I'm learning how to auto-land the 738 to runway ILS 10R. There are lots of errors shown in this YouTube video for sure. What did I miss?  How come I can't get both CMD-A and CMD-B to work concurrently for auto-landing ? Should I have pressed the VOR/LOC and APP button at some point, and when?  

I created the IFR low-altitude route in this video: San Francisco, KSFO (28R).OSI.SAPID.SANTY.ZEBED.MINCK.RWY10R at KMRY Monterey Regional airport. I know that the 737 is not used for this route in real life since it's real short but having fun is the name of the game here.

Jump to the 7:15 minute mark to quickly view the approach to ZEBED (the IAF). All constructive feedback and negative comments welcome also! 🙂
 

 

 

Edited February 5, 20251 yr by anavsun
Added tags.

I just skimmed the video and I note you ended up in FAC and GP for lateral and vertical modes.  Look at your Flight Mode Annunciator (FMA) along the top of your PFD (the display with the artificial horizon) to see what modes you're in. 

For an ILS approach and therefore for an autoland, you need to be in LOC and GS, for localizer and glideslope.  You were in Final Approach Course and Glidepath.  This is indicative of an IAN approach.  IAN mode is an option on 737s that almost no operators have in reality, because it's just a dumbed-down and limited way to fly a non-precision approach.  Most airlines use LNAV/VNAV for this because it's much more capable.  PMDG however, has decreed that your 737 shall have IAN installed with no way to deselect it. 

So in the PMDG, if you press Approach before you're receiving valid localizer AND glideslope indications, you'll end up with some flavor of IAN armed, and that means no autoland.  Watch the localizer and glideslope scales to see either white or magenta diamonds (NOT carats or pointers, but diamonds) indicating valid localizer and glide slope reception, THEN arm approach and you should end up in LOC and GS.

Summary of autoland requirements:

1.  Tune the ILS frequency on both nav radios (the 73 will not tune anything for you. 

2.  Set the inbound course in both MCP course windows.

3.  When receiving valid localizer and glideslope indications (DIAMONDS), press Approach.

4.  When in approach mode (LOC and GS annunciations), autothrottles on, select the second autopilot and it should engage.

Very helpful info. IAN is a new term for me and I did look it up after you mentioned it. Since IAN also has both lateral and vertical guidance I still don't understand how it is a simplified version of ILS. Exactly what makes it different from ILS.

I was not looking at the FMA, so I have to make a habit of that. The same thing with the "diamonds" indication. I have to look out for that too.  I did tune the ILS frequency (even before I took off and I did set the inbound course beforehand). What I really missed big time was looking out for your #3 above. Also, checking what caused the Master Caution alert among other things. 

Thank you.

Found a video which explains the difference between the IAN and the ILS:

 

I've learned something new today ! 

Thx ! 

Same here, thanks Stearman. The difference in when to press the APP button on the Boeing and the Airbus has always wondered me. I think its a little more forgiving in the Airbus, meaning you can arm it a little earlier than normal without the aircraft taking any sudden short corners, which has happened to me in the Boeing. The above makes more sense with the LOC and ILS needing to be "in range" for the 737.

1 hour ago, anavsun said:

Found a video which explains the difference between the IAN and the ILS:

Watch his tutorial playlist on the 737 https://youtube.com/playlist?list=PLtFw-RsDhI85SH4R18hrswGV39hebQIyy&feature=shared

12 hours ago, flyingscampi said:

Watch his tutorial playlist on the 737 https://youtube.com/playlist?list=PLtFw-RsDhI85SH4R18hrswGV39hebQIyy&feature=shared

Wow, 132 videos. Feels like it'll take a year to really learn them all.  Study level is an understatement. It's hard to imagine how much time he spent producing these videos. Thank you.

 

10 hours ago, anavsun said:

Wow, 132 videos. Feels like it'll take a year to really learn them all.  Study level is an understatement. It's hard to imagine how much time he spent producing these videos. Thank you.

 

I've watched almost all of them, some of them several times. Learning as much as I can about how a complex aircraft (model) works is one of the pleasures I get from simming 🙂

On 2/6/2025 at 6:03 AM, anavsun said:

Since IAN also has both lateral and vertical guidance I still don't understand how it is a simplified version of ILS. Exactly what makes it different from ILS.

The essential difference is that with ILS you have a "precision" approach meaning, relevantly, that the aeroplane knows where it is thanks to EXTERNAL sources (radio waves beamed from the ground) whereas with a "non-precision" approach it has to CALCULATE where it is based on a mixture of data and assumptions. With the increased accuracy and reliability of GPS, the importance of this difference is diminishing but for the acutely sensitive operation of actually landing the thing, only a true "precision" approach is deemed suitable for widespread use.

Edited February 7, 20251 yr by tfm

A recommendation with approaches if you're still learning how they work is to jump into a trainer like 172, tune the nav radio to the ils and set course to the chart approach course. Then fly a 5 mile circuit and see visually what happens with the horizontal and vertical indicators on your instruments when you are getting lined up onto approach. Flying manually by hand at 70 knots is a much easier way to see what your aircraft needs to do than at 180 knots on your heavy and fast jet!

Once you GET how it works you can try slightly larger ac with autopilot and get it to follow the glideslope down to 200ft then take over yourself (presuming you can see the runway look up minimums on chart lol). 

The first time you get an ac autopilot to lock on the localiser (horizontal) and then the glideslope (vertical) it's a magical sim moment. 

By learning in a jet you're learning to sprint before learning to walk and run. Certainly doable but it's extra stress and panic for sure! 

When you press APP and the ac starts descending below the mcp set altitude you know you've done something right. Except you'll be too busy managing your approach speed /flaps /gear /spoiler to pat yourself on the back yet! 

Like the others have said- This is what i do IRL as a 737 pilot and as per Boeing FCTM

1) frequencies - SET them on both sides - Look at your PFD for the ident in the top left and corner under the FMA box.

2) set courses on both sides

3) set your auto brake

4) VREF speed as flap 40 and wind additive as needed (max 15 knots)

5) set your MINIMA but as radio minimums not BARO minimums

6) Auto land is normally flap 40

once your localizer is alive press VOR/LOC on the MCP panel. Once captured your Middle FMA box Will say VOR/LOC in bright green and maybe LNAV in white underneath it which means your missed approach route tracking is armed incase of a go around.

Once captured on the localizer arm the APP mode on the MCP and engage CMD A/B as required. Remember the 2nd A/P has to be armed before 800ft AGL otherwise after that the airplane wont accept another A/P engagement hence we engage it right after app is armed.

At 500 ft with the G/S captured and descending. were looking to be stable with Flare armed on the FMA. at some point on the PFD the aircraft will do a self check and start flashing the localizer and glideslope, that's totally normal.

Flaps 40 normally for a Autoland so we cycle through flap 25 then 40 as needed.

at 50ft RA were looking for flare to become active on the PFD and 27ft RA the FMA should say RETARD as the throttle start moving towards idle. If you don't disconnect the throttles it will automatically disconnect after 2 seconds. 

 

hope this helps- Any question ill be happy to answer.

55 minutes ago, Bilal2104 said:

Like the others have said- This is what i do IRL as a 737 pilot and as per Boeing FCTM....

.......once your localizer is alive press VOR/LOC on the MCP panel. Once captured your Middle FMA box Will say VOR/LOC in bright green and maybe LNAV in white underneath it which means your missed approach route tracking is armed incase of a go around....

Once captured on the localizer arm the APP mode on the MCP......

That is interesting. I always pressed VOR/LOC first on the MCP panel, and then APP when VOR/LOC mode had engaged. However, I was then told to not bother pressing the VOR/LOC button, and just press APP instead. You seem to be saying that the first method is the correct one, since it is "as per Boeing FCTM".

As most people are aware, I fly the PMDG Boeing 737-600.

9 hours ago, Bilal2104 said:

4) VREF speed as flap 40 and wind additive as needed (max 15 knots)

Wind additive on an autoland is always +5kts regardless of wind for us, since the autothrottles remain engaged to touchdown.  I know that's a Boeing recommendation as well.  Does your operator add standard wind additives for an autoland?  Have they ever said why they opt to do so?  I'm always interested in hearing why companies make the operational decisions they do. 

8 hours ago, Christopher Low said:

That is interesting. I always pressed VOR/LOC first on the MCP panel, and then APP when VOR/LOC mode had engaged. However, I was then told to not bother pressing the VOR/LOC button, and just press APP instead. You seem to be saying that the first method is the correct one, since it is "as per Boeing FCTM".

I've seen this repeated often in the sim world (VOR/loc first, then Approach) and I've always wondered where it comes from.  I've never flown for, nor talked to friends who fly for, an airline at which this is standard.  There's no harm in it, but seemingly no point either.  And yet, it's a common enough trope in the sim world that it seems likely to be coming from somewhere; makes me wonder if there are places in the world for which this is standard.  Something else I'd be interested to hear. 

Our philosophy is simple: use VOR/loc when you want to track the localizer only.  When you're cleared for the approach (meaning you want to track both loc and glideslope), use Approach.  Why one and then the other, if cleared for the approach?

7 hours ago, Stearmandriver said:

I've seen this repeated often in the sim world (VOR/loc first, then Approach) and I've always wondered where it comes from.  I've never flown for, nor talked to friends who fly for, an airline at which this is standard.  There's no harm in it, but seemingly no point either.  And yet, it's a common enough trope in the sim world that it seems likely to be coming from somewhere; makes me wonder if there are places in the world for which this is standard.  Something else I'd be interested to hear. 

Our philosophy is simple: use VOR/loc when you want to track the localizer only.  When you're cleared for the approach (meaning you want to track both loc and glideslope), use Approach.  Why one and then the other, if cleared for the approach?

....and yet Bilal2104 is saying exactly that, and he states that he is a real world 737 pilot??