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View Full Version : Another Ifr Question...


BEWELCH
10-26-2006, 04:46 PM
When (da) Is Reached On The Glide Slope, What Visibility Do I Need To Continue With The Approach Before Going Missed?


overspeed
10-26-2006, 04:56 PM
91.175, I think it is... The visibility prescribed in the approach for your aircraft category, or if you're flying at a higher speed the appropriate category. You will always go below DA/H though, you just can't "continue" below DA/H. Essentially the vis on the bottom of the approach plate, for you probably the Cat. A.

aero550
10-26-2006, 06:10 PM
When (da) Is Reached On The Glide Slope, What Visibility Do I Need To Continue With The Approach Before Going Missed?

You need to at least have the approach lights in sight in order to continue the approach. If you do not see the "runway environment" (REILs, and at least the first several runway lights) within the next one hundred feet, then you should then go missed.


ToiletDuck
10-26-2006, 07:20 PM
You need to at least have the approach lights in sight in order to continue the approach. If you do not see the "runway environment" (REILs, and at least the first several runway lights) within the next one hundred feet, then you should then go missed.

Don't forget the approach to landing has to be able to be made in a safe manner. Seeing the beacon as you pass over doesn't give you the right to just dump flaps, bank her 90 degrees and bring her in.

RedGuy
10-26-2006, 07:39 PM
Don't forget the approach to landing has to be able to be made in a safe manner. Seeing the beacon as you pass over doesn't give you the right to just dump flaps, bank her 90 degrees and bring her in.

Damn it!:mad:

Illini
10-26-2006, 08:42 PM
Visibility is that of whatever is on the plate. 91.175 (d)(2)

To descend, you must have one of the following:
-Approach Lighting - allows you to descend to 100 feet ABOVE the TDZE

-Threshold
-Threshold Markings
-Threshold Lights
-REILS
-VASI
-Touchdown zone or Touchdown Zone Markings
-Touchdown zone lights
-Runway or runway markings
-Runway lights

multipilot
10-26-2006, 08:48 PM
91.175, I think it is... The visibility prescribed in the approach for your aircraft category, or if you're flying at a higher speed the appropriate category. You will always go below DA/H though, you just can't "continue" below DA/H. Essentially the vis on the bottom of the approach plate, for you probably the Cat. A.

Right, 91.175 outlines three things you need to continue the approach to the runway.


you must be able to descend from the DA to the runway using normal maneuvers
you must meet the visibility and ceiling minimums prescribed in the IAP.
you must be able to visually identify one of the ten things that make up the runway environment
the touchdown zone
the touchdown zone markings
the touchdown zone lights
runway end identifier lights (REIL)
VASI
touchdown zone or touchdown zone markings
touchdown zone lights
the runway or runway markings
the runway lights
the approach light system - once you have this in sight, you are allowed to descend to 100 feet above the touchdown zone elevation unless the red terminating bars are also visible.A lot of students have the misconception that only having the ALS will allow you to go 100 feet below the DA.

If you do not meet these three criteria, then you must go missed.

undflyboy06
10-26-2006, 09:45 PM
I always thought that if you have the ALS you are able to descend down to 100 above the TZDE? I know that once you're 100 above the TZDE and you don't meet the 3 requirement you have to go missed approach.

Also, you don't have to have the ceiling requirements in order to land. The regs only state that "The flight visibility is not less than the visibility prescribed int he standard istrument appraoch being used" It can be broken at 150 ft, but as long as you have the visibility, runway environment, and normal descent you can continue.

sigep_nm
10-26-2006, 11:52 PM
Remember that it is flight visibility not reported ground visibility. The missed approach point on a precision approach is the DH unless you have the ALS in sight as previously stated. You can descend below the DH however it is the point at which you must decide whether to continue the approach or go missed. I teach this in the following way: The DH is like a trapoline in which you either break through or spring up(Missed), where as an MDA is like a brick wall that you cannot penetrate without 3 criteria being met (runway environment in sight, prescribe visibility, continuos position to land)

Illini
10-27-2006, 04:07 AM
Right, 91.175 outlines three things you need to continue the approach to the runway.


you must be able to descend from the DA to the runway using normal maneuvers
you must meet the visibility and ceiling minimums prescribed in the IAP.
you must be able to visually identify one of the ten things that make up the runway environment
the touchdown zone
the touchdown zone markings
the touchdown zone lights
runway end identifier lights (REIL)
VASI
touchdown zone or touchdown zone markings
touchdown zone lights
the runway or runway markings
the runway lights
the approach light system - once you have this in sight, you are allowed to descend to 100 feet above the touchdown zone elevation unless the red terminating bars are also visible.A lot of students have the misconception that only having the ALS will allow you to go 100 feet below the DA.

If you do not meet these three criteria, then you must go missed.

Didn't I effectively just post this right above you?

ctd57
10-27-2006, 06:11 AM
Yes you did. I don't know what anyone didn't see in your post.

Ottopilot
10-29-2006, 04:42 AM
When (da) Is Reached On The Glide Slope, What Visibility Do I Need To Continue With The Approach Before Going Missed?

It all depends what aircraft and rules you are flying. Since this is the airline pilot forum and I fly 757/767, the answer is "0". Cat III, Land III- don't need anything to land. :D

multipilot
10-29-2006, 06:07 AM
Didn't I effectively just post this right above you?

Yes you did. There was a little more to it than what you posted, but it was unnecessary for me to list what you had already posted. My apologies.

Yes you did. I don't know what anyone didn't see in your post.

Please allow me to clarify. In addition to what Illini posted, you need to have the weather minimums and be able to descend to the runway using normal maneuvers.

I'm going to exaggerate a little, but let’s say you are on an NDB approach and you break out a to mile to the right or left of the intended runway, at your MDA, at your missed approach point, you have the runway environment in sight (what Illini posted), and have the weather minimums. You've satisfied the wx minimums and the runway environment but there would be no way you can continue to the runway using a normal descent if you are that far off centerline. You would have to go missed.

BEWELCH
10-29-2006, 06:08 AM
THATS WHY I POSTED IT IN FLIGHT TRAINING!:o