737 FMC "Reset MCP Alt" Message

[Flaps30 3]

I thought I had the 737 FMC down pretty well, but while flying up the Florida coast at 4000 feet, I keep getting a FMC chime and a "reset MCP altitude" message and I don't know why. I am at 4000 feet and have the legs - VKZ AR1 BLUFI COMET ATHOL OMN KIZER ORL KMCO set. I also have a hold set at ATHOL at 200 knots, 7 mile legs, and at 4000 ft, my current alt. On my way to COMET, I get the chime and message, but on the Legs page each fix from COMET until the descent point has 4000 set as the altitude. The descent point is past OMN. My MCP is also set to 4000. Every time I try and reengage VNAV I get the same message. I enter 3500 in the MCP window just to see what happens and I am able to reconnect VNAV, but upon reaching my hold at ATHOL, I get another chime and a "VNAV Disconnect" message. It won't let me reengage. I thought the "reset" message only comes on to remind you to reset if a descent is coming up upon reaching the next waypoint, and the MCP window doesn't have a lower altitude entered. I made sure each leg in the legs page does not have a lower altitude set for several more fixes. What am I missing??? Thanks. Tom

[veldthui 0]

Its telling you that you need to reset your altitude to the correct value for the upcoming descent. Sounds like you have hard set altitudes in the legs page and the VNAV wants to try and get them but because you have a higher or lower altitude set it cant do it so disconnects.What I do on a descent if I am not given a altitude is to set the level down to what I will pick the localiser/gs up and let the FMC do all the work. If I am set a target by ATC then I follow that and will get the same result. A disconnect.John Veldthuishttp://www.virtualpilots.org/signatures/vpa475.png

[Guest jumbojock]

Also, check CRZ page of VNAV. What is your cruising alt set to? What modes are displayed on the PFD? As above, what hard altitudes are selected on your FMC?David "jumbojock" Robertson

[Holclo 3]

> I thought I had the 737 FMC down pretty well, but while>flying up the Florida coast at 4000 feet, I keep getting a FMC>chime and a "reset MCP altitude" message and I don't know why.>I am at 4000 feet and have the legs - VKZ AR1 BLUFI COMET>ATHOL OMN KIZER ORL KMCO set. I also have a hold set at ATHOL>at 200 knots, 7 mile legs, and at 4000 ft, my current alt. On>my way to COMET, I get the chime and message, but on the Legs>page each fix from COMET until the descent point has 4000 set>as the altitude. The descent point is past OMN. My MCP is also>set to 4000. Every time I try and reengage VNAV I get the same>message. I enter 3500 in the MCP window just to see what>happens and I am able to reconnect VNAV, but upon reaching my>hold at ATHOL, I get another chime and a "VNAV Disconnect">message. It won't let me reengage. > I thought the "reset" message only comes on to remind you>to reset if a descent is coming up upon reaching the next>waypoint, and the MCP window doesn't have a lower altitude>entered. I made sure each leg in the legs page does not have a>lower altitude set for several more fixes. What am I>missing??? Thanks. TomSorry I can't be any help on your question but may I ask how do you set up the PMDG to get a "chime" when a new FMC message arrives. I am building a home cockpit and unless I have the FMC continually open and watch the scratchpad I do not know when a message appears. Sorry again I hope this doesn't divert any attention from your questionBill

[dave_paige 11]

From the description of your flight it sounds like your doing flight 4 from Tim Metzinger's Advanced Tutorial for the PMDG. If so, and if you have everything set as described in the tutorial you should not be getting that message.The message is telling you that the FMC would like to proceed to a different altitude but the MCP is preventing it because the the MCP has priorty over the FMC.My guess is, like others have said, that you have a cruise altitude other than 4000ft set one the perf init page of the FMC.

[Flaps30 3]

Thanks for the help, guys. Dave, you are right - I am following TM's tutorial #4. I reflew it and my Perf Init. page is correctly set at 4000. All legs through to ORL are initially set to 250/4000. It seems the problem is when I enter the hold at ATHOL and the speed to 200 per the tutorial, it changes the altitudes to 2300 after Ormond Beach. On this latest flight, as I enter the hold is when VNAV disconnects. By the way, is the speed in the upper right corner of the hold page for just the hold or the other legs as well? When I changed this to 200 it also changed speeds for other waypoints on the legs page. Thanks. Tom

[dave_paige 11]

I don't remember having any trouble with that flight but I'll try it again, been meaning to anyway. I'll see if I have any trouble this time.

[Flaps30 3]

Hi Dave, Just flew the whole lesson again and this time it went beautifully. I made one change though, and it seemed to do the trick. In the tutorial, after Tim gives the go ahead to do some sithtseeing off of Cape Canaveral, I immediately set up the hold even though it was a good 100 miles away and before BLUFI. This time, I waited until after I passed BLUFI on the leg between BLUFI and COMET. This time, no reset warnings at all. VNAV stays on all the way through the hold. Seems that when I change the speed at the hold to 200, the FMC changes all the other legs speeds as well including those past the hold. I would then change it back to 250 since I didn't want to go up the coast at only 200 knots. I think it also altered the descent profile from 4000 if I remember correctly. This must be why it wanted me to reset and start down. I guess you shouldn't set up the hold too soon before entering it? Thanks again. Tom