Visibility to land on Pt 121?

[Rally]

I was just at a interview and the tech guy asked me what we needed to descend below DH. I said approach lights or airport enviroment. Approach lights to 100 feet then airport enviroment or red bars. In addition at all times below DH you need to have your visibility. OR go missed. This question was posed after the visiblity had gone down after the FAF. He did'nt like that because he told me that no matter what you could could land even if you did'nt have your vis because you had runway enviroment. WTF? Needless to say I did'nt get the job because it stirred me up. The regs plainly state you need required vis for the IAP. Am I overlooking something or am I right for thinking these guy is a douch bag giving people interviews and giving them false information. Should'nt the examiner know the regs? jeez

 

[mmmdonut]

*sigh*


vis required to start the apch

vis not required to continue after the faf

da is lowest authorized alt

if you have at least one of the magic thingys listed in the FARs in sight at or above the DA, you may land.


its only complicated if you make it complicated

 

[Rally]

Oh really?

Upon reaching DH or at MDA, and at any time before the missed approach point, the pilot may continue the approach below DH or MDA if either the requirements of §91.175(l) of this chapter, or the following requirements are met:

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and where that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach procedure being used

Whats that then?

 

[mmmdonut]

You had that all cut & pasted and ready to go....

RVR transmissometers don't measure flight vis - only your eyes do.

Maybe you turned the interviewers off in other ways.

 

[skeezer]

*sigh*


vis required to start the apch

vis not required to continue after the faf

da is lowest authorized alt

if you have at least one of the magic thingys listed in the FARs in sight at or above the DA, you may land.

You forgot flight visibility is required to land.

You don't need the reported vis from the FAF to DH, but you still need it to land.... Flight visibility that is.

I think most of the confusion results from two people thinking the same thing but not communicating it in the same way.


Skeezer

PS I just read your post and it looks like you are saying the same thing, just in a different way. See what I mean

 

[Rally]

This guy was adament that RVR even if RVR was 1000 and the chart said 1800 you could land as long as you had your runway enviroment. He told me to forget visbility and anways how are you going to tell what the vis is? I said "the decsion bars are 1000 feet from the runway" Thinking thats a good measure. (like a yard stick) I was just pretty to surprised to hear a pilot at a interview representing his company saying stuff that was blantently contradicting FARs. Hmm.

 

[mmmdonut]

Decision bars?

Do you mean aim point markings?

                                                          _
                                                _   
                                       _           The GP length is more than 1000'
                               _        
                        _
_______________________________________
                     |-------1000'----|

Looking down thru fog, you can often see the ground... looking out and down, you usually can't see the runway in front of you.

Flight vis is not measured.

 

[skeezer]

That guy was a douche then. Every company has one or two and sometimes they end up doing the interviews. We had a real big one at my company for a while and he finally got the boot. Usually those guys are nothing like the bulk of the pilot group at the company, just a freak who got placed in the wrong position.

Or, it could have been some grand scheme to test your CRM skills with a douche bag captain who wants to break the rules.

Peace!

Skeezer

 

[minitour]

Upon reaching DH or at MDA, and at any time before the missed approach point, the pilot may continue the approach below DH or MDA if either the requirements of §91.175(l) of this chapter, or the following requirements are met:

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers, and where that descent rate will allow touchdown to occur within the touchdown zone of the runway of intended landing;

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach procedure being used

Whats that then?

If you're willing to chance that because some operator told you it was okay, then good for you. If this is truly how this company operates, I don't think I'd want to work for them anyway. Some day I'm going to be PIC and if the feds are there some day and I don't go missed when the visibility is below minimums, its not going to be enough to say, "they told me it was okay."

Sounds like the guy was either on a power trip ("How much can I make him/her feel like I know more than he/she does") or didn't know what he was talking about. Either way, gotta move on. Good luck!

-mini

PS
Not in 121 ops, but I did stay at a Holiday Inn a week and a half ago...

 

[mmmdonut]

PS
Not in 121 ops, but I did stay at a Holiday Inn a week and a half ago...

Holiday Inn Express !!!

 

[BoeingBoy]

It really comes down to one question. Do you have the flight visibility required by the approach chart?

If the answer is yes you can land, if not, you must go around.

The FAA says that even though transmissometers measure vis down the runway (not flight vis--duh), if they are reporting less than mins and you have an incident (blown tire, veer off runway) they will absolutely violate you. The thinking is that flight vis at 1 foot above the runway = RVR. You get paid for flight time, go around and think about it...maybe your wake turbulence will clear the fog for the next pass.

Prevailing visibility is another thing altogether...the tower can frequently be calling less than 1/2 mile while your runway has better than 6000 vis.

Be conservative, if your runway's RVR is less than that required for the approach, go around early and make it easy on yourself. If you're out of gas and on fire it doesn't matter what the vis is...you're exercising PIC emergency authority....land.

 

[typhoonpilot]

This is an age old debate and I tend to agree with Rally and minitour here. The FARs are quite explicit when they say, " the flight visibility is not less than the visibility prescribed in the standard instrument approach being used ". One must be careful to listen to the question very clearly though. I would not try to land if the RVR was below minimums because they are telling you the condition on the runway. However, if the tower reported visibility was below the charted visibility minimums you could have a good argument to use flight visibility. Who knows how far away the tower is from the threshold and how different the wx conditions are ? In an interview you might want to look for ways to make it work and not be too rigid in your stance, but always have a bottom line that you will not cross for safety.

Another point slightly off topic on how to make it work is to ask the tower for the visibility or RVR again. It used to be some places would make it work for you. Arcata/Eureka was a prime example of that.

Typhoonpilot

 

[minitour]

Holiday Inn Express !!!

Nah...I sleep at the mainline locatioins...

 

[Singlecoil]

This does have the odor of a CRM question. He's giving you the scenario of a Captain insisting its OK to land and he wants to see how you'll react. He should be more up front with you that it is a hypothetical situation in my opinion. Personally I think going up against RVR is not wise. Anybody who has ever flow in blowing snow knows what I mean. You can see the runway just fine until you start your flare, then you can't see a bloody thing. Flight vis was 10 miles, but RVR was 1000 for a reason.

 

[A Squared]

Posted by mmmm donut:

>>>>"The GP length is more than 1000' "

Yeah, you're right, for 1000' horizontally the glidepath distance is longer. More specifically for a 3 degree glidepath the distance is 1001.37 feet. What was your point again? That the extra 18 inches is going to make the difference when your required RVR is 1800 ????

 

[mmmdonut]

Good math, but you measured from the wrong point.


TDZ to start of runway : 1000'

Rope extended from end of aimpoint markings to point in space along glide slope at DA (200') : way more than 1000'

I think you measured to TCH. (approx 50')

keep workin on it though.

 

[Andy Neill]

So if you saw the fixed distance markers (1000' down the runway) at a DH of 200 above touchdown, then the run to the asphalt would be 200/sin(3 degrees) = 3821' (3827' flight vis). If you had descended to 100 above touchdown before seeing the fixed distance markers then the run to the asphalt would be 1911' (1913' flight vis). I don't see what either one of those calculations has to do with the point at hand, however.

If I were wearing the 4 stripes, and I saw the required amount of visibility from my nose to the ashphalt, I would land regardless of what the RVR or prevailing visilbility was being reported. If I couldn't see that far down the runway, I wouldn't even if the RVR was reporting above mins.

 

[A Squared]

Good math, but you measured from the wrong point.


TDZ to start of runway : 1000'

Rope extended from end of aimpoint markings to point in space along glide slope at DA (200') : way more than 1000'

I think you measured to TCH. (approx 50')

keep workin on it though.

Ahhh, OK, I misunderstood you the first time around, I thought that you were trying to say that the flight visibility was more than the ground visibility because it was measured along the glidepath (sloping) rather than horiozontally.

 

[mmmdonut]

Ahhh, OK, I misunderstood you the first time around, I thought that you were trying to say that the flight visibility was more than the ground visibility because it was measured along the glidepath (sloping) rather than horiozontally.

Naw... skeezer was right.. this is just a commonly miscommunicated subject. I'm confused!!

 

[atldc9]

On another note, for Cat II or III ops, if you receive a report of required RVR being less then required for the approach at any point prior to touchdown, you must execute a missed approach. The old rule of once inside the FAF does not apply to CAT II and III ops.