Narrative:

During the takeoff roll from runway 31C at mdw; the primary attitude indicator showed the 'off' flag and was indicating a 50 to 60 degree nose up attitude. As soon as I noticed the issue; I called for abort and got the airplane slowed to taxi speed. The tower said we could pull off to the holding pad at the end of the runway. Once off the runway; we tested the ai and did not note any abnormalities. During our discussion; we reviewed what had occurred and the pilot not flying stated that he had called V1. I did not hear him call V1 and that is why I called the abort. In hindsight; when the attitude indicator flagged and rolled like it did; I fixated on that situation and I think that is why I didn't hear the pilot not flying call V1. Throughout the entire abort process; I was never concerned that we were going to run off the end of the runway. I estimate that we got the plane slowed to taxi speed with at least 1;000 ft of runway left. During the next departure briefing; I stated that if I noticed the situation again at that speed I would just transfer controls to the pilot not flying. Also; the pilot not flying was very clear when announcing V1. Ultimately; while I don't have issues with why I called for an abort; I do feel that I made a mistake calling for the abort in light of the fact that the pilot not flying did call V1; even though I don't recall hearing him announce it.

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Original NASA ASRS Text

Title: When his attitude indicator failed the First Officer of a business jet rejected the takeoff from MDW after the Captain had called V1. The event occurred during night VMC conditions.

Narrative: During the takeoff roll from Runway 31C at MDW; the primary attitude indicator showed the 'OFF' flag and was indicating a 50 to 60 degree nose up attitude. As soon as I noticed the issue; I called for abort and got the airplane slowed to taxi speed. The Tower said we could pull off to the holding pad at the end of the runway. Once off the runway; we tested the AI and did not note any abnormalities. During our discussion; we reviewed what had occurred and the pilot not flying stated that he had called V1. I did not hear him call V1 and that is why I called the abort. In hindsight; when the attitude indicator flagged and rolled like it did; I fixated on that situation and I think that is why I didn't hear the pilot not flying call V1. Throughout the entire abort process; I was never concerned that we were going to run off the end of the runway. I estimate that we got the plane slowed to taxi speed with at least 1;000 FT of runway left. During the next departure briefing; I stated that if I noticed the situation again at that speed I would just transfer controls to the pilot not flying. Also; the pilot not flying was very clear when announcing V1. Ultimately; while I don't have issues with why I called for an abort; I do feel that I made a mistake calling for the abort in light of the fact that the pilot not flying did call V1; even though I don't recall hearing him announce it.

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.