Crj-900 flight crew reported taking the clearance of another company's flight with the same flight n...

Narrative:

During our descent on the BOOVE3 arrival; we were given instructions to descend via and given runway 17C into dfw. I believe we were around delmo when we were given some ATC instructions. I was the pilot not flying and was getting updated ATIS information so I am not sure what the instructions were. I believe my captain thought he heard ATC instructions to descend to 5000 feet on 210 KIAS. When I got off the radio TCAS announced traffic and I was looking to see where the traffic was. Shortly after that the captain asked ATC to verify our descent instructions to 5000 feet. ATC replied negative; climb immediately to 11000 feet. The captain turned the auto pilot off and initiated a climb immediately. Shortly after that TCAS started issuing instructions to climb immediately; which we already climbing per ATC instructions. Prior to all that ATC had alerted us that there was another aircraft; [different company but same flight number] on the approach frequency. I believe the captain thought he heard our company name but it seems the descend information was for the other company. I thought I heard him repeat the descent instructions to ATC as we always do and since he was not corrected; thought he gotten the instructions for our flight.a few minutes later; ATC contacted us and gave us a phone number to give dfw approach control a call to discuss a possible pilot deviation.I would say when there are two similar call signs; pilots should be extra vigilant and make sure ATC instructions are for their aircraft. Also if a pilot is off the radios and did not hear the last ATC instructions that involves a climb or descent; they should query ATC for the last instructions to ensure both pilots are on the same sheet of music.

Original NASA ASRS Text

Title: CRJ-900 flight crew reported taking the clearance of another company's flight with the same flight number and descending below their assigned altitude. This resulted in a TCAS RA.

Narrative: During our descent on the BOOVE3 Arrival; we were given instructions to descend via and given runway 17C into DFW. I believe we were around DELMO when we were given some ATC instructions. I was the pilot not flying and was getting updated ATIS information so I am not sure what the instructions were. I believe my Captain thought he heard ATC instructions to descend to 5000 feet on 210 KIAS. When I got off the radio TCAS announced traffic and I was looking to see where the traffic was. Shortly after that the Captain asked ATC to verify our descent instructions to 5000 feet. ATC replied negative; climb immediately to 11000 feet. The Captain turned the auto pilot off and initiated a climb immediately. Shortly after that TCAS started issuing instructions to climb immediately; which we already climbing per ATC instructions. Prior to all that ATC had alerted us that there was another aircraft; [different company but same flight number] on the approach frequency. I believe the Captain thought he heard our company name but it seems the descend information was for the other company. I thought I heard him repeat the descent instructions to ATC as we always do and since he was not corrected; thought he gotten the instructions for our flight.A few minutes later; ATC contacted us and gave us a phone number to give DFW Approach Control a call to discuss a possible pilot deviation.I would say when there are two similar call signs; pilots should be extra vigilant and make sure ATC instructions are for their aircraft. Also if a pilot is off the radios and did not hear the last ATC instructions that involves a climb or descent; they should query ATC for the last instructions to ensure both pilots are on the same sheet of music.

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.

Attributes
ACN	1306991
Time
Date	201511
Local Time Of Day	0001-0600
Place
Locale Reference	DFW.Airport
State Reference	TX
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 900 (CRJ900)
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR BOOVE 3
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Crj-900 flight crew reported taking the clearance of another company's flight with the same flight number and descending below their assigned altitude. This resulted in a TCAS RA.