Weather

[Tbrown]

ATIS is reporting weather as "X" and tower reports weather as "Y" Which one is controlling?

[ZUM]

I'd say Tower, because they will always have the most up to date information

[stuckingfk]

I am not completely sure, but I believe that for takeoffs under VFR you have to abide by whichever source is reporting the lower visibility, or ceiling.

[bluelake]

well, which weather is the most current ?

Ruppert is correct, I believe.

Tower will usually only make a report if they feel that the current METAR is reporting higher vis or ceilings than they feel it is at that current time, but in general which ever report is lower is the one you use.

[say_speed]

Tower observation is more accurate than ATIS. If the ATIS is reporting below 1sm and the tower says it is 5sm, you can go. The controller hasn't had time to change the ATIS yet, but he will soon. Same when flying IFR, the ATIS is reporting vis below 1/2sm for the ils, but if the tower tells you the vis is 3/4sm, you are legal to start the approach and land.

[SUSPilot]

[ QUOTE ]
Tower observation is more accurate than ATIS. If the ATIS is reporting below 1sm and the tower says it is 5sm, you can go. The controller hasn't had time to change the ATIS yet, but he will soon. Same when flying IFR, the ATIS is reporting vis below 1/2sm for the ils, but if the tower tells you the vis is 3/4sm, you are legal to start the approach and land.

[/ QUOTE ]

Remember ATIS only changes when there is official weather. This is usually once an hour or if conditions change rapidly warranting a SPECI observation. When tower is calling out RVRs or visibility, that is the current condition and you can fly the approach.

[stuckingfk]

I thought you were allowed to fly the approach anyway, and if at the MAP, you are in condition to land, runway environment in sight, and the required visibility and ceilings, you are good to land. And doesn't inflight visibility overrule ground visibility.

[SteveC]

[ QUOTE ]
I thought you were allowed to fly the approach anyway, and if at the MAP, you are in condition to land, runway environment in sight, and the required visibility and ceilings, you are good to land. And doesn't inflight visibility overrule ground visibility.

[/ QUOTE ]
Depends on whether you're Part 91 or not. Part 135 & 121 have different rules.

[say_speed]

[ QUOTE ]
Remember ATIS only changes when there is official weather. This is usually once an hour or if conditions change rapidly warranting a SPECI observation. When tower is calling out RVRs or visibility, that is the current condition and you can fly the approach.

[/ QUOTE ]

Air Traffic Controllers are trained and approved to change the ATIS at their airport when condition prevail. If at the bottom of the hour the field went from IFR to VFR, the controllers will change the ATIS... And even if they don't, if they tell you on the freq that the field is VFR, that's all you need. Good to go.
No different with the RVRs, or vis, like you said.

[say_speed]

[ QUOTE ]
And doesn't inflight visibility overrule ground visibility.

[/ QUOTE ]

For what purpose are you talking about inflight visibility? For approach and landing mins, ground vis is what you need.

[Mr_Creepy]

No that's not correct. If you read 91.175, in order to continue below minimums you need flight visibility.

If you are talking about initiating an approach, in order to proceed past the FAF you need RVR, or if that isn't available, tower vis.

Remember that rabbits are 2400-3000' long, and if you are at one end and can see the other, you have at least 1/2 mile.

[Mr_Creepy]

Also, the rule about initiating the approach only applies to 135 and 121. 91 operators can initiate an approach below minimums, but I don't recommend it.

[mtsu_av8er]

[ QUOTE ]
91 operators can initiate an approach below minimums, but I don't recommend it.

[/ QUOTE ]

I used to do this at Pitt-Greenville all the time. If you listen to the AWOS, you'd have to wait 5 hours to shoot the approach. it would be reporting <1/4 mile, indefinate ceilings, etc. I've never shot an approach there and broken out any lower than 1200 feet!!

[say_speed]

[ QUOTE ]
No that's not correct. If you read 91.175, in order to continue below minimums you need flight visibility.

[/ QUOTE ]

You are right John, I need to go back to the FARs a little more often...

[Mr_Creepy]

That's a big interview question too. Or at least it was in my day.

[stuckingfk]

How come nobody gave me credit for being right. But thanks John for backing it up with a FAR. I knew I wasn't smokin something because I had been taught what I wrote in my earlier post.