Narrative:

I usually fly at a flying school which operates small aircraft's which have been retrofitted with 180 hp engines. These include a, B, and C models, but we use the X model handbook because of their . On the date mentioned, I rented an small aircraft from another FBO. I used the X handbook to calculate the weight and balance for myself, full fuel, and 3 passenger. The gtow was 2530, 30 pounds under gross weight for the X model. On the flight from prc-sez, I noticed that aircraft performance was 'unusual.' maximum rate of climb was 200 FPM. I figured that this was due to the lower horsepwr engine and density altitude. On final approach to sez (located on a mesa), with full power and 30 degrees flaps, min descent rate was bout -200 FPM. Due to strong downdrafts. Performance on the return leg was better. A couple days ago, I found an old model book I had used while renting aircraft in canada. I wanted to transfer the aircraft I rented most often (weight and moment) in the 'X' model book, which was in much better shape. A comparison of the maximum gross takeoff weight of both aircraft caught my attention. The maximum gross takeoff weight of an 'a' model is 2300 pounds. I now estimate that at takeoff, the aircraft was approximately 220 pounds over maximum gross takeoff weight. A lesson has been learned. It is now my habit to check the aircraft poh (under weight and balance) to verify the maximum gross takeoff weight prior to flying an unfamiliar airplane, even if it is of the same type.

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Original NASA ASRS Text

Title: SMA PLT PERFORMS A TKOF PROC EXCEEDING THE ACFT ALLOWABLE GROSS WT.

Narrative: I USUALLY FLY AT A FLYING SCHOOL WHICH OPERATES SMA'S WHICH HAVE BEEN RETROFITTED WITH 180 HP ENGS. THESE INCLUDE A, B, AND C MODELS, BUT WE USE THE X MODEL HANDBOOK BECAUSE OF THEIR . ON THE DATE MENTIONED, I RENTED AN SMA FROM ANOTHER FBO. I USED THE X HANDBOOK TO CALCULATE THE WT AND BAL FOR MYSELF, FULL FUEL, AND 3 PAX. THE GTOW WAS 2530, 30 POUNDS UNDER GROSS WT FOR THE X MODEL. ON THE FLT FROM PRC-SEZ, I NOTICED THAT ACFT PERFORMANCE WAS 'UNUSUAL.' MAX RATE OF CLB WAS 200 FPM. I FIGURED THAT THIS WAS DUE TO THE LOWER HORSEPWR ENG AND DENSITY ALT. ON FINAL APCH TO SEZ (LOCATED ON A MESA), WITH FULL PWR AND 30 DEGS FLAPS, MIN DSCNT RATE WAS BOUT -200 FPM. DUE TO STRONG DOWNDRAFTS. PERFORMANCE ON THE RETURN LEG WAS BETTER. A COUPLE DAYS AGO, I FOUND AN OLD MODEL BOOK I HAD USED WHILE RENTING ACFT IN CANADA. I WANTED TO TRANSFER THE ACFT I RENTED MOST OFTEN (WT AND MOMENT) IN THE 'X' MODEL BOOK, WHICH WAS IN MUCH BETTER SHAPE. A COMPARISON OF THE MAX GROSS TKOF WT OF BOTH ACFT CAUGHT MY ATTN. THE MAX GROSS TKOF WT OF AN 'A' MODEL IS 2300 POUNDS. I NOW ESTIMATE THAT AT TKOF, THE ACFT WAS APPROX 220 POUNDS OVER MAX GROSS TKOF WT. A LESSON HAS BEEN LEARNED. IT IS NOW MY HABIT TO CHK THE ACFT POH (UNDER WT AND BAL) TO VERIFY THE MAX GROSS TKOF WT PRIOR TO FLYING AN UNFAMILIAR AIRPLANE, EVEN IF IT IS OF THE SAME TYPE.

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.