III Corps

Which airports and what carriers certified to use them?

johnso29

*If the WX is below CAT I mins and even if the crew and aircraft are CAT IIIC qualified, the departure airport could NOT be your takeoff alt. As someone stated earlier, some ops specs(so he needs to familiar with company ops specs) prevent two engine airplanes from shooting CAT II/III approaches single engine. The purpose of a takeoff alt is provide someone an alternative course of action if their departure point is below CAT I mins and they lose an engine, (hence why it has to be within 1 hour single engine at normal cruise speed in still air) so why you maybe able to depart in less than standard mins, you would not be able to list it as your takeoff alt. Hope that helps.

subicpilot

Is there ever a case when your departure airport CAN be your takeoff alternate?

Has nothing to do with wx or crew qualifications.

VTcharter

Take-off minimums are not dependent on the take-off alternate except as to say that if you are below the landing min, then you need a takeoff alternate. In my opinion, the original question being what are the take-off min's has nothing to do with alternates, and therefore the pilot would be limited the same as any other 135 or 121 pilot would...whatever the chart says that the ops specs allow.

Some of the confusion may be coming from the reduction of the "standard" takeoff minimum. For instance, in my Ops Specs, if the runways takeoff minimums are standard or lower, I may reduce the standard takeoff minimum (1 mile or 1/2 mile) to straight in Cat I landing minimum. After that, my Ops Specs allow the use of less than standard takeoff minimums to 600 RVR, as long as it is authorized per part 97; ie airport / runway diagram. None of this however, has anything to do with the take-off alternate, which for my company would be required if you are departing lower than the Cat I straight in for that airport.

johnso29

No, that was my point. It would defeat the purpose of the takeoff alt.

subicpilot

I think the point is, your departure airport is NEVER your takeoff alternate. Period.

Your first statement alluded to wx and aircrew qualification, as if to imply that there may be a situation where if those factors are satisfied, that you may be able to call your departure airport your takeoff alternate.

Just wanted to make sure we were all on the same sheet of music.

johnso29

Yeah, we're on the same page, I just worded poorly. I also think the original poster is trying to ask if your departure point can be your takeoff alt, but he/she uses the term takeoff mins. I think in the past some interviewers have tried to confuse an applicant into thinking if the a/c and crew were CAT III qualified and your departure point was below CAT I mins you could use it as your takeoff alt. This of course is not true, as it would defeat the purpose of a takeoff alt.

III Corps

Big difference between Cat II and III but with III the difference was that you had a decision height (DH) with IIIA but an alert height (AH) with IIIB. Our ops was based on anything below Cat I being flown on the autopilot and any non-precision below 1000/3 also being flown on the autopilot. Although the latter seems a bit stringent, statistics show you are more likely to bust your butt on a non-precision than a precision so it makes sense.

Finally remember the world's most deadly accident was essentially a taxi accident at Tenerife. And if wx was below 6-6-6 (some operators have lower takeoff mins) why even taxi? Taxiing in IIIB is VERY interesting and scary...

When it takes longer to get from the runway to the gate than it does to get from the outer marker to the runway, you know things are bad and the fog very THICK.

fender1

To Takeoff - The reduced visibility requirements (1 sm / 1000 RVR / 6-6-6 / ect. BASED ON THE OPS SPEC)

For a T/O Alternate - Yes, they need one somewhere else within an 1 hour SE. It's based on CAT 1 Mins. (again according to the ops spec)

My question is this. Everyone keeps saying that a T/O alternate is required when wx is "below landing minimums." Is this based on visibility only or BOTH visibility and ceiling???

subicpilot

Are you sure? At least in my world, they are both alert heights (AH) in that the CAP takes the aircraft by AH on ALL CAT III approaches. The difference between IIIa and IIIb is that rollout control is not available on IIIa, which requires A/P disconnect after touchdown. This means the CAP has to see something prior to touchdown...he can still proceed below AH without any visual cues.