Hey Devs/Testers,

 

I am more of a 74'/737NG guru so the T7 has me stumped on a few things.

 

I am reading through the Honeywell FMS manual (for Block Point 15), in particular about holding patterns. In the 737, I know the FMC will calculate what entry is required (Direct, Parallel, Teardrop [Or Sector1, 2, 3 for those of you who use that terminology]), however in the NG it will not display the actual entry procedure into the hold on the ND.

 

So my question regarding the T7, is the entry procedure shown on the ND?

 

According to the manual; When the map range is 80 NM or less and the holding entry segment is the active leg or the next active leg, the holding pattern entry is displayed on the ND. The holding pattern entry is removed from display when the holding pattern entry segment is sequenced and the holding pattern is the active leg.

 

If it is displayed, does it looks similar to this image of a parallel entry (Which I love doing when my turn to join the outbound leg on the ILS procedure is >30deg and a hold over the IAF is required).

 

 

 

Did the bus do all of that for you?  It hasn't here.  

We will have to wait and see when the 777LRX comes out

Did the bus do all of that for you?  It hasn't here.  

We will have to wait and see when the 777LRX comes out

I am not too sure on the Airbus... Thing with Airbus is there are two FMGS available (Honeywell and Thales), and therefore modelling the numerous options offered by the two is quite difficult (just like modelling the different software revisions of the NG FMC is a pain in the a$$).

 

However IIRC the Thales manual correct (rev 3A+), I do not believe the Airbus draws the entry procedure into the hold on the ND (Although our good Irish friend Ronan could help us out B) ).

Airbus doesn't draw the entry procedure, that I have seen (A3xx/330/340). A380 and A350 might, but they are completely different avionics.

 

That parallel entry doesn't look right. It should cross the fix, then literally fly parallel to the inbound track on the outside of the hold. The turn in should then start outside the inbound turn of the hold, crossing the inbound turn as it turns back in to join the inbound track to the fix.

 

If the aircraft flies it as drawn in your sketch, it's not flying it correctly.

 

Best regards,

Robin.

Airbus doesn't draw the entry procedure, that I have seen (A3xx/330/340). A380 and A350 might, but they are completely different avionics.

 

That parallel entry doesn't look right. It should cross the fix, then literally fly parallel to the inbound track on the outside of the hold. The turn in should then start outside the inbound turn of the hold, crossing the inbound turn as it turns back in to join the inbound track to the fix.

 

If the aircraft flies it as drawn in your sketch, it's not flying it correctly.

 

Best regards,

Robin.

Hi Robin,

 

As per the manual;

 

"Parallel entries are constructed with a leg parallel to the inbound course and a 180deg turn towards the holding fix, as shown in the picture. After the turn, LNAV captures the inbound course. The length of the parallel leg is 2.41 times the turn radius. The crosstrack distance of the leg is determined by LNAV control using course angle error and groundspeed when the hold fix is crossed."

 

If I was doing it in my 172, I would fly through and commence the outbound parallel track on the 'dead' side of the hold, however I pulled this straight out of the manual so this is just what Honeywell are publishing and I assume what the T7 is displaying (if it does happen to display the entry hold procedure).

 

 

If the aircraft flies it as drawn in your sketch, it's not flying it correctly.

Technically since the outbound track is still parallel to the original/planned/published inbound heading, it can still be called a parallel entry. The diagram for a teardrop entry in the manual is also a little sketchy.

 

EDIT: There is also a note saying "To permit construction of a continuos entry path, the hold entry leg parallel to the inbound course may be extended by the FMS as needed to permit the aircraft to cross the holding fix inbound."

 

This would indicate in some circumstances the aircraft flying through/past the navaid and thence commencing the parallel (downwind) track to enter the hold.

Hmm.... would have thought they would have been more careful.

 

Best regards,

Robin.

 

 

So my question regarding the T7, is the entry procedure shown on the ND?

 

It'll do it, but it won't show it, no.

That parallel entry doesn't look right. It should cross the fix, then literally fly parallel to the inbound track on the outside of the hold. The turn in should then start outside the inbound turn of the hold, crossing the inbound turn as it turns back in to join the inbound track to the fix.

 

If the aircraft flies it as drawn in your sketch, it's not flying it correctly.

 

Best regards,

Robin.

Does it really matter? The whole maneuver is at safe side, therefore no safety risk at all.

Does it really matter? The whole maneuver is at safe side, therefore no safety risk at all.

As I said, theoretically the figure in my original post is still a parallel entry.

 

However most pilots, and all my theory CPL books show diagrams/examples of the plan flying completely through the holding fix and commencing the downwind/parallel leg on the 'dead' side. As long as you have ensured no other traffic is at the same level holding at the same fix (either by assurance from ATC, CTAF call, or by other means), the whole area around the hold should be free for you to play with.

 

It'll do it, but it won't show it, no.

Thanks Kyle.

 

Unless one of the devs come along and makes a comment, I will just assume the wording in the manual is wrong (As I have all my trust in the dev team that they have it spot on.. Unfortunately I am yet to get a ride on a CAE sim like I have had with the NG/74' where I could check it out :ph34r: ).

Yes actually, it does matter, because the real thing should be getting it right, and the drawings should be accurate to what the aircraft will do in reality.

 

As per the drawing in the OP, it makes it look like the aircraft will turn early, then fly the inbound track but in the opposite direction, which is entirely wrong. You should cross the fix (overfly), then turn to parallel (hence the name of the procedure - parallel entry).

 

Best regards,

Robin.

 

 

Unless one of the devs come along and makes a comment, I will just assume the wording in the manual is wrong (As I have all my trust in the dev team that they have it spot on.. Unfortunately I am yet to get a ride on a CAE sim like I have had with the NG/74' where I could check it out ).

 

I really need to throw a disclaimer in my posts to be sure people don't take it as the official word, but I don't recall seeing it.  I'll have another look tonight.  I think I had my map range higher than 80, so that may have been why.  What it ended up flying looked very similar to that picture, above, though.

I really need to throw a disclaimer in my posts to be sure people don't take it as the official word, but I don't recall seeing it.  I'll have another look tonight.  I think I had my map range higher than 80, so that may have been why.  What it ended up flying looked very similar to that picture, above, though.

You already have one over at the VATSIM forum so why not here (even if they are different in nature) :lol:

 

Nah seriously, no dramas...I am not going to loose any sleep over it (if I ever get to sleep, at this rate I won't be).

Yes actually, it does matter, because the real thing should be getting it right, and the drawings should be accurate to what the aircraft will do in reality.

 

As per the drawing in the OP, it makes it look like the aircraft will turn early, then fly the inbound track but in the opposite direction, which is entirely wrong. You should cross the fix (overfly), then turn to parallel (hence the name of the procedure - parallel entry).

 

Best regards,

Robin.

Entirely wrong? Don't you think that's a little bit exaggerated? Do you know what's behind design of holding entries? 

Yes actually, it does matter, because the real thing should be getting it right, and the drawings should be accurate to what the aircraft will do in reality.

 

As per the drawing in the OP, it makes it look like the aircraft will turn early, then fly the inbound track but in the opposite direction, which is entirely wrong. You should cross the fix (overfly), then turn to parallel (hence the name of the procedure - parallel entry).

 

Best regards,

Robin.

Ok, last post before I got sleep.

 

I just had a quick swizz over the FCOM and found some additional information regarding holding. In particular this statement;

 

For all holding entry types, lateral guidance directs the airplane to fly-by or fly-over the holding fix and to remain on the holding side of the inbound holding course.

 

As you can see from what I have bolded, the FMC's lateral guidance bounds the aircraft to remain on the holding side of the inbound holding course, which corresponds to the picture. While this may be different to what you to do in a conventional hold in a 172, I assume it may have something to do with RNP holding and to meet the requirements of such holding.

 

In regards to my OP, and in addition to the reference in the Honeywell FMS manual, the FCOM also states: The holding entry path displays on the ND.

 

I look forward to your seeing you pic when I am enjoying my breakfast, Kyle (Just kidding mate, take as long as you want to get back to me.. I really need to try and stay of this place lol!).

 

 

Yes actually, it does matter, because the real thing should be getting it right, and the drawings should be accurate to what the aircraft will do in reality.

 

Ehhhh...yes and no.

 

You're right that it wouldn't fit the explicit definition of the term, and it goes against what many are taught.  While even the FAA publications depict it on a course parallel to and opposite the inbound leg, there's no real metric of how parallel you should be.

 

In the end, though, it doesn't quite matter in cases where you're in radar coverage, as controllers will be protecting that airspace.  Where it does certainly matter is when the procedure is not in radar coverage, which is the case with many smaller fields (that you really wouldn't put a 73 or 77 into anyway) in more mountainous terrain.  It would be smart to offset the course to be sure you don't conflict with someone else flying the hold already at the same altitude, though the likelihood that's going to happen is rather slim.  It's made even more slim by the fact that as a 73, you're going to be IFR and under ATC direction, into an airport where the hold likely also be in the radar service volume.

 

...always remember that some of these procedures were initially written when ATC was a dude standing on the ground with flags:

 

 

You already have one over at the VATSIM forum so why not here (even if they are different in nature)

 

True.  I might get around to it.