Sign in to follow this  
Guest kappes

Small bugs in PFD of 737NG during takeoff?

Recommended Posts

Dear PMDG team,first I have to say that I'm very satisfied with your 737NG. I really like its complexity and much enjoy the flights with it. However, I think I have discovered two small issues during takeoff and it would be great if they could be repaired in a future patch or the 800/900 upgrade. I looked for related topics on this forum but couldn't find anything. I have the latest patch (version 1.3) installed and I'm using FS9.The first thing are the flap minimum maneuvering-speed (FMMS) bugs. For takeoff I select Flaps 15, turn on the FDs, arm the autothrottle and press TO/GO. Reaching the flap retraction height all FMMS bugs (15, 10, 5, 2, 1) are there and when selecting flaps 10 FMMS bug 15 is removed as expected. However, when I now select flaps 5 not only FMMS bug 10 vanishes but also those for 5 and 2 (1 is still visible). After selecting flaps 2 the bug for 2 suddenly reappears and now everything is correct for the rest of the flap retraction schedule. This seems not correct to me. Is anyone else observing this?The second issue is related to the pitch mode during takeoff. Reaching the flap retraction height the pitch mode correctly shows TO/GA. Then I select N1 as thrust mode (I'm not turning on the autopilot) and set the MCP SPD to flaps-up speed. According to my knowledge, the pitch mode in the PFD should now change from TO/GA to MCP SPD as the autopilot computer commands a pitch to reach the new speed set in the MCP. The latter is also obviously done as selecting pitch according to the FD accelerates the plane till it reaches the MCP speed.Best regards Alexander Kappes

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Hi there,If you didn't know yet, flaps 2 are skipt on the B737.So its logical that flaps 5 and 2 are not showen on the PFD. (with flaps 5 takeoff)Ramon

Share this post


Link to post
Share on other sites

Dear AlexanderDon't try to find bugs we already have smashed! ;-) Just kiddin'Regarding your two findings. They are exactly what you could expect from the NG. The flap bugs behaviour is correct according to the real NG pilots we have in the beta team. And as Ramon just mentioned the reason why you don't see the flaps 2 bug is because you always go from flaps 5 to 1 and clean.As per your other issue I had to make a short flight to find out what was wrong. You are just missing one small thing while climbing out. Selecting N1 tells the auto throttle to keep the N1 fed from the FMC. Roll mode is still wings level (standard TO/GA mode). You are selecting a new speed in the speed window. So far so good. But you have not commanded the A/P to any pitch mode. You have to select either VNAV, LVL CHG, or V/S to tell the auto pilot to change it's current TO/GA pitch mode (which is to keep V2+20). In your case you should select LVL CHG. With that selected the FMA will show FMC SPD as current pitch mode.Oh, and a flaps 15 take off? Are you trying to take off from your back yard? :-) Usually if you have enough runway you take off with flaps 1. Shorter length is flaps 5 and very rarely you can do a flaps 10 departure.Hope it helps,

Share this post


Link to post
Share on other sites

Dear Ramon and Mats,thanks for the fast answers. The flaps 2 issue sounds logical to me. But why does the flaps 5 bug vanish if I go from 10 to 5 if 5 is a standard flap setting in the retraction schedule for takeoff? B.t.w., actually I have my 737 parked in the garage and as the other side of road is not far away I have to take flaps 15 for takeoff. Concerning the pitch mode issue I have to admit that I would never have wondered about it if I didn't had the chance to play around with a computer based training course for the 737NG from Boeing. According to this source the flight mode annunciation should change from TO/GA to MCP SPD if you tune in a new speed on the MCP after takeoff (I suppose it makes no difference but in my original post I didn't mention that I press HDG as roll mode at 400 AGL). Best regards and happy flying Alexander

Share this post


Link to post
Share on other sites

Alexander,The pitch mode behaviour could be operator dependent then, I guess. But I'm out of a good answer! :-)Cheers,

Share this post


Link to post
Share on other sites

"Concerning the pitch mode issue I have to admit that I would never have wondered about it if I didn't had the chance to play around with a computer based training course for the 737NG from Boeing."Do you still have access to this training course, Alexander?Does one click of the knob produce a 20 kt increase... or a 21kt increase (as in PMDG). Also, my manuals are telling me that the N1 button on the MCP should be illuminated in VNAV (during climb) and in LVL CHG (Climb). I'm not getting this in PMDG.Options?Thanks.Cheers.Ian.

Share this post


Link to post
Share on other sites

Dear Ian,yes, you are right concerning the N1 button on the MCP. According to the training manual it should illuminate if VNAV or LVL CHG for climbing are pressed. The other issue I cannot check with this training course, sorry.Cheers Alexander

Share this post


Link to post
Share on other sites

Hi Mats,hmm, operator dependend pitch mode behaviour sounds a little bit odd to me. Do you know any opinion of a real-world 737NG pilot (I suppose you had some on the Beta team)?Coming back to the flaps issue. After looking into the documentation again I think the correct behaviour should be that for takeoff flaps setting you see the next two flap speeds from the retraction schedule, e.g. using takeoff flaps 15 means that you see flaps 5 and 1 speeds, using takeoff flaps 5 means you only see flaps 1. This is correctly displayed in the PMDG 737. If you start the flap retraction schedule I think you should always see the current flap speed plus the next two speeds. Starting with flaps 15 you select flaps 5 at the flaps retraction height. Now the speed tape should show flaps 5 and flaps 1 maneuvering speeds, however on the PMDG 737 the flaps 5 bug is missing. Indeed, this bug is necessary as according to the 737 manual you should go to the next flaps setting if the maneuvering speed limit of the current flaps setting, i.e. flaps 5, is reached. Cheers Alexander

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this