Narrative:

We were cruising at FL350 when center cleared us to cross 30 north of corkr at FL330. I was the pilot not flying and read the clearance back to center correctly. My first officer entered 'corkr/-30' into the FMS and put it into LSK2 and I confirmed it. I don't remember verifying the change with the altitude pre-select knob; or the altitude entered in the FMS for the new clearance. While we were descending through FL330; center advised us to climb and maintain FL330. Then before we could respond; they advised us to climb and maintain FL330 and turn left 30 degrees. We saw traffic at FL320 off to our right; and it was then that I noticed our mistake; and that our altitude pre-select was set to FL300. The first officer disengaged the auto-pilot; and initiated the climbing left turn. Center then asked us to verify that we were assigned FL330; and I confirmed the clearance.several things contributed to this event. The similar-sounding clearance was confusing...'30 miles and FL330.' another factor was complacency on my part. I neglected to confirm the assigned altitude on the altitude pre-select. And finally; we had a jumpseater that created a distraction because I was involved in a conversation with him at the time.selecting the newly-assigned altitude with the altitude knob on the pre-select first; and then setting up the FMS would help eliminate some confusion. Making sure I confirm the assigned altitude is entered into the FMS along with the assigned fix and not allowing a jumpseater to distract me during the flight would also be of help.

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Original NASA ASRS Text

Title: A CRJ-700 flight crew failed to properly program the altitude alert and the FMS to properly schedule a crossing restriction from ATC. They descended below the crossing and conflicted with aircraft below. ATC caught the error and a correction was made in a timely fashion.

Narrative: We were cruising at FL350 when Center cleared us to cross 30 north of CORKR at FL330. I was the pilot not flying and read the clearance back to Center correctly. My First Officer entered 'CORKR/-30' into the FMS and put it into LSK2 and I confirmed it. I don't remember verifying the change with the altitude pre-select knob; or the altitude entered in the FMS for the new clearance. While we were descending through FL330; Center advised us to climb and maintain FL330. Then before we could respond; they advised us to climb and maintain FL330 and turn left 30 degrees. We saw traffic at FL320 off to our right; and it was then that I noticed our mistake; and that our altitude pre-select was set to FL300. The First Officer disengaged the auto-pilot; and initiated the climbing left turn. Center then asked us to verify that we were assigned FL330; and I confirmed the clearance.Several things contributed to this event. The similar-sounding clearance was confusing...'30 miles and FL330.' Another factor was complacency on my part. I neglected to confirm the assigned altitude on the altitude pre-select. And finally; we had a jumpseater that created a distraction because I was involved in a conversation with him at the time.Selecting the newly-assigned altitude with the ALT knob on the pre-select first; and then setting up the FMS would help eliminate some confusion. Making sure I confirm the assigned altitude is entered into the FMS along with the assigned fix and not allowing a jumpseater to distract me during the flight would also be of help.

Data retrieved from NASA's ASRS site as of July 2013 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.