Narrative:

An adjacent center advised me that air carrier X was declaring an emergency. The aircraft was experiencing pressurization problems. Instead of landing ZZZ airport; which he was closest to at that time; the pilot insisted that he wanted to continue on his route of flight to land at ZZZ1 airport. When he checked on; I issued the current altimeter and asked what type of approach he would be requesting and also informed him that I was aware of his emergency situation. I also told him to let me know when he had the current weather and notams. He advised me that he had the weather; but requested any notams for the airport. I told him I would look at the ones pertaining to the airport and advise him of any that were pertinent; however I found none. He then asked for an approach using runway xx into ZZZ1; and since there are two; I asked him to specify his request for the lda approach or the GPS approach. He chose the [latter] and I cleared him correctly for the approach. During this time; I also asked him for the fuel remaining in time and also the souls on board when he had a chance. About a minute after commencing the approach; the pilot informed me that he set up the approach wrong and requested a vector back to ZZZ VOR to begin the approach again or to just make a right 360 degree turn. At this point his altitude displayed 12;900 ft. After clarifying with him what exactly he was requesting; I cleared him 'as requested' to make his right 360 to begin the approach again. My biggest mistake here was that I did not issue an altitude to maintain. I imagine that if I had done so; I would have remembered the 12;400 ft mia block off to his right that I had just cleared him through for his 360 request. I called TRACON X and told them what was going on since he would be re-entering their airspace and they gave me control. As he began his 360 turn he was still in the descent and now below the mia. The OM at the front desk called my supervisor and told me to climb the aircraft back up to a safe altitude; but it was already too late. I climbed the aircraft up to 13;000 ft and a couple minutes later issued a 'low altitude alert.' I then re-issued him his approach clearance into ZZZ1. My thoughts at the time were disappointment in myself. I know that 12;400 ft mia block very well. We issue clearances through it all day long. But being as how it was my last session of the night before I was able to go home; and the pilot had informed me of his emergency; I thought of nothing else but helping him out as much as I could without hesitation. I know that; even in an emergency; we still cannot vector aircraft below the mia. It was just a stupid mistake and I was not thinking clearly in the excitement of the situation.

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Original NASA ASRS Text

Title: Enroute Controller described a failure to comply with MIA requirements during the handling of an emergency aircraft; the reporter listing concentration on assisting the emergency as a causal factor.

Narrative: An adjacent Center advised me that Air Carrier X was declaring an emergency. The aircraft was experiencing pressurization problems. Instead of landing ZZZ airport; which he was closest to at that time; the Pilot insisted that he wanted to continue on his route of flight to land at ZZZ1 airport. When he checked on; I issued the current altimeter and asked what type of approach he would be requesting and also informed him that I was aware of his emergency situation. I also told him to let me know when he had the current weather and NOTAMs. He advised me that he had the weather; but requested any NOTAMs for the airport. I told him I would look at the ones pertaining to the airport and advise him of any that were pertinent; however I found none. He then asked for an approach using Runway XX into ZZZ1; and since there are two; I asked him to specify his request for the LDA approach or the GPS approach. He chose the [latter] and I cleared him correctly for the approach. During this time; I also asked him for the fuel remaining in time and also the souls on board when he had a chance. About a minute after commencing the approach; the Pilot informed me that he set up the approach wrong and requested a vector back to ZZZ VOR to begin the approach again or to just make a right 360 degree turn. At this point his altitude displayed 12;900 FT. After clarifying with him what exactly he was requesting; I cleared him 'as requested' to make his right 360 to begin the approach again. My biggest mistake here was that I did not issue an altitude to maintain. I imagine that if I had done so; I would have remembered the 12;400 FT MIA block off to his right that I had just cleared him through for his 360 request. I called TRACON X and told them what was going on since he would be re-entering their airspace and they gave me control. As he began his 360 turn he was still in the descent and now below the MIA. The OM at the front desk called my Supervisor and told me to climb the aircraft back up to a safe altitude; but it was already too late. I climbed the aircraft up to 13;000 FT and a couple minutes later issued a 'low altitude alert.' I then re-issued him his approach clearance into ZZZ1. My thoughts at the time were disappointment in myself. I know that 12;400 FT MIA block very well. We issue clearances through it all day long. But being as how it was my last session of the night before I was able to go home; and the Pilot had informed me of his emergency; I thought of nothing else but helping him out as much as I could without hesitation. I know that; even in an emergency; we still cannot vector aircraft below the MIA. It was just a stupid mistake and I was not thinking clearly in the excitement of the situation.

Data retrieved from NASA's ASRS site as of April 2012 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.