Does the C510 have a manual trim control? Is it fully controllable at max aft trim with max aft CG?
My TR182 is definitely not controllable with full aft trim. I find Cirrus’ decision to not provide a manual trim control to be quite surprising. The trim system in the Cirrus is quite different from the rest, using springs. It is also the reason why the DFC90 controls pitch via trim and not via elevator like all other GA autopilots. The DFC90 only moves the elevator when it needs major input. In the SR20 there is not even an elevator servo.
It’s a common place that you hand fly the airplane in situations like that.
Only if
It’s a poor implementation to have just one source of airdata because you can be sure that whenever that fails is also going to be a really crap time to be suddenly (or not even suddenly) hand flying the plane…
This is the fashionable (and, incredibly, certified) legacy of abandoning gyro-derived pitch/roll with a gravity vector based erection process e.g. the not exactly reliable vac pump + KI256 system which doesn’t care what happens outside the aircraft
and replacing it with visually attractive compact “glass” instruments which offer a lot of bang for the euro but which derive the pitch/roll from an algorithm which uses an AHRS gyro for short term feedback (which is OK) but which uses airdata for the background erection process (which is vulnerable to pitot or static system failures, or in the Garmin case, loss of GPS ).
Does the C510 have a manual trim control? Is it fully controllable at max aft trim with max aft CG?
Yes it has manual trim. But amazingly in the sim the trim jammed as soon as it was fully aft
Yes it is controllable if you keep the speed down but not pleasant.
The airdata is not necessary to erect the attitude indicator of the EXP5000 PFD. There’s a “FAST ERECT” button on the PFD that can be used to reset the AI in flight in case of failure or after a momentary power loss.
Mooney_Driver wrote:
As the AF447 and some other incidents show the Airbus protections are far from failsafe! Particularly pitot icing will produce very dangerous and unwanted effects, also with the Airbus logic.
The “Airbus logic” didn’t produce a dangerous situation. The flight computers correctly observed that air data was unreliable and turned off the protections, just to avoid situations like in the DFC90 example. It was the pilots that messed up by not understanding what was happening.
Exactly. The accident was reproduced many times in Sims all around the world and it was initially not a big deal to recover the plane. Only towards the end, when it was in a deep stall, the only possible way to get it out would have been full power, which was somehown counter-intuitive to the pilots. But when you read the transcript and watch the videos it is clear that the pilots acted totally confused. It was almost never even clear who was in “control” …
Tragic, but the result of bad flight training. Could have been done with any 767 or 757 just the same ….
A contributing factor to the confusion was the disabling of the stall warner once the IAS dropped below 60kt.
That is really stupid. If you are going to disable it, use the weight-on-wheels switches or something similar.
For sure the designers never expected somebody to be flying an A330 below 60kt IAS…
In this case it helped to confuse the pilots into believing it was not stalled.
Could have been done with any 767 or 757 just the same
Except that the yokes on those are joined together, so you can’t have one pilot pushing and the other pulling, etc.
Just to clarify: the pitot heat failed on me in flight and was not inoperative at the start of the flight as then I would of course hand fly the aircraft or even better not fly in sub-zero air where there would be a risk of it icing up. So … the pitot heat failed (and the light to warn did not go on, so a second failure) and then the pitot tube was iced up and the aircraft nose went down pointing about straight to the ground just like that in a split second while cruising along. That is what I don’t like.
Other than that, the DFC90 is a way more stable A/P than the STEC55, has nice features (if I remember) like a blue “LEVEL” button and envelope protection. So, yes, if I would be flying an Avidyne Cirrus I would opt for this AP instead of the STEC55, so read my “dumping” story more as a frustration that it is also responding to the frozen pitot tube in such a basic manner.
Yes, of course. I wouldn’t have liked that one either ;-)
But the autopilot, which only knows the speed of the plane, and no angle of attack, can only interprete the blocked pitot tube as “too slow”.
Didn’t you see the IAS go down? I guess not, probably happened too fast.
By the way: The Garmin GFC700 would have done exactly the same, because it does’t have an AOA either.
That’s the limitations of our toy planes. A $ 10.000 autopilot cannot save you in all possible scenarios …
Except that the yokes on those are joined together, so you can’t have one pilot pushing and the other pulling, etc.
But that’s really the most basic thing you learn in Airbus training, that the one who presses the priority button is in control. Pilots who don’t understand that or mess it up under stress should not be in an Airbus cockpit.
