OpSpecs and RVR

[flyingcheesehead]

I was playing around with LiveATC and FlightAware today, listening to and "watching" the airliners trying to get into MSN...

KMSN 261953Z 17011KT 1/4SM FG VV001 02/02 A2977 RMK AO2 SLP091 T00170017
KMSN 261853Z 18009KT 1/4SM FG OVC001 01/01 A2979 RMK AO2 SLP100 T00110011
KMSN 261830Z 18010KT 1/4SM FG OVC001 01/01 A2981 RMK AO2 SFC VIS 1/2
KMSN 261824Z 17012KT 1/2SM FG OVC003 01/01 A2981 RMK AO2
KMSN 261753Z 18012KT 1SM BR OVC003 01/01 A2983 RMK AO2 SFC VIS 1 1/4 SLP112 4/014 933017 T00110006 10011 21017 58017

I heard a couple of them say that they needed "1800 RVR" when the approach plate states 2400 RVR for all categories, and from what I could tell, a SkyWest flight landed when the RVR was even less than that. (FWIW, NWA229 and EGF3687 both diverted to Milwaukee.)

So, the question is... Well, questions are...

1) Does the FAA really approve OpSpecs that allow airlines to go below published minimums on approaches?

2) If so, does the FAA actually flight-check these approaches to the lower mins?

Curious as usual,

 

[RotorAndWing]

In the upper left hand part of the approach plate it states : Vis Cat A/B/C/D RVR 1800 authorized with use of FD or AP or HUD to DA.

 

[RotorAndWing]

and from what I could tell, a SkyWest flight landed when the RVR was even less than that.

If ATC reported the RVR lower than 1800 once he was inside the FAF he could continue the approach.

 

[flyingcheesehead]

In the upper left hand part of the approach plate it states : Vis Cat A/B/C/D RVR 1800 authorized with use of FD or AP or HUD to DA.

Aha - Thanks! That clears it right up. ("Duh" moment for me, I guess!)

If ATC reported the RVR lower than 1800 once he was inside the FAF he could continue the approach.

It was changing rapidly right around that time. Based on what I heard, it was clear that the tower couldn't see the runway. There were several reports in that zone and I think the last one I heard before the SkyWest flight landed was actually 1200, but it may not have been that bad at the moment they got to DH, or I may have even missed the tower calling out an improved one, as that feed on LiveATC appears to be a scanner going between 135.45/120.1/119.3 continuously.

I think I heard another 1600 after they landed, and another 1200 after that, and it hasn't improved at all:

KMSN 270553Z 18008KT 1/8SM FG VV001 07/07 A2969 RMK AO2 SLP059 4/011 T00670067 10072 20033 400721061 58004

It's a balmy 45 degrees out, though!

 

[HPNPilot1200]

As already pointed out, 1800 RVR can be used as the visibility minimum for all categories for the straight-in approach with the use of FD/AP/HUD to the DA.

In terms of takeoff, our OpsSpecs agree with §135.225(h) and and authorize us to use §135.225(i):

(h) Except as provided in paragraph (i) of this section, if takeoff minimums are not prescribed in part 97 of this chapter for the takeoff airport, no pilot may takeoff an aircraft under IFR when the weather conditions reported by the facility described in paragraph (a)(1) of this section are less than that prescribed in part 91 of this chapter or in the certificate holder's operations specifications.

(i) At airports where straight-in instrument approach procedures are authorized, a pilot may takeoff an aircraft under IFR when the weather conditions reported by the facility described in paragraph (a)(1) of this section are equal to or better than the lowest straight-in landing minimums, unless otherwise restricted, if—

(1) The wind direction and velocity at the time of takeoff are such that a straight-in instrument approach can be made to the runway served by the instrument approach;

(2) The associated ground facilities upon which the landing minimums are predicated and the related airborne equipment are in normal operation; and

(3) The certificate holder has been approved for such operations.

Often with all ILS components operative including ALS, that allows us to depart IFR with only 1800 RVR (which is the same minimum we use when completing the instrument approach to that runway).

Also note §135.217 which allows operators to depart with visibility above takeoff minimums, but below authorized landing minimums with an alternate airport within 1 hour of flying time.

 

[RotorAndWing]

\
Often with all ILS components operative including ALS, that allows us to depart IFR with only 1800 RVR (which is the same minimum we use when completing the instrument approach to that runway).

Also note §135.217 which allows operators to depart with visibility above takeoff minimums, but below authorized landing minimums with an alternate airport within 1 hour of flying time.

Our OpSpecs allow us to take off with RVR of 500/500/500 as long as all the runway requirements are met.

 

[Speed]

Keep in mind that the airlines have their own airline specific charts as well, through Jeppesen. The minimums they are looking at may be less than what you see on the typical 11-1 chart.