Narrative:

While on a maintenance check flight; C172 for maintenance department; the elevator became restr from full and proper upward deflection. The elevator could travel from the full downward position up to about 3-5 degrees above center. This limited the overall nose-up pitch control of the aircraft during flight. The elevator restr was present during the entire flight in the traffic pattern for runway 7R but was only noticeably present during the approach and flare stages of flight. Due to my failure to fully recognize the situation and the cause of it; I performed a second flight around the traffic pattern to continue my test of the instruments. Once the issue was fully recognized during the second flight in the traffic pattern; the maximum nose up trim and full flaps were established to ensure the safest possible landing. I was performing this maintenance flight to test for errors in the directional gyro and a new installed attitude indicator. The flight was flown during VFR conditions and the indicated airspeed ranged from 60-100 KTS in-flight. Prior to takeoff; the checklist was used to perform the run-up (power) check which included a check of the flight controls. All of the checks were performed and everything seemed to operate properly. After returning from the flight; the issue was inspected by an airframe and power plant certified maintenance technician. The technician found that the yoke was restr by a vacuum hose that was attached to the attitude indicator that was just installed. Callback conversation with reporter revealed the following information: the reporter stated on the first flight the control check appeared normal and takeoff and climb were ok and only on the landing flare was the limited yoke movement noted. Everything checked ok on the ground so a second flight was made immediately without any mechanical inspection. On the second flight it was recognized the problem was limited yoke movement in pitch. This was hidden as the airplane trimmed fine in pitch and again the limited movement was experienced on landing in the flare stage. Inspection was made of the yoke and a vacuum hose was found routed incorrectly allowing the yoke to pinch the hose; limiting the movement.

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Original NASA ASRS Text

Title: A C172; ON A MAINT TEST FLT; PLT NOTED IN FLARE STAGE LIMITED YOKE MOVEMENT IN PITCH. FOUND VACUUM HOSE RESTRICTING YOKE MOVEMENT.

Narrative: WHILE ON A MAINT CHK FLT; C172 FOR MAINT DEPT; THE ELEVATOR BECAME RESTR FROM FULL AND PROPER UPWARD DEFLECTION. THE ELEVATOR COULD TRAVEL FROM THE FULL DOWNWARD POS UP TO ABOUT 3-5 DEGS ABOVE CTR. THIS LIMITED THE OVERALL NOSE-UP PITCH CTL OF THE ACFT DURING FLT. THE ELEVATOR RESTR WAS PRESENT DURING THE ENTIRE FLT IN THE TFC PATTERN FOR RWY 7R BUT WAS ONLY NOTICEABLY PRESENT DURING THE APCH AND FLARE STAGES OF FLT. DUE TO MY FAILURE TO FULLY RECOGNIZE THE SITUATION AND THE CAUSE OF IT; I PERFORMED A SECOND FLT AROUND THE TFC PATTERN TO CONTINUE MY TEST OF THE INSTS. ONCE THE ISSUE WAS FULLY RECOGNIZED DURING THE SECOND FLT IN THE TFC PATTERN; THE MAX NOSE UP TRIM AND FULL FLAPS WERE ESTABLISHED TO ENSURE THE SAFEST POSSIBLE LNDG. I WAS PERFORMING THIS MAINT FLT TO TEST FOR ERRORS IN THE DIRECTIONAL GYRO AND A NEW INSTALLED ATTITUDE INDICATOR. THE FLT WAS FLOWN DURING VFR CONDITIONS AND THE INDICATED AIRSPD RANGED FROM 60-100 KTS INFLT. PRIOR TO TKOF; THE CHKLIST WAS USED TO PERFORM THE RUN-UP (PWR) CHK WHICH INCLUDED A CHK OF THE FLT CTLS. ALL OF THE CHKS WERE PERFORMED AND EVERYTHING SEEMED TO OPERATE PROPERLY. AFTER RETURNING FROM THE FLT; THE ISSUE WAS INSPECTED BY AN AIRFRAME AND PWR PLANT CERTIFIED MAINT TECHNICIAN. THE TECHNICIAN FOUND THAT THE YOKE WAS RESTR BY A VACUUM HOSE THAT WAS ATTACHED TO THE ATTITUDE INDICATOR THAT WAS JUST INSTALLED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED ON THE FIRST FLT THE CTL CHK APPEARED NORMAL AND TKOF AND CLB WERE OK AND ONLY ON THE LNDG FLARE WAS THE LIMITED YOKE MOVEMENT NOTED. EVERYTHING CHKED OK ON THE GND SO A SECOND FLT WAS MADE IMMEDIATELY WITHOUT ANY MECHANICAL INSPECTION. ON THE SECOND FLT IT WAS RECOGNIZED THE PROB WAS LIMITED YOKE MOVEMENT IN PITCH. THIS WAS HIDDEN AS THE AIRPLANE TRIMMED FINE IN PITCH AND AGAIN THE LIMITED MOVEMENT WAS EXPERIENCED ON LNDG IN THE FLARE STAGE. INSPECTION WAS MADE OF THE YOKE AND A VACUUM HOSE WAS FOUND ROUTED INCORRECTLY ALLOWING THE YOKE TO PINCH THE HOSE; LIMITING THE MOVEMENT.

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.