121 Reg T/Off confusion

[Mtnjam]

Obviously standards are 1 mile for A/C with 2 or less Eng. and 1/2 mile with more than 2 Eng.
I Also understand that each Jepp. plate lists takoff RVR.
I Also understand that you can take off with 600RVR if you have centerline lights and runway marking to maintain directional control thoughout the takeoff run. My question is if you can take off with 600 RVR, then why do airports list RVR T/off mins on Jepp plates??
So it goes like this, I Figure.
If you have no center lights you use Standard Takeoff mins??
So when do you use Published Takeoff minimums if you can takeoff with 600RVR?? That's my question........... Alrighty then.........

 

[Rally]

Ok...
You have

Standard-1 sm (2 engines)

1/4- with adequate visual range

and

600 rvr (666) sometimes (66)

For standard ALL you need is 1 mile no runway markings at all.
Forget about lights and RVR outages etc.

For 1/4 you need "adequate visual reference" and a report from the touchdown RVR meter however a mid RVR sensor can take the place if the TD is broken. Adequate visual range, is CL (centerline lighting) RCLM (runway centerline marking) if those are not there you need and other combination of features on the runway that identify the surfrace. Say for example the CL and RCLM are covered with snow but you have the runway edge lights or markings. You are good to go because you have "adequate visual reference"

For 600 RVR you need ALL three RVR sensor readings (except that if one is broken you can use any of the other two) The all/both need to be above 600 RVR to takeoff and you need BOTH CL and RCLM to takeoff. If they are covered with snow its a no go. If any of the RVR readings are below 600 its a no go.


Why the difference? As far a I can tell....Not all runways have CL. Not all runways have three sensors TD, Mid, and Rollout. Some only have TD, some only have TD and MID etc. Therefore you can't to a 666 takeoff (600,600,600 rvr). Then you move up to 1/4 adequate visual reference, if you don't have those criteria (which I doubt it would ever happen) then its a 1 sm standard.


Having just busted a interview on this stuff I and spending hours on it afterwards I think I've finally got it.

 

[Mtnjam]

Posted RVR.

Yes, I have an interview coming up and I'm probabally looking into this more than I should, but the post on Landing Mins were good too. However what about the posted RVR for the airport for Takeoff mins??
1. so if you have no RCL and or RCLM you cannot use the 600 RVR ??
2. then it goes to posted mins???
3. Then standard of 1 mile?
RVR posted on apprch charts is usually lower than 5000 RVR.

 

[Rally]

Yes, I have an interview coming up and I'm probabally looking into this more than I should, but the post on Landing Mins were good too. However what about the posted RVR for the airport for Takeoff mins??
1. so if you have no RCL and or RCLM you cannot use the 600 RVR ??
2. then it goes to posted mins???
3. Then standard of 1 mile?
RVR posted on apprch charts is usually lower than 5000 RVR.

Actually I think you're looking into it fine, not worth busting a interview.

1. Yes.
Per the Jepp for say Orlando Intl (MCO) 17l/r 18l/r 35l 36l/r
"CL & RCLM any RVR out other two required"
In other words to use the 600 rvr you need to have centerline lighting, runway centerline markings and three RVR readings 600 or above. If one RVR sensor is not working the other two sensors have to both be reading 600 or above.

2. Now on the SAME runway it has "adequate vis ref" 16 rvr or 1/4.
You can use the adequate vis ref minimums if:

TD Rvr is available (Mid can be used if TD inop, but TD is controlling)
-RVR is above 1600
You have ONLY ONE of the following aids:
HIRL
CL
RCLM
If you don't have any of these you may still depart however you must be able to "continously identify the takeoff surface...."

IE. edge markings etc.

If you don't have ANY of the above (unlikely like I said but possible) Then you have to use the standard visibility.


I may not be answering your question completely because I don't know what you mean by "posted mins". If you mean landing minimums. You can takeoff with less then landing mins if you have a takeoff alternate above minimums for THAT airport with one engine cruise in still air.

Above example.

The ILS 18L requires 1800 rvr to land.

The airport's RVR readings are measuring 600,700,1000 rvr respectively. The centerline lighting is not notamed and the runway centerline markings are not covered by something and visible, you may takeoff but you need a takeoff alternate within one hour cruise on one engine in still air.

 

[Singlecoil]

Since you guys are practicing for interviews, here's one for ya.

Using the above example at Orlando, can you take off if the RVR is 1600, 400, 400?

By the way, I think MtnJam is getting confused about "standard" takeoff mins. The one mile, half mile mins don't apply to any 121 carrier. They all have approved reduced mins which are the ones you are talking about. Basically, if you have 1600 or a quarter mile, you can blast off. Oops did I give it away?

 

[lawfly]

121 Reg T/Off Confusion

A whole new generation of pilots has come along since I was flying scheduled 135 in Twin Otters. Not sure about 121 per se, but, as I recall, we had non-standard everything per our approved ops specs. Non standard takeoff mins, non-standard alternate mins. Under the standard stuff, there would be have been days we couldn't have taken off or have had any legal alternates within range, even though they were at or above landing mins. Not sure about the 600 RVR stuff. Just thought I'd interject the "ops specs" factor. For nostalgia, if nothing else.

 

[Rally]

Since you guys are practicing for interviews, here's one for ya.

Using the above example at Orlando, can you take off if the RVR is 1600, 400, 400?

By the way, I think MtnJam is getting confused about "standard" takeoff mins. The one mile, half mile mins don't apply to any 121 carrier. They all have approved reduced mins which are the ones you are talking about. Basically, if you have 1600 or a quarter mile, you can blast off. Oops did I give it away?

Nope, all RVRs must be 600 or above.

Thats why its says
TDZ RVR 6
Mid RVR 6
Rollout RVR 6

 

[Rally]

Actually some say:

TDZ RVR 6
Rollout RVR 6

(or mid and roll, or roll and tdz etc)

In that case yes both must be at or above 600 rvr.

 

[xdashdriver]

If the published minimums are greater than standard in the first place, then you cannot reduce at all. That would be an excellent reason to put minimums on the plate.

 

[146guy]

Rally- if the touchdown is 1600 you are good to go regardless of what the other two say. I dont' have my ops specs in front of me to quote exactly, but trust me.