Good question about a ceiling requirement for a non-presision approach. All I found was the statement in the Jeps Intro, " In some parts of the world..." but nothing more than that. Couldn't find any reason why so I looked in TERPS, but couldn't find an answer cuz I was immediately overtaken by uncontrollable drowziness and couldn't go on.

My guess is that "...some parts of the world..." have antiquated criteria, or there are cases of obstacle clearance problems in the final segment that can't be worked around any other way and still have a doable approach. The latter is most likely.

I looked in my old Jeps but couldn't find an example but then if you just go back and forth to BNA, you don't run into such problems !! Some sharpshooter on here will have the scientific answer...

 

[profile]

Other parts of the world have different procedures, some include ceiling requirements at some airfields. They are hardly "antiquated", in fact, in many respects, it is the U.S. that needs to catch up in both facilities and procedures.

 

[bafanguy]

Well, Profile, you're right..."antiquated" is not the right word. The US did, at one time, require ceilings if I remember correctly but changed to the visibility criterion so long ago I'd have to dig for the date. You caught me in an unconscious display Amerocentrism ( just made that up, pretty good, huh ? ).


As for going back to ceiling requirements in the US, don't know...I think our current system gives the crew more say-so. For example, if the required viz for the approach is OK, but you know the ceiling is so low there's no chance ( or in your judgement as PIC there's no chance ) of seeing enough to land, you just don't make the approach. If, though, due to irregular cloud bases, transient precip, fill in your own reasons, you think that even though the ceiling is lower than MDA/DA you feel there's a reasonable chance of making a safe approach and seeing something anyway, you have the legal option of trying the approach ( how's that for a runon sentence ? ). Being stuck with a ceiling requirement removes the exercise of your judgement and experience as PIC.

Just a thought.

 

[SkyWestCRJPilot]

I agree with everything said here. Visibility is the only limiting factor. But regarding the ceiling on nonprecision approaches, every time I've gone missed approach was when the visibility was met but the ceiling was below the MDA. I tried to get in but couldn't. In the future I will still continue to try to get in when the visibility allows but from my experience when the ceiling is below the MDA I have never gotten in. Something to consider.

 

[bafanguy]

Skywest,

I'm not surprised at your experience with ceilings below MDA, but at least you had the option to shoot/not shoot the approaches. Your "front line" feel/judgement for a situation is probably better than some FAA lawyer who writes FAR's.

 

[profile]

I would say that the "vis only" requirement was pushed more by the operators than the pilots. I doubt it was ALPA that pushed for that, I would guess it was ATA driven, with the associated implications. It might be true that it gives the PIC more options, but also means that the Capt is put in a position of explaining his/her actions if he/she decides not to fly the approach when all the weather is ok except the ceiling.

 

[bafanguy]

Profile,


THAT sort of thing would depend on who you work for, I guess. The people I flew for ( 3 very different companies ) never once, to my knowledge, questioned the captain's decision in ops-related issues. And two of the companies were very small so we WOULD have heard about it. Only insane/stupid management would pressure pilots into doing things they weren't comfortable with...an accident is a lot more "inconvenient" than the occasional diversion because the captain felt an approach ( for any reason ) wasn't wise.

I know you'll say there ARE managements out there who WILL/DO pressure people. I'm just talking about pure operational considerations...not the labor/management side of it.

If one has to explain his actions, "so be it" as we say in some companies.

 

[profile]

I doubt any of the larger companies would push the issue either, I know mine wouldn't, but I think that I wasn't that clear on my thoughts on the matter. More accurately, I think the pilots would push themselves. I think most pilots tend to try to fly an approach that's legal to fly. An example is the published demonstrated x-wind numbers. Those aren't published as limitations, and, as a result, I've watched pilots at virtually all the major carriers operate in winds in excess of them.

My company does treat them as hard limitations, our performance computer will just show the winds as out of limits and that's the end of it. I sat in CDG one night, unable to fly with the winds, while all the other carriers (except UAL at the time, the only other carrier that had the "hard limit", others may now, I don't know) were all operating in and out. I know they were operating in winds in excess of the demonstrated numbers because I had flown the types of aircraft they were operating that night, and the numbers are manufacturer numbers, not company driven.

I think the ceiling is the same, no limit, so pilots tend to try to do it, just as part 91 operators often fly approaches with the reported vis below mins -- with statistically higher tragic results.

 

[ThomasR]

Precision Approach

I am not going to defend by original yes or no answers because it is debatable what the actual Wx would be at arrival.

But if you are only non-precision equipt I consider a Wx report suggesting vis below minimums as a good reason to go to the alternate and leave the approachs clear for those with precision approach equipment. I personally don't like holding with thousands of tons flying around above and below me over the same spot. I don't like the idea that people go IMC for practice. And when in icing conditions you might not have a choice whether to land or not and someone holding up the approach on the off chance they can make it on an NDB approach might mean your brand new ILS equipment gets you only to pancakeville.

 

[100LL... Again!]

I mean this in the nicest possible way, but ThomasR, you do not sound that confident in anyone's skills. Your own or theirs. What's up?

100 & 1/2 is no big deal if you are prepared for it. (ILS, of course)

Non-precision? Little trickier, but not too bad.

Point is ,we get paid to get it done, and if it doable, we do it. The pilot must have complete confidence in his/her skills, of course.

 

[ThomasR]

I mean this in the nicest possible way, but ThomasR, you do not sound that confident in anyone's skills. Your own or theirs. What's up?

100 & 1/2 is no big deal if you are prepared for it. (ILS, of course)

Non-precision? Little trickier, but not too bad.

Point is ,we get paid to get it done, and if it doable, we do it. The pilot must have complete confidence in his/her skills, of course.

Don't have a problem with skills or getting the job done; just need to set a limit as to when to leave it and go to the alternate. I fly mostly helicopters and I flew in Michigan wx which means ice and lots of it. It buids in a blink and you can't get it off the aircraft. It can jam your controls, knock out your ratios, over gross your aircraft, destroy visibility or kill your engine. We lost a Million Dollar cessna one winter coming back from a Chicago charter. Wings booted ice fine but on final the wind shield froze over. We emptied the anti freeze trying to clear forward vision. We hit the runway center line on an ILS backcourse one of us looking out the side for the runway and the other on instruments. We difted after touch down and hit the snow bank from the plows clearing the runway.

Helicopters don't have any anti icing equipment. If the blades sling ice unevenly you get a sever lateral vibration that is impossible to handle.
As far as flying near jumbo jets in a helicopter; it is suicide. The vortex from a jet liner will knock a helicoper out of the sky. If it does not knock it inverted it can push it out of altitude at least a thousand feet easily. I am willing to go IMC and I am good in IFR weather; but I don't like it and if there is anyway I can avoid it I will. Small aircraft and ice

I have always admired those big aircraft and I enjoy being able to converse with some of you that fly them, but I am just a little guy trying to keep out of the way from being crunched.

 

[pilotyip]

Standard 121 ILS mins 4000 RVR

Standard ILS minimums for 121 air carrier without Op Spec C54 is 4000 RVR. 121 flt crews are not authorized to go below 4000 RVR unless they are trained to lower than standard minimums under the provisions of Op Spec C54 and 15% must be added to the LFL if using lower than standard minimums.

 

[vclean]

Standard ILS mins are 1/2 mile, 2400 RVR.

 

[bafanguy]

pilotyip is correct. This issue is governed by Ops Specs under 121. The 4000RVR(3/4 mile) is called Basic Turbojet Minima ( and includes a 200' HAT...used to be 250' many years ago ). There are additional requirements for 121 crews to be able to use anything lower but it's not an issue since training/dispatch programs take care of the legal mumbo-jumbo and you don't really run up against it.


Our Ops Specs said: "The Pilot-in-Command must be specifically qualified and authorized to use minima below RVR 4000 or 3/4 mile visibility".

There is the requirement for the additional runway as pilotyip said AND our Ops Specs also require precision instrument runway markings OR CL to operate below RVR 4000. This last one would only come up when the CL's are OTS and/or there is construction/repaving under way leaving no precision markings. MLB was like this for a long time as the runway (9-27, I think ) was extended, resurfaced, or whatever they were doing to it at the time.

There will most likely be some variations in Ops Specs from one company to another so yours may not require all the same stuff as ours. But, RVR 4000 as Basic Turbojet Minima is likely something basic to FAA Master Ops Specs as would come into play at your 121 company. It's just not normally a player.

 

[aroundtheblock]

Remember that these are all predicated on different mins. At US Air, for example, if you had to circle weather had to be at least a ceiling 1000 and vis of 3 miles as per op specs.

 

[bafanguy]

atb,


Yeah, it's interesting to see that there are differences between airlines ops specs when they fly the same airplanes into the same airports under the same regs.