Narrative:

I filed an IFR flight plan with flight service for a flight from ZZZ1 to ZZZ2. The route requested was GPS direct. On the ground in the airplane; I called approach and was given a clearance and void time. The clearance was direct abc then direct ZZZ2; expecting the GPS runway 31 approach. I programmed ZZZ2 into the GPS unit but did not enter the approach at that time; thinking it was easy to do in the air. Sometimes the routing is changed by approach in the air anyway. I took off and after calling approach on the radio; climbed to the assigned altitude of 6000 ft. Part of the climb was through IMC; but the cloud tops were about 5700-6300 ft; so I was on top part of the time. Meanwhile; I tried to enter the approach into the GPS but was not successful. I am much more familiar with the garmin series 400 and 500 GPS units. This airplane (cessna stationair T206) has a honeywell bendix/king KLN94 installed. The operation is similar to the garmin; but there was enough difference to confuse my ability to program it during the stress of this flight. During this flight; I was having considerable difficulty maintaining the controller assigned directions and altitudes. At first; I thought that it was the activity of programming the GPS that was taking my attention from the flight instruments. This was probably partly the problem. However; after having been cleared and descending to a lower altitude (completely in IMC); I started to have a serious control problem. Fortunately this airplane has a backup attitude indicator (ai) (artificial horizon) on the copilot's side (but fairly low on the far side of the copilot's yoke). At some point I looked at the back up and I and noticed it was showing a steep turn while the one in front of me (on the pilot's side) was showing level. I then realized that my ai was failing and started to use the backup ai. However; because of my instrument training; it was very hard to get used to referring to the backup ai constantly and ignoring the primary ai in front of me. During all of this time; the direction control and altitude control was very difficult; deviating maybe 30 degrees from the assigned heading and maybe +/-400 ft from the assigned altitude. Perhaps because I had slowed the airplane down considerably during all of this; approach control let at least one faster airplane (malibu) go past me. To do this; I was constantly assigned new headings to put me in a kind of holding pattern. This went on for several mins while I struggled with the airplane. (I did report the faulty instrument to approach but I also mentioned my back-up ai.) 1 passenger got sick from the motion. Finally I was assigned 3000 ft and upon reaching that altitude could see ground below me. I continued down and canceled IFR after reaching about 2600 ft MSL. After that; there were no problems with airplane control and I proceeded to pao to land smoothly. I had noticed when I was at ZZZ2 earlier in the day that the ai took a long time to orient itself. Once in the air I did not notice a problem with this instrument; but I was VFR from ZZZ2 to ZZZ3 and later from ZZZ3 to ZZZ1. In retrospect; there were many things I could have done to make the problem less serious: first; I should have programmed the KLN94 GPS completely on the ground at ZZZ1 prior to takeoff. Although I was confused in the air; I would have figured it out on the ground (or canceled the clearance). Once recognizing the key difference from the garmin programming procedure; I may not have had a problem reprogramming this GPS if later required in the air. Second; once recognizing a bad ai; I should have covered it so I would not be able to inadvertently use it. I have kept a suction cup type cover in my flight bag for maybe 18 yrs for this purpose but never needed it before; and forgot about it this time when I did need it. Third; I should have had more training on this specific GPS. The particular programming sequence to do what was needed for this flight contains at least 1 step that is much more confusing than the steps for programming approachs into the garmin 530. On this note; I would like to add that there needs to be more standardization among the different GPS brands and models. I feel that the garmin is more intuitive compared to the KLN94. But the KLN94 has some steps that could be important in flight programming that would be more difficult to implement in the garmin 530 during flight in instrument conditions. Especially for a renter of airplanes; it is necessary to be proficient in different models of GPS units when renting airplanes with different equipment.

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Original NASA ASRS Text

Title: A IFR/IMC C206 PILOT REPORTS CONFUSION AND ATTITUDE CTL PROBLEMS USING AN UNFAMILIAR ADVANCED NAV SYSTEM IN FLT FOLLOWING AN ADI FAILURE.

Narrative: I FILED AN IFR FLT PLAN WITH FLT SVC FOR A FLT FROM ZZZ1 TO ZZZ2. THE RTE REQUESTED WAS GPS DIRECT. ON THE GND IN THE AIRPLANE; I CALLED APCH AND WAS GIVEN A CLRNC AND VOID TIME. THE CLRNC WAS DIRECT ABC THEN DIRECT ZZZ2; EXPECTING THE GPS RWY 31 APCH. I PROGRAMMED ZZZ2 INTO THE GPS UNIT BUT DID NOT ENTER THE APCH AT THAT TIME; THINKING IT WAS EASY TO DO IN THE AIR. SOMETIMES THE ROUTING IS CHANGED BY APCH IN THE AIR ANYWAY. I TOOK OFF AND AFTER CALLING APCH ON THE RADIO; CLBED TO THE ASSIGNED ALT OF 6000 FT. PART OF THE CLB WAS THROUGH IMC; BUT THE CLOUD TOPS WERE ABOUT 5700-6300 FT; SO I WAS ON TOP PART OF THE TIME. MEANWHILE; I TRIED TO ENTER THE APCH INTO THE GPS BUT WAS NOT SUCCESSFUL. I AM MUCH MORE FAMILIAR WITH THE GARMIN SERIES 400 AND 500 GPS UNITS. THIS AIRPLANE (CESSNA STATIONAIR T206) HAS A HONEYWELL BENDIX/KING KLN94 INSTALLED. THE OP IS SIMILAR TO THE GARMIN; BUT THERE WAS ENOUGH DIFFERENCE TO CONFUSE MY ABILITY TO PROGRAM IT DURING THE STRESS OF THIS FLT. DURING THIS FLT; I WAS HAVING CONSIDERABLE DIFFICULTY MAINTAINING THE CTLR ASSIGNED DIRECTIONS AND ALTS. AT FIRST; I THOUGHT THAT IT WAS THE ACTIVITY OF PROGRAMMING THE GPS THAT WAS TAKING MY ATTN FROM THE FLT INSTS. THIS WAS PROBABLY PARTLY THE PROB. HOWEVER; AFTER HAVING BEEN CLRED AND DSNDING TO A LOWER ALT (COMPLETELY IN IMC); I STARTED TO HAVE A SERIOUS CTL PROB. FORTUNATELY THIS AIRPLANE HAS A BACKUP ATTITUDE INDICATOR (AI) (ARTIFICIAL HORIZON) ON THE COPLT'S SIDE (BUT FAIRLY LOW ON THE FAR SIDE OF THE COPLT'S YOKE). AT SOME POINT I LOOKED AT THE BACK UP AND I AND NOTICED IT WAS SHOWING A STEEP TURN WHILE THE ONE IN FRONT OF ME (ON THE PLT'S SIDE) WAS SHOWING LEVEL. I THEN REALIZED THAT MY AI WAS FAILING AND STARTED TO USE THE BACKUP AI. HOWEVER; BECAUSE OF MY INST TRAINING; IT WAS VERY HARD TO GET USED TO REFERRING TO THE BACKUP AI CONSTANTLY AND IGNORING THE PRIMARY AI IN FRONT OF ME. DURING ALL OF THIS TIME; THE DIRECTION CTL AND ALT CTL WAS VERY DIFFICULT; DEVIATING MAYBE 30 DEGS FROM THE ASSIGNED HDG AND MAYBE +/-400 FT FROM THE ASSIGNED ALT. PERHAPS BECAUSE I HAD SLOWED THE AIRPLANE DOWN CONSIDERABLY DURING ALL OF THIS; APCH CTL LET AT LEAST ONE FASTER AIRPLANE (MALIBU) GO PAST ME. TO DO THIS; I WAS CONSTANTLY ASSIGNED NEW HDGS TO PUT ME IN A KIND OF HOLDING PATTERN. THIS WENT ON FOR SEVERAL MINS WHILE I STRUGGLED WITH THE AIRPLANE. (I DID RPT THE FAULTY INST TO APCH BUT I ALSO MENTIONED MY BACK-UP AI.) 1 PAX GOT SICK FROM THE MOTION. FINALLY I WAS ASSIGNED 3000 FT AND UPON REACHING THAT ALT COULD SEE GND BELOW ME. I CONTINUED DOWN AND CANCELED IFR AFTER REACHING ABOUT 2600 FT MSL. AFTER THAT; THERE WERE NO PROBS WITH AIRPLANE CTL AND I PROCEEDED TO PAO TO LAND SMOOTHLY. I HAD NOTICED WHEN I WAS AT ZZZ2 EARLIER IN THE DAY THAT THE AI TOOK A LONG TIME TO ORIENT ITSELF. ONCE IN THE AIR I DID NOT NOTICE A PROB WITH THIS INST; BUT I WAS VFR FROM ZZZ2 TO ZZZ3 AND LATER FROM ZZZ3 TO ZZZ1. IN RETROSPECT; THERE WERE MANY THINGS I COULD HAVE DONE TO MAKE THE PROB LESS SERIOUS: FIRST; I SHOULD HAVE PROGRAMMED THE KLN94 GPS COMPLETELY ON THE GND AT ZZZ1 PRIOR TO TKOF. ALTHOUGH I WAS CONFUSED IN THE AIR; I WOULD HAVE FIGURED IT OUT ON THE GND (OR CANCELED THE CLRNC). ONCE RECOGNIZING THE KEY DIFFERENCE FROM THE GARMIN PROGRAMMING PROC; I MAY NOT HAVE HAD A PROB REPROGRAMMING THIS GPS IF LATER REQUIRED IN THE AIR. SECOND; ONCE RECOGNIZING A BAD AI; I SHOULD HAVE COVERED IT SO I WOULD NOT BE ABLE TO INADVERTENTLY USE IT. I HAVE KEPT A SUCTION CUP TYPE COVER IN MY FLT BAG FOR MAYBE 18 YRS FOR THIS PURPOSE BUT NEVER NEEDED IT BEFORE; AND FORGOT ABOUT IT THIS TIME WHEN I DID NEED IT. THIRD; I SHOULD HAVE HAD MORE TRAINING ON THIS SPECIFIC GPS. THE PARTICULAR PROGRAMMING SEQUENCE TO DO WHAT WAS NEEDED FOR THIS FLT CONTAINS AT LEAST 1 STEP THAT IS MUCH MORE CONFUSING THAN THE STEPS FOR PROGRAMMING APCHS INTO THE GARMIN 530. ON THIS NOTE; I WOULD LIKE TO ADD THAT THERE NEEDS TO BE MORE STANDARDIZATION AMONG THE DIFFERENT GPS BRANDS AND MODELS. I FEEL THAT THE GARMIN IS MORE INTUITIVE COMPARED TO THE KLN94. BUT THE KLN94 HAS SOME STEPS THAT COULD BE IMPORTANT IN FLT PROGRAMMING THAT WOULD BE MORE DIFFICULT TO IMPLEMENT IN THE GARMIN 530 DURING FLT IN INST CONDITIONS. ESPECIALLY FOR A RENTER OF AIRPLANES; IT IS NECESSARY TO BE PROFICIENT IN DIFFERENT MODELS OF GPS UNITS WHEN RENTING AIRPLANES WITH DIFFERENT EQUIP.

Data retrieved from NASA's ASRS site as of January 2009 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.