Narrative:

During my preflight of the cessna 172R rental aircraft; I noticed an entry in the maintenance/discrepancy log noting the engine missing during takeoff and climb out while using full power. The mechanic wrote next to that comment that he was unable to duplicate the problem. Another entry in the maintenance/discrepancy log [3 days later] indicated a similar problem and the mechanic indicated he fixed that problem [a few days later] and it was no longer an issue.I was next to fly the airplane [several days later]. I obtained my clearance and completed my run up of the aircraft with no problems. I taxied to the runway and was given a takeoff clearance. Takeoff was normal; and I began to climb out at 75-80 KTS airspeed. At approximately 400 feet AGL; the engine started to run really rough as it was missing badly/momentarily turning on and off. I checked the mixture/fuel cut off/fuel selector valve and they were all in the normal takeoff configuration.I was able to maintain altitude; but the aircraft was having difficulty climbing. At this time I heard the tower give a clearance to a small aircraft to land; so I told the tower I was having engine problems and that I would like to request a right turn back to [the runway] (to avoid the traffic landing). The tower granted my request and told me to make right closed traffic back to [the runway]. Because of this; the tower had to cancel the takeoff for a B747 on [another runway] that may have conflicted with my closed right traffic.I landed without incident. Lesson learned - I made the decision to return to the airport because I was unsure of the status of the engine. I requested a right turn back to the runway because I believed it would keep me away from the landing traffic. The tower granted my request but this would have been problematic had it happened 15 seconds later as the B747 would have been unable to abort its takeoff and could have resulted in a major conflict.while it all worked out; I believe a contributing factor was an inexperienced tower controller who appeared to be getting training at the time of my flight. While I never declared an emergency; my request to turn to the right was approved so I never deviated from ATC.

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Original NASA ASRS Text

Title: C172 pilot reported a rough running engine after takeoff and returned to land. Tower canceled takeoff clearance of a B747 to allow for the safe return.

Narrative: During my preflight of the Cessna 172R rental aircraft; I noticed an entry in the maintenance/discrepancy log noting the engine missing during takeoff and climb out while using full power. The Mechanic wrote next to that comment that he was unable to duplicate the problem. Another entry in the maintenance/discrepancy log [3 days later] indicated a similar problem and the Mechanic indicated he fixed that problem [a few days later] and it was no longer an issue.I was next to fly the airplane [several days later]. I obtained my clearance and completed my run up of the aircraft with no problems. I taxied to the runway and was given a takeoff clearance. Takeoff was normal; and I began to climb out at 75-80 KTS airspeed. At approximately 400 feet AGL; the engine started to run really rough as it was missing badly/momentarily turning on and off. I checked the mixture/fuel cut off/fuel selector valve and they were all in the normal takeoff configuration.I was able to maintain altitude; but the aircraft was having difficulty climbing. At this time I heard the Tower give a clearance to a small aircraft to land; so I told the Tower I was having engine problems and that I would like to request a right turn back to [the runway] (to avoid the traffic landing). The Tower granted my request and told me to make right closed traffic back to [the runway]. Because of this; the Tower had to cancel the takeoff for a B747 on [another runway] that may have conflicted with my closed right traffic.I landed without incident. Lesson learned - I made the decision to return to the airport because I was unsure of the status of the engine. I requested a right turn back to the runway because I believed it would keep me away from the landing traffic. The Tower granted my request but this would have been problematic had it happened 15 seconds later as the B747 would have been unable to abort its takeoff and could have resulted in a major conflict.While it all worked out; I believe a contributing factor was an inexperienced Tower controller who appeared to be getting training at the time of my flight. While I never declared an emergency; my request to turn to the right was approved so I never deviated from ATC.

Data retrieved from NASA's ASRS site as of July 2013 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.