Narrative:

Early morning launch. Tower was using 26L for landing, 8R for noise abatement takeoffs. After watching several aircraft land and clear 26L, our flight was cleared into 'position and hold 8R.' we did so, completing 6 final items of takeoff checklist as per company procedure. As we did this, we observed an aircraft (light twin cargo type?) taxi out a few thousand ft down 8R and heard tower clear that aircraft for takeoff while we were taking position at the end. Note: tower never told us they planned to launch that aircraft with us in position. We (copilot and myself) watched the takeoff airplane roll, break ground, and make a very impressive (tight right turnout), takeoff and turn downwind. Tower then made a transmission that both my copilot and myself assumed was a takeoff clearance for us. My copilot acknowledged by saying something to the effect '(call sign), cleared for takeoff, but we can't duplicate that' and thought we heard a 'roger.' we turned on landing lights, I gave control to copilot and we began our takeoff roll. A few seconds later we both saw a small single engine aircraft taxiing out and begin a takeoff in front of us on 8R. This aircraft was about half way down the runway. We were not going very fast and easily braked to a stop. I called that we were aborting for a small aircraft in front of us, assuming that aircraft was in error. Tower transmitted to us '(our call sign), you were not cleared for takeoff!' there was no conflict with the light aircraft. We waited in position and in a min were cleared for takeoff. That one was uneventful. Contributing factors: tower launched 2 aircraft in front of us while in position on runway. We saw and expected the first aircraft which was closer to us and cleared for takeoff as we were cleared into 'position and hold.' tower did not advise us that he was launching a second aircraft in front of us. We were 'expecting' the next transmission to be 'our' takeoff clearance. Upon our readback of what we assumed was 'our' takeoff clearance, tower said nothing (possible covered transmission by other aircraft which took the clearance)? Distrs of a) doing last few items on takeoff checklist. B) watching high performance takeoff/turnout by first aircraft to launch in front of us. Tower was probably trying to get as many aircraft off on 8R as he could before inbound traffic for 26L. (Note: 26R-8L closed.) corrective actions: I don't know if it is policy, but I like to be told when aircraft will be launched on a runway I am cleared onto with my aircraft in position. I'll have to listen more attentively for my call sign, not assume that the next call is for my aircraft. Tower controller should be aware that any aircraft put in 'position and hold' will probably be expecting takeoff clearance next. Tower should inform that aircraft (when possible) if some other operation will be preceding the expected clearance. (We did expect the launch of the first aircraft in front of us, as he was cleared while we were still taxiing into position and he was close enough to us to be easily seen taxiing out.) we were not expecting a second aircraft to be cleared out onto the runway half way down the runway after we were positioned! Callback conversation with reporter revealed the following information: reporter states he feels biggest problem is lack of any TA indicating what sequence off departure was being used. Naturally feels he will be next for takeoff when already in position and aircraft ahead has departed. Could not see other aircraft at intersection half way down the runway. Did not hear any communication with that aircraft prior to takeoff clearance. They were the only other aircraft at the runway as far as they knew. That's why they never questioned the takeoff clearance.

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Original NASA ASRS Text

Title: ACR IN POS AND HOLD HEARS TKOF CLRNC. BEGINS TKOF ROLL. ABORTS AS SEE ACFT HALF WAY DOWN RWY ON TKOF ROLL.

Narrative: EARLY MORNING LAUNCH. TWR WAS USING 26L FOR LNDG, 8R FOR NOISE ABATEMENT TKOFS. AFTER WATCHING SEVERAL ACFT LAND AND CLR 26L, OUR FLT WAS CLRED INTO 'POS AND HOLD 8R.' WE DID SO, COMPLETING 6 FINAL ITEMS OF TKOF CHKLIST AS PER COMPANY PROC. AS WE DID THIS, WE OBSERVED AN ACFT (LIGHT TWIN CARGO TYPE?) TAXI OUT A FEW THOUSAND FT DOWN 8R AND HEARD TWR CLR THAT ACFT FOR TKOF WHILE WE WERE TAKING POS AT THE END. NOTE: TWR NEVER TOLD US THEY PLANNED TO LAUNCH THAT ACFT WITH US IN POS. WE (COPLT AND MYSELF) WATCHED THE TKOF AIRPLANE ROLL, BREAK GND, AND MAKE A VERY IMPRESSIVE (TIGHT R TURNOUT), TKOF AND TURN DOWNWIND. TWR THEN MADE A XMISSION THAT BOTH MY COPLT AND MYSELF ASSUMED WAS A TKOF CLRNC FOR US. MY COPLT ACKNOWLEDGED BY SAYING SOMETHING TO THE EFFECT '(CALL SIGN), CLRED FOR TKOF, BUT WE CAN'T DUPLICATE THAT' AND THOUGHT WE HEARD A 'ROGER.' WE TURNED ON LNDG LIGHTS, I GAVE CTL TO COPLT AND WE BEGAN OUR TKOF ROLL. A FEW SECONDS LATER WE BOTH SAW A SMALL SINGLE ENG ACFT TAXIING OUT AND BEGIN A TKOF IN FRONT OF US ON 8R. THIS ACFT WAS ABOUT HALF WAY DOWN THE RWY. WE WERE NOT GOING VERY FAST AND EASILY BRAKED TO A STOP. I CALLED THAT WE WERE ABORTING FOR A SMALL ACFT IN FRONT OF US, ASSUMING THAT ACFT WAS IN ERROR. TWR XMITTED TO US '(OUR CALL SIGN), YOU WERE NOT CLRED FOR TKOF!' THERE WAS NO CONFLICT WITH THE LIGHT ACFT. WE WAITED IN POS AND IN A MIN WERE CLRED FOR TKOF. THAT ONE WAS UNEVENTFUL. CONTRIBUTING FACTORS: TWR LAUNCHED 2 ACFT IN FRONT OF US WHILE IN POS ON RWY. WE SAW AND EXPECTED THE FIRST ACFT WHICH WAS CLOSER TO US AND CLRED FOR TKOF AS WE WERE CLRED INTO 'POS AND HOLD.' TWR DID NOT ADVISE US THAT HE WAS LAUNCHING A SECOND ACFT IN FRONT OF US. WE WERE 'EXPECTING' THE NEXT XMISSION TO BE 'OUR' TKOF CLRNC. UPON OUR READBACK OF WHAT WE ASSUMED WAS 'OUR' TKOF CLRNC, TWR SAID NOTHING (POSSIBLE COVERED XMISSION BY OTHER ACFT WHICH TOOK THE CLRNC)? DISTRS OF A) DOING LAST FEW ITEMS ON TKOF CHKLIST. B) WATCHING HIGH PERFORMANCE TKOF/TURNOUT BY FIRST ACFT TO LAUNCH IN FRONT OF US. TWR WAS PROBABLY TRYING TO GET AS MANY ACFT OFF ON 8R AS HE COULD BEFORE INBOUND TFC FOR 26L. (NOTE: 26R-8L CLOSED.) CORRECTIVE ACTIONS: I DON'T KNOW IF IT IS POLICY, BUT I LIKE TO BE TOLD WHEN ACFT WILL BE LAUNCHED ON A RWY I AM CLRED ONTO WITH MY ACFT IN POS. I'LL HAVE TO LISTEN MORE ATTENTIVELY FOR MY CALL SIGN, NOT ASSUME THAT THE NEXT CALL IS FOR MY ACFT. TWR CTLR SHOULD BE AWARE THAT ANY ACFT PUT IN 'POS AND HOLD' WILL PROBABLY BE EXPECTING TKOF CLRNC NEXT. TWR SHOULD INFORM THAT ACFT (WHEN POSSIBLE) IF SOME OTHER OP WILL BE PRECEDING THE EXPECTED CLRNC. (WE DID EXPECT THE LAUNCH OF THE FIRST ACFT IN FRONT OF US, AS HE WAS CLRED WHILE WE WERE STILL TAXIING INTO POS AND HE WAS CLOSE ENOUGH TO US TO BE EASILY SEEN TAXIING OUT.) WE WERE NOT EXPECTING A SECOND ACFT TO BE CLRED OUT ONTO THE RWY HALF WAY DOWN THE RWY AFTER WE WERE POSITIONED! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES HE FEELS BIGGEST PROBLEM IS LACK OF ANY TA INDICATING WHAT SEQUENCE OFF DEP WAS BEING USED. NATURALLY FEELS HE WILL BE NEXT FOR TKOF WHEN ALREADY IN POS AND ACFT AHEAD HAS DEPARTED. COULD NOT SEE OTHER ACFT AT INTXN HALF WAY DOWN THE RWY. DID NOT HEAR ANY COM WITH THAT ACFT PRIOR TO TKOF CLRNC. THEY WERE THE ONLY OTHER ACFT AT THE RWY AS FAR AS THEY KNEW. THAT'S WHY THEY NEVER QUESTIONED THE TKOF CLRNC.

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