47 minutes ago, Christopher Low said:

Should the 737NG be capable of that?

Highly doubt it without the use of spoilers.

Yes, flaps 40 is draggy, but the 737-600 has a similar empty weight as an A318, which needs 30° speed brakes deflection on final into EGLC.

 

12 hours ago, ahsmatt7 said:

The speed brakes when deployed in flight do absolutely nothing. Zilch, nada.

Very strange. Whenever 'More Drag' on the PFD or 'Drag Reqd' in the box appears, there's always a response in both the 737 and A32x when I pull the speed brakes lever.

Go to as close to vanilla as possible in your sim to see if an add-on is causing a conflict?

Speed brake use on a 737 is prohibited beyond flaps 10.  You sure wouldn't be riding speed brakes with approach flaps. 

I've never tried a 5.5 degree glide path but I suspect a light -600 at flaps 40 could do it.  Flaps 40 is an AWFUL lot of drag; speed brakes would be a minor extra amount in comparison.

I had no idea that speed brakes were not used beyond a certain flap setting. My descent on the 5.5 degree glide slope was at a flaps setting of 30, and a weight of 50 tons (no passengers or cargo, but two thirds fuel load). Don't ask me why I do it like that 😉

If you're using a speedbrake axis, there is likely some sort of calibration disconnect. Test it clean - with the axis disabled and yoink the lever in the VC and see if that is different to your current experience. 

48 minutes ago, Christopher Low said:

I had no idea that speed brakes were not used beyond a certain flap setting. My descent on the 5.5 degree glide slope was at a flaps setting of 30, and a weight of 50 tons (no passengers or cargo, but two thirds fuel load). Don't ask me why I do it like that 😉

Well, you know, I state that definitively, but I've learned more than once from flight sim communities that things I think are absolutes about my airplane aren't *always* absolutes ;).  So now I'm curious - does anyone fly 737s into there?  Can we find a video?  If spoilers are up it would be visible...

50 minutes ago, Aamir said:

If you're using a speedbrake axis, there is likely some sort of calibration disconnect. Test it clean - with the axis disabled and yoink the lever in the VC and see if that is different to your current experience. 

And I'm sure that Fenix modelled the difference in max speedbrake deflection with AP on/off? This also catches people out in their understanding and comparisons.

Edited October 25, 20241 yr by G MIDY

19 minutes ago, Stearmandriver said:

So now I'm curious - does anyone fly 737s into there?

No, there was never any certification of the 737 into EGLC.

A318, Avro RJ/BAe146, CS100/A220-100, Do328JET, ERJ and E-Jets are the only permitted jet airliners.

1 hour ago, Stearmandriver said:

Well, you know, I state that definitively, but I've learned more than once from flight sim communities that things I think are absolutes about my airplane aren't *always* absolutes ;).  So now I'm curious - does anyone fly 737s into there?  Can we find a video?  If spoilers are up it would be visible...

No, 737s are not certified for London City in the real world, but I fly my virtual 737 into any airport that has a runway long enough

Edited October 25, 20241 yr by Christopher Low

6 hours ago, Christopher Low said:

test the 5.5 degree glideslope into EGLC London City with my PMDG 737-600... not only can I get it to hold the 128 knots final approach speed @ 50 tons landing weight, but I can do it without using the speedbrakes at all. Should the 737NG be capable of that? After all, it is not (to the best of my knowledge) rated for landings at this airport.

Just because it's not certified, doesn't mean it's impossible - just no one had the need to pay out for that certification. Flap 40 is very draggy so I'm not surprised and it is likely possible IRL albeit maybe not within certification criteria, as being certified for the 5.5 deg glidepath means actually being capable of a steeper descent to counteract deviations from the glidepath.

Use of wing speedbrakes/spoilers during approach is a big no-no unless the aircraft is suitably certified - the A318 deploys them during steep approach through use of a special switch that changes the flight control logic and EGPWS, and retracts the spoilers automatically. Same goes for the E-jets. Both typres required some minor adaptions to earn certification.

Edited October 25, 20241 yr by ckyliu

Last year when flying into Bergen Norway for reals on a KLM 738 we came in rather steep.  The spoilers came out very early and they stayed up the entire approach.  The sensation of slowing down was not there but at least we did not speed up.  It was not until around 10000 feet that the pilots leveled off and we actually started to slow down.  The spoilers stayed up until the flaps started going down.  The 737NG's are a slippery airplane and I think PMDG got it mostly right.  A tiny bit more of spoiler drag would not hurt and I think iFly nailed it a bit better on the MAX they created since you can descend and slow down a tiny bit.  On the PMDG 737NG unless you are descending at less than 1500 FPM you are not slowing down even with the spoilers up.     

Back in the old days this used to be an easy thing to adjust either in the air file or the aircraft.cfg file but I have no idea if it can be done in FS2020?

The funny thing that I noticed for years is that a lot of simmers have an off opinion on speed brake effectiveness. Contrary to popular beliefs, they are effective. Now, I have come across some folk who spare the boards for passenger comfort😏. The thing about speed brakes is that they are noisy and cause a lot of vibration. They bite into the air like nobody's business and cause a ton of drag. If you rip them out, the aircraft jolts and pitches with a sudden loud noise and vibrations. Yes, they will grab a passengers attention that way. When I was a young pup, an old guy said "Using the boards is like sneaking out and back into bed without your spouse knowing. You ease them out and then you ease them back in".

Also, when you need them, you use them early. The earlier you use them, the less you will need. You have to stay ahead of the jet and know when they may be needed. Challenging arrivals and slam dunks are the main ones that will get you. If you are at that point where you have called for the descent and the delay starts, slow down. I don't go too wild with passenger comfort because a passenger knows a plane does what a plane does. If I need the boards, they are coming out. When I flew DC10s, I could use the boards up to flaps 5 before the trade off. In the Gulfstream, I can have them out up to flaps 20. That's real nice because of some of the places you fly into, you can get slam dunked and fight your way through it.

Here are some ideas of effectiveness from a couple of jets, these can be found in the training manual: 777-200

310kts/.84 2300 per minute clean 5500 with speedbrake

250 1400 per minute clean 3500 with speedbrake

Clean min man 1100 per minute clean 2400 with speedbrake

In the DC10, we had the rule 150:

Idle Thrust - 300 feet per NM
Speed Brakes - 150 feet per NM
Landing Gear - 150 feet per NM
Slats - 150 feet per NM

2 hours ago, G MIDY said:

And I'm sure that Fenix modelled the difference in max speedbrake deflection with AP on/off? This also catches people out in their understanding and comparisons.

Yep!

6 hours ago, Aamir said:

If you're using a speedbrake axis, there is likely some sort of calibration disconnect. Test it clean - with the axis disabled and yoink the lever in the VC and see if that is different to your current experience. 

I don’t actually have an axis programmed but I do have switches being used on my thrust lever set up.

 Does the keyboard binding have any negative effect as well? 
 

I will say that I use the keyboard button (/) predominantly over my calibrated joystick button. 
 

I’ll try that this weekend on my trip. I use a laptop at work and I wonder if the problem persists on the laptop considering I use the Xbox controller and no other controllers. On the contrary, my home set up uses the HOTAS warthog.

5 hours ago, G550flyer said:

I need the boards, they are coming out.

Amen.  Precise flight path management always takes priority.  Plus, after commuting to the old job for 15 years, riding in back twice a week, I can confidently say that pax absolutely do not care about things such as speed brakes or early gear extension etc.  They're watching their movies, they're sleeping, chatting... Doing anything except paying attention to the airplane.  I used to find it hilarious when I flew with someone who got themselves all twisted up trying to solve a high and fast without brakes because of concerns for the pax... Who absolutely could not care less 😁.

12 hours ago, G MIDY said:

 

A common use for these fast and short descents is if the approach isn't speed limited and the excess can be bled off very late with the speed brakes. This is really good for fuel consumption as almost the entire approach can be conducted at IDLE but it's a terrible idea for restrictive and controlled approaches.

This is not correct although it might seem that it should be.
A descent at a higher Cost Index, or manually entered descent speed, just means that the aircraft is spending longer in the cruise phase than in the idle descent phase. The extra fuel burnt will equate to the fuel used in the cruise between the calculated TOD of the higher CI (or manually entered high speed) and the calculated TOD of the lower CI (or manually entered slower speed). The FMS will calculate an idle descent path for both cases. The higher speed descent will take less time, but the fuel saved is minimal as it is a saving at the idle fuel flow rate versus the extra time spent in the cruise at cruise speed Fuel flow rate.