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KORDATC

Difficult Approach Into SFO

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So, was just trying to replicate my real-world flight from ORD-SFO in the new QOTS II.  I was flying the DYAMD3 arrival into SFO just like the tutorial.  However, instead of choosing 28R, I flew the ILS into RWY28L as we did in real life.  I know it doesn't look challenging, but I had to end up going around because of an unstabilized approach.  After realizing I wasn't going to be at 1800 by the FAF, I kicked it into VS mode to try and make it but I couldn't get it down in time.  By the time I got to the FAF, I was way too high and struggling to get down.  I know that the 747 fmc doesn't shallow out the descent path for slowing to VAPP, and I slowed down using speed intervene extremely early too.  I think part of the problem with this particular approach is that all of the waypoints on the extended RWY centerline with the exception of the FAF are listed as soft altitude restrictions, as in /3100A.  Even after slowing down early, she just couldn't make it down.  I think next time while doing this approach, I will try creating a hard altitude restriction at each of these waypoints.  Maybe that would help.  Anyways, for anyone looking to challenge themselves, please try flying this approach into SFO with the Queen.  Make sure you use RWY28L instead of the approach to RWY28R.

 

 

 

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So, was just trying to replicate my real-world flight from ORD-SFO in the new QOTS II. I was flying the DYAMD3 arrival into SFO just like the tutorial. However, instead of choosing 28R, I flew the ILS into RWY28L as we did in real life. I know it doesn't look challenging, but I had to end up going around because of an unstabilized approach. After realizing I wasn't going to be at 1800 by the FAF, I kicked it into VS mode to try and make it but I couldn't get it down in time. By the time I got to the FAF, I was way too high and struggling to get down. I know that the 747 fmc doesn't shallow out the descent path for slowing to VAPP, and I slowed down using speed intervene extremely early too. I think part of the problem with this particular approach is that all of the waypoints on the extended RWY centerline with the exception of the FAF are listed as soft altitude restrictions, as in /3100A. Even after slowing down early, she just couldn't make it down. I think next time while doing this approach, I will try creating a hard altitude restriction at each of these waypoints. Maybe that would help. Anyways, for anyone looking to challenge themselves, please try flying this approach into SFO with the Queen. Make sure you use RWY28L instead of the approach to RWY28R.

Did that exact same thing today. I didnt have the priblems you had though. First flight with the airplane. The biggest advice I can tell you is to use V/S. mode to have more control over your descent as your coming into the bay area.

 

Also, get flaps out early, don't be afraid to on this arrival. 180 knots is a pretty comfortable speed to be at when you get on final. I would say be around 200 as you're coming through 6000 to 5000 and start slowing to 180 around 4000. This shoukd set you up nicely to be able to slow down and still be able to keep a good descent on final.

 

 

Disclaimer: I don't have the arrival In front of me do I can only give you altitudes and not fixes for speed guidance.

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Yeah definitely using VS earlier on for this one. Cause with VNAV, all of the waypoints except the very last one are soft restrictions. This is fine and all, but the FAF is a hard restriction of 1800'. The one right before it is a soft restriction of 3100' So with the soft restrictions I was over 900' higher than 3100 when crossing it. It was just impossible to get down to 1800. Will try again tomorrow morning though using vs.

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@KORDATC - just curious, did you not perhaps have a bit of tailwind pushing you as well during the descent?   I find that that is the greatest difficulty in steeper approaches sometimes.   That and of course, if you look at the last 777 crash there at SFO, most real world pilots did comment that it was a bit of a steep approach and you have to be ahead of the aircraft a bit.   I have not flown this approach in years so at the moment, I am completely unfamiliar with it :-).

 

Alas, you have thrown down the gauntlet to us simmers so now I wil HAVE to go and fly it today hahaha.

 

Regards

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Hello,

In the simulator I use V/S mode and manually setting the airspeed and not using VNAV mode when descending. I have more control during the approach especially can get the aircraft around 180-200kts before entering approach segments.

The Queen glides like a piano so it is quite easier to slow down when we are fast and/or high. Hand fly so beautiful and I like it more than T7.

Will do Taipei - San Francisco today and try the 28L approach.
Cheers.
Hoang Le

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Even after slowing down early...

 

Higher speeds give steeper descent angles. Try slowing down later, and hopefully you'll get a better result.

 

 

Glad you didn't select FLCH ...

 

Why wouldn't you use FLCH?

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If you were using real world weather last night, I don't think the 28 runways were in use. I know they were departing on 10 L/R, so likely arriving on 19 L/R. I'm sure the tailwind didn't help.

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OK here is some advice

 

1. Open the SPD window and descend to next altitude in VNAV SPD (before hitting the first APP waypoint) or in VNAV PTH (after hitting the first APP waypoint) with speedbrakes extended.

 

2. Use flaps. Flaps 10 and higher add a lot of drag to the plane.

 

3. Extend gear early in addition to speedbrakes and flaps 10 if you have to "dive". They add even more drag!

 

4. Use the speed REST(riction) ALT(itude) line (LSK 4L in VNAV DES page) and add something like 170/3000. You can add/edit/delete anything you want there. Point is that the FMC will plan a deceleration segment automatically to meet this speed requirement and adjust the entire path.

 

4. Using VS for prolonged periods is not very good technique...better leave it for low tech aircraft models or 1000 ft descends from altitude to altitude.

 

Best,

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