Thanks for the heads up. It may be a situation of the FAA looking for a problem where none exists.
My understanding of the way that CWS works with the STEC is that the system will capture the rate of change of altitude or heading at the time the CWS is engaged and continue that rate. The system is rate based and not attitude based.
I think the concern is that a pilot may select CWS in a circumstance that is beyong the capability of the aircraft to preform. Say you engage CWS at 2500’ msl at a 1000 fpm climb straight ahead and then do nothing. At a certain point, the aircraft will no longer be able to climb at 1000 fpm regardless of how much up pitch is commanded and eventually the wing will stall. I don’t know if anybody ever got into trouble doing this. The AOPA news release suggests that the FAA has no accident data or human factors information to support the theory that it is a problem. I can’t see it being a problem. You put the aircraft in the attitude you want, hit CWS and the STEC will continue the same rate of change of altitude or heading that you had when engaged. You continue your scan and confirm that the system is doing what you want it to. If it does not, you hit the autopilot disengage, also on the control stick, and put the aircraft into the proper attitude and re-engage CWS.
I have heard that the concern extends beyond CWS to the altitude pre-select function as well. The concern is again that a pilot will select a rate of climb that the aircraft cannot do, and that the system will put the plane in a stalled attitude.
I recall reading on STEC’s website some while ago that there has never been an accident attritubatable to one of their autopilots. If this is so, apparantly that is not enough reassure some of these “were from the Government and we are here to help you” folks over at FAA.
I’m sure that AOPA would be pleased to hear from the Cirrus community, whether you are a member or not. I suspect that an overwhelming percentage of us are members. They exist to serve the members and make their member’s concerns known to the FAA and others.
Cirrus’s official position is that there are other autopilot suppliers out there, and that if there is a problem they can substitute another make. I don’t think this is too reasonable, since STEC has nearly all of the market. I think that the matter has to be worked out between STEC, the FAA, Cirrus AOPA and it’s members.
Finally, does anyone know whether CWS is enabled on the SR22’s that have been delivered to date? They appear to have the full STEC 55x system installed.
Saw this on AOPA’s web site - not much information but it describes a little bit about FAA’s objections to Control Wheel Steering (CWS); this may be the heart of the problems with the S-Tec 40x & 50x getting FAA certification?
AOPA questions FAA’s control-wheel autopilot controls policy
Feb. 22 Â— AOPA is opposing a proposed new FAA policy on autopilot controls. Concerned about pilots inadvertently engaging or disengaging the autopilot during critical phases of flight, FAA wants to remove or limit autopilot controls (sometimes called CWS Â— control wheel steering) on the control wheel.
But AOPA said that FAA has not published any “supporting human factors research or accident/incident reports” to justify the change. AOPA asked FAA to supply the data, and to allow more time for pilots to comment on the proposal.
“I’m concerned about single pilots operating in the IFR environment,” said AOPA President Phil Boyer. “We are constantly expressing concern about too much ‘heads down’ time. Using control wheel buttons cuts back substantially on looking down to activate an autopilot mode.”
Boyer pointed out that the military practice is to put multiple control buttons on the stick and throttle so that a pilot does not have to remove his hands from the primary flight controls to activate critical aircraft systems.