I usually set up a HOLD in the Fenix Airbus FMGS that I can use to achieve a particular Altitude Restriction. If I know I am not going to make the ALT Restriction I will Execute the HOLD to get things cleaned up and then exit out of the HOLD and continue to the next Waipoint (ALT restriction).  If I make the restriction I will  "Ignore" the HOLD. Just curious if anyone else does similar.

Edited October 16, 20232 yr by TomCYYZ

I've done the same thing in the past when ATC screwed me for an approach that I was expecting to be downwind, but they assigned a straight in.  Normally you shouldn't have to use holds to meet restrictions, provided they are set up accurately in the FMC/CDU.  If you are using STARs and published approaches, then it shouldn't be a problem 95% of the time.  FWIW I did see something similar on FlightAware, and it did appear as though they were too high and did a couple circles to get down.  S-turns can sometimes provide the same solution.

Thanks, Makes sense, I don't always use the HOLDS, they are there, for me preferably to use as a "Just In Case" type thing. If I don't need it I have to remember to "IMM Exit" (Cancel) though because it's live up to HOLD point. Also, there can be more than 1 HOLD on the Arrival charts, I use the one closest to the Airport.

I try to avoid those things at all cost.  I was heading into KSUN today in the Cessna Caravan with the GTN750.  The wind favored the straight in to 13 but ATC tried to tell me to fly downwind to 31.  Obviously, I could have just leveled off and did the pattern to 31, but I'm prepared to land with the wind at my nose and already committed to the visual down the valley.  No approach plates for 13, so I just place the airport altitude into the GTN750 and use that to be more precise for descent.  In the Airbus or Boeing, I just make sure I have a good STAR and plan for landing.  The Fenix does a decent job making constraints, but it does have a tendency to dive to meet them.  I hope the next update alleviates that.  The PMDG is better in some ways, but the LNAV is so ridiculous.  So one could say the Fenix handles LNAV beautifully and not so much VNAV, whereas the PMDG does VNAV good much it rather poor at LNAV. 😕

Edited October 16, 20232 yr by Orlaam

I'd prefer to self vector to lose altitude than enter a hold. Pretend it's vectors for spacing or something.

5 hours ago, TomCYYZ said:

I usually set up a HOLD in the Fenix Airbus FMGS that I can use to achieve a particular Altitude Restriction. If I know I am not going to make the ALT Restriction I will Execute the HOLD to get things cleaned up and then exit out of the HOLD and continue to the next Waipoint (ALT restriction).  If I make the restriction I will  "Ignore" the HOLD. Just curious if anyone else does similar.

ProATC X/SR does this, you have to add the holds, which takes some time, I have holds added to most of the airports I use on a regular basis.

No, I don't do this. I can't remember a single case where speed brakes weren't enough to let the Fenix respect all alt restrictions on descent.

What I sometimes do though, is changing 'at or above' restrictions to just 'at' restrictions. This can help avoid being hot and high in the late approach, giving you the opportunity to slow down and meeting the glide path from below.

Holdings I just did for fun and testing purposes. 

5 hours ago, Orlaam said:

I try to avoid those things at all cost.  I was heading into KSUN today in the Cessna Caravan with the GTN750.  The wind favored the straight in to 13 but ATC tried to tell me to fly downwind to 31.  Obviously, I could have just leveled off and did the pattern to 31, but I'm prepared to land with the wind at my nose and already committed to the visual down the valley.  No approach plates for 13, so I just place the airport altitude into the GTN750 and use that to be more precise for descent.  In the Airbus or Boeing, I just make sure I have a good STAR and plan for landing.  The Fenix does a decent job making constraints, but it does have a tendency to dive to meet them.  I hope the next update alleviates that.  The PMDG is better in some ways, but the LNAV is so ridiculous.  So one could say the Fenix handles LNAV beautifully and not so much VNAV, whereas the PMDG does VNAV good much it rather poor at LNAV. 😕

 "The Fenix does a decent job making constraints, but it does have a tendency to dive to meet them.  I hope the next update alleviates that.  The PMDG is better in some ways, but the LNAV is so ridiculous.  So one could say the Fenix handles LNAV beautifully and not so much VNAV, whereas the PMDG does VNAV good much it rather poor at LNAV.😕"

Sorry, but I completely disagree with this statement. I fly both the Fenix and the PMDG every day and they "both" perform beautifully with both L and VNAV.

5 hours ago, SierraHotel said:

 

Sorry, but I completely disagree with this statement. I fly both the Fenix and the PMDG every day and they "both" perform beautifully with both L and VNAV.

I fly both the Fenix and the PMDG, and with a little planning ahead, using Vnav on either one, I never have to use a hold. I call it "fly the plane"   😉

Edited October 16, 20232 yr by Bobsk8

5 hours ago, NovemberUniform said:

I sometimes do though, is changing 'at or above' restrictions to just 'at' restrictions. This can help avoid being hot and high in the late approach, giving you the opportunity to slow down and meeting the glide path from below

This is exactly what I personally do in real world operations, although   Just a note you should not be modifying anything downstream of the FAF.

This height loss scenario loosely speaking will tend to be handled differently by ATC depending on where you are in the world, in the US and Europe you’re likely so get vectors off track to lose height. I’ve noticed other places like India in particular like to give you a 360 degree turn, simply done in HDG SEL rather than setting up a formal hold.

Although, normally if you aren’t going to make a required height it’s because you’ve completely messed up in descent planning and management , which doesn’t tend to happen at commercial level aviation.

Much more likely is that ATC have kept you high or delayed your initial descent deliberately due traffic, in which case it’s their mess to sort out !

Occasionally though where a waypoint has a height and speed restriction and you are high on profile, if you have a word ATC will let you disregard the speed reduction allowing you keep high speed and thus a greater* descent rate ( *although that may not necessarily be the case depending on what aircraft you’re flying)

47 minutes ago, jon b said:

This is exactly what I personally do in real world operations, although   Just a note you should not be modifying anything downstream of the FAF.

Cool, good to know what I do is being done irl. 

What I also do, again just a personal thing, is change fixed restrictions to at or belows on a STAR.

It allows you to get below path, and therefore lose energy which can be a handy thing to keep up your sleeve if things start to go adrift in the decent profile.

For example, on the  NUGRA 1H into EGLL , TOBID FL200 I change to FL200B that way if cleared down to the next restriction,  FL150 level SOPIT, I just reset the MCP to 150, the aircraft will continue its decent perhaps passing TOBID low at FL190 as I’ve entered the 200 OR below, otherwise it would level off and maintain FL200 until passing TOBID.

Its important to remember that , in the UK at least once cleared to a new restriction by ATC for example FL150 at SOPIT that then removes the previous restriction of FL200 at TOBID. Not a lot of RW pilots are aware of that, but I have checked it is the case with the ATC instructors at London ATCC.

One thing to watch out for though if doing that and getting low on the profile is to check for minimum altitudes on each leg of the star which may be published on the chart, these tend to be there for terrain, nav aid reception or airspace reasons and must be adhered to, eg 11500T for terrain.

Although most RNAV STARS nowadays tend to have these minimum heights hard coded in the procedure by a gates at waypoints eg 13000B 10000A, giving a degree of flexibility on the height the waypoint is passed ,allowing descent below the FMC calculated path for energy management, but remaining above minimum terrain heights.

11 hours ago, SierraHotel said:

 "The Fenix does a decent job making constraints, but it does have a tendency to dive to meet them.  I hope the next update alleviates that.  The PMDG is better in some ways, but the LNAV is so ridiculous.  So one could say the Fenix handles LNAV beautifully and not so much VNAV, whereas the PMDG does VNAV good much it rather poor at LNAV.😕"

Sorry, but I completely disagree with this statement. I fly both the Fenix and the PMDG every day and they "both" perform beautifully with both L and VNAV.

I think in the Fenix is depends on the cost index as to whether it dives too much to meet restrictions.  But it does do this sometimes.  And for sure the PMDG is awful in turns.  It twitches all over the place as if it's being hand-flown.  So, unless you know of a way to fix this, it's a problem that continues to happen despite the last update supposedly addressing it.  What I mean is, it'll bank 25 degrees, then start to level out then bank again during a turn.  The Fenix makes one sweeping turn that is precise and accurate, not the PMDG.

 

Stearmandriver posted this on the PMDG forums.  He flew, or still flys, 737s.  I'm not the only one who see problems in that plane.

Quote

- the aircraft still can't use ARINC 424 data / can't fly RF legs. The LNAV 2.0 is an improvement to the pseudo-waypoint approach, but not correct. The aircraft still deviates from its computed lateral track, re-calculations still occur at each pseudo-waypoint, and the roll mode flight guidance bangs from side to side.
- VNAV is similarly sloppy. It routinely overspeeds a climb speed in VNAV SPD, and it routinely blows a level-off by several hundred feet.
- selected lateral mode routinely drops and must be re-selected during a missed approach.

 

Edited October 16, 20232 yr by Orlaam