Narrative:

I recently shot an approach into ZZZ. The conditions were overcast; tops at 5000 - 5500; bases around 3500 so I did not expect there to be any issues as the weather was well above the minimums. ATC was vectoring me for the ILS. I had an instrument rated copilot so I was happy to have a second set of hands to work the radios and a second set of eyes to ensure we were safe.I was on a northbound heading at 5000 feet parallel to the ILS. ATC gave me a descent to 4000 feet. As I started the descent; they gave me a turn to the left; about 70 degrees. 'Vectors for sequencing.' passing [approximately] 4300 feet on my way down ATC called to us to 'climb immediately; minimum vectoring altitude in your sector is 5000 feet. Expedite climb.' I looked at my copilot and he looked like he was taken aback as I was. I pushed in full power; and I told the controller that I would comply; and I thought they had told me to descend. Post flight postmortem. Both my copilot and I had heard the controller tell us to descend to 4000. There was another tail number similar to mine; 1 digit different in the last 3 characters; and the controller was using abbreviated call signs. It is possible I picked up a descend clearance for the other aircraft; but if that was the case; both of us would have misheard the controller; and they did not catch the error when we read back the descend clearance. Had we turned to the right to intercept the approach course; this altitude did not seem unreasonable. We were outside of the FAF which has a crossing altitude of 3800 feet. Turning to the left; however; put me uncomfortably close to obstacles as high as 3700 feet to my 9 o'clock; and climbing terrain fairly far away straight ahead of us. I knew where we were; but I was concentrating more on being bounced around in the clouds and following instructions than I was on double checking ATC and looking at my chart for obstructions. I am glad the controller caught the mistake; because I am not sure I would have.if I accidentally picked up the clearance for another aircraft; my suggestion would be for ATC to not use abbreviated clearances when similar call signs are on frequency. If ATC gave me the descent in error; a prevention measure would be for me to maintain solid situational awareness to prevent a controlled flight into terrain. It would be helpful for pilots to be able to know the minimum vectoring altitudes in the area.

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Original NASA ASRS Text

Title: PA32 pilot reported an excursion from an assigned altitude due to a similar call sign communication breakdown.

Narrative: I recently shot an approach into ZZZ. The conditions were overcast; tops at 5000 - 5500; bases around 3500 so I did not expect there to be any issues as the weather was well above the minimums. ATC was vectoring me for the ILS. I had an instrument rated copilot so I was happy to have a second set of hands to work the radios and a second set of eyes to ensure we were safe.I was on a northbound heading at 5000 feet parallel to the ILS. ATC gave me a descent to 4000 feet. As I started the descent; they gave me a turn to the left; about 70 degrees. 'Vectors for sequencing.' Passing [approximately] 4300 feet on my way down ATC called to us to 'climb immediately; minimum vectoring altitude in your sector is 5000 feet. Expedite climb.' I looked at my copilot and he looked like he was taken aback as I was. I pushed in full power; and I told the Controller that I would comply; and I thought they had told me to descend. Post flight postmortem. Both my copilot and I had heard the Controller tell us to descend to 4000. There was another tail number similar to mine; 1 digit different in the last 3 characters; and the Controller was using abbreviated call signs. It is possible I picked up a descend clearance for the other aircraft; but if that was the case; both of us would have misheard the Controller; and they did not catch the error when we read back the descend clearance. Had we turned to the right to intercept the approach course; this altitude did not seem unreasonable. We were outside of the FAF which has a crossing altitude of 3800 feet. Turning to the left; however; put me uncomfortably close to obstacles as high as 3700 feet to my 9 o'clock; and climbing terrain fairly far away straight ahead of us. I knew where we were; but I was concentrating more on being bounced around in the clouds and following instructions than I was on double checking ATC and looking at my chart for obstructions. I am glad the Controller caught the mistake; because I am not sure I would have.If I accidentally picked up the clearance for another aircraft; my suggestion would be for ATC to not use abbreviated clearances when similar call signs are on frequency. If ATC gave me the descent in error; a prevention measure would be for me to maintain solid situational awareness to prevent a controlled flight into terrain. It would be helpful for pilots to be able to know the minimum vectoring altitudes in the area.

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.