Problems with VNAV ALT and aircraft not responding to new altitude setting.

[virge 1]

I recently flew tutorial one, from Gatwick airport "EGKK" to Schiphol airport " EHAM ", and I was not able to change the altitude from 5000 to 6000. I think i followed the directions correctly. Here is how tried to do it. To get out of VNAV ALT mode, which was displayed on the in the FMA pitch mode box, I turned the MCP ALTITUDE knob up to 6000 as required, and then I pressed (clicked the on the click spot ) for the ALT INTV button, but nothing  happened. The aircraft did not respond, and continued to maintin the 5000 foot level that had been previously set. In order to change the altitude, I had to use the V/S knob by setting a rate of climb in order to get to 6000. Does anyone know why this feature seems not to work. Thank you in advance.

[scandinavian13 5,192]

 

 

Does anyone know why this feature seems not to work.

 

Was there a 5000' restriction on the LEGS page somewhere?

[MrPlaneDriver 41]

Was there a 5000' restriction on the LEGS page somewhere?

 

He had the altitude knob set at 6000 and pressed the ALT INTV button, so it should have cleared the 5000ft restriction, if there was one.

 

I recently flew tutorial one, from Gatwick airport "EGKK" to Schiphol airport " EHAM ", and I was not able to change the altitude from 5000 to 6000. I think i followed the directions correctly. Here is how tried to do it. To get out of VNAV ALT mode, which was displayed on the in the FMA pitch mode box, I turned the MCP ALTITUDE knob up to 6000 as required, and then I pressed (clicked the on the click spot ) for the ALT INTV button, but nothing  happened. The aircraft did not respond, and continued to maintin the 5000 foot level that had been previously set. In order to change the altitude, I had to use the V/S knob by setting a rate of climb in order to get to 6000. Does anyone know why this feature seems not to work. Thank you in advance.

 

If the ALT INTV button don't work, try pressing the VNAV button twice (once to desengage and again to reengage VNAV). That usually does the trick.

[virge 1]

Was there a 5000' restriction on the LEGS page somewhere?

No. I had just come out of a restriction, which was the 5000 feet. The FMA pitch mode box was displaying VNAV ALT. The next setting was an iincrease in altitude to 6000 feet, which i was not able to activate.

He had the altitude knob set at 6000 and pressed the ALT INTV button, so it should have cleared the 5000ft restriction, if there was one.

 

 

If the ALT INTV button don't work, try pressing the VNAV button twice (once to desengage and again to reengage VNAV). That usually does the trick.

Is this a known issue that sometimes happens? Also is this the usual way aroung this glitch? Thanks for a solution. I hope it works. Thanks.

He had the altitude knob set at 6000 and pressed the ALT INTV button, so it should have cleared the 5000ft restriction, if there was one.

 

 

If the ALT INTV button don't work, try pressing the VNAV button twice (once to desengage and again to reengage VNAV). That usually does the trick.

I noticed that you have Topcat, and Active sky 2012, and I was wondering if these programs work from within FSX or not. What I mean, do these programs seem to have a negative effect on FSX as it realated to overall performance, such FPS? There is another program being developed by the company that made Topcat, which is very close to release. This other program with Topcat will in my opinion, will be very helpful for simmers.

[MrPlaneDriver 41]

Is this a known issue that sometimes happens? Also is this the usual way aroung this glitch?

 

I don't know. Maybe it has something to do with conditions you must meet with in order for this procedure to work that your airplane, for some reason, wasn't complying with. I know that, in order to delete an altitude restriction using ALT INTV, the altitude bug must be set above the restriction, but I don't know if the non-existance of restrictions between your current altitude and the altitude set in the MCP will prevent the VNAV from commanding the airplane to climb.

 

I noticed that you have Topcat, and Active sky 2012, and I was wondering if these programs work from within FSX or not. What I mean, do these programs seem to have a negative effect on FSX as it realated to overall performance, such FPS? There is another program being developed by the company that made Topcat, which is very close to release. This other program with Topcat will in my opinion, will be very helpful for simmers.

 

I have a low end computer (old CPU and weak GPU) and none of these programs make any difference on the way my sim performs. TOPCAT is a tool used outside of FSX, so it has no impact whatsoever in performace. Active Sky, on the other hand, actually changes the FSX environment. It has custom textures that you can choose to install, and depending on the quality level you select and on your hardware, the FPS impact can be bigger or smaller. The weather options can also influence performance, but on a smaller scale, I believe. Adding too many cloud layers, for example, will have a hit in FPS. It's just a matter of adjusting all this things in the options menu in order to get the best settings for your personal taste and your system's capabilities.

[virge 1]

I don't know. Maybe it has something to do with conditions you must meet with in order for this procedure to work that your airplane, for some reason, wasn't complying with. I know that, in order to delete an altitude restriction using ALT INTV, the altitude bug must be set above the restriction, but I don't know if the non-existance of restrictions between your current altitude and the altitude set in the MCP will prevent the VNAV from commanding the airplane to climb.

 

 

I have a low end computer (old CPU and weak GPU) and none of these programs make any difference on the way my sim performs. TOPCAT is a tool used outside of FSX, so it has no impact whatsoever in performace. Active Sky, on the other hand, actually changes the FSX environment. It has custom textures that you can choose to install, and depending on the quality level you select and on your hardware, the FPS impact can be bigger or smaller. The weather options can also influence performance, but on a smaller scale, I believe. Adding too many cloud layers, for example, will have a hit in FPS. It's just a matter of adjusting all this things in the options menu in order to get the best settings for your personal taste and your system's capabilities.

I DID fully understand your possible solution, and I will try it, but I was just asking if this problem I had, if it is a known problem, and was your solution just a guess on your part, or was it an actual accepted solution to the problem. That was all I was asking.

[markadeane 272]

As silly as it sounds, from the default captains eye position, the ALT INTV is almost completely obscured by the ALT selector dial. Try moving back in your seat a little to see if it helps. This issue caught me out recently on the climb out of EGLL, as most if not all of the SIDs have a hard altitude constraint in them.

[Tabs 2,790]

Have never seen this myself nor have I seen anyone else report it. (I wrote the tutorial, so I'm pretty familiar with the route)

 

I agree with Mark above - make sure you're actually clicking the correct clickspot.

 

Also, to whoever said disconnecting VNAV and reconnecting it does the same thing as ALT INTV - that is definitely not true. As soon as you press ALT INTV you should see the mode change from VNAV ALT to VNAV SPD.

[MrPlaneDriver 41]

I DID fully understand your possible solution, and I will try it, but I was just asking if this problem I had, if it is a known problem, and was your solution just a guess on your part, or was it an actual accepted solution to the problem. That was all I was asking.

 

Ok, I get it. Sorry for trying to help too much 

 

Also, to whoever said disconnecting VNAV and reconnecting it does the same thing as ALT INTV - that is definitely not true. As soon as you press ALT INTV you should see the mode change from VNAV ALT to VNAV SPD.

 

I never said pressing VNAV twice causes "exactly" the same effects as ALT INTV, but as far as this topic is concerned, it would solve the OP's problem: the airplane would resume climbing. BTW, desengaging and reengaging VNAV will change the vertical mode from VNAV ALT to VNAV SPD, but only if the climb has been interrupted by the altitude set in the MCP window, which is the case here.