KLGA Star problem/s

[Guest stang]

Hi Don. Sure. Address is in the "Read This First" file, 737NG@hotpop.com.RegardsTerry

[Guest pagotan]

Hi Terry, >>Just how would this waypoint altitude restriction show up on an airline's FMC?<

[pipper 0]

Hi Don, Terry and Michael:Once again my thanks for your help with this thread......I greatly appreciate your help and this GREAT conversation. Terry....I double checked my information and re downloaded a current FAA MIP.3 STAR (dated 23 Dec 2004) # 04050, and the crossing altitude for BEUTY is 10000 feet. Specifically, the instructions state "Expect to cross (BEUTY) at 10000 feet. The STAR also states for MARRC to be crossed AT FL180, and VIBES to be crossed AT 13000. The plates do not have any reference at all for "at or above" altitudes and 10000 feet must be considered a "hard" crossing altitude. There appears therefore to be a discrepancy between sources of information regarding this STAR. I guess I thought/think that the document I named above was the prima facto source. As Don and I had stated, the issue I originally had was that if I followed the FMC STAR as is currently written, I would most likely cross it at around 8000 feet and doing so would violate my alt restriction. To date I had just been manually editing the LEGS page of the STAR during a flight, and thats when I noticed the "issue" with this STAR. Yesterday I went and explored the latest AIRAC nav data info and just manually edited the MIP.3 STAR but have yet to try it out. I plugged in the above hard altitude restrictions so I just have to see how it goes. Terry, it is amazing the amount of information you provide to the sim community......just awesome. It is greatly appreciated too! Without guys like you this sim just wouldn't be the same. Thanks once again......Joe Swier

[Guest stang]

Hi Michael and all. >What do you think should be the best approach? to make the >simmer's life easy and have the altitude hard coded or to >stay as close as possible to the real world definitionsI tend to lean toward the real world approach as that is what the 737NG is all about, simulating as close as possible the real aircraft and it's operation. With this particular KLGA example I tend to lean towards taking the approach that "Expect to Cross At" instructions are discretionary not mandatory, unless someone can point me to a document that stipulates it is mandatory. And using your Jeppesen description it would mean that the Expect to Cross At 10000 foot waypoint modifier would not show up in an electronic database so the pilot would have to punch it into the FMC manually in any case. As for the AT and ABOVE 8000, that came from a real world source and I do see the 8000 printed on the chart. In this example I am thinking I should leave it as it is for the reasons above.However, for those that want it hard coded anyway, all you have to do is open the KLGA.TXT file and change the fix "... FIX BEUTY AT OR ABOVE 8000 ..." to read "... FIX BEUTY 10000 ...". Further information about writing SIDs/STARs/IAPs and some troubleshooting hints are in my tutorial at http://home.sw.rr.com/filesherenow/index.html.>Terry, if you are interested I have a copy of the entire directive >from Jeppesen there are many other "exception" listed.Sure. I think it would be interesting reading and good backup material. Thanks.RegardsTerry

[Guest pagotan]

Hi,OK, if we take the "real world" approach for this simulation then we should albeit by the real world rules/constaints. As I explained earlier and substantiated with a document from Jeppesen which by the has been approved by the FAA, neither the "Expect to cross at" nor the MEAs "Minimum enroute altitudes" should be hard coded in the procedures. It remains at the pilot's discretion to punch the altitudes following instructions he may or may not receive from ATC.So here if we follow the Jeppesen document and the real world onboard database structure all references to MEA's and Expect to cross should be deleted from all procedures not only KLGA. Terry it's really up to you since you are the only one having access to the routines. But as far as I am concerned the fix BEUTY in our specific example should nor have any altitude or constrain attached to it (neither 10,000 nor 8,000).Document from Jeppesen is on its way to you. You will be amazed by the number of items which are not included in the real world onboard database. If you were to implement only half of the exclusions the writing of procedures for PMDG would be done in a second but sim-pilots may find it over-stressing to have to punch in ATCs instructions. Michael

[Guest pagotan]

Hi Ryan,That is an interesting statement. I would assume that UAL codes the "expect to cross at" altitude as guidance only pending ATC clearance. Probably UAL has issued some internal directives to that effect in order to not contradict with established rules.Here are two more exerts from the interpretation of the "expect to cross at" phraseology:Clearance to "descend via" authorizes a pilot's discretion descent to comply with published altitude and/or speed crossing restrictions. "Expect" altitudes/speeds are not considered STAR/FMSP crossing restrictions until verbally issued by ATC. They should be used only for planning purposes and should not be used in the event of lost communications, unless ATC has specifically advised the pilot to expect these altitudes/speeds as part of a further clearance. Source: NATCA ATC briefingandIn addition to the verbal transmissions of what pilots may expect, there are also visual "transmissions" placed on charts for planning purposes. Standard Terminal Arrivals (STARs) and Standard Instrument Departures (SIDs) very often include expected altitudes, expected course guidance, expected speeds, etc. Here again, remember that the printing of those expect values on the charts does not constitute an ATC clearance to descend, climb, turn, etc. If the chart says expect, the pilot still needs a specific clearance from the controller before the action is authorized. However, when the altitudes, routes, speeds, etc., are printed without the word expect, they are mandatory. Profile descent procedures contain good examples of these mandatory crossing altitudes and tracks to be flown, and do not seem to cause nearly as many problems as do the STARs and SIDs. Probably the STARs/SIDs are more often confused because they may contain both mandatory and expect values.Source: ASRS directivesMichael

[roundy 0]

I would guess the "Expect" altitudes are placed on an STAR because ATC issues those altitudes a great majority of the time, maybe as high as 90%. There may be occassions when a different altitudes are assigned (pilot request, slower traffic on the STAR, etc.) but I would bet that the assigned altitude would be higher, rather than lower, than 10,000. I just did some flight plan checking and it looks like the MIP STAR is a heavily used route from ORD with aircraft entering the STAR from over Keating (ETG).What we need is for someone to go to Chicage, buy a ticket on UAL to LGA, tune in Channel 9 on the Inflight Entertainment System, and take notes. I'd go myself but it looks much to cold in the east for this California boy. :-sun1 Don

[Guest pagotan]

Hi Terry,Have you had a chance to read through the material I sent you? if yes what are your conclusions? If you decide to implement some or all of the exceptions listed please let this community know as more and more simmers are writing procedures. Sofar the manuals to write procedures have focused on syntax rather than on what should be included and what should not. When I look at user written procedures we start to see substantial deviations from the on-board database in real FMCs (not due to PMDG syntax limitations but rather to interpretation of paper charts). Michael

[Guest stang]

Hi there Michael. >Have you had a chance to read through the material I sent you? >if yes what are your conclusions? I have finally read through the Jeppesen definitions. First I have to put that document in perspective. It is only a paper that was presented to a seminar back in Apr 2001. This to me says that it is not regulatory and just explains how Jeppesen creates databases and the problems of conversion between the paper product and an electronic database. It even said that some of the ways they do things may change in the future, so nothing said was set in concrete for Jeppesen. The paper was good though at pointing out the problems of creating an electronic database but it also said that various database supplies may do things differently. This opens up the arena for more interpretations. I ask questions to airline pilots from time to time about what is in the FMC database. It seems it is not consistent because airlines can order how they want the database. It would seem that one database will not please everyone even if it accurately mimics a real airline database.In the final analysis I like what Jeppesen said, "Because of the incomplete set of path terminators in some avionics systems, pilots need to ensure their avionics systems will take them on the routes depicted on the charts. If the avionics systems don

[Guest pagotan]

Hi Terry,> I have finally read through the Jeppesen definitions. First I have >to put that document in perspective. It is only a paper that was >presented to a seminar back in Apr 2001. This to me says that it is >not regulatory and just explains how Jeppesen creates databases and >the problems of conversion between the paper product and an >electronic database.Fair enough. Here is a link to the ASRS site with an interesting interpretation especially the paragraph "Expect-ations"http://asrs.arc.nasa.gov/directline_issues/dl4_expect.htmand another one from NATCA where the paragraph 4-5-7 "Altitudes" is worth readinghttp://nwp.natca.net/Administration/Docume...RF.HTM#P0405007This however reamins theoratical in view of the many interpretations by different airlines. Therefore it may be sufficient to list a few reliable documents on this or your sites for writers of procedures. I guess the point is to try to have a common ground for the writers so that users do not get confused when comparing the FMC loaded procedures with paper charts.Michael

[Guest tmetzinger]

This issue just came up during a recent FAA safety seminar, under the discussion of "being cleared for an arrival, and then losing comms".The gist of the guidance we got was that the minimum altitudes for each segment were the lowest ones available to us, and unless we were told to cross a certain fix at a certain altitude, the "expect to cross" guidance on the chart was NOT a limitation. A "cross XXX at yyy" marking on the chart IS a limitation.Based on that, I'd agree with the consensus here that the DAFIF file puts in the minimum altitude for each segment unless a specific crossing restriction is specified, and that's how it should be. (it does this for the approach procedures too in many cases). The pilot is responsible for modifying the FMC restrictions in accordance with ATC instructions, or by just setting the MCP altitude to the appropriate setting.