Narrative:

Was proceeding toward mia on trip from 6r0 to ism when I engaged autoplt. The autoplt was switched to track mai VOR, which it did correctly. I wanted to look at chart and recompute gndspd and range, so after watching the autoplt operate properly maintaining course, I looked at chart and made a calculation when I felt a change in direction and a wing drop abruptly. I checked the VOR head and the needle was close to proper course. The dg and compass were spinning very fast. I thought the VOR receiver had malfunctioned and was not receiving mai VOR. I switched radios and checked breaker for radio. I then grabbed the wheel but felt increasing opposition and had to fight autoplt to turn back 180 degrees to get back on course to VOR, all while turning the autoplt to heading mode with no release of autoplt control force, so I then turned it off immediately. The small aircraft type a autoplt would still not release in off position, so I grabbed for the circuit breaker, but it is the flush mount kind and I could not pull it out. I continued to fight autoplt to come back to heading to mai VOR while trying to switch autoplt off and pull breaker. All of this took place in less than 1-2 mins. After regaining course, controller asked what was wrong, and I initially replied that something had happened to my VOR receiver or head, as I could not figure what had happened. I also thought at first I lost the vacuum pump, which I knew could then make the autoplt malfunction, but this was noticed to be operating properly with adequate pressure. Later I then reengaged the autoplt and it worked. Then after a minute or so it took off dropping a wing, but I then caught it and by clicking the off switch on the autoplt while fighting the force of autoplt had the autoplt release. It took several attempts to release it, but I was ready for it and remained on course. On the ground at ism I checked the autoplt and the operation was erratic. The off/heading/omni switch was not operating properly and took repeated attempts to shut off. I had checked it on preflight and it turned off and operated with no problems. The heading function was also noticed not to operate properly. I plan on installing a new circuit breaker or switch so I can quickly release the electrical power. I have also used autoplts on an small aircraft (similar or same autoplt). This autoplt takes a lot more force to override and would not shut off. Also I looked momentarily at map and hit my calculator and it caught me off guard. I had received about 10 hours of dual instruction in IFR flying/transition to the small aircraft manual for all systems, but the manual is short and terribly insufficient for this model aircraft. I plan to go to flight safety T9O take the systems course after this second emergency, the first being an in-flight electrical fire/direct short in alternator-condenser unit which grounded to frame due to mechanic improperly installed condenser/alternator unit. Perhaps this other electrical short which literally blackened and burned alternator and part of harness 20 hours before is responsible for the autoplt malfunction.

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Original NASA ASRS Text

Title: SMA PLT ENCOUNTERS AUTOPLT PROBLEM.

Narrative: WAS PROCEEDING TOWARD MIA ON TRIP FROM 6R0 TO ISM WHEN I ENGAGED AUTOPLT. THE AUTOPLT WAS SWITCHED TO TRACK MAI VOR, WHICH IT DID CORRECTLY. I WANTED TO LOOK AT CHART AND RECOMPUTE GNDSPD AND RANGE, SO AFTER WATCHING THE AUTOPLT OPERATE PROPERLY MAINTAINING COURSE, I LOOKED AT CHART AND MADE A CALCULATION WHEN I FELT A CHANGE IN DIRECTION AND A WING DROP ABRUPTLY. I CHKED THE VOR HEAD AND THE NEEDLE WAS CLOSE TO PROPER COURSE. THE DG AND COMPASS WERE SPINNING VERY FAST. I THOUGHT THE VOR RECEIVER HAD MALFUNCTIONED AND WAS NOT RECEIVING MAI VOR. I SWITCHED RADIOS AND CHKED BREAKER FOR RADIO. I THEN GRABBED THE WHEEL BUT FELT INCREASING OPPOSITION AND HAD TO FIGHT AUTOPLT TO TURN BACK 180 DEGS TO GET BACK ON COURSE TO VOR, ALL WHILE TURNING THE AUTOPLT TO HDG MODE WITH NO RELEASE OF AUTOPLT CONTROL FORCE, SO I THEN TURNED IT OFF IMMEDIATELY. THE SMA TYPE A AUTOPLT WOULD STILL NOT RELEASE IN OFF POS, SO I GRABBED FOR THE CB, BUT IT IS THE FLUSH MOUNT KIND AND I COULD NOT PULL IT OUT. I CONTINUED TO FIGHT AUTOPLT TO COME BACK TO HDG TO MAI VOR WHILE TRYING TO SWITCH AUTOPLT OFF AND PULL BREAKER. ALL OF THIS TOOK PLACE IN LESS THAN 1-2 MINS. AFTER REGAINING COURSE, CTLR ASKED WHAT WAS WRONG, AND I INITIALLY REPLIED THAT SOMETHING HAD HAPPENED TO MY VOR RECEIVER OR HEAD, AS I COULD NOT FIGURE WHAT HAD HAPPENED. I ALSO THOUGHT AT FIRST I LOST THE VACUUM PUMP, WHICH I KNEW COULD THEN MAKE THE AUTOPLT MALFUNCTION, BUT THIS WAS NOTICED TO BE OPERATING PROPERLY WITH ADEQUATE PRESSURE. LATER I THEN REENGAGED THE AUTOPLT AND IT WORKED. THEN AFTER A MINUTE OR SO IT TOOK OFF DROPPING A WING, BUT I THEN CAUGHT IT AND BY CLICKING THE OFF SWITCH ON THE AUTOPLT WHILE FIGHTING THE FORCE OF AUTOPLT HAD THE AUTOPLT RELEASE. IT TOOK SEVERAL ATTEMPTS TO RELEASE IT, BUT I WAS READY FOR IT AND REMAINED ON COURSE. ON THE GND AT ISM I CHKED THE AUTOPLT AND THE OPERATION WAS ERRATIC. THE OFF/HDG/OMNI SWITCH WAS NOT OPERATING PROPERLY AND TOOK REPEATED ATTEMPTS TO SHUT OFF. I HAD CHKED IT ON PREFLT AND IT TURNED OFF AND OPERATED WITH NO PROBS. THE HDG FUNCTION WAS ALSO NOTICED NOT TO OPERATE PROPERLY. I PLAN ON INSTALLING A NEW CB OR SWITCH SO I CAN QUICKLY RELEASE THE ELECTRICAL PWR. I HAVE ALSO USED AUTOPLTS ON AN SMA (SIMILAR OR SAME AUTOPLT). THIS AUTOPLT TAKES A LOT MORE FORCE TO OVERRIDE AND WOULD NOT SHUT OFF. ALSO I LOOKED MOMENTARILY AT MAP AND HIT MY CALCULATOR AND IT CAUGHT ME OFF GUARD. I HAD RECEIVED ABOUT 10 HRS OF DUAL INSTRUCTION IN IFR FLYING/TRANSITION TO THE SMA MANUAL FOR ALL SYSTEMS, BUT THE MANUAL IS SHORT AND TERRIBLY INSUFFICIENT FOR THIS MODEL ACFT. I PLAN TO GO TO FLT SAFETY T9O TAKE THE SYSTEMS COURSE AFTER THIS SECOND EMER, THE FIRST BEING AN INFLT ELECTRICAL FIRE/DIRECT SHORT IN ALTERNATOR-CONDENSER UNIT WHICH GNDED TO FRAME DUE TO MECH IMPROPERLY INSTALLED CONDENSER/ALTERNATOR UNIT. PERHAPS THIS OTHER ELECTRICAL SHORT WHICH LITERALLY BLACKENED AND BURNED ALTERNATOR AND PART OF HARNESS 20 HRS BEFORE IS RESPONSIBLE FOR THE AUTOPLT MALFUNCTION.

Data retrieved from NASA's ASRS site as of July 2007 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.