Narrative:

On our climb up to our departure assigned heading of 7;000 feet; ATC advised of a cessna traffic at our 11 o-clock doing circles in the vicinity and at a similar altitude as us. We reported the cessna in sight and continued visual separation.we were then assigned an altitude of 15;000 feet. As we continued to climb; ATC assigned us a left turn to a heading of 310 degrees. We concluded that this new heading was in conflict with our previous traffic due to the aircraft maintaining a continuous climb and circling pattern. The captain proceeded to advise of the conflict yet ATC disregarded with no response.ATC then issued a new clearance for a continued left turn to a heading of 260 degrees alongside an amendment of maintaining an altitude of 12;000 feet.as the captain advised ATC again of the traffic conflict; he told me to take the turn slowly in order to maintain visual separation and we proceeded by doing so in increments to avoid the traffic which was in proximity to nearby clouds.as we cleared the traffic; the captain reminded me that the controller wanted 260. I misunderstood and set a new altitude of FL260; when what he meant was that of a heading of 260 degrees.I recalled that ATC had mentioned 12;000 [feet] previously and asked the captain for confirmation. As he did so with ATC; we were in the midst of passing 12;000 feet. The captain immediately took control of the aircraft and descended back down to 12;000 feet from an altitude of roughly 12;600 feet.we communicated what had occurred with ATC; and once again; we were disregarded and shortly after passed on to another agency.what we should have done differently... We should have advised ATC 'unable' on the conflicting assigned heading [and] confirm immediately what is being issued prior to setting new altitudes; headings; or airspeeds. We should have divided the workload and confirmed with each other instead of fixating on the problem with the nearby conflicting traffic.

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Original NASA ASRS Text

Title: EMB-170 flight crew reported miscommunication led to overshooting a crossing restriction.

Narrative: On our climb up to our Departure assigned heading of 7;000 feet; ATC advised of a Cessna traffic at our 11 o-clock doing circles in the vicinity and at a similar altitude as us. We reported the Cessna in sight and continued visual separation.We were then assigned an altitude of 15;000 feet. As we continued to climb; ATC assigned us a left turn to a heading of 310 degrees. We concluded that this new heading was in conflict with our previous traffic due to the aircraft maintaining a continuous climb and circling pattern. The Captain proceeded to advise of the conflict yet ATC disregarded with no response.ATC then issued a new clearance for a continued left turn to a heading of 260 degrees alongside an amendment of maintaining an altitude of 12;000 feet.As the Captain advised ATC again of the traffic conflict; he told me to take the turn slowly in order to maintain visual separation and we proceeded by doing so in increments to avoid the traffic which was in proximity to nearby clouds.As we cleared the traffic; the Captain reminded me that the controller wanted 260. I misunderstood and set a new altitude of FL260; when what he meant was that of a heading of 260 degrees.I recalled that ATC had mentioned 12;000 [feet] previously and asked the Captain for confirmation. As he did so with ATC; we were in the midst of passing 12;000 feet. The Captain immediately took control of the aircraft and descended back down to 12;000 feet from an altitude of roughly 12;600 feet.We communicated what had occurred with ATC; and once again; we were disregarded and shortly after passed on to another agency.What we should have done differently... We should have advised ATC 'unable' on the conflicting assigned heading [and] confirm immediately what is being issued prior to setting new altitudes; headings; or airspeeds. We should have divided the workload and confirmed with each other instead of fixating on the problem with the nearby conflicting traffic.

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.