Is with VNAV on?
1 Like
Only if it turned itself on…I never use it intentionally.
1 Like
should be VNAV what causes this then:
You’ll see, this is how VNAV manages approach speeds, consider always radio altitude (not BARO) and flaps full and VNAV on:
- for RA > 2000, autothrottle will be set to 225 knots.
- for RA > 1800 and < 2000, autothrottle will be set to 200 knots.
- for RA > 1500 and < 1800, autothrottle will be set to 185 knots…
- for RA > 1250 and < 1500, autothrottle will be set to 160 knots.
- for RA > 750 and < 1250, autothrottle will be set to 148 knots.
If flaps weren’t full, it will set to 240 knots.
Below 750, it will be calculated based on wind factor and Fuel weight (somewhere between 122knots and 148 knots).
And Below 80, autotrottle will dissengages to allow to detent the plane (if approach is active).
What happens with this is the following. Imagine that between the runway and you there is a terrain elevation that leaves your plane at 750ft RA, then VNAV would lower the speed to 148knots but it would increase again if the radio altitude increased, regardless of the runway. That is why I told you that you should be careful with the elevations of terrain in between (this is something i could correct by keeping the speeds unchanged in each conditional if you are not at a certain distance from the runway). If that’s the case, I would disable VNAV, and adjust the autotthrottle manually.
I would do a test mapping the spd increase / decrease buttons on your keyboard, because I think you are accidentally activating it when manipulating the knob (I have to correct it to prevent users from hitting the up arrow by accident).
2 Likes
if liveweather is ON, there may still be a bug in which MSFS is not adjusting the exterior temperature correctly. Try putting setting a clear skies preset just to to diagnose if the plane returns to the correct speeds.
1 Like
2 Likes
Here’s whats happening …just a short clip
1 Like
I know the question is for CodemanJack, but let me ask something that might help the analysis: since the F-14’s flight control system normally manages wing sweep and flaps automatically, why are you going to full flaps if the aircraft doesn’t think you need it?
That’s not VNAV, otherwise it would be displayed on the FMA as VNAV PTH, VNAV SPD or VNAV ALT.
I have found once you go fast and the flaps fully auto retract they must be placed in the down position manually to configure for landing…or so it appears
If its not VNAV that comes up…what is it doing? VNAV was just a guess…because i dont really know what it did…but the speedbox changes modes automatically to something else
In that video I don’t see much information, I can’t see the radio altitude, I don’t know how far you are from the runway, I don’t understand that you don’t have the landing gear down yet, I do see that the plane has accelerated to 180 knots. , and when rising it has lost the glideslope. Nor do I see if you have the approach mode or only the locator (maybe because the video resolution is low). If it was VNAV I would have shown it to you at the FMA.
1 Like
The video should have rendered to 4k…but here was the scenario… I dont use the radar altimiter, in real life we only set that to 200 agl for an ILS but in this plane I just use the main altimeter… the approach would go like this… Prior to the Intermediate Fix I was level at 3000’ speed set to 180kts following the GPS track with the approach mode armed …upon reaching the IF I switched from GPS mode to NAV mode like you would in real life if appropriate and then watched for the glideslope to come alive…a standard thing would be once the glideslope starts to come in you set the flaps to first notch…but because they are mostly auto I just set them to full at this point… then the plane appeared to start a go around, even though thats not what it was… if that didnt occur then the next standard call would be “one dot above, gear down”…thats when the gear is normally dropped in the planes I’ve flown… There are many more standard calls but wouldnt really be applicable to this plane…but the ones mentioned above work well…minus the flap induced climb out.
1 Like
My knowledge of these planes is quite limited aside from the crash courses I’ve put myself through to fly them relatively-well, but it’s almost like some kind of auto throttle function kicked in on you. I’ve never seen that, and I fly a TON in the 14 and 15. I’m interested to see what’s doing it. Hopefully you get it sorted soon.
1 Like
The only thing I could think of to tell you is that it is due to the lift of the flaps you have lost the glideslope at that point.
that is, the autopilot has not been able to calculate the trajectory in time and has not corrected the error. Have you done the test with the flaps fully deployed?
2 Likes
it doesnt happen all the time, only when I’ve gone fast for a bit and at some point my flaps were auto retracted to full up… but it can easily be worked around by either lowering flaps during descent prior to starting approach or once the DLC is enguaged after the gear drops (I think). I only brought it up because I had a few people ask me about it on my channel. Once I knew how to replicate it I figured CodnameJack447 might have the anwser…more out of curiosity than anything else though.
Aside from AT or a bug, is there a feature of the aircraft that would cause this? I think that’s the right question here. This seems abnormal. What could/would cause it? I find the 14 to be incredibly stable and predictable on landings. I have 90 hours w/69 landings in the 14 per Volanta. This vid is the first time I’ve ever seen that. #stumped
1 Like
Very interesting…And yeah if the flaps are fully deployed before the approach the crazy climb doesnt happen
1 Like
the flaps can only autoretract if you go above mach 0.425, or if you go with manual wing sweep to avoid damaging the fuselage.
Now, if it is that the airport were at a very high altitude above the sea, it is possible that they are retracting earlier than they should when converting to airspeed. But I think it’s a matter of the flaps. It is not a bug, it is that we are talking about a carrier, according to natops it generates a lot of lift when deploying the last level of flaps and requires a trim correction or using airbrake to compensate, while in an airliner I understand that the impact must be less
2 Likes