Narrative:

As I climbed through about 4000 ft MSL, while departing sue, I noticed both engine temperatures of my BE58 rapidly increasing toward red line. I had been cleared by grb approach to climb and maintain 6000 ft and contact ZMP. I immediately reduced power and leveled off at about 4500 ft MSL. I quickly noted the outside air temperature to be -16 degrees C and the engine cowl flaps to be fully open. I then checked in with ZMP and informed them that I needed an immediate turn and descent to land back at sue. I began my left turn and descent as I was getting clearance to do so. Center asked if I was declaring an emergency and I responded 'negative at this time. I have an engine temperature problem that seems to be under control at a greatly reduced power setting.' shortly after this, I was switched back to grb approach and cleared for the visual into sue. I canceled my IFR flight plan on short final to runway 27 at sue. Once on the ground at sue, I advised grb approach, as they had requested and taxied to the ramp. I shut down the engines, got out and inspected the aircraft. Upon inspection, I found that the homemade cowling plugs, which were nonstandard, had not been removed during preflight. (By nonstandard, I mean that they were not red and had no visual indications from the cockpit of their presence in the cowling.) I believe that this was a major factor in my failure to notice that the cowling plugs were still in the cowling.

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Original NASA ASRS Text

Title: PLT OF AN ATX BEECH BE58 RETURNED TO LAND AFTER BOTH ENGS' TEMPS WERE RAPIDLY INCREASING TO THE RED LINE.

Narrative: AS I CLBED THROUGH ABOUT 4000 FT MSL, WHILE DEPARTING SUE, I NOTICED BOTH ENG TEMPS OF MY BE58 RAPIDLY INCREASING TOWARD RED LINE. I HAD BEEN CLRED BY GRB APCH TO CLB AND MAINTAIN 6000 FT AND CONTACT ZMP. I IMMEDIATELY REDUCED PWR AND LEVELED OFF AT ABOUT 4500 FT MSL. I QUICKLY NOTED THE OUTSIDE AIR TEMP TO BE -16 DEGS C AND THE ENG COWL FLAPS TO BE FULLY OPEN. I THEN CHKED IN WITH ZMP AND INFORMED THEM THAT I NEEDED AN IMMEDIATE TURN AND DSCNT TO LAND BACK AT SUE. I BEGAN MY L TURN AND DSCNT AS I WAS GETTING CLRNC TO DO SO. CTR ASKED IF I WAS DECLARING AN EMER AND I RESPONDED 'NEGATIVE AT THIS TIME. I HAVE AN ENG TEMP PROB THAT SEEMS TO BE UNDER CTL AT A GREATLY REDUCED PWR SETTING.' SHORTLY AFTER THIS, I WAS SWITCHED BACK TO GRB APCH AND CLRED FOR THE VISUAL INTO SUE. I CANCELED MY IFR FLT PLAN ON SHORT FINAL TO RWY 27 AT SUE. ONCE ON THE GND AT SUE, I ADVISED GRB APCH, AS THEY HAD REQUESTED AND TAXIED TO THE RAMP. I SHUT DOWN THE ENGS, GOT OUT AND INSPECTED THE ACFT. UPON INSPECTION, I FOUND THAT THE HOMEMADE COWLING PLUGS, WHICH WERE NONSTANDARD, HAD NOT BEEN REMOVED DURING PREFLT. (BY NONSTANDARD, I MEAN THAT THEY WERE NOT RED AND HAD NO VISUAL INDICATIONS FROM THE COCKPIT OF THEIR PRESENCE IN THE COWLING.) I BELIEVE THAT THIS WAS A MAJOR FACTOR IN MY FAILURE TO NOTICE THAT THE COWLING PLUGS WERE STILL IN THE COWLING.

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.