Thrust/Speed Issues during ILS Approach

[bobsk8]

AFAIK the FMC ref landing speed is already with +5 knots in mind. So you don't need to add 5. If FMC shows for instance 30/145 dial 145 on MCP. PMDG AT is pretty laggy.


Sincerely yours
Clifford Sherman

That is not correct, you have to add 5 knots.

[brianprice6]

Hello Brian, Hello all.

I have absolutely indentical issue on approach and short final with mine B738.

Before reinstalling the AC and the FlightSim, I suggest you to pay attention to the previous post in this thread. Namely regarding simulation of gust wind and max weight of your craft.

I have experienced this problem between between flaps 15 and further decrease to 30 or 40. Ususally it happenes when I have alsmost maximum landind weight and facing some gusty head or cross wind. At this moment yellow floor is get up and down / up and down , and when it hits my current speed - I recieve low speed alert.

If you get your payload from simbrief OFP, I assume that 90% of flights your craft is at its maximum operational weight. In this case, on approach and short final try to keep your speed around 10 knots higher of your usuall entry, so you will have more gap to the alert. Also, first decrease your flaps, then decrease your speed, when you see that yellow bar is going down, and your speed is not about to hit it.

I am new to B738, but I think that higher weight of the aircraft assume that you should have certain speed margin.

Please correct me if I am wrong.

In my case, I usually have around 180 knots at 10NM with flap 5, then 160 knots at 4 NM initiating flaps 15 and gears down and scroll my speed down on MCP. With this speed and landing configuration I get "low speed alert" quite often. In this case I have almost maximum allowed landing weight.

So, what I do is keep 170 - 175 knots at 5NM with flaps 5 or 10, then initiating flaps 15 gear down keeping the same speed. When flaps set 15 and three greens I initiate flaps 30 or 40, wait a couple of seconds, see that yellow floor is going down, then decrease your speed to Vref + 5/10 knots. Doing this I have no speed alerts.

Thanks for the information on this. I did test a number of times with reasonable landing weights and various combos of flaps, speed etc. Nothing worked. I deleted all my cloud information for all aircraft, and have been rebuilding all my settings and testing mappings etc. So far I've spent a number of days on that and have several major issues. So I can't even get the aircraft to operate correctly even on the ground, much less flying and approaches. If I can get all these issues squared away I will attempt flying again and repost. I suspect I will have the same issue but its worth at least one try. If I can't get it done - abandon the PMDG aircraft and move on to flying something else. I'm tired of fighting this aircraft with this simulator. And the PMDG Operation Center is non-functional. Says it can't connect to the server.

[Want2BFlyin]

What version is your Operation Center?

[brianprice6]

I just updated it using instructions on the website and it's working now. Thanks. Now back to the other five issues I have. Aarrggg/

[brianprice6]

Yes thanks everyone - my landing weight was fine, flaps, speed etc. I opened up a ticket with support and they told me the only thing that might work is to delete the MSFS cloud information. All configurations, profiles, controller mappings, all the configurations for all aircrafts. Needless to say with who knows how many aircraft and five controllers this was a daunting task. It's taken me several weeks working off and on to reconfigure everything, but now it's working as it should. No Alpha Floor at 165 kts or whatever, and I have a normal ILS approach and landing. Finally after three months this is fixed. Of course no idea what caused the problem in the first place. Something in the MSFS PMDG interface. Hope it doesn't happen again. cause I'm not going through this process again. Wish me luck. And thanks again.

[Want2BFlyin]

Glad to hear that it's working again for you. Unfortunately, in the flight sim world there are never any guarantees that once something starts working, it will keep working. For example, I installed xEnviro 2020 recently because I had read some good reviews about it. Well, it turns out that installing xEnviro messed up the file that has FSUIPC start automatically when I launch Microsoft Flight Simulator. Which, of course, meant that everything that requires FSUIPC suddenly wasn't working. That led to a couple of frustrating hours trying to figure out why FSUIPC wasn't working before I realized that it simply wasn't starting, then another hour or so to figure out why it wasn't starting and that I needed to hand-edit the file that xEnviro broke to get it working again. These things do happen in the flight sim world, and you just have to learn to roll with the punches.

[brianprice6]

Glad to hear that it's working again for you. Unfortunately, in the flight sim world there are never any guarantees that once something starts working, it will keep working. For example, I installed xEnviro 2020 recently because I had read some good reviews about it. Well, it turns out that installing xEnviro messed up the file that has FSUIPC start automatically when I launch Microsoft Flight Simulator. Which, of course, meant that everything that requires FSUIPC suddenly wasn't working. That led to a couple of frustrating hours trying to figure out why FSUIPC wasn't working before I realized that it simply wasn't starting, then another hour or so to figure out why it wasn't starting and that I needed to hand-edit the file that xEnviro broke to get it working again. These things do happen in the flight sim world, and you just have to learn to roll with the punches.

Absolutely. Been doing this for a number of years with various problems to solve, but this one has been going on for months, with lots of support contact, probably 20-30 hours spent solving this over several weeks. MSFS does not have a way to export various configuration profiles, including controller mappings. Thus recreating everything for every aircraft and all graphic and other settings. I've had many issues with both XP and MSFS - this one takes the cake!

[Captain Kevin]

Glad to hear that it's working again for you. Unfortunately, in the flight sim world there are never any guarantees that once something starts working, it will keep working. For example, I installed xEnviro 2020 recently because I had read some good reviews about it. Well, it turns out that installing xEnviro messed up the file that has FSUIPC start automatically when I launch Microsoft Flight Simulator. Which, of course, meant that everything that requires FSUIPC suddenly wasn't working. That led to a couple of frustrating hours trying to figure out why FSUIPC wasn't working before I realized that it simply wasn't starting, then another hour or so to figure out why it wasn't starting and that I needed to hand-edit the file that xEnviro broke to get it working again. These things do happen in the flight sim world, and you just have to learn to roll with the punches.

Yeah, have to love it. Had an issue with P3D crashing when flying around the Boston area, and the culprit appears to be a scenery for Bogota. Figure that one out.

[brianprice6]

Yeah, have to love it. Had an issue with P3D crashing when flying around the Boston area, and the culprit appears to be a scenery for Bogota. Figure that one out.

Ouch. How would you even that out. Seems pretty random.

[Paulyg123]

On the same issue: I need help here.
It seems like the MAX speed at FLAP 40 is sooo close to Vref +5 that is it impossible to maintain that narrow speed. I fI go over, the flaps start to automatically retract (Is that a real 74=37 thing anyway of the flaps retracting if over-speed/). Then the wind speeds are all over the place and I get the AIR SPED low on many approaches. Even if yoy make a pitch correction the yellow speed tape races up to and catches you and you get a AIR SPEED LOW waring.

So 1;
Should I land at FLAP 30 to resolve this?
2 is auto flap retraction real on a 737 for over speed? and if yes, will it auto deploy when I slow down???

[Want2BFlyin]

On the same issue: I need help here.
It seems like the MAX speed at FLAP 40 is sooo close to Vref +5 that is it impossible to maintain that narrow speed. I fI go over, the flaps start to automatically retract (Is that a real 74=37 thing anyway of the flaps retracting if over-speed/). Then the wind speeds are all over the place and I get the AIR SPED low on many approaches. Even if yoy make a pitch correction the yellow speed tape races up to and catches you and you get a AIR SPEED LOW waring.

So 1;
Should I land at FLAP 30 to resolve this?
2 is auto flap retraction real on a 737 for over speed? and if yes, will it auto deploy when I slow down???

Flaps 30 is the default landing flaps setting for the 737. You would typically only use flaps 40 on a steeper-than-normal approach or when landing on a shorter runway.

And yes, the 737 has flap overspeed protection for flaps 40. If you go above the protected speed the flaps will automatically retract to 30, and I believe they will extend back to 40 when you are back below the protected speed.

[Captain Kevin]

Ouch. How would you even that out. Seems pretty random.

Quite simple, actually. Install Bogota scenery, fly around the Boston area, have P3D crash three times in the same general area, remove Bogota scenery, fly around the Boston area, everything is fine again. Seeing as I've flown New York to Boston a lot without issue, the fact that I suddenly had issues right after I installed that scenery was the clue.

[mariodingenen]

The problem does not seem to be solved,
I have the same problems.
Glideslope taken , flaps 15 gear down , then decelerate to flaps 30 and suddenly speed to low warnings , and the plane itself starts acceleration and climbs . Very annoying , I took this to a real B737-800 pilot and gave a whiff along with him and he says this is a bug .
Has anyone found a solution in the meantime? If so , may I also know ?
Thank you .
Regards.

[frieteboer]

Flaps 30 is the default landing flaps setting for the 737. .

Is that regardless of weight??

Danny Vincken.

[Want2BFlyin]

Is that regardless of weight??

Danny Vincken.

Hi Danny,

Yes. Flaps 40 is typically only used for short runways, and flaps 15 is only used for single-engine approaches. The flap setting won't change due to weight, but the VREF speed will. Higher weights will result in a higher VREF speed, and vice versa.