Troubleshooting a mag heading error
The weather in Albuquerque has really been all over the place this winter and spring. We have been having a lot of winds blowing and several storms coming through. Between the storms I got the chance to take my airplane up to Santa Fe Aero to have all of the last squawks cleared. They went through all of them and before I knew it the airplane was ready. I arrived to pick up the airplane to fly back to Double Eagle. Everything was working well except for a few intermittent cross check attitude messages that continued to arise from time to time. The attitude solution was always good when compared to the MFD and mechanical back-up on my aircraft. (yes, I do have triple redundancy on my airplane!)
I decided that I would use my airplane as a test bed for trying to figure out what these pesky messages were all about. We made several flights to take some data and decided that we would replace the RSM and recalibrate the headings to see if we had an RSM that might be close to the limits. In the Aspen AHRS solution the magnetic heading information is used by the filtering routines that determine the attitude, and therefore if there are inaccurate or inconsistent headings from the RSM, this could affect the solution enough to trigger a message. The really nice thing about the Aspen system is that it provides this indication to assure the pilot that they have the necessary indications to crosscheck attitude when it detects anything that isn’t expected from the sensors. So, one early morning our A&P mechanic came out and made the necessary modifications and we headed out to the tarmac for a compass swing to re-calibrate the headings.
As I am sure many of you know and that I have mentioned in previous postings of this blog, the magnetometer technology is very dependent on adjacent magnetic structures of equipment in the airplane and how accurate the compass swing is. All in all this was a very interesting experience as it gave my a lot of insight into what the dealers perform when they install an Aspen system. After this was done we went up for a flight test. We did not see any cross check attitude messages and the system worked flawlessly. I have since taken the airplane up on several other flights and everything has been nothing short of perfect. This includes first flight for our welsh corgi dog to see how she handled being in an airplane, which she did very well!
I have decided that I will take my airplane to Sun-n-Fun to experience a long cross country with the Aspen System. I just recently finished instrument ground school and will also take the chance to get some simulated instrument flying. I will be taking a CFII with me so the trip besides being a lot of fun will also be instructional. We plan on leaving on Sunday and arriving in Lakeland on Monday. We will be parking at the Aspen GA parking area and I invite all of you to come by and see the airplane. I will be spending as much time out there as possible so I also look forward to meeting with other pilots and answer any questions regarding Aspen or my experiences. I look forward to seeing you there.