Narrative:

My plan had me flying 15 miles away to pick up my son at another airport. I had filed an instrument flight plan (ifp) to commence from the next airport after picking him up. However; about 30 seconds into my takeoff climb; I sensed the need to relieve nose down trim and turned the trim wheel slightly for nose up. The nose down pressure got worse; and my initial thought was a stuck elevator. I visually checked and the elevator was moving properly. However; I was gaining airspeed but could not climb even though I had the yoke pulled back to my stomach with tremendous force required. I trimmed a bit more and the problem worsened - I was now almost 'full' nose up trim with the yoke fully back. I was about to look for a place to put down as I didn't know how long I could hold the yoke back and knew landing was going to be very difficult (at this point I was past the emergency landing field). On a hunch; I turned the trim wheel the opposite direction - nose down - and immediately felt a relief of the pressure. Further nose down trim relieved the nose down pressure. After some back and forth with the trim wheel; I realized that the trim cable had been installed/wound backward on the spool. By operating the trim opposite of normal; I was able to recover normal control; turn around and make a normal landing at the airport I had departed from. Upon return I reported the incident to the flight chief. Recently the operator had lost its' mechanic (an excellent one; by the way) and had had [aircraft] firewall work done by a private aviation service on airport. Upon re-inspection; the operator and mechanic determined that the trim cable had been re-installed backward as part of the firewall work and I was the first person to fly the plane post-repair.I had checked both manual and electric trim as part of the pre-flight checklist and took off with trim in 'takeoff' position. However; I now realize that the preflight checklist I used included a check that; electric trim was 'in motion' when activated by the yoke-mounted button; but did not include noting a proper direction of motion. I have since added that check to my pre-flight checklist and have advised others to do so. In talking to the flight chief; this is apparently something well known to cessna mechanics; but an easy mistake for a less experienced mechanic to make.

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Original NASA ASRS Text

Title: During takeoff climb in a Cessna 172 aircraft; pilot notices that increasing the amount of nose up trim required a greater amount of pulling back on the control yoke. He could not climb even though the yoke was pulled back to his stomach. Moving trim wheel nose down in opposite direction brought the aircraft's nose up. Trim cable had been installed backwards on spool.

Narrative: My plan had me flying 15 miles away to pick up my son at another airport. I had filed an Instrument Flight Plan (IFP) to commence from the next airport after picking him up. However; about 30 seconds into my takeoff climb; I sensed the need to relieve nose down trim and turned the trim wheel slightly for nose up. The nose down pressure got worse; and my initial thought was a stuck elevator. I visually checked and the elevator was moving properly. However; I was gaining airspeed but could not climb even though I had the yoke pulled back to my stomach with tremendous force required. I trimmed a bit more and the problem worsened - I was now almost 'full' nose up trim with the yoke fully back. I was about to look for a place to put down as I didn't know how long I could hold the yoke back and knew landing was going to be very difficult (at this point I was past the emergency landing field). On a hunch; I turned the trim wheel the opposite direction - nose down - and immediately felt a relief of the pressure. Further nose down trim relieved the nose down pressure. After some back and forth with the trim wheel; I realized that the trim cable had been installed/wound backward on the spool. By operating the trim opposite of normal; I was able to recover normal control; turn around and make a normal landing at the airport I had departed from. Upon return I reported the incident to the Flight Chief. Recently the Operator had lost its' Mechanic (an excellent one; by the way) and had had [aircraft] firewall work done by a private aviation service on airport. Upon re-inspection; the Operator and Mechanic determined that the trim cable had been re-installed backward as part of the firewall work and I was the first person to fly the plane post-repair.I had checked both Manual and Electric Trim as part of the Pre-flight Checklist and took off with trim in 'Takeoff' position. However; I now realize that the Preflight Checklist I used included a check that; Electric Trim was 'in motion' when activated by the yoke-mounted button; but did not include noting a proper DIRECTION of motion. I have since added that check to my Pre-flight Checklist and have advised others to do so. In talking to the Flight Chief; this is apparently something well known to Cessna mechanics; but an easy mistake for a less experienced mechanic to make.

Data retrieved from NASA's ASRS site 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.