I was asked this the other day and am completly drawing a blank.

On an IFR approach what takes precidence, vis, cig level or both?

 

Only need the vis to commence the final approach segment.

 

Thats what I thought, where would you find that IFR oral exam guide?

 

Yep it's vis. And it should be in the FAR/AIM.

 

91.175 lists what's needed (for part 91, I got the impression you weren't looking for the 121 regs). Specifically:

91.175(c)(2)Operation below DH or MDA: The flight visibility is not less than the visibility prescribed in the standard instrument approach being used

...

Edit: Ok here's some 121 on the subject:

121.651(c) If a pilot has begun the final approach segment of an instrument approach procedure in accordance with paragraph (b) of this section and after that receives a later weather report indicating below-minimum conditions, the pilot may continue the approach to DH or MDA. 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 and touch down if --
(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach procedure being used

 

Are we talking 91 or 121?

Part 91, you don't need any particular weather minimums to attempt an approach, however when you get to the bottom of the approach you need to see at least one of the things in 91.175.

For part 121, you need the visibility that is published to attempt the approach when you cross the FAF.

 

It's great hearing gen. aviation aircraft getting in when you are out holding waiting for the weather and vis to pick up.

 

...you get paid by the minute, right?

 

To add another shade of gray to the answer of your question. It also depends on if the approach is a straight-in (Vis only) or circle (Vis & Cieling). It gets more complicated when you throw in RVR, RVV, Tower Vis vs official wx, etc.

 

NightSky got it right...to land you need to have the required FLIGHT VISIBILITY, which if you have, will automatically guarantee you have the proper ceiling, so long as you don't bust minimums...basically this means that if you can see the runway environment at the MAP, then you have the required visibility and ceiling; if you can't, you don't.