Narrative:

My friend and I were flying a plane I had just purchased. We were about 25 minutes into the first leg of our trip level at 12;000 feet. As speed built the cabin door popped open. There was much confusion in the cockpit. The wind noise made it impossible to communicate with my passenger. It was very cold. I could barely hear ATC. After stabilizing the aircraft and gaining composure I advised ATC what happened; and that we would be slowing the airplane to try to close the door. During this time all the alarms and warnings were going off in my headset from the electronic avionic instruments (which I had just learned how to use). Unable to close the door; we requested to go to the nearest airport. I identified the airport on the multi-function display screen and initiated a GPS course direct.during the descent I got an additional warning that alternator no. 1 failed with a loud annunciator. It was then I knew we had to get down right away. I checked my ipad; which was difficult to see and manipulate; but confirmed the straight-in runway. I could see the airport and it concurred with my GPS and ipad. I never saw the intended airport but was in fact seeing a nearby air force base. As I approached the airport; I cancelled my IFR when asked. I was sure I could make the runway as we needed to land immediately. As I approached; I saw a runway which concurred with my ipad. I began to make announcements over the unicom. On short final I noticed something looked wrong; but at that point I made the decision to land as I considered this an emergency. I landed and pulled off the runway. As I looked down at my ipad; it changed from my intended airport to the air force base. I called ground and held position until they met me on the ramp. I explained to them that this was a situation and landing.I should have declared it while in the air but in all the confusion; and sure I would make the runway; I didn't declare it until on the ground. If I had done that that would have given me priority handling. I should have not cancelled my IFR flight plan; but I wanted to make sure I could make announcements to other traffic at the airport (I know I could cancel on the ground but I wasn't focused on that) and when asked if I wanted to cancel I responded in the affirmative. I should have noticed the different airport identifiers but only the last letter was different and in all the confusion I didn't notice the difference. The air force base safety officers who interviewed us concurred that this has created problems before. Similar airport ids and the close proximity to the muni. If they were totally different; I think I would have never inputted it wrong or would have noticed the wrong airport identification.

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Original NASA ASRS Text

Title: GA Pilot reported diverting due to an open cabin door and a failed alternator landed at an Air Force Base instead of the intended nearby airport.

Narrative: My friend and I were flying a plane I had just purchased. We were about 25 minutes into the first leg of our trip level at 12;000 feet. As speed built the cabin door popped open. There was much confusion in the cockpit. The wind noise made it impossible to communicate with my passenger. It was very cold. I could barely hear ATC. After stabilizing the aircraft and gaining composure I advised ATC what happened; and that we would be slowing the airplane to try to close the door. During this time all the alarms and warnings were going off in my headset from the electronic avionic instruments (which I had just learned how to use). Unable to close the door; we requested to go to the nearest airport. I identified the airport on the multi-function display screen and initiated a GPS course direct.During the descent I got an additional warning that alternator No. 1 failed with a loud annunciator. It was then I knew we had to get down right away. I checked my iPad; which was difficult to see and manipulate; but confirmed the straight-in runway. I could see the airport and it concurred with my GPS and iPad. I never saw the intended airport but was in fact seeing a nearby Air Force Base. As I approached the airport; I cancelled my IFR when asked. I was sure I could make the runway as we needed to land immediately. As I approached; I saw a runway which concurred with my iPad. I began to make announcements over the UNICOM. On short final I noticed something looked wrong; but at that point I made the decision to land as I considered this an emergency. I landed and pulled off the runway. As I looked down at my iPad; it changed from my intended airport to the Air Force Base. I called ground and held position until they met me on the ramp. I explained to them that this was a situation and landing.I should have declared it while in the air but in all the confusion; and sure I would make the runway; I didn't declare it until on the ground. If I had done that that would have given me priority handling. I should have not cancelled my IFR flight plan; but I wanted to make sure I could make announcements to other traffic at the airport (I know I could cancel on the ground but I wasn't focused on that) and when asked if I wanted to cancel I responded in the affirmative. I should have noticed the different airport identifiers but only the last letter was different and in all the confusion I didn't notice the difference. The Air Force Base safety officers who interviewed us concurred that this has created problems before. Similar airport IDs and the close proximity to the Muni. If they were totally different; I think I would have never inputted it wrong or would have noticed the wrong airport ID.

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.