Back to topic – there are two types of FD display – the “single pointer” version, which is moving up/down to command pitch and TURNS left/right to command roll, and a cross-pointer type (as in the Concorde sim image), with a horizontal bar commanding pitch and a vertical bar commanding roll.
In the Concorde image, the vertical bar is hidden behind the aircraft symbol, indicating pitch is good, but the vertical bar is to the right, which means the angle of bank should be increased to the right.
I first encountered a Flight Director when I started flying a KFC 150-equipped Bonanza in 1999, shortly after getting my IR. I found out that the “F” in KFC signified that the autopilot had something called a flight director, while the “A” in KAP 150 meant that this was a “mere” autopilot. The actual (mechanical) flight instrument looked precisely as Peter’s in his picture above.
After wondering for a while whatever it was good for, I then found I could use the FD to brilliantly handfly any approach that the autopilot could fly, impressing passengers and boosting my ego.
I do miss one feature of the FD. Back in the Bonanza days I got into a habit of always engaging FD mode first whenever I wanted to use autopilot. That way, if the autopilot and I were not on initially the same wavelength, I would see that on the FD arrows without the airplane suddenly pitching or turning unexpectedly. I still think that is a good way to use an FD.
It is some time since a last flew an FD-equipped airplane. The G1000 Diamond Star I fly now does not have it. I wonder why, since in any glass cockpit airplane with autopilot, I would think that all it should take was a bit of software.
Also, back then, I found the FD as a way to use the guidance form the autopilot while still getting full feed-back through the controls, something that I used once or twice because someone had told me I would crash and die immediately if the autopilot was on while entering icing conditions. It was not really necessary – the Bonanza looses a lot of speed with only a thin, invisible layer on the wings and before anything is felt through the controls.
Besides, I am not sure why I could not just press the CWS (Control Wheel Steering) button to do just that – get the control feed-back. Mayby because in FD mode, I could use the elevator trim freely, whereas in autopilot mode, once I touched the elevator trim (with or without the CWS pressed), the autopilot would disengage completely.
Is it time for a thread on CWS now? I seems there is no industry standard for what a botton labeled CWS will do!
My 2006 SR22 does have it (see first photo thread), and the FD of the (retrofit) digital DFC90 autopilot really makes you look good when hand flying. I don’t really have much practice flying IFR approaches, but with the FD… it’s really easy. It doesn not have CWS though. Maybe not necessary in the SR22 when you can AWLAYS overpower the A/P by hand …
The CWS button isn’t just for overpowering the autopilot. It can be used to adjust the VS, the pitch and/or roll attitude in the ROL mode, it can be used to change the altitude in the altitude hold mode, etc. When you let go of the button, the autopilot will pick up the current settings (generally).
Overpowering the autopilot is an all-out emergency scenario.
It does not have CWS though. Maybe not necessary in the SR22
That is surprising. The DFC90 does support CWS and it was part of the STC for the C182. Maybe they just forgot to install it? It is a great feature because it allows you to quickly correct without having to program anything or switch modes. Before that, I often got into a “fight” with the AP. And as Peter said, you can even “reprogram” the AP with just one button on the yoke. The most frequent use of CWS (at least for me) is to quickly avoid a convective cloud. Without it, you have to disengage the AP, fly by hand and then engage again which might be good or not depending on how the AP works (e.g. aggressive previous track intercept which you might not want). Of course one could also use HDG mode and switch back to NAV but CWS is neat.
Of course with the CWS feature you momentarily disconect the servos as log as the button is pressed. Yes, the DFC90 HAS that feature but it is not used in the SR22 installations. My guess is that there’s just not enough room on the side yoke for another button.
So you simply press HDG and steer with the HDG knop on the PFD, and then you just press GPSS or NAV again.
(I don’t know about about Perspective versions, maybe they have it!)
Nope, that (simulated) concorde is flying pretty much straight & level in landing configuration
I stand corrected. I really should have looked at some of the other configured items ;-). But yes, it is astonishing – I guess that’s why they needed the droop nose, and must be because Concorde doesn’t have any flaps. I read the landing pitch up attitude is 11.5 degrees.
The only thing almost ‘wrong’ with that image, is that at 3000 ft, the speed of 250kts is just on the legal limit for below 10,000 ft is it not?
Peter,
brings back memories. It was this FD I did my IR on, with a KFC 150 on the Senecas II and III
Alexis
Well, that’s probably close to the stall :-)
Look at the speed bugs. That pitch is pretty normal. In slow flight, which for Concorde was anything below about 300 kts, Concorde had to be flown with rather a lot of power and pitch, which was one reason they had very few time to wait in holding patterns or likewise. I recall one friend who flew the Filton simulator used by BA telling me that during approach they used to fly with about 80% power and quite a pitch up. Concorde had no flaps or other lift devices, so the only way speed control happened was via pitch and drag.
BTW, as far as I know that program shown here is now used to drive the re-used Filton simulator which is now in a museum. It is the only way these days that pilots can experience what it was to fly Concorde… I know the people who developed this sim (both the museum one and the program for MSFSX) and have seen some reactions by the former Concorde pilots they work with. At least one of them said publicly that the software is better than the Simulators they used to train on. I tried it, it is extremely complex but very educating.
Re CWS: That is a real pity. CWS is one of the nicest features any AP can have. What it does is it allows you to actually hand fly the aircraft while the AP is still engaged and depending on the mode will then take over from you exactly as you leave it. I learnt to use CWS while doing model verifications on the MD11, where it came pretty close to what Airbus uses in their FBW philosophy. Much simplified, an A320 handflown is pretty much in CWS mode all the time as if you release the stick, it will keep going exactly in the way you flew it (pitch/bank) before you released the stick, unless you are outside the protection parameters. That is a lovely feature I’d like very much to see on GA AP’s. Maybe you need to investigate if you need a special upgrade to get it as you upgraded your S-TEC to the Avidyne AP, maybe the “straight” upgrade does not include CWS but there is a way to implement it? It would be worth it, believe me.
(( The delta wing of the Concorde does not have flaps, because a) they would be counterproductive, their extension would lower the nose and ther eis now elevator to keep the nose up then… and B) Concordedoes not NEED flaps, because at high angles of attack the massive delta wing produces very strong vortices that improve the slow flight characteristics better than flaps could. ))
I would be worried about a plane which has an AP but no CWS. That goes against the way “classical” aircraft systems are supposed to work. For example in ROL mode (the most basic AP mode, obtained by pressing the AP button alone) the CWS button will program the roll angle and the pitch attitude.
