bubi352

Could someone shed some light on this? Please include a reference if you can.

1) Let say you are about to depart from an airport with RVR reporting less than 600 feet (and assuming you can depart with no less than 6/6/6) and the flight visibility is reported as 6 miles as it could possibly with shallow fog (measuring equipments at different heights) - I know RVR is controlling but would you be allowed in this case to use the reported flight visibility (greater than takeoff minimums) to essentially do a "normal takeoff" without having to go through all the "low visibility takeoff" requirements?

2) We all know a takeoff alternate is based on landing minimums at departure. From what I have read, it doesn't specify CAT I (even in my company OSPECS). Could you use CAT II or CAT III minimums to determine the need for a takeoff alternate provided you can shoot one of those approach single engine?

3) Does anyone know who and what equipment is certified CAT III C? I am under the impression that no one is in the United States but I am sure I may be wrong.

joepilot

I believe that you are correct about nobody having CAT IIIC capabilities. My understanding is CAT IIIA means autoland,
CAT IIIB adds auto rollout,
CAT IIIC adds auto taxi to the gate.

It is possible that some type of synthetic vision technology may allow manual CAT IIIC.

Joe

rickair7777

No. T/O RVR is controlling period, if available for your runway. Flight vis would be hard to justify, since you are not in flight yet. They would consider the RVR to be accurate for TO since it is on the ground, where the TO is conducted. If you use a runway that does not have RVR, that might be a different story, if ATIS provides a general visibility report in addition to RVRs (not sure they can do that though?).

We can't, our derived mins are based on CAT I but I think it would come down to opspecs. Look up where it explains alternate min methods, somewhere in there it probably says you have to use CAT I (or maybe allows something else).

It is usually ultra-long range heavies IIRC. The certification and equipment is expensive, but not as expensive as diverting a 747/777 or canceling due to a poor destination forecast.

Twin Wasp

As has been said, RVR is controlling for that runway. I've heard crews try to get the airport turned around for approach when the RVR was 1000/1200/2400. If it's reported 6/6/6 and that's below your Ops Specs, you need to find a different runway.

It's Ops Specs specific if you can use a CAT II or III approach to skip a TO alternate.

No one in the US (and I believe the rest of the world) is CAT IIIc. And I've been about as ultra long range heavy as it gets.

Phantom Flyer

1) RVR is controlling as several posts have stated.

2) A take-off alternate is required if the published weather is below landing minimums. The only concern is a) your qualifications; b) the capability of your aircraft and c) an available runway which meets your Ops Specs at the departure airport. If you're Cat III and the weather is above those minimums, you're legal for take-off. Twin Wasp is right on, check your Ops Specs.

3) I'm not aware of any operational Cat IIIc runways in the U.S.

Gosh, the DC-3 was a great aircraft. Thanks Twin Wasp for the memories

G'day Mates

bubi352

I asked the first question because I recalled reading something about it but couldn't remember exact details about it. Look at the weather reports below. You are up for RWY 35 with 20SM of visibility reported and because of drifting snow you might not be in a position to land. This being quite frequent in Canada (as an example), I thought that ought to be an exception to this.

METAR CYFB 161600Z 32024G31KT 20SM DRSN FEW091 BKN230 M19/M20 A2963
REBLSN RMK AC2CI2 RVR RWY 35 600 FT VIS N 2 SLP036=

SPECI CYFB 161638Z 32030G35KT 2SM BLSN SCT091 OVC240 RMK AC3CI2 RVR
RWY 35 1600 FT VIS VRB 11/2-21/2=

I finally found the document I read previously but it is only mentioning Part 91.

FAA Legal Interpretation

March 10, 1986
Dear Mr. Johnson:

This is in response to your letter of February 6 requesting an interpretation
of Federal Aviation Regulation (FAR) Part 91, Section 91.116.

Specifically, you request clarification of the term "flight visibility" in
connection with the requirement in FAR 91.116(c) that an aircraft not be
operated below a published decision height or minimum descent altitude if the flight visibility is less than the visibility prescribed in the standard
instrument approach procedure being used. The question arises as to whether descent below the DH or MDA can be made when the runway visual range (RVR) is reported at less than the published minimum RVR for the approach but the flight visibility is greater than that minimum.

The flight visibility is controlling. If the flight visibility exceeds the
published minimum for the approach, then the pilot may proceed as long as the other requirements of paragraph 91.116(c) are met regardless of the reported RVR. The National Transportation Safety Board (NTSB) has upheld this interpretation in several enforcement cases. However, the pilot's judgment of flight visibility is not necessarily conclusive if there is a question as to the actual flight visibility conditions at the time of the approach. Reported visibility and other evidence of record may be considered by the Federal Aviation Administration and the NTSB in determining the actual flight visibility.

Enforcement action would be taken only in those cases in which the pilot
could not reasonably conclude that flight visibility was at or above approach
minimums, but the pilot nevertheless proceeded to land or descend below DH or MDA.

Sincerely,

David L. Bennett Manager, Airspace & Air Traffic Law Branch Regulations &
Enforcement Division

Twin Wasp

While 91 (and 121) give you the limited "look see" the 121 TO rules are more straight forward.
§ 121.651 Takeoff and landing weather minimums: IFR: All certificate holders.

(a) Notwithstanding any clearance from ATC, no pilot may begin a takeoff in an airplane under IFR when the weather conditions reported by the U.S. National Weather Service, a source approved by that Service, or a source approved by the Administrator, are less than those specified in—
(1) The certificate holder's operations specifications; or
(2) Parts 91 and 97 of this chapter, if the certificate holder's operations specifications do not specify takeoff minimums for the airport.

So nothing about flight vis for TO.

PF, must have had half a dozen calls asking if we needed the trucks. Was running up one night in TUL and a T38 goes by. We hear, "I'll tell them" and then "The T38 says it looks like your engine's on fire." We tell him "That's normal" and the tower repeats it to the Tweet on UHF. The burners light up as the Tweet rolls and the F/O says "I dare you to tell him his engine's on fire." I said "No, they'd punch going down the runway."

To get back on topic, was taxiing out in ground fog one night and Tower asked how deep it was. I said it came up to the side window of the Three and Tower past it on that way to an arriving flight.

Fun times

rickair7777

I misread the original post, I didn't notice the "C". I don't know of any CAT IIIC either.

bubi352

Here is the answer from someone quite knowledgeable with the regs regarding takeoff alternates. Just thought I would share it:

The flight plan (or flight release) must specify a takeoff alternate if the weather at the takeoff airport is below landing minimums for that airport. Any landing minimums at the takeoff airport that are authorized for the certificate holder may be considered including Category II or III ILS approaches.

The reference is:
§ 121.617 Alternate airport for departure.
(a) IF the WEATHER conditions at the airport of takeoff are BELOW the LANDING MINIMUMS in the CERTIFICATE HOLDER'S OPERATIONS SPECIFICATIONS FOR THAT AIRPORT, no person may dispatch or release an aircraft from that airport unless the dispatch or flight release specifies an alternate airport located within the following distances from the airport of takeoff:
(1) Aircraft having two engines. Not more than one hour from the departure airport at normal cruising speed in still air with one engine inoperative.
(2) Aircraft having three or more engines. Not more than two hours from the departure airport at normal cruising speed in still air with one engine inoperative.
(b) For the purpose of paragraph (a) of this section, the alternate airport weather conditions must meet the requirements of the certificate holder's operations specifications.
(c) No person may dispatch or release an aircraft from an airport unless he lists each required alternate airport in the dispatch or flight release.

So…
If the Certificate Holder’s Operations Specifications authorize Category II or III approaches; and the aircraft and crew are qualified for those approaches; and those approaches are published and operational for that airport; the crew may CONSIDER the fact that they could easily return to the departure airport if there were a problem and therefore they could CONSIDER not having to file a takeoff alternate.

Multitudes of things can happen after takeoff that can degrade the landing capability of an aircraft. It might be PRUDENT to file a takeoff alternate if the departure airport weather is below Category I minimums, but it is NOT required, unless specifically stated by your company procedures.

A takeoff alternate is… by definition… a place to go if you can’t legally land back at your departure airport.

If your Op Specs allow Category II or III approaches and the aircraft/crew/airport are so equipped then there is no LEGAL reason to file a takeoff alternate.

You might also CONSIDER if the aircraft/crew/company is approved to do single engine Category II or III approaches. Many companies are; some are not. But again it is only something to be considered. There are many other things that could go wrong that may necessitate a return to the departure airport.

There may also be further limitations written into your GOM. Or not.

But once again the reg only states:
“IF the WEATHER conditions at the airport of takeoff are BELOW the LANDING MINIMUMS in the CERTIFICATE HOLDER'S OPERATIONS SPECIFICATIONS FOR THAT AIRPORT, no person may dispatch or release an aircraft from that airport unless the dispatch or flight release specifies an alternate…”

So if your Op Specs allow Cat III approaches and the aircraft/crew/airport are qualified and equipped then THAT is the legal criteria to determine if you need a takeoff alternate.

Nothing prevents you from specifying a takeoff alternate just because you want one in case you happen to fry an engine, but that is simply good judgment, not a legal requirement.

Phantom Flyer

The purpose of my reply was to say that the sole determination of your legality for takeoff under FAR 121, is your company Ops Specs. I guess I wasn't clear.

We have so many experienced pilots come through recurrent and trip on the question " Can you takeoff on Runway 16R at SEATAC with the reported RVR of 5-5-5 ?" On the Jepp plates, it specifies the requirements which must me met and in the classroom example, we meet all of the stated requirements. The "Gotcha" is that our company Ops Specs clearly states that we must have 6-6-6 for all takeoffs. Opps.

Have a good day and read and know your Ops Specs !!!

G'Day Mates