Autopilot

[Dorel Mornea 5]

Hello everyone,

Could someone explain to me how exactly the vertical speed hold mode functions on PSS Concorde? All the manual says is that the vertical speed button will maintain the existing VS at the time the VS hold mode was engaged. But, how exactly can I change the desired VS to be maintained once I have activated this mode. For instance..let's say I want the plane to climb and maintain...20000 feet; when I reach the desired VS, I press the VS hold button, AP will maintain that VS, so far so good. But if afterwards I want to change my VS, I don't really know what to do. If I press VS hold button, it won't disengage, so I suppose I have to choose another vertical mode instead, so I choose attitude hold, which will (as it's supposed to) disengage VS hold, then I can apparently change my VS simply by yoke input, next, when I reach my (new) desired VS, I press VS hold button again, and that's where crazy things happen. The plane would enter a deadly dive like crazy and smash the ground if I don't take over. I noticed that in some instances, if the plane is high enough so it won't hit the ground, AP manages to maintain my new desired VS...but only after that crazy dive. So my question is..how to change my VS once the VS hold mode has been engaged?

Thank you so much, MIB!

[martinlest2 58]

After you set VERT SPEED on the MCP, use the AP Datum Adjust to move the nose up or down.

 

The a/c is VERY sensitive, especially after Mach 1, and I would use the MAX CLIMB function in the Auto Pilot rather than try to adjust things manually. I only adjust the climb rate at early or late stages of the flight (i.e. the first ten minutes or so after takeoff and before landing)

 

Martin

[pschlute 37]

This is the technique for a typical takeoff from London/Paris/ some NY runways where noise abatement is an issue:  Immediately after  takeoff  you should be climbing at 250 kias and have turned off the reheats, and reduced the thrust to about 93% N2. Engage Pitch hold then autopilot (if desired), and use the datum adjust (if using A/P) to maintain your speed. Increase N2 by 2% each 1000 feet above 3000 until you are at 8000 feet when you should be on full thrust. At 10,000 feet or earlier if given permission use the datum adjust to lower the nose to allow your speed to increase gradually to 390-400 kias. At this point change the climb mode to IAS (IAS A/P mode...NOT A/T mode) to maintain just below 400 kias. If the departure requires a subsonic phase (London for example) then engage Altitude hold at 28,000 feet and use autothrottle to maintain M0.94. At the start of the transonic phase change to pitch hold , use full throttle and reheats, and use the datum adjust initially to maintain 400 kias, but very quickly you should be changing to MAX CLIMB. You should not be using V/S in the climb at all unless ATC are being very unhelpful !

 

The Canarsie climb out of NY was very different, and a good description is given here http://www.sstsim.com/forums/lofiversion/index.php?t2671.html

 

Peter

[martinlest2 58]

Actually I have flown several times with Concorde since I posted and I have no problems: I don't activate ALT ACQ until I am on my flight path (and press INS). Until then I never use the VERT SPEED button (which usually causes the nose to rise dramatically anyway) Concorde climbs at a steady rate and I can adjust this with the yoke, or Datum adjust if necessary (though at this early stage in the flight, just adjusting the pitch and throttles is always sufficient).

 

The only issue is that at over FL540 the PSS a/c tends to fall a lot - maybe a two or three thousand feet to maintain Mach 2. Just a small problem with the IDE I guess. The real Concorde would also descend slightly to maintain speed, but not to this extent.

 

I remembered the other day I have the ITVV 2-DVD set of Concorde, which I have been watching. It's extremely detailed, full of technical information and totally fascinating. In FS9 I am basically copying what they do on the DVD (which I highly recommend - the best cockpit video I have ever seen).

 

Martin

[pschlute 37]

Martin

 

The DVD you mention is superb, I agree.

 

The SSTSIM will also sometimes descend up to 2000 feet. Not very often but I think it can be caused by a weather engine if you are using one. If you dont already use FSUIPC smoothing options I recommend it. An alternative is to disable winds aloft (with Active Sky) for a smoother flight.

 

Peter

[martinlest2 58]

I'll have a look at the FSUIPC - I have a registered version but hardly make use of it. I could also disable winds aloft in Active Sky. You really think this is the reason Concorde can descend to far to maintain speed? (I guess temperature effects are not modelled!).

[martinlest2 58]

I already have wind smoothing active in FSUIPC .. Maybe I need to deactivate the 'Extend top wind layer upwards' and 'Allow gusts in upper winds'.  I need to look at the FSUIPC manual again to be honest ...