Cannot Engage Approach or LOC

[chiozza 0]

I keep having issues where the LOC or the APP will not engage. It seems to be sporadic. On another flight last night into SEA it happened again. I have attached pics to show. Any help would be appreciated. ILS is tuned and it is a valid ILS.

 

https://www.evernote.com/l/AAfK_zXmJPRD_pDc1_H1ksQC7vpvYYV6aus

 

[vonmar 123]

Which approach at SEA is it?

 

What is your initial LOC intercept altitude set to?

 

How far out are you?

[777simmer 117]

I keep having issues where the LOC or the APP will not engage. It seems to be sporadic. On another flight last night into SEA it happened again. I have attached pics to show. Any help would be appreciated. ILS is tuned and it is a valid ILS.

 

https://www.evernote.com/l/AAfK_zXmJPRD_pDc1_H1ksQC7vpvYYV6aus

would it not be easier to continue this in the previous thread you opened about this?

 

http://forum.avsim.net/topic/464785-no-loc-or-apr/

 

You have not ARMED the APP mode, so it cant engage!

[downscc 1,327]

Neither LOC nor APP will activate if the signal is not received.  Wait until you see an indication on the PFD that the LOC/GS bugs are ON before pressing the LOC or APP buttons.

[Mike777 163]

 

 

I keep having issues where the LOC or the APP will not engage. It seems to be sporadic. On another flight last night into SEA it happened again. I have attached pics to show. Any help would be appreciated. ILS is tuned and it is a valid ILS.

 

Hi, Chris,

 

As far as I can see, you do not have an ILS or localizer tuned -- as Dan is suggesting.  There would be pips visible on the ND (the ones that are visible are from LNAV & VNAV).  Also, as Rob said, neither the localizer nor the approach is armed -- you would see white "loc" under LNAV and white "GS" under V/S.  So either you did not press either button, or if you did, it did not arm because you weren't receiving a localizer or GS signal.  

 

You need to open up the map in FSX, click on the airport, and see what runways and what frequencies are showing there.  Then check them against the frequency and course autotuned on the NAV/RAD page of the CDU.

 

KSEA has changed since FSX came out.  If you only have the stock scenery, the western-most runway will be missing and the frequencies will not correspond to what is in the FMC's database. 

 

Remember to sign your name in PMDG forums.

 

Mike

[chiozza 0]

I will check that tonight and report back.

[chiozza 0]

I did a flight into OAK 29 and the FMC set the ILS to 108.7 which is correct and the flight was flawless. On the RAD/NAV button it showed 108.7, do I have to click the LSK next to 108.7 to activate? See link below

 

https://www.evernote.com/l/AAewvJJkrl9KxJUno-kbJcLTrMoaWHXyoFE

[Mike777 163]

 

 

I did a flight into OAK 29 and the FMC set the ILS to 108.7 which is correct and the flight was flawless. On the RAD/NAV button it showed 108.7, do I have to click the LSK next to 108.7 to activate? See link below

 

Hi, Chris,

 

Everything looks good, except for the "M" next to the ILS frequency.  It's better to let the FMC autotune the frequency according to the runway you selected, although you should check it against the chart for that runway.  In FSX you want to check it against the frequency set in the scenery, especially if the scenery is old.  Airports that come to mind where runways, and most likely frequencies, have changed since FSX was made are:  KORD, KIAD, KATL, KSEA (as you may have found out!).  There are many, many others, and it's best to make sure you have an updated AFCAD for airports you use frequently.

 

But the "M" means that you manually tuned the frequency, probably  by clicking on the LSK key next to it.  To answer your question, there is no need to click to set the ILS frequency; the FMC does it automatically.  The danger in manually tuning is that, if ATC instructed you to switch runways or you decided to do it yourself, you would still have the wrong frequency tuned.  At airports with parallel runways, such as KSFO, KLAX, KIAD, KATL, KJFK, KSEA, etc., this easily could lead you to land on the wrong runway.  It's better to leave the FMC to autotune -- you  can go back to autotuning by clicking delete and then the LSK next to the ILS frequency. 

 

Two other points: 1) you are fast, given that you are perhaps 3-1/2 miles from touchdown.  You can see that you are on the GS, but still descending at 1200 ft/min.  This is high, and due to excessive speed.  You could still slow down in time but it's better to be @ 180 or less by the final approach fix (last waypoint before runway, typically @ 5 miles out). By this point the MCP speed window should be at the landing target speed (yours is set to 175).   The 777 doesn't slow down very quickly -- it's "slippery."  2) I'm not sure whether you have the go-around target altitude selected in your Altitude window on the MCP (showing on upper right of PFD, 2500).  I don't have time to check the chart right now (you can also tell by checking the go-around highest altitude after the runway on the LEGS page of the CDU), but it's something to keep in mind.

 

Did you ever figure out what went wrong at KSEA? 

 

Mike

[chiozza 0]

Mike,

 

Thanks very much for the feedback. Yes, I was fast as I was monitoring the ILS and the potential frequency issue. As far as the KSEA issue I think it was the frequency issue. Thanks again for all the information. Great Help!

 

Chris

Not should what happened but the link above is not working, re-shared:

 

https://www.evernote.com/l/AAewvJJkrl9KxJUno-kbJcLTrMoaWHXyoFE