Stacked holding pattern / FMS Question

[pager94 4]

Hi All,When I took my IFR checkride around KPHX (by the way AZ is the worst place to get IFR training, need to go to CA for clouds and IFR conditions) the designated examinaer (DE) introduced me into a stacked holding pattern, commonly used at high density airports (KLAX, KJFK, KORD, etc). Essentially, upon entering a highly stacked holding pattern outside the airport each aircraft stepped down one level in the stack until it was their turn to shoot the approach. Does anyone know if the PMDG 737NG FMS will stimulate this downstepping in the holding pattern automatically or will the hold be consistent but the step wise drop down the stack will be manual via MCP? Anyway, while were all in a stacked holding pattern waiting for final approach clearance for the PMDG 737NG, I thought I would share some shots from my recently aquired A2A Piper Cub. I took her out for some spin testing over the Grand Canyon MegaScenery Style and she handled them perfectly. Does anyone know if the PMDG 737NG will be certified for spins? :( Next a nice power ON steep stall with constant hard rudder, result --> Nice snap roll, OUCH........................... my neck hurts :( Cheers,BillyBob

[Ben Cap 89]

I've often wondered this myself. I am from the Atlanta area so whenever I fly into ATL we almost always get put into a hold or get vectored off some random "tangent" for spacing.Best Regards,

[yyzflier 11]

If I understand the question correctly, descents in a holding pattern are done only on instruction from ATC. The pilots, getting a clearance to a lower altitude, would select the new altitude in the MCP and down they go. As the planes on the bottom are steered out of the holding pattern and vectored for the approach, the higher aircraft are stepped down on by one by ATC. On a clear day, the stack of jets makes for an impressive sight for pilots and passengers. Hope your checkride went smoothly.

[pager94 4]

If I understand the question correctly, descents in a holding pattern are done only on instruction from ATC. The pilots, getting a clearance to a lower altitude, would select the new altitude in the MCP and down they go. As the planes on the bottom are steered out of the holding pattern and vectored for the approach, the higher aircraft are stepped down on by one by ATC. On a clear day, the stack of jets makes for an impressive sight for pilots and passengers. Hope your checkride went smoothly.

Yes, it went smoothly. I got my IFR rating without going through 1 cloud. LOLBut I was asking if the FMC has the capacity, once IN the hold, to step down via VNAV or will it require a manual descent via MCP / FLCH for each step down?BB

[dazz 69]

There's a target altitude in the hold page of the FMC for what I know

[Jack_C 1]

There's a target altitude in the hold page of the FMC for what I know

You still have to put the altitude on the mcp. You would most likely be in LVL CHG or V/S in the hold.JackColwill

[dazz 69]

You still have to put the altitude on the mcp. You would most likely be in LVL CHG or V/S in the hold.JackColwill

Yeah, it works like the speed/altitude restriction in a waypoint right? you still need to set the mcp altitude to the hold assigned target altitude or lower (if descending) for the VNAV path to comply.So even if it's not normal, it can be flown in VNAV. correct?

[asdf987 0]

ATC will assign a level that ensures 1000FT separation between other aircraft in the stack. It's best that you use V/S and select a decent rate (500-800fpm) so that you don't waste the controller's time. It is not safe to hope that VNAV will some how coordinate with other aircraft to prevent a collision.CheersNick Jones

[Spidierox 4]

Yeah, it works like the speed/altitude restriction in a waypoint right? you still need to set the mcp altitude to the hold assigned target altitude or lower (if descending) for the VNAV path to comply.So even if it's not normal, it can be flown in VNAV. correct?

Well not so sure. Since Jack said you have to be in LVL CHG or VS mode, you are not in VNAV mode, so based on that I would say it cannot be flown in VNAV.Maybe someone can helps us further here ? I am curious now...

[Tabs 2,790]

I don't think Jack meant that VNAV isn't possible, just that the standard way of doing it at his airline is to use LVL CHG or V/S. Any use of VNAV would be VNAV SPD mode anyway, which is almost identical to LVL CHG basically (just the FMC's calculated speed vs. the pilot's MCP selected speed). I'd think you could edit the altitude on the HOLD page, roll the MCP down to it and engage a VNAV SPD descent, but I could very well be wrong.Good question by the way - I definitely don't know the answer myself...

[scandinavian13 5,192]

Regarding the vertical modes:From an ATC perspective, if we're stacking holds, we have a lot of traffic. If we clear a lower level, expect we're bringing in someone to take your spot. That being said, whatever gets you off of that altitude of the hold and down to the next faster is much preferred.

[Tabs 2,790]

Ok... curiosity got the better of us here - one of our tech team members tried this in a Level-D NG sim this morning. You actually cannot do it in VNAV period. Changing the altitude data doesn't create or update a new hold in the FMC. It must be done in LVL CHG or V/S.Case solved.

[dazz 69]

Ok... curiosity got the better of us here - one of our tech team members tried this in a Level-D NG sim this morning. You actually cannot do it in VNAV period. Changing the altitude data doesn't create or update a new hold in the FMC. It must be done in LVL CHG or V/S.Case solved.

Thanks Ryan for checking it. That's a surprise to me. Ok, I have no idea of real life operations, but you can do it in the PMDG MD11, so thought that would be the case for the Boeings too. It's been a while since I last flew the 744 but I'll have to try it there

[tcas_climb 45]

But would changing the hold altitude in the FMC cause a change in best holding speed?

[dazz 69]

But would changing the hold altitude in the FMC cause a change in best holding speed?

For what I know, in the PMDG MD11 it doesn't change the speed. You can add altitude targets (At or Above/ At or Below or exactly at) and the leg time and direction of turn.You can obviously change the speed going to V/S though