Narrative:

While performing aerobatics, I adjusted the power to 92% in order to set up for a cloverleaf. While accelerating to 320 KIAS, I encountered a low frequency rumble. I checked the engine instruments. Everything indicated normal. I turned to a west heading, retarded the power to 70% and traded altitude for airspeed and leveled off at 17500 ft. I retrieved ATIS information from iwa ATIS. I contacted iwa tower and they cleared me into class B airspace. I performed a precautionary sfo to runway 30R landing without incident. In-flight, the rumble ceased as the power was reduced through 87%. The rest of the flight was made at 70% with no rumble and normal instrument readings were observed throughout.

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Original NASA ASRS Text

Title: CANADAIR T133 EXPERIENCES ENG RUMBLE ROUGHNESS DURING AEROBATIC TRAINING AND MAKES PRECAUTIONARY LNDG AT IWA. THE T133 IS ACTUALLY A LOCKHEED T33 BUILT UNDER LICENSE BY CANADAIR.

Narrative: WHILE PERFORMING AEROBATICS, I ADJUSTED THE PWR TO 92% IN ORDER TO SET UP FOR A CLOVERLEAF. WHILE ACCELERATING TO 320 KIAS, I ENCOUNTERED A LOW FREQ RUMBLE. I CHKED THE ENG INSTS. EVERYTHING INDICATED NORMAL. I TURNED TO A W HDG, RETARDED THE PWR TO 70% AND TRADED ALT FOR AIRSPD AND LEVELED OFF AT 17500 FT. I RETRIEVED ATIS INFO FROM IWA ATIS. I CONTACTED IWA TWR AND THEY CLRED ME INTO CLASS B AIRSPACE. I PERFORMED A PRECAUTIONARY SFO TO RWY 30R LNDG WITHOUT INCIDENT. INFLT, THE RUMBLE CEASED AS THE PWR WAS REDUCED THROUGH 87%. THE REST OF THE FLT WAS MADE AT 70% WITH NO RUMBLE AND NORMAL INST READINGS WERE OBSERVED THROUGHOUT.

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.