Narrative:

Flight was out of gate on time. After 20 mins wait at runway 26R, first officer received what he understood to be air carrier 1 cleared for immediate takeoff. First officer read back 'air carrier 1 cleared for immediate takeoff.' normal takeoff until at about 100'. First officer saw small aircraft which had apparently taken off at mid-runway intersection. First officer sidestepped to avoid overflying aircraft. Soon afterward tower called and informed us that takeoff clearance wasn't for us. The captain, at time of clearance, was talking to company, and when first officer was asked, 'is that for us?', first officer said, 'yeah.' there had been constant radio chatter for the last 20 mins and first officer had been listening for our call # all that time. Possibly the mixture of poor transmission quality (the controller was sounding quite rushed and there appeared to be interference when first officer got call) and listening for one call for so long, may have been automatic-suggestive. Lights at end of 26L made seeing the small aircraft impossible until we had climbed to his altitude or higher. Tower did not respond to our readback, therefore reinforcing our belief that we were indeed cleared to go. The tower supervisor said during phone conversation that a similar mistake had been made about 30 mins earlier. Often when phx controllers feel rushed, the first part of their xmissions are cut off, which can add confusion. Factors involved probably were: long wait with no indication of our sequence, much radio congestion making long term concentration on radio dull, the stressing of 'immediate' in the clearance, which makes the crew focus on the matter of takeoff west/O second guessing the perceived clearance, and commonality of similar takeoff clrncs at that time of night in phx.

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Original NASA ASRS Text

Title: SMT TOOK OFF RWY WITHOUT CLRNC AND OVERFLEW AN SMA DEPARTING SAME RWY DOWNFIELD.

Narrative: FLT WAS OUT OF GATE ON TIME. AFTER 20 MINS WAIT AT RWY 26R, F/O RECEIVED WHAT HE UNDERSTOOD TO BE ACR 1 CLRED FOR IMMEDIATE TKOF. F/O READ BACK 'ACR 1 CLRED FOR IMMEDIATE TKOF.' NORMAL TKOF UNTIL AT ABOUT 100'. F/O SAW SMA WHICH HAD APPARENTLY TAKEN OFF AT MID-RWY INTXN. F/O SIDESTEPPED TO AVOID OVERFLYING ACFT. SOON AFTERWARD TWR CALLED AND INFORMED US THAT TKOF CLRNC WASN'T FOR US. THE CAPT, AT TIME OF CLRNC, WAS TALKING TO COMPANY, AND WHEN F/O WAS ASKED, 'IS THAT FOR US?', F/O SAID, 'YEAH.' THERE HAD BEEN CONSTANT RADIO CHATTER FOR THE LAST 20 MINS AND F/O HAD BEEN LISTENING FOR OUR CALL # ALL THAT TIME. POSSIBLY THE MIXTURE OF POOR XMISSION QUALITY (THE CTLR WAS SOUNDING QUITE RUSHED AND THERE APPEARED TO BE INTERFERENCE WHEN F/O GOT CALL) AND LISTENING FOR ONE CALL FOR SO LONG, MAY HAVE BEEN AUTO-SUGGESTIVE. LIGHTS AT END OF 26L MADE SEEING THE SMA IMPOSSIBLE UNTIL WE HAD CLBED TO HIS ALT OR HIGHER. TWR DID NOT RESPOND TO OUR READBACK, THEREFORE REINFORCING OUR BELIEF THAT WE WERE INDEED CLRED TO GO. THE TWR SUPVR SAID DURING PHONE CONVERSATION THAT A SIMILAR MISTAKE HAD BEEN MADE ABOUT 30 MINS EARLIER. OFTEN WHEN PHX CTLRS FEEL RUSHED, THE FIRST PART OF THEIR XMISSIONS ARE CUT OFF, WHICH CAN ADD CONFUSION. FACTORS INVOLVED PROBABLY WERE: LONG WAIT WITH NO INDICATION OF OUR SEQUENCE, MUCH RADIO CONGESTION MAKING LONG TERM CONCENTRATION ON RADIO DULL, THE STRESSING OF 'IMMEDIATE' IN THE CLRNC, WHICH MAKES THE CREW FOCUS ON THE MATTER OF TKOF W/O SECOND GUESSING THE PERCEIVED CLRNC, AND COMMONALITY OF SIMILAR TKOF CLRNCS AT THAT TIME OF NIGHT IN PHX.

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.