Narrative:

I was flying a rental aircraft round trip from aiken, sc, to pickens, sc. The rental was a C172 which uses a control lock to secure the yoke while parked on the ground. The plane I own and normally fly is a cherokee 180, which uses seatbelts to secure the yoke. After a normal preflight, my flight from aiken to pickens was uneventful. In pickens, after landing, I secured the yoke with the control lock. On returning to the plane parked at the pickens airport, I discovered I had left my flashlight in aiken. It was after XA00 and dark but the lighting outside the plane was adequate for a preflight inspection of the exterior of the plane. The lighting on the interior was marginal and some of the lights were inoperable leaving portions of the dash hard to see, but I judged I had enough light to safely taxi and operate the plane. On looking over the exterior of the plane, I noticed the controls were locked but knowing the control yoke was secure, I continued with my inspection thinking I could verify operation of the controls after removing the yoke lock. After entering the plane, my primary attention was focused on getting enough light on the control panel to operate the plane safely and I forgot completely about the yoke lock. The yoke lock was totally invisible with the lighting available. During the runup at the end of the taxiway, I always check for full operation of the controls. It is a habit firmly entrenched from yrs of flying. Anyone who has ever flown with me knows I run the yoke through the full extremities of its operation to show them where they have to put their legs and knees to be sure they don't get banged during landing. If I had been asked to bet on whether I had checked the operation of the yoke just before taking the runway at pickens, I would have bet any amount of money that I had. Obviously, though, I had not, and I still cannot tell you why. After the plane reached 80 KTS and was showing no signs of lifting off, I realized for the first time that something was wrong. The first thing I did was adjust the trim to make sure I hadn't adjusted it wrong because of the poor lighting. When this did no good, I pulled back hard on the yoke and suddenly realized the lock must be in place. With the plane still accelerating for takeoff, I felt for and found the yoke lock, but was unable to remove it. At that time, I immediately shut the engine down and applied full brakes but too little runway remained for the plane to stop safely and it went off the end of the runway down a grassy slope. The damage to the plane was not severe and the event has been termed an incident rather than an accident but it easily could have been much worse. I worked for 18 yrs as an engineer for a chemical company, which is noted worldwide for its reputation on putting safety first. From that experience I would like to offer a suggestion about yoke locks. Since my incident numerous people have shared horror stories with me about yoke locks. They've mentioned numerous accidents where people have died because they left the lock in place and still more incidents where near misses occurred for the same reason. Even though a proper preflight and runup protect against this problem, if chemical company safety standards were applied, the method for locking yokes would be redesigned to eliminate the possibility of leaving the lock in place accidentally. Human error is always assumed possible and fail-safe safeguards are used to protect against someone making an error that can make the situation unsafe whenever practical.

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Original NASA ASRS Text

Title: C172 PLT WENT OFF THE FAR END OF A 5002 FT RWY AFTER ATTEMPTING TKOF WITH THE CTL LOCK IN PLACE.

Narrative: I WAS FLYING A RENTAL ACFT ROUND TRIP FROM AIKEN, SC, TO PICKENS, SC. THE RENTAL WAS A C172 WHICH USES A CTL LOCK TO SECURE THE YOKE WHILE PARKED ON THE GND. THE PLANE I OWN AND NORMALLY FLY IS A CHEROKEE 180, WHICH USES SEATBELTS TO SECURE THE YOKE. AFTER A NORMAL PREFLT, MY FLT FROM AIKEN TO PICKENS WAS UNEVENTFUL. IN PICKENS, AFTER LNDG, I SECURED THE YOKE WITH THE CTL LOCK. ON RETURNING TO THE PLANE PARKED AT THE PICKENS ARPT, I DISCOVERED I HAD LEFT MY FLASHLIGHT IN AIKEN. IT WAS AFTER XA00 AND DARK BUT THE LIGHTING OUTSIDE THE PLANE WAS ADEQUATE FOR A PREFLT INSPECTION OF THE EXTERIOR OF THE PLANE. THE LIGHTING ON THE INTERIOR WAS MARGINAL AND SOME OF THE LIGHTS WERE INOPERABLE LEAVING PORTIONS OF THE DASH HARD TO SEE, BUT I JUDGED I HAD ENOUGH LIGHT TO SAFELY TAXI AND OPERATE THE PLANE. ON LOOKING OVER THE EXTERIOR OF THE PLANE, I NOTICED THE CTLS WERE LOCKED BUT KNOWING THE CTL YOKE WAS SECURE, I CONTINUED WITH MY INSPECTION THINKING I COULD VERIFY OP OF THE CTLS AFTER REMOVING THE YOKE LOCK. AFTER ENTERING THE PLANE, MY PRIMARY ATTN WAS FOCUSED ON GETTING ENOUGH LIGHT ON THE CTL PANEL TO OPERATE THE PLANE SAFELY AND I FORGOT COMPLETELY ABOUT THE YOKE LOCK. THE YOKE LOCK WAS TOTALLY INVISIBLE WITH THE LIGHTING AVAILABLE. DURING THE RUNUP AT THE END OF THE TXWY, I ALWAYS CHK FOR FULL OP OF THE CTLS. IT IS A HABIT FIRMLY ENTRENCHED FROM YRS OF FLYING. ANYONE WHO HAS EVER FLOWN WITH ME KNOWS I RUN THE YOKE THROUGH THE FULL EXTREMITIES OF ITS OP TO SHOW THEM WHERE THEY HAVE TO PUT THEIR LEGS AND KNEES TO BE SURE THEY DON'T GET BANGED DURING LNDG. IF I HAD BEEN ASKED TO BET ON WHETHER I HAD CHKED THE OP OF THE YOKE JUST BEFORE TAKING THE RWY AT PICKENS, I WOULD HAVE BET ANY AMOUNT OF MONEY THAT I HAD. OBVIOUSLY, THOUGH, I HAD NOT, AND I STILL CANNOT TELL YOU WHY. AFTER THE PLANE REACHED 80 KTS AND WAS SHOWING NO SIGNS OF LIFTING OFF, I REALIZED FOR THE FIRST TIME THAT SOMETHING WAS WRONG. THE FIRST THING I DID WAS ADJUST THE TRIM TO MAKE SURE I HADN'T ADJUSTED IT WRONG BECAUSE OF THE POOR LIGHTING. WHEN THIS DID NO GOOD, I PULLED BACK HARD ON THE YOKE AND SUDDENLY REALIZED THE LOCK MUST BE IN PLACE. WITH THE PLANE STILL ACCELERATING FOR TKOF, I FELT FOR AND FOUND THE YOKE LOCK, BUT WAS UNABLE TO REMOVE IT. AT THAT TIME, I IMMEDIATELY SHUT THE ENG DOWN AND APPLIED FULL BRAKES BUT TOO LITTLE RWY REMAINED FOR THE PLANE TO STOP SAFELY AND IT WENT OFF THE END OF THE RWY DOWN A GRASSY SLOPE. THE DAMAGE TO THE PLANE WAS NOT SEVERE AND THE EVENT HAS BEEN TERMED AN INCIDENT RATHER THAN AN ACCIDENT BUT IT EASILY COULD HAVE BEEN MUCH WORSE. I WORKED FOR 18 YRS AS AN ENGINEER FOR A CHEMICAL COMPANY, WHICH IS NOTED WORLDWIDE FOR ITS REPUTATION ON PUTTING SAFETY FIRST. FROM THAT EXPERIENCE I WOULD LIKE TO OFFER A SUGGESTION ABOUT YOKE LOCKS. SINCE MY INCIDENT NUMEROUS PEOPLE HAVE SHARED HORROR STORIES WITH ME ABOUT YOKE LOCKS. THEY'VE MENTIONED NUMEROUS ACCIDENTS WHERE PEOPLE HAVE DIED BECAUSE THEY LEFT THE LOCK IN PLACE AND STILL MORE INCIDENTS WHERE NEAR MISSES OCCURRED FOR THE SAME REASON. EVEN THOUGH A PROPER PREFLT AND RUNUP PROTECT AGAINST THIS PROB, IF CHEMICAL COMPANY SAFETY STANDARDS WERE APPLIED, THE METHOD FOR LOCKING YOKES WOULD BE REDESIGNED TO ELIMINATE THE POSSIBILITY OF LEAVING THE LOCK IN PLACE ACCIDENTALLY. HUMAN ERROR IS ALWAYS ASSUMED POSSIBLE AND FAIL-SAFE SAFEGUARDS ARE USED TO PROTECT AGAINST SOMEONE MAKING AN ERROR THAT CAN MAKE THE SIT UNSAFE WHENEVER PRACTICAL.

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.