Gate Number problem (Not in database)

[RobnaBav 1]

I'm stll learning but have stumbled with Gate No on the fmc.

No matter what I try the result is: Not in database

[pcubine 143]

I'm stll learning but have stumbled with Gate No on the fmc.

No matter what I try the result is: Not in database

Only some airports, primarily European, have their gate numbers in the database. Just skip the gate number entry in the FMC. If you leave the gate number empty you will not receive the message about not being in the database.

[fnav77 56]

Don't worry about the gate number, it is not necessary to get the FMC set up.

[rondon9898 84]

As Michael says, this is pretty common. I get it at EHAM, for example. Just use your aerodrome charts for the correct lat/long and insert that rather than inserting stand number, or cheat and use Shift+Z :wink:

[RobnaBav 1]

Thanks everyone for prompt info!  I had been using the Lat/Lon approach but was not sure if I was doing the right thing. It's a shame about gate numbers though....

[Jet Tech 31]

There's actually an easier more accurate solution.  Select the GPS position from the Init Ref page and load that into the scratchpad and then load it into the INIT boxes and you have a very accurate position.  If your concerned about it's accuracy,  check the gate plot on the chart.

[downscc 1,327]

 

 

It's a shame about gate numbers though....

 

Gate number location data is provided by the sidstar file, from Navigraph or whomever you use as a navdata supplier. Not much PMDG can do about this.  Paul has the easiest solution.

[scandinavian13 5,192]

This was really only relevant prior to GPS inclusion in the FMS. Before that, it was best to use some known position like a gate to ensure a good init position was provided. Now we have GPS, which is going to be just as precise.

[rondon9898 84]

Sorry to reiterate Kyle but is that standard procedure in Boeing aircraft with GPS - to insert the GPS position and then presumably crosscheck it with the position shown on the chart? Just out of interest

[scandinavian13 5,192]

Sorry to reiterate Kyle but is that standard procedure in Boeing aircraft with GPS - to insert the GPS position and then presumably crosscheck it with the position shown on the chart? Just out of interest

 

Depends on the operator. I'm sure there are some operators that follow the "this is how we've always done it" mantra. Now, there are multiple layers of cross checking going on, to the level where I wouldn't expend too much effort cross checking things.

 

To put this in perspective, UAL operates a mixed fleet of 757s, and some of them do not have GPS at all (they're DME/DME/IRU). Knowing that, how might one expect they get the initial position into the system? Either hand entering it from a gate marker (you can see them just to the right of A08, here), a chart, or pulling it out of the gate function. (UAL may have retired these aircraft by now, but I know that they were still being used as late as 2012.)

 

The aircraft simulated by the NGX is clearly GPS capable. As such, you have a direct interface to highly accurate information without having to dig through databases, or charts. You could even punch in the airport code alone and compare that position with the GPS position on PAGE 2/2 of the INIT POS page and see that it's close enough. Keep in mind that the aircraft will then poll both GPS units, along with ground references continuously throughout the flight to keep an accurate position.

 

Have a look at the POS REF page in flight and watch as the positions slightly differ, even between the two GPS units, and two IRUs. With a constellation of 24 satellites, the absolute lowest number of satellites you'd theoretically see is 6, which is above the 4 needed for a 3D position, and double the requirement for a simple, deduced 2D correlation (what that page is getting you). Now that we have a 30 satellite constellation (32, technically, but one is in reserve and one is still being commissioned), you're generally going to have higher accuracy through seeing more satellites simultaneously, at all times.

 

In the days of Concorde, setting a good initial position was an imperative. The rest of your flight depended on a good initial position, though DME/DME updates helped. Now, GPS alone can be used for certain approaches (uncorrected by WAAS, even), so while I understand a little bit of cross checking by the crew, I don't find it wholly necessary. Pulling in the airport alone will do the trick for getting a good known position to compare against the GPS position.

 

As a final note of perspective, the FAA ran a study for three calendar months back in 2014, finding that the 95% error of your GPS position (horizontal) was less than a quarter the width of your NGX's horizontal stabilizer, though the mode was somewhere around 0.8, or the distance between the inner and outer wheels on one of your main landing gear. This same report also noted that the worst possible theoretical location never saw fewer than 7 satellites. So, it might be a good comfort metric, but with a system that reliable, the gate function is superfluous.

[rondon9898 84]

Great response, Kyle, and an extremely impressive demonstration of satellite knowledge B)

 

It would be my first instinct to do it the fuddy duddy way, so punch it in from the aerodrome chart/stand sign and then crosscheck with GPS and that's the way I've been doing it ever since I first flew the NGX (and later the 777), because it feels more belt and braces but while that kind of crosschecking was vital on the old INS you'd see on the Concorde, 742 etc. you've convinced me that it probably isn't neccessary now.

 

BTW, if anyone has real-world experience of FMS position setting in the Boeings, would still be interesting to see how a certain airline approaches it.

[downscc 1,327]

 

 

As a final note of perspective, the FAA ran a study for three calendar months back in 2014, finding that the 95% error of your GPS position (horizontal) was less than a quarter the width of your NGX's horizontal stabilizer, though the mode was somewhere around 0.8, or the distance between the inner and outer wheels on one of your main landing gear. This same report also noted that the worst possible theoretical location never saw fewer than 7 satellites. So, it might be a good comfort metric, but with a system that reliable, the gate function is superfluous.

 

I recall that early sometime in the Clinton administration the military turned off a level of dithering in the constellation that was intended to purposely increase position error, which of course military receivers were designed to work around and gain full design precision.  This was due to the overwhelming need by many business needs and not just aviation, think for example engineers and surveyors. To my knowledge that dithering is still turned off but there is no guarantee that this will remain as such.  Do be surprised to find your GPS (without WAAS) precision suddenly drop to 30 m CPE or more if the military deems it necessary.

[scandinavian13 5,192]

I recall that early sometime in the Clinton administration the military turned off a level of dithering in the constellation that was intended to purposely increase position error, which of course military receivers were designed to work around and gain full design precision.  This was due to the overwhelming need by many business needs and not just aviation, think for example engineers and surveyors. To my knowledge that dithering is still turned off but there is no guarantee that this will remain as such.  Do be surprised to find your GPS (without WAAS) precision suddenly drop to 30 m CPE or more if the military deems it necessary.

 

I was going to add this in, actually, but figured I wouldn't add that level of complexity. I wouldn't expect it to be sudden, but it's good to keep an eye on things just in case. The gov here is notoriously bad at communicating between branches, though surprisingly the DoD and FAA are usually pretty good at it. It helps that they both work at the ATCSCC out in Vint Hill.

[downscc 1,327]

 

 

though surprisingly the DoD and FAA are usually pretty good at it

 

During my stint as a ground communications officer, I had several GCA's colocated in FAA TRACONs such as Offutt AFB. The local facility here at Corpus pretty much counts 90% of it's traffic as Navy. So yeah, I think the FAA and Military have many good working relationships. Never had a complaint on the local level. All very professional.

[RobnaBav 1]

I have had better luck with Heathrow EGLL and W.Europe.  I remain impressed by the level and quality of replies...

 

One handy reason for retaing gate numbers is that readily short and understood positions, in the event of a fire say, can be communicated to lay persons in an emergency. This is despite the fact the 99% of the population now own a mobile phone with all the attendant geometric and astrometric accoutrements. It is not easy to stop and enter details in the heat of the moment but "Go to gate B60!" is more easily understood and signposted. In other words: sound semiotic sense and reason.

(Er, not very concise but I'm sure everyone can see my point.)