Narrative:

Today; I went for a training flight. My intention was to fly to lyh and do a low approach and then fly to lku for a full stop and to get fuel before heading back home. My aircraft has two garmin (GNS) 430s; avidyne entegra 5000 multi-function display (mfd) and primary flight display (pfd); and an stec autopilot. The autopilot operates off GNS1 as do the mfd and pfd. My standard procedure is to use GNS1 for all navigation programming data. I do not leave GNS1 on auto crossfill to GNS2. On the way to lyh; I was VFR but then the clouds thickened up and after obtaining the ATIS information approximately 50 miles out from lyh; I asked for an IFR clearance for the low approach and then to head to lku. I was given the clearance; told to climb to 7000 and go direct to lyh. I armed the RNAV 22 approach in GNS1 and briefed the paper chart. I was ready. Meanwhile; I entered lku in GNS2 so that I would have heading information to lku at the ready once I had flown the approach and missed approach at lyh. I was IMC. All was well. I was using the autopilot on navigation gpss mode to fly the approach at that point. Roanoke approach asked me to go direct to kujum and descend to 4500 so I highlighted kujum and hit 'direct' 'enter' and the aircraft began to turn direct to kujum and I began my descent. I then entered 'direct' to lku on GNS2 and that is when things began to go awry. Suddenly; the autopilot began to turn the aircraft to lku and lku appeared on the pfd and mfd. I still had a picture of the approach on the mfd and I could see that I was flying away from kujum. I thought I must have made a mistake when entering the info so I again selected the approach on GNS1 and activated it to go direct to kujum and began heading there on the navigation gpss autopilot function. I then again attempted to get the heading information to lku by entering direct to lku on GNS2. The aircraft again began to turn to lku. I had no idea what was happening at that point so I began to hand fly the aircraft to kujum but; due to the series of events; I began to become spatially disoriented. So I rearmed the autopilot and told the controller that I wanted to abandon the approach and go direct to lku. This is where I now know I made a mistake. I should have declared the equipment malfunction to the controller; put the autopilot on heading mode and asked for a heading until he could send me direct to lku. Unfortunately; I did not think to do that so I deviated from the last assigned heading and turned toward lku without being told by ATC to do so. Naturally; this alarmed (and infuriated) the controller and his supervisor. I believe it was the supervisor who came on the air to ream me out. I was in thick IMC throughout this entire experience. Once things got settled; I began to think about what might have happened and it suddenly dawned on me... Earlier that month; I flew the aircraft for a 2-day recurrent training course. One of the instructors rode back to my home base with me. He sat in the right seat and handled the radios and navigation while I flew the airplane. He mentioned to me that he likes to use GNS2 for his flight data entry because it is easier to reach than GNS1. He apparently uses automatic cross fill from GNS2 to GNS1 so that GNS1 will always have the flight data to feed the autopilot; mfd and pfd. He apparently left on the auto crossfill from GNS2 to GNS1 at the end of the flight. I did not realize this today when I launched my training flight. Thus; when I tried to use GNS2 (as I typically do) to get my situational awareness for the next stop of the flight to lku; the automatic cross fill sent the GNS2 data (lku) to GNS1 and obliterated my instrument approach. Twice. Meanwhile my airplane was wallowing around in IMC trying to figure out whether I wanted it to go to lku or kujum. The wallowing and transition left me in a poor position to hand-fly the airplane. This was particularly true because the flight director was getting bad information so I did not have that reference from which to try to keep the plane straight and level; never mind on course. Truly; it is a wonder I did not kill myself. In the midst of it all; I took what I felt was the safest course of action and re-activated the autopilot and let it fly me out of the approach and over to lku as it kept trying to do because I kept thinking 'fly the airplane' and I realized that punching data into the gnss was not getting me anywhere at that point. I now realize that I could have done so much better by talking to ATC and letting them know I was having equipment problems and needed a heading to fly. If I had this to do over again; that is what I would do because I know this was perhaps almost as distressing to roanoke approach as it was to me. I have learned something from this. Never hesitate to let ATC know that you are having troubles. I did not have time to explain the troubles but I could have alerted them to that fact so that they would have known that there might have been a reason why I was deviating off the assigned heading and perhaps given me some assistance.

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Original NASA ASRS Text

Title: General aviation pilot becomes confused when GNS#2 does not function as a passive navigation unit as previously set up; but instead takes control of the autopilot at an inopportune time. Pilot takes over manually but does not comply with clearance and does not initially inform ATC.

Narrative: Today; I went for a training flight. My intention was to fly to LYH and do a low approach and then fly to LKU for a full stop and to get fuel before heading back home. My aircraft has two Garmin (GNS) 430s; Avidyne Entegra 5000 multi-function display (MFD) and primary flight display (PFD); and an STEC autopilot. The autopilot operates off GNS1 as do the MFD and PFD. My standard procedure is to use GNS1 for all navigation programming data. I do not leave GNS1 on auto crossfill to GNS2. On the way to LYH; I was VFR but then the clouds thickened up and after obtaining the ATIS information approximately 50 miles out from LYH; I asked for an IFR clearance for the low approach and then to head to LKU. I was given the clearance; told to climb to 7000 and go direct to LYH. I armed the RNAV 22 Approach in GNS1 and briefed the paper chart. I was ready. Meanwhile; I entered LKU in GNS2 so that I would have heading information to LKU at the ready once I had flown the approach and missed approach at LYH. I was IMC. All was well. I was using the autopilot on NAV GPSS mode to fly the approach at that point. Roanoke approach asked me to go direct to KUJUM and descend to 4500 so I highlighted KUJUM and hit 'direct' 'enter' and the aircraft began to turn direct to KUJUM and I began my descent. I then entered 'direct' to LKU on GNS2 and that is when things began to go awry. Suddenly; the autopilot began to turn the aircraft to LKU and LKU appeared on the PFD and MFD. I still had a picture of the approach on the MFD and I could see that I was flying away from KUJUM. I thought I must have made a mistake when entering the info so I again selected the approach on GNS1 and activated it to go direct to KUJUM and began heading there on the NAV GPSS autopilot function. I then again attempted to get the heading information to LKU by entering direct to LKU on GNS2. The aircraft again began to turn to LKU. I had no idea what was happening at that point so I began to hand fly the aircraft to KUJUM but; due to the series of events; I began to become spatially disoriented. So I rearmed the autopilot and told the controller that I wanted to abandon the approach and go direct to LKU. This is where I now know I made a mistake. I should have declared the equipment malfunction to the controller; put the autopilot on HDG mode and asked for a heading until he could send me direct to LKU. Unfortunately; I did not think to do that so I deviated from the last assigned heading and turned toward LKU without being told by ATC to do so. Naturally; this alarmed (and infuriated) the controller and his supervisor. I believe it was the supervisor who came on the air to ream me out. I was in thick IMC throughout this entire experience. Once things got settled; I began to think about what might have happened and it suddenly dawned on me... Earlier that month; I flew the aircraft for a 2-day recurrent training course. One of the instructors rode back to my home base with me. He sat in the right seat and handled the radios and navigation while I flew the airplane. He mentioned to me that he likes to use GNS2 for his flight data entry because it is easier to reach than GNS1. He apparently uses automatic cross fill from GNS2 to GNS1 so that GNS1 will always have the flight data to feed the autopilot; MFD and PFD. He apparently left on the auto crossfill from GNS2 to GNS1 at the end of the flight. I did not realize this today when I launched my training flight. Thus; when I tried to use GNS2 (as I typically do) to get my situational awareness for the next stop of the flight to LKU; the automatic cross fill sent the GNS2 data (LKU) to GNS1 and obliterated my instrument approach. Twice. Meanwhile my airplane was wallowing around in IMC trying to figure out whether I wanted it to go to LKU or KUJUM. The wallowing and transition left me in a poor position to hand-fly the airplane. This was particularly true because the flight director was getting bad information so I did not have that reference from which to try to keep the plane straight and level; never mind on course. Truly; it is a wonder I did not kill myself. In the midst of it all; I took what I felt was the safest course of action and re-activated the autopilot and let it fly me out of the approach and over to LKU as it kept trying to do because I kept thinking 'fly the airplane' and I realized that punching data into the GNSs was not getting me anywhere at that point. I now realize that I could have done so much better by talking to ATC and letting them know I was having equipment problems and needed a heading to fly. If I had this to do over again; that is what I would do because I know this was perhaps almost as distressing to Roanoke Approach as it was to me. I have learned something from this. Never hesitate to let ATC know that you are having troubles. I did not have time to explain the troubles but I could have alerted them to that fact so that they would have known that there might have been a reason why I was deviating off the assigned heading and perhaps given me some assistance.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.