The flight crew of a crj-700 descended to FL270 vice 290 as cleared. Contributing factors were a dis...

Narrative:

We were level at FL360; I was pilot flying and the captain was pilot not flying. We were cleared to what we believed was FL270. Right when we received the clearance from ATC the cabin called. The captain answered the radio and I took the call from the back. When I came back a few seconds later I saw 27;000 in the altitude selector and said 'two seven zero'; captain replied 'two seven zero set'. I then began the descent.as we were about to level off at FL270 ATC told us to turn 25 degrees right. As we were turning ATC advised us that we were supposed to be at FL290 and to climb back to FL290. As we began our climb back to FL290 ATC asked us what altitude we thought we were cleared to. The captain replied FL270. A few moments later that controller gave us another frequency; we switched and continued to without further incident. There were no TA's or RA's during the incident. I believe the event occurred for a couple of reasons. First; we actually thought we heard FL270; and when the captain read that back; he was not corrected. Secondly; when we received the instructions; I was talking to the flight attendant for about 10 seconds; when I checked back with the captain; he had verified with ATC FL270 and saw no reason to doubt it. Had I not been talking to the back; I may have noticed the discrepancy.

Original NASA ASRS Text

Title: The flight crew of a CRJ-700 descended to FL270 vice 290 as cleared. Contributing factors were a distracting concurrent call from the Flight Attendant and the flight crew's failure to wear headsets to insure optimum reception of transmissions.

Narrative: We were level at FL360; I was pilot flying and the Captain was pilot not flying. We were cleared to what we believed was FL270. Right when we received the clearance from ATC the cabin called. The Captain answered the radio and I took the call from the back. When I came back a few seconds later I saw 27;000 in the altitude selector and said 'two seven zero'; Captain replied 'two seven zero set'. I then began the descent.As we were about to level off at FL270 ATC told us to turn 25 degrees right. As we were turning ATC advised us that we were supposed to be at FL290 and to climb back to FL290. As we began our climb back to FL290 ATC asked us what altitude we thought we were cleared to. The Captain replied FL270. A few moments later that Controller gave us another frequency; we switched and continued to without further incident. There were no TA's or RA's during the incident. I believe the event occurred for a couple of reasons. First; we actually thought we heard FL270; and when the Captain read that back; he was not corrected. Secondly; when we received the instructions; I was talking to the Flight Attendant for about 10 seconds; when I checked back with the Captain; he had verified with ATC FL270 and saw no reason to doubt it. Had I not been talking to the back; I may have noticed the discrepancy.

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.

Attributes
ACN	980195
Time
Date	201111
Local Time Of Day	1201-1800
Place
Locale Reference	ZHU.ARTCC
State Reference	TX
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Air/Ground Communication
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Commercial
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Clearance Flight Deck / Cabin / Aircraft Event Other / Unknown

The flight crew of a crj-700 descended to FL270 vice 290 as cleared. Contributing factors were a distracting concurrent call from the flight attendant and the flight crew's failure to wear headsets to insure optimum reception of transmissions.