Narrative:

While holding short of runway 8 for departure; we received instructions from tower to position and hold for runway 8. I thought that my first officer had read back position and hold. Due to the 4 different volume controls in the airplane I had been having difficulty adjusting the volume so that I could hear tower clearly. After completing runway items checklist; the first officer; who was the PF for this leg; started to take off. I questioned him about our clearance and he stated that we were cleared for takeoff. While attempting to contact the tower to verify our clearance; the first officer had begun rolling and as he was setting power; deviated right of runway centerline. After gaining control and returning to centerline; I heard tower call us. I asked tower to 'say again' and tower responded with 'disregard' and we continued the takeoff; only to later find out that we did not have a takeoff clearance. The following; I feel; are contributing factors. First I failed to clarify a disagreement between PF and PNF by asking ATC for verification. Second; I allowed the flight to continue out of the ramp without resolving a radio volume problem I was having and assumed that my first officer heard his radio and clearance clearly. Third; I was temporarily distraction with the initial takeoff roll by the first officer who was having difficulty early on in maintaining directional control. Fourth; since we were early in our takeoff roll and tower questioned us; but later said disregard; I feel it was an opportunity for the controller to tell us to abort which would have broke the chain of events that I had allowed but could have been stopped by him. In talking to the tower supervisor; it was later determined that the controller saw me rolling and was not sure if he had given me clearance or not which resulted in a loss of situational awareness on behalf of the controller. In closing; I am at fault and take personal responsibility for not being more assertive and allowing the takeoff to continue. In the future when faced with similar situations; I will stop all operations until verification is received. Supplemental information from acn 682722: bur tower handed us off to socal departure on frequency 135.05 without further comment. It wasn't until we arrived and then departed that company called us en route to our next destination and said that bur tower would like to discuss with us a 'pilot deviation.' after we landed; we called tower and they informed us that we departed without a clearance. Contributing factors and corrections: upon reviewing the chain of events; it is clear that there were numerous factors that led to the pilot deviation. First; both the captain and myself; were confident with each other's plting abilities and allowed ourselves to become complacent. This led to not verifying with the tower that we were in fact cleared for takeoff. I mistakenly wrote down the departure time and didn't question myself when the captain asked if we were cleared for takeoff. The radio volume on our aircraft was not set properly. It took the captain 1/2 way to destination to properly set the volume and squelch. It was later revealed that the trim was so far out of alignment that the captain had centered it on the 'originating check' assuming the previous pilot had not set it properly or was engaged in a training flight doing single engine approachs and had; therefore; forgotten to reset the trim after landing. As I applied power and deviated slightly from centerline; I was able to correct; but both the captain and I were distraction. Bur tower had numerous opportunities to 'stop' our takeoff roll. On the initial call-up when we said 'say again' and then when they called us and said 'air carrier X; um; disregard.' both of which would have stopped us before we crossed runway 15/33 on our takeoff roll. We later found out that the bur tower controller couldn't recall if a takeoff clearance had been issued and thus allowed us to take off. The captain and myself should have aborted when we realized there might be some confusion on our takeoff. In the end; I ultimately started a chain of events by not questioning tower about our takeoff clearance and take full responsibility for my lapse in judgement. The chain of events could have been stopped by the captain; the controller or myself; had we all used better judgement. I have learned a few lessons from this incident and truly believe it will not happen again.

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Original NASA ASRS Text

Title: A BE99 DEPARTED BUR WITHOUT TKOF CLRNC BECAUSE OF THE CAPT'S LOW ATC RADIO VOLUME AND THE FO FORGETTING THE CLRNC WAS POS AND HOLD.

Narrative: WHILE HOLDING SHORT OF RWY 8 FOR DEP; WE RECEIVED INSTRUCTIONS FROM TWR TO POS AND HOLD FOR RWY 8. I THOUGHT THAT MY FO HAD READ BACK POS AND HOLD. DUE TO THE 4 DIFFERENT VOLUME CTLS IN THE AIRPLANE I HAD BEEN HAVING DIFFICULTY ADJUSTING THE VOLUME SO THAT I COULD HEAR TWR CLRLY. AFTER COMPLETING RWY ITEMS CHKLIST; THE FO; WHO WAS THE PF FOR THIS LEG; STARTED TO TAKE OFF. I QUESTIONED HIM ABOUT OUR CLRNC AND HE STATED THAT WE WERE CLRED FOR TKOF. WHILE ATTEMPTING TO CONTACT THE TWR TO VERIFY OUR CLRNC; THE FO HAD BEGUN ROLLING AND AS HE WAS SETTING PWR; DEVIATED R OF RWY CTRLINE. AFTER GAINING CTL AND RETURNING TO CTRLINE; I HEARD TWR CALL US. I ASKED TWR TO 'SAY AGAIN' AND TWR RESPONDED WITH 'DISREGARD' AND WE CONTINUED THE TKOF; ONLY TO LATER FIND OUT THAT WE DID NOT HAVE A TKOF CLRNC. THE FOLLOWING; I FEEL; ARE CONTRIBUTING FACTORS. FIRST I FAILED TO CLARIFY A DISAGREEMENT BTWN PF AND PNF BY ASKING ATC FOR VERIFICATION. SECOND; I ALLOWED THE FLT TO CONTINUE OUT OF THE RAMP WITHOUT RESOLVING A RADIO VOLUME PROB I WAS HAVING AND ASSUMED THAT MY FO HEARD HIS RADIO AND CLRNC CLRLY. THIRD; I WAS TEMPORARILY DISTR WITH THE INITIAL TKOF ROLL BY THE FO WHO WAS HAVING DIFFICULTY EARLY ON IN MAINTAINING DIRECTIONAL CTL. FOURTH; SINCE WE WERE EARLY IN OUR TKOF ROLL AND TWR QUESTIONED US; BUT LATER SAID DISREGARD; I FEEL IT WAS AN OPPORTUNITY FOR THE CTLR TO TELL US TO ABORT WHICH WOULD HAVE BROKE THE CHAIN OF EVENTS THAT I HAD ALLOWED BUT COULD HAVE BEEN STOPPED BY HIM. IN TALKING TO THE TWR SUPVR; IT WAS LATER DETERMINED THAT THE CTLR SAW ME ROLLING AND WAS NOT SURE IF HE HAD GIVEN ME CLRNC OR NOT WHICH RESULTED IN A LOSS OF SITUATIONAL AWARENESS ON BEHALF OF THE CTLR. IN CLOSING; I AM AT FAULT AND TAKE PERSONAL RESPONSIBILITY FOR NOT BEING MORE ASSERTIVE AND ALLOWING THE TKOF TO CONTINUE. IN THE FUTURE WHEN FACED WITH SIMILAR SITUATIONS; I WILL STOP ALL OPS UNTIL VERIFICATION IS RECEIVED. SUPPLEMENTAL INFO FROM ACN 682722: BUR TWR HANDED US OFF TO SOCAL DEP ON FREQ 135.05 WITHOUT FURTHER COMMENT. IT WASN'T UNTIL WE ARRIVED AND THEN DEPARTED THAT COMPANY CALLED US ENRTE TO OUR NEXT DEST AND SAID THAT BUR TWR WOULD LIKE TO DISCUSS WITH US A 'PLTDEV.' AFTER WE LANDED; WE CALLED TWR AND THEY INFORMED US THAT WE DEPARTED WITHOUT A CLRNC. CONTRIBUTING FACTORS AND CORRECTIONS: UPON REVIEWING THE CHAIN OF EVENTS; IT IS CLR THAT THERE WERE NUMEROUS FACTORS THAT LED TO THE PLTDEV. FIRST; BOTH THE CAPT AND MYSELF; WERE CONFIDENT WITH EACH OTHER'S PLTING ABILITIES AND ALLOWED OURSELVES TO BECOME COMPLACENT. THIS LED TO NOT VERIFYING WITH THE TWR THAT WE WERE IN FACT CLRED FOR TKOF. I MISTAKENLY WROTE DOWN THE DEP TIME AND DIDN'T QUESTION MYSELF WHEN THE CAPT ASKED IF WE WERE CLRED FOR TKOF. THE RADIO VOLUME ON OUR ACFT WAS NOT SET PROPERLY. IT TOOK THE CAPT 1/2 WAY TO DEST TO PROPERLY SET THE VOLUME AND SQUELCH. IT WAS LATER REVEALED THAT THE TRIM WAS SO FAR OUT OF ALIGNMENT THAT THE CAPT HAD CTRED IT ON THE 'ORIGINATING CHK' ASSUMING THE PREVIOUS PLT HAD NOT SET IT PROPERLY OR WAS ENGAGED IN A TRAINING FLT DOING SINGLE ENG APCHS AND HAD; THEREFORE; FORGOTTEN TO RESET THE TRIM AFTER LNDG. AS I APPLIED PWR AND DEVIATED SLIGHTLY FROM CTRLINE; I WAS ABLE TO CORRECT; BUT BOTH THE CAPT AND I WERE DISTR. BUR TWR HAD NUMEROUS OPPORTUNITIES TO 'STOP' OUR TKOF ROLL. ON THE INITIAL CALL-UP WHEN WE SAID 'SAY AGAIN' AND THEN WHEN THEY CALLED US AND SAID 'ACR X; UM; DISREGARD.' BOTH OF WHICH WOULD HAVE STOPPED US BEFORE WE CROSSED RWY 15/33 ON OUR TKOF ROLL. WE LATER FOUND OUT THAT THE BUR TWR CTLR COULDN'T RECALL IF A TKOF CLRNC HAD BEEN ISSUED AND THUS ALLOWED US TO TAKE OFF. THE CAPT AND MYSELF SHOULD HAVE ABORTED WHEN WE REALIZED THERE MIGHT BE SOME CONFUSION ON OUR TKOF. IN THE END; I ULTIMATELY STARTED A CHAIN OF EVENTS BY NOT QUESTIONING TWR ABOUT OUR TKOF CLRNC AND TAKE FULL RESPONSIBILITY FOR MY LAPSE IN JUDGEMENT. THE CHAIN OF EVENTS COULD HAVE BEEN STOPPED BY THE CAPT; THE CTLR OR MYSELF; HAD WE ALL USED BETTER JUDGEMENT. I HAVE LEARNED A FEW LESSONS FROM THIS INCIDENT AND TRULY BELIEVE IT WILL NOT HAPPEN AGAIN.

Data retrieved from NASA's ASRS site as of January 2009 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.