Narrative:

Bhm approach cleared us direct to spatt 'for now' and to expect the ILS 24 approach. This clearance set us on an approximate course of 100 degrees to spatt and the 'for now' part of the clearance placed a biased expectation in my mind that at some point ATC would give us a left turn vector to parallel the localizer course outbound before turning us inbound. This was in keeping with how this approach has been conducted in the past. At this point we were descending to 3000 ft. As we got closer to spatt; I commented to the first officer that ATC needed to turn us out soon as the turn inbound from spatt was way too tight. This indicates the mindset of my expectation. About 4 NM from spatt ATC assigned us a right turn heading 180 to join the localizer; maintain 2600 feet until established. This was unexpected by me and I realized that it was a close-in turn onto the approach. I immediately pulled the power back to slow down but we soon were crossing the localizer. ATC; aware of this; gave us a heading of 270 to rejoin. We rejoined the localizer inside of hukev. Somewhere in the automation selection; I lost the vertical command bar in the turn to try to intercept the localizer and I lost vertical situational awareness to the extent that a 'terrain ahead' caution was initiated due; I think; to the rate of descent. I descended to 2000 feet where the minimum altitude was 2200 feet at lowga. I initiated a climb to an appropriate altitude on the approach as the taws (terrain avoidance warning system) display displayed only green terrain contours as soon as the climb was started. The approach was stabilized by the time we arrived at lowga and the rest of the approach and landing were normal. Crossing the localizer and rushing to get established and configured. Taws alert. Because of a biased expectation about how the flight would be set up for the approach; I found myself going from a place of comfort with the approach to suddenly being severely behind the 'eight ball'.as we were nearing spatt; the thought occurred to me to query ATC as to what their plan was for vectoring me onto the approach. I should have acted upon that thought. As soon as I received the heading I did not expect and realized that it was a tight turn-on creating a rushing situation; I should have abandoned the approach and requested vectors back around instead of trying to salvage the approach. This would have preempted the problems that occurred with the rushing that led to automation confusion and altitude deviation.

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Original NASA ASRS Text

Title: Turboprop flight crew reports an unexpected turn to intercept to the localizer at BHM resulting in the Captain overshooting the LOC and descending 600 feet below the assigned altitude of 2;600 feet. A Terrain Avoidance Warning System (TAWS) 'Terrain Ahead' warning is annunciated and the crew climbs back to 2;600 feet.

Narrative: BHM approach cleared us direct to SPATT 'for now' and to expect the ILS 24 approach. This clearance set us on an approximate course of 100 degrees to SPATT and the 'for now' part of the clearance placed a biased expectation in my mind that at some point ATC would give us a left turn vector to parallel the localizer course outbound before turning us inbound. This was in keeping with how this approach has been conducted in the past. At this point we were descending to 3000 ft. As we got closer to SPATT; I commented to the FO that ATC needed to turn us out soon as the turn inbound from SPATT was way too tight. This indicates the mindset of my expectation. About 4 NM from SPATT ATC assigned us a right turn heading 180 to join the localizer; maintain 2600 feet until established. This was unexpected by me and I realized that it was a close-in turn onto the approach. I immediately pulled the power back to slow down but we soon were crossing the localizer. ATC; aware of this; gave us a heading of 270 to rejoin. We rejoined the localizer inside of HUKEV. Somewhere in the automation selection; I lost the vertical command bar in the turn to try to intercept the localizer and I lost vertical situational awareness to the extent that a 'TERRAIN AHEAD' caution was initiated due; I think; to the rate of descent. I descended to 2000 feet where the minimum altitude was 2200 feet at LOWGA. I initiated a climb to an appropriate altitude on the approach as the TAWS (Terrain Avoidance Warning System) display displayed only green terrain contours as soon as the climb was started. The approach was stabilized by the time we arrived at LOWGA and the rest of the approach and landing were normal. Crossing the localizer and rushing to get established and configured. TAWS alert. Because of a biased expectation about how the flight would be set up for the approach; I found myself going from a place of comfort with the approach to suddenly being severely behind the 'eight ball'.As we were nearing SPATT; the thought occurred to me to query ATC as to what their plan was for vectoring me onto the approach. I should have acted upon that thought. As soon as I received the heading I did not expect and realized that it was a tight turn-on creating a rushing situation; I should have abandoned the approach and requested vectors back around instead of trying to salvage the approach. This would have preempted the problems that occurred with the rushing that led to automation confusion and altitude deviation.

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.