Narrative:

I was beginning a local flight for training purposes, and was sole occupant of aircraft. I was cleared to taxi to runway 20 midfield (intersection of 20 and taxiway bravo). On completion of runup I called the tower, saying 'executive tower, ready for departure 2-0 midfield, right turnout.' after a short delay, during which I believe some other radio exchanges took place, I was told to expect departure on runway 16 as there was a # of other aircraft both in the pattern and awaiting departure, I took this statement to mean that I should expect an immediate departure, and completely failed to hear the new runway assignment. I responded, 'will be ready.' it should be noted that runway 20 and 16 intersection at the point I was waiting at, yet I did not know this and had never been given this clearance in numerous previous takeoffs from the field. When given clearance to takeoff, I was in a mindset to expedite and, if tower gave the runway # again I missed it again, and took off on 20. Tower shortly after informed me of my error, and asked direction of flight. I had checked the runway and the area for traffic, and no actual safety had been compromised (no near misses or runway conflicts with other aircraft). I must assume that the tower thought I was needed to franklin field, a nearby training field that runway 16 points almost directly at, judging from the incompatibility of a right turnout from 16 across the upwind area of the active, runway 20, and from the later query of 'say direction of flight' once airborne. Core responsibility lies with myself, as I had become complacent in operations from this airport, such that when a new instruction was placed, I did not hear what actually was being said this may have been amplified by the tower's clearance to takeoff for an aircraft on short final. Yet in final analysis I failed to hear what the tower said, tower was indeed trying to expedite by clearing me on 16, yet I expected expedition to be something else and failed to really listen. Had the controller added 'cross runway 20' to the takeoff clearance, the possibility of misunderstanding would significantly been reduced, although I am not attempting to blame the controllers for what I accept as my error.

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Original NASA ASRS Text

Title: PLT OF SMA MISSES CHANGE OF RWY IN TKOF CLRNC AND TAKES OFF ON WRONG RWY.

Narrative: I WAS BEGINNING A LCL FLT FOR TRNING PURPOSES, AND WAS SOLE OCCUPANT OF ACFT. I WAS CLRED TO TAXI TO RWY 20 MIDFIELD (INTXN OF 20 AND TXWY BRAVO). ON COMPLETION OF RUNUP I CALLED THE TWR, SAYING 'EXECUTIVE TWR, READY FOR DEP 2-0 MIDFIELD, RIGHT TURNOUT.' AFTER A SHORT DELAY, DURING WHICH I BELIEVE SOME OTHER RADIO EXCHANGES TOOK PLACE, I WAS TOLD TO EXPECT DEP ON RWY 16 AS THERE WAS A # OF OTHER ACFT BOTH IN THE PATTERN AND AWAITING DEP, I TOOK THIS STATEMENT TO MEAN THAT I SHOULD EXPECT AN IMMEDIATE DEP, AND COMPLETELY FAILED TO HEAR THE NEW RWY ASSIGNMENT. I RESPONDED, 'WILL BE READY.' IT SHOULD BE NOTED THAT RWY 20 AND 16 INTXN AT THE POINT I WAS WAITING AT, YET I DID NOT KNOW THIS AND HAD NEVER BEEN GIVEN THIS CLRNC IN NUMEROUS PREVIOUS TKOFS FROM THE FIELD. WHEN GIVEN CLRNC TO TKOF, I WAS IN A MINDSET TO EXPEDITE AND, IF TWR GAVE THE RWY # AGAIN I MISSED IT AGAIN, AND TOOK OFF ON 20. TWR SHORTLY AFTER INFORMED ME OF MY ERROR, AND ASKED DIRECTION OF FLT. I HAD CHKED THE RWY AND THE AREA FOR TFC, AND NO ACTUAL SAFETY HAD BEEN COMPROMISED (NO NEAR MISSES OR RWY CONFLICTS WITH OTHER ACFT). I MUST ASSUME THAT THE TWR THOUGHT I WAS NEEDED TO FRANKLIN FIELD, A NEARBY TRNING FIELD THAT RWY 16 POINTS ALMOST DIRECTLY AT, JUDGING FROM THE INCOMPATIBILITY OF A RIGHT TURNOUT FROM 16 ACROSS THE UPWIND AREA OF THE ACTIVE, RWY 20, AND FROM THE LATER QUERY OF 'SAY DIRECTION OF FLT' ONCE AIRBORNE. CORE RESPONSIBILITY LIES WITH MYSELF, AS I HAD BECOME COMPLACENT IN OPS FROM THIS ARPT, SUCH THAT WHEN A NEW INSTRUCTION WAS PLACED, I DID NOT HEAR WHAT ACTUALLY WAS BEING SAID THIS MAY HAVE BEEN AMPLIFIED BY THE TWR'S CLRNC TO TKOF FOR AN ACFT ON SHORT FINAL. YET IN FINAL ANALYSIS I FAILED TO HEAR WHAT THE TWR SAID, TWR WAS INDEED TRYING TO EXPEDITE BY CLRING ME ON 16, YET I EXPECTED EXPEDITION TO BE SOMETHING ELSE AND FAILED TO REALLY LISTEN. HAD THE CTLR ADDED 'CROSS RWY 20' TO THE TKOF CLRNC, THE POSSIBILITY OF MISUNDERSTANDING WOULD SIGNIFICANTLY BEEN REDUCED, ALTHOUGH I AM NOT ATTEMPTING TO BLAME THE CTLRS FOR WHAT I ACCEPT AS MY ERROR.

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.