Narrative:

We had been holding short at the approach end of runway 26R in the #1 position for approximately 10 mins. At XA30 phx is very busy with arrs. At approximately XA34 a takeoff clearance was issued and we understood it to be for us. As captain, I was monitoring company frequency as well as tower which is a normal practice. At the same time the clearance was issued, company frequency came alive and due perhaps to the close proximity to the company facility, the transmission was louder than tower's and partially blocked the clearance in my headset. I asked the first officer if it was for us. He affirmed that it was and said we'd been cleared for an 'immediate.' he was not listening to company frequency. At this time I brought the power levers forward and began taxiing onto the runway. The first officer then keyed his microphone and clearly read back the takeoff clearance using our call sign. We proceeded into position and since it was just getting dark, turned on all aircraft lights including strobes, landing, taxi, recognition and wing ice lights. The runway appeared clear and we then transferred control of the aircraft from captain to first officer and accomplished the takeoff. Shortly after rotation, as I was trimming power, the first officer saw an aircraft climbing out ahead of us and turned our aircraft to the right. We believe we were never closer than approximately 600' horizontal and 300' vertical. When we reached approximately 300' AGL, phx tower told us we had been cleared for takeoff, to fly the runway heading and contact departure. We later learned that the takeoff clearance had been issued to an small aircraft from an intersection 4500' down from our position. The small aircraft did not acknowledge the clearance verbally, but we had, and with no further response from tower we believed we were in compliance and took off as expeditiously as we could as there was traffic on final approach. The misunderstanding on my part was due perhaps to the interference of company frequency. In the first officer's case due perhaps to the anticipation of the 'immediate' due to the busy situation. Other contributing factors were that tower did not acknowledge our readback as being incorrect and apparently did not see us taxi onto the runway, or takeoff, only seeing us finally in the climb. Also the fact that it had just become dark perhaps contributed to our not seeing the small aircraft in his initial climb while we were on the roll due to runway and airport lighting distraction and our busy workload.

Related reports:

Google
 

Original NASA ASRS Text

Title: SMT TOOK ANOTHER ACFT'S TKOF CLRNC, TOOK OFF WITHOUT CLRNC AND CAUSED A CONFLICT.

Narrative: WE HAD BEEN HOLDING SHORT AT THE APCH END OF RWY 26R IN THE #1 POS FOR APPROX 10 MINS. AT XA30 PHX IS VERY BUSY WITH ARRS. AT APPROX XA34 A TKOF CLRNC WAS ISSUED AND WE UNDERSTOOD IT TO BE FOR US. AS CAPT, I WAS MONITORING COMPANY FREQ AS WELL AS TWR WHICH IS A NORMAL PRACTICE. AT THE SAME TIME THE CLRNC WAS ISSUED, COMPANY FREQ CAME ALIVE AND DUE PERHAPS TO THE CLOSE PROX TO THE COMPANY FAC, THE XMISSION WAS LOUDER THAN TWR'S AND PARTIALLY BLOCKED THE CLRNC IN MY HEADSET. I ASKED THE F/O IF IT WAS FOR US. HE AFFIRMED THAT IT WAS AND SAID WE'D BEEN CLRED FOR AN 'IMMEDIATE.' HE WAS NOT LISTENING TO COMPANY FREQ. AT THIS TIME I BROUGHT THE PWR LEVERS FORWARD AND BEGAN TAXIING ONTO THE RWY. THE F/O THEN KEYED HIS MIC AND CLEARLY READ BACK THE TKOF CLRNC USING OUR CALL SIGN. WE PROCEEDED INTO POS AND SINCE IT WAS JUST GETTING DARK, TURNED ON ALL ACFT LIGHTS INCLUDING STROBES, LNDG, TAXI, RECOGNITION AND WING ICE LIGHTS. THE RWY APPEARED CLR AND WE THEN TRANSFERRED CONTROL OF THE ACFT FROM CAPT TO F/O AND ACCOMPLISHED THE TKOF. SHORTLY AFTER ROTATION, AS I WAS TRIMMING PWR, THE F/O SAW AN ACFT CLBING OUT AHEAD OF US AND TURNED OUR ACFT TO THE RIGHT. WE BELIEVE WE WERE NEVER CLOSER THAN APPROX 600' HORIZ AND 300' VERT. WHEN WE REACHED APPROX 300' AGL, PHX TWR TOLD US WE HAD BEEN CLRED FOR TKOF, TO FLY THE RWY HDG AND CONTACT DEP. WE LATER LEARNED THAT THE TKOF CLRNC HAD BEEN ISSUED TO AN SMA FROM AN INTXN 4500' DOWN FROM OUR POS. THE SMA DID NOT ACKNOWLEDGE THE CLRNC VERBALLY, BUT WE HAD, AND WITH NO FURTHER RESPONSE FROM TWR WE BELIEVED WE WERE IN COMPLIANCE AND TOOK OFF AS EXPEDITIOUSLY AS WE COULD AS THERE WAS TFC ON FINAL APCH. THE MISUNDERSTANDING ON MY PART WAS DUE PERHAPS TO THE INTERFERENCE OF COMPANY FREQ. IN THE F/O'S CASE DUE PERHAPS TO THE ANTICIPATION OF THE 'IMMEDIATE' DUE TO THE BUSY SITUATION. OTHER CONTRIBUTING FACTORS WERE THAT TWR DID NOT ACKNOWLEDGE OUR READBACK AS BEING INCORRECT AND APPARENTLY DID NOT SEE US TAXI ONTO THE RWY, OR TKOF, ONLY SEEING US FINALLY IN THE CLB. ALSO THE FACT THAT IT HAD JUST BECOME DARK PERHAPS CONTRIBUTED TO OUR NOT SEEING THE SMA IN HIS INITIAL CLB WHILE WE WERE ON THE ROLL DUE TO RWY AND ARPT LIGHTING DISTR AND OUR BUSY WORKLOAD.

Data retrieved from NASA's ASRS site as of August 2007 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.