Narrative:

I was working the north area low sectors combined. Saturday morning traffic is usually slow and easy as it was when aircraft X [had a problem]. As I realized the aircraft needed more attention than the 'normal' [situation]; the sector started to get busy; so I had the supervisor split the sector off. Aircraft X was flying eastbound when I noticed the aircraft was not level and looked like it had made a quick 180 degree turn. I thought for a second; maybe it's the normal mode C hiccup that centers sometimes get. I waited for the next update and it had not corrected. I told the pilot I showed him off course and not at the assigned altitude. The pilot came right back and said we're declaring. I could tell he was trying to get the 7700 code in. The pilot told me he was having trouble with his number 1 engine and having a hard time controlling the aircraft.I gave the pilot the location of ZZZ which was 10 miles to the southwest of him. I gave the pilot the weather and runway information; then the same for [another nearby airport]. Aircraft X asked about ZZZ2 130 miles to the east. I ultimately convinced him that ZZZ3 was the best place. It was 40 miles away; and from his present position was almost lined up with runway. I told him early on that altitude was his discretion; and ultimately gave him a block of 4000 ft to 9000 ft. When he had some control of the aircraft; I asked if he could take a frequency switch; and he said yes. I switched him to approach and later I got the call he landed safely. It was a malfunction of an aircraft; a twin piston at that; you lose the left engine so you have reverse P factor on the right engine. The most difficult thing in multi engine flying is keeping a plane like that straight and level.

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Original NASA ASRS Text

Title: ZAU Center Controller and Developmental reported working an aircraft with control problems that resulted in a diversion to a nearby airport.

Narrative: I was working the north area low sectors combined. Saturday morning traffic is usually slow and easy as it was when Aircraft X [had a problem]. As I realized the aircraft needed more attention than the 'normal' [situation]; the sector started to get busy; so I had the Supervisor split the sector off. Aircraft X was flying eastbound when I noticed the aircraft was not level and looked like it had made a quick 180 degree turn. I thought for a second; maybe it's the normal Mode C hiccup that centers sometimes get. I waited for the next update and it had not corrected. I told the pilot I showed him off course and not at the assigned altitude. The pilot came right back and said we're declaring. I could tell he was trying to get the 7700 code in. The pilot told me he was having trouble with his number 1 engine and having a hard time controlling the aircraft.I gave the pilot the location of ZZZ which was 10 miles to the southwest of him. I gave the pilot the weather and runway information; then the same for [another nearby airport]. Aircraft X asked about ZZZ2 130 miles to the east. I ultimately convinced him that ZZZ3 was the best place. It was 40 miles away; and from his present position was almost lined up with runway. I told him early on that altitude was his discretion; and ultimately gave him a block of 4000 ft to 9000 ft. When he had some control of the aircraft; I asked if he could take a frequency switch; and he said yes. I switched him to Approach and later I got the call he landed safely. It was a malfunction of an aircraft; a twin piston at that; you lose the left engine so you have reverse P factor on the right engine. The most difficult thing in multi engine flying is keeping a plane like that straight and level.

Data retrieved from NASA's ASRS site 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.