FDC NOTAMs: lesson learned

[BeechBoy]

At Milwaukee's Mitchell Field there's an FDC NOTAM that changes the takeoff minimums on 7R. The NOTAM gives the new takeoff minimums as, "300-1 or Standard with a minimum climb of 482 ft/nm to 900 feet".

A couple of weeks ago the RVR was 3,500 and, for a while, they were still using 7R. I thought this violated the NOTAM because, like an idiot, I thought "Standard" meant "Standard" (i.e. RVR 5,000 for a twin).

This bothered me enough that I talked to the FSDO about it and discovered that, in this case, "Standard" actually means "Lower than Standard" (i.e. if lower than standard takeoff minimums listed for that runway you can legally use them). However, if specific numbers are used (i.e. if the NOTAM stated, "... 5,000 RVR with minimum climb of 482 ft/nm ...") then, in this case, 5,000 RVR would be the absolute lowest regardless of any lower than standard minimums listed.

That seems rather confusing so I thought I'd pass this on to anyone interested.

In the end, this NOTAM doesn't change the takeoff minimums at all so I wonder why it's even posted.

 

[casey]

the notam sets up 2 scenarios, depending on your climb ability.

1) less than 482 ft/min to 900 ft - 300/1
2) more than 482 ft/min to 900 ft - standard

if you fall into category one you are pretty much stuck there since you have a ceiling requirement (300 ft) in addition to the 1 mile vis. I dont recall if you can reduce that in part 91 ops, but if you can it would be 'adequate visual reference'. in 121 with a ceiling requirement (higher than standard mins) you cannot reduce (or at least we cant).

If you fall into category 2, essentially able to be above 900 ft 2nm from the end of the runway you have standard mins. part 91 allows you to reduce standard mins to 1/4sm (iirc) or adequate visual reference. part 121 gets more complicated but if the mins are 'standard' or lower a bunch of rules come into effect and depending on the equipment on the ground you can reduce to 1600, 1200, 1000 or 600 RVR in most cases.