LNAV/VNAV minimums setting

[PeanuckleCRJ]

At DL we set field elevation rounded up to next hundred, then at 1000 feet AGL we reselect to missed approach altitude.

 

[boman]

At CAL "0000" is set nearing FAF. In the event of GA, the missed approach altitude is called for after gear comes up.

Seems to work just fine.

 

[pianoman]

At CAL "0000" is set nearing FAF. In the event of GA, the missed approach altitude is called for after gear comes up.

Seems to work just fine.

Just on the 737. The 777 I know you set field elev, and the 756 I think is the same. Some software limitation on the 'ultra modern' 737.

 

[HalinTexas]

At ATA on the B737, when we were setting up these approaches, we'd leave the FMS alone, as it would take us to the runway. The MCP would be set to the nearest increment above MDA. That would usually be a little be higher than the MDA, next 100' above. No big deal, you could set it to the field once you have visual, or you could bump the yoke and it would continue. Then, our POI made the "brilliant" observation the if you hit TOGA on path, at MDA, the airplane would still descend below MDA while executing the miss. So his solution was to set the MCP up to 140' above MDA. Here's how it worked: you set the MCP to the next highest altitude increment above MDA as determined by the FMS. If this resulted in less than 50' increase, we set it another 100'. This was a royal pain in the a$$. Really FUBAR. When you reached (captured, but not hold) your MCP MDA the NFP would then spin up the MAA. The FP would "bump" the yoke to continue the descent, on path, to the published MDA. If you "timed" it right, you'd stay on path. Like I said, really screwed up. All that magic only to be trick-f@cked at the most crucial point.

 

[Going2Baja]

At ATA on the B737, when we were setting up these approaches, we'd leave the FMS alone, as it would take us to the runway. The MCP would be set to the nearest increment above MDA. That would usually be a little be higher than the MDA, next 100' above. No big deal, you could set it to the field once you have visual, or you could bump the yoke and it would continue. Then, our POI made the "brilliant" observation the if you hit TOGA on path, at MDA, the airplane would still descend below MDA while executing the miss. So his solution was to set the MCP up to 140' above MDA. Here's how it worked: you set the MCP to the next highest altitude increment above MDA as determined by the FMS. If this resulted in less than 50' increase, we set it another 100'. This was a royal pain in the a$$. Really FUBAR. When you reached (captured, but not hold) your MCP MDA the NFP would then spin up the MAA. The FP would "bump" the yoke to continue the descent, on path, to the published MDA. If you "timed" it right, you'd stay on path. Like I said, really screwed up. All that magic only to be trick-f@cked at the most crucial point.

My God!! Even w/ a fresh cup of coffee that gave me a head ache. I feel for all of you ATA guys. That POI should be shot.

At Alaska: On a published part of the appch, at or past IAF, LNAV/VNAV Path, Dial the dirt and watch the magic.

That Easy - Even a Cave Man Could Do It!!!

Baja.

 

[Green Banana]

At Alaska,............Even a Cave Man Could Do It!!!

Baja.

And they do, have you seen some of the crusties in ANC?

 

[Whine Lover]

"My God!! Even w/ a fresh cup of coffee that gave me a head ache. I feel for all of you ATA guys. That POI should be shot."

Agreed.

But it wasn't all that bad...At ATA the "procedures" changed almost bi-weekly and were never really etched in stone, so as long as you did at least something that had been taught in the last 2-3 years you were good to go.

Seriously.

It was a fun place....Can't figure out why they went out of business.


YKMKR

 

[Toobdrvr]

In the Airbus (F9), when you get "Final Approach" FMA, we set missed approach alt. DH is in the FMS and the A/P disconnects when you reach DH...

I Think...

 

[boman]

Just on the 737. The 777 I know you set field elev, and the 756 I think is the same. Some software limitation on the 'ultra modern' 737.

Thanks for the correction.

That Guppy has all kinds of limitations and half measures... I am looking forward to the switchover to speed/alt. tapes instead of the electronic representation of the round dial. Its sure to happen soon.

Cheers

 

[BlueandWhite]

At ATA on the B737, when we were setting up these approaches, we'd leave the FMS alone, as it would take us to the runway. The MCP would be set to the nearest increment above MDA. That would usually be a little be higher than the MDA, next 100' above. No big deal, you could set it to the field once you have visual, or you could bump the yoke and it would continue. Then, our POI made the "brilliant" observation the if you hit TOGA on path, at MDA, the airplane would still descend below MDA while executing the miss. So his solution was to set the MCP up to 140' above MDA. Here's how it worked: you set the MCP to the next highest altitude increment above MDA as determined by the FMS. If this resulted in less than 50' increase, we set it another 100'. This was a royal pain in the a$$. Really FUBAR. When you reached (captured, but not hold) your MCP MDA the NFP would then spin up the MAA. The FP would "bump" the yoke to continue the descent, on path, to the published MDA. If you "timed" it right, you'd stay on path. Like I said, really screwed up. All that magic only to be trick-f@cked at the most crucial point.

Assuming we're still talking LNAV/VNAV, I don't think this POI had any idea what LNAV/VNAV was. The LNAV/VNAV uses a DA, just like an ILS DA/DH. It is the point along the descent path where the missed approach begins. If you commence the missed approach and hit TOGA at the DA, you are guaranteed obstacle clearance, even if the aircraft dips below the DA on a missed approach. DA is not a "minimum altitude". MDA is for LNAV-only approaches, and will not guarantee obstacle clearance if you descend below.

Setting MCP to TDZE or missed approach altitude will vary depending on company, aircraft or avionics software load, but it should not normally be set at or near the DA. That will cause most aircraft to start to level off prior to reaching the DA. If that happens, you have no way of determining where your missed approach point is.

I personally like the "dial to the dirt" for the MCP, and reset as part of the go-around/MAP flow.