Narrative:

The situation I am reporting is a failure of the manifold pressure gauge on my club's C182 while in-flight. There had been problems with the gauge previously, and upon my arrival at my airport to take the plane for the flight, I was informed that the gauge had been fixed. My plan was to practice several approachs to toledo VFR, but as I began to follow vectors to the first approach, I realized that I would not be able to maintain legal VFR, so I requested and obtained a local IFR clearance to continue the approachs. On the first approach, after making a power reduction to join the GS, I discovered that I was having difficulty remaining on the GS. I checked the manifold pressure and realized that although the gauge said 21 inches, the power output was more like 12-16 inches. I informed approach that I was having an instrument problem, and would like a return to my home airport rather than multiple approachs at toledo. I flew the missed approach segment and then the approach to my base by pitch and airspeed, and was able to return home in a safe manner. I feel that if I had not been so well trained, however, this situation could have been disastrous. Upon consultation with my mechanic after my return, we concluded that the most likely cause was a faulty seal, and he grounded the plane per far 91.208 until the situation could be repaired. As this situation was not a near miss, controller error, or possible violation, I am not really sure what else you need to know, so please contact me if you need any further information.

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Original NASA ASRS Text

Title: C182 WAS PLANNING NUMEROUS IFR APCHS. ON GS WAS HAVING PROBS MAINTAINING GS AND REALIZED MANIFOLD PRESSURE GAUGE WAS NOT WORKING, SHOWED 21 INCHES BUT ENG WAS ONLY PRODUCING ABOUT 12 INCHES. ADVISED CTLR AND RETURNED TO HOME BASE.

Narrative: THE SIT I AM RPTING IS A FAILURE OF THE MANIFOLD PRESSURE GAUGE ON MY CLUB'S C182 WHILE INFLT. THERE HAD BEEN PROBS WITH THE GAUGE PREVIOUSLY, AND UPON MY ARR AT MY ARPT TO TAKE THE PLANE FOR THE FLT, I WAS INFORMED THAT THE GAUGE HAD BEEN FIXED. MY PLAN WAS TO PRACTICE SEVERAL APCHS TO TOLEDO VFR, BUT AS I BEGAN TO FOLLOW VECTORS TO THE FIRST APCH, I REALIZED THAT I WOULD NOT BE ABLE TO MAINTAIN LEGAL VFR, SO I REQUESTED AND OBTAINED A LCL IFR CLRNC TO CONTINUE THE APCHS. ON THE FIRST APCH, AFTER MAKING A PWR REDUCTION TO JOIN THE GS, I DISCOVERED THAT I WAS HAVING DIFFICULTY REMAINING ON THE GS. I CHKED THE MANIFOLD PRESSURE AND REALIZED THAT ALTHOUGH THE GAUGE SAID 21 INCHES, THE PWR OUTPUT WAS MORE LIKE 12-16 INCHES. I INFORMED APCH THAT I WAS HAVING AN INST PROB, AND WOULD LIKE A RETURN TO MY HOME ARPT RATHER THAN MULTIPLE APCHS AT TOLEDO. I FLEW THE MISSED APCH SEGMENT AND THEN THE APCH TO MY BASE BY PITCH AND AIRSPD, AND WAS ABLE TO RETURN HOME IN A SAFE MANNER. I FEEL THAT IF I HAD NOT BEEN SO WELL TRAINED, HOWEVER, THIS SIT COULD HAVE BEEN DISASTROUS. UPON CONSULTATION WITH MY MECH AFTER MY RETURN, WE CONCLUDED THAT THE MOST LIKELY CAUSE WAS A FAULTY SEAL, AND HE GNDED THE PLANE PER FAR 91.208 UNTIL THE SIT COULD BE REPAIRED. AS THIS SIT WAS NOT A NEAR MISS, CTLR ERROR, OR POSSIBLE VIOLATION, I AM NOT REALLY SURE WHAT ELSE YOU NEED TO KNOW, SO PLEASE CONTACT ME IF YOU NEED ANY FURTHER INFO.

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.