Narrative:

On oct/sun/94 at about PM00 in a 1974 cessna 182P, after completing a thorough preflight and runup, I departed from runway 30 at anp. The departure was normal, I climbed to 2000 ft and contacted bwi approach on 119.0. I asked for clearance into the class B airspace with my destination being gai. After I got a squawk code, I requested 2500 ft and a change of destination to carroll county (W54). The controller told me to turn to a heading of 340 degrees, as I started my turn to the right I noticed the controls felt strange. The yoke was fluttering considerably. I felt like I was fighting to keep the plane flying straight and level. I called bwi to request a turn back to anp, I felt like an aileron was loose. I looked out the windows and saw that the ailerons were both on the plane and there was nothing hanging from the wings (because that is what the fluttering yoke felt like). Before bwi could answer my call, I started to make a very slow shallow skidding turn with the rudder. Bwi called me and I proceeded to tell them I had a problem. I said I wasn't sure what was wrong but I felt like I was about to lose a control surface. I said I was going back to anp and I wasn't sure if I would make it. The controller asked me if I needed assistance, I replied no I have the runway in sight. I was on a long final for runway 12 at anp. I was instructed to change to 122.9 and contact the bwi tower upon landing. I then declared an emergency at anp. I told the traffic I would be landing on runway 12 and to please clear the pattern. Everyone complied and, while fighting the plane, I was able to make an uneventful landing. I proceeded to the maintenance hangar where a mechanic met me and checked the plane over while I called the bwi tower. The mechanic saw nothing that was apparent to him to cause such symptoms. I was about to leave the plane with him to check out when a person who heard my story came over and told me he once experienced the same symptoms. He asked me if I had an autoplt. I said yes and checked the position of the switches. The autoplt had been activated inadvertently. This autoplt has been inoperative for as long as I have been flying this plane (3 yrs). Somehow the autoplt was activated probably when I set the transponder code (the autoplt is directly below the transponder). When the autoplt kicked on, the wing leveler or heading holder took over and tried to control the plane. Since I have never flown a plane while under autoplt control, I had no idea how the controls would feel to fight with the autoplt. After turning off the autoplt, I went up in the pattern. When I was on the downwind leg, I turned on the autoplt and got the same symptoms I had experienced earlier. I felt pretty embarrassed by the event, but I did learn one lesson from it. I learned that under what I thought were emergency conditions I kept my wits about me and flew the plane to a safe landing.

Related reports:

Google
 

Original NASA ASRS Text

Title: EMER DECLARED WHEN THE AUTOPLT WAS INADVERTENTLY SWITCHED ON.

Narrative: ON OCT/SUN/94 AT ABOUT PM00 IN A 1974 CESSNA 182P, AFTER COMPLETING A THOROUGH PREFLT AND RUNUP, I DEPARTED FROM RWY 30 AT ANP. THE DEP WAS NORMAL, I CLBED TO 2000 FT AND CONTACTED BWI APCH ON 119.0. I ASKED FOR CLRNC INTO THE CLASS B AIRSPACE WITH MY DEST BEING GAI. AFTER I GOT A SQUAWK CODE, I REQUESTED 2500 FT AND A CHANGE OF DEST TO CARROLL COUNTY (W54). THE CTLR TOLD ME TO TURN TO A HDG OF 340 DEGS, AS I STARTED MY TURN TO THE R I NOTICED THE CTLS FELT STRANGE. THE YOKE WAS FLUTTERING CONSIDERABLY. I FELT LIKE I WAS FIGHTING TO KEEP THE PLANE FLYING STRAIGHT AND LEVEL. I CALLED BWI TO REQUEST A TURN BACK TO ANP, I FELT LIKE AN AILERON WAS LOOSE. I LOOKED OUT THE WINDOWS AND SAW THAT THE AILERONS WERE BOTH ON THE PLANE AND THERE WAS NOTHING HANGING FROM THE WINGS (BECAUSE THAT IS WHAT THE FLUTTERING YOKE FELT LIKE). BEFORE BWI COULD ANSWER MY CALL, I STARTED TO MAKE A VERY SLOW SHALLOW SKIDDING TURN WITH THE RUDDER. BWI CALLED ME AND I PROCEEDED TO TELL THEM I HAD A PROB. I SAID I WASN'T SURE WHAT WAS WRONG BUT I FELT LIKE I WAS ABOUT TO LOSE A CTL SURFACE. I SAID I WAS GOING BACK TO ANP AND I WASN'T SURE IF I WOULD MAKE IT. THE CTLR ASKED ME IF I NEEDED ASSISTANCE, I REPLIED NO I HAVE THE RWY IN SIGHT. I WAS ON A LONG FINAL FOR RWY 12 AT ANP. I WAS INSTRUCTED TO CHANGE TO 122.9 AND CONTACT THE BWI TWR UPON LNDG. I THEN DECLARED AN EMER AT ANP. I TOLD THE TFC I WOULD BE LNDG ON RWY 12 AND TO PLEASE CLR THE PATTERN. EVERYONE COMPLIED AND, WHILE FIGHTING THE PLANE, I WAS ABLE TO MAKE AN UNEVENTFUL LNDG. I PROCEEDED TO THE MAINT HANGAR WHERE A MECH MET ME AND CHKED THE PLANE OVER WHILE I CALLED THE BWI TWR. THE MECH SAW NOTHING THAT WAS APPARENT TO HIM TO CAUSE SUCH SYMPTOMS. I WAS ABOUT TO LEAVE THE PLANE WITH HIM TO CHK OUT WHEN A PERSON WHO HEARD MY STORY CAME OVER AND TOLD ME HE ONCE EXPERIENCED THE SAME SYMPTOMS. HE ASKED ME IF I HAD AN AUTOPLT. I SAID YES AND CHKED THE POS OF THE SWITCHES. THE AUTOPLT HAD BEEN ACTIVATED INADVERTENTLY. THIS AUTOPLT HAS BEEN INOP FOR AS LONG AS I HAVE BEEN FLYING THIS PLANE (3 YRS). SOMEHOW THE AUTOPLT WAS ACTIVATED PROBABLY WHEN I SET THE XPONDER CODE (THE AUTOPLT IS DIRECTLY BELOW THE XPONDER). WHEN THE AUTOPLT KICKED ON, THE WING LEVELER OR HDG HOLDER TOOK OVER AND TRIED TO CTL THE PLANE. SINCE I HAVE NEVER FLOWN A PLANE WHILE UNDER AUTOPLT CTL, I HAD NO IDEA HOW THE CTLS WOULD FEEL TO FIGHT WITH THE AUTOPLT. AFTER TURNING OFF THE AUTOPLT, I WENT UP IN THE PATTERN. WHEN I WAS ON THE DOWNWIND LEG, I TURNED ON THE AUTOPLT AND GOT THE SAME SYMPTOMS I HAD EXPERIENCED EARLIER. I FELT PRETTY EMBARRASSED BY THE EVENT, BUT I DID LEARN ONE LESSON FROM IT. I LEARNED THAT UNDER WHAT I THOUGHT WERE EMER CONDITIONS I KEPT MY WITS ABOUT ME AND FLEW THE PLANE TO A SAFE LNDG.

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.