Narrative:

This was a demonstration flight for out company sales department. In the jumpseat was the chief pilot for the customer. Located in the cabin was the customer. After the briefing and fielding several questions about the aircraft, I returned to the cockpit and reviewed the departure clearance with the copilot. We started and prepared to taxi. The copilot called ground control at the same time the prospective buyer's chief pilot attempted to question me about the aircraft. My attention was given to the line personnel's direction out of parking and once clear of other aircraft, I came to a full stop on the ramp. I asked the copilot if we had received clearance to taxi and he replied yes, ground said taxi to runway 36. From leaving the ramp to the time we changed from ground control frequency to tower control frequency at the approach end of runway 36, we did not receive any communication from ground control. We came to a stop behind a light high wing single engine aircraft holding for departure and began our pretkof checklists. The aircraft ahead of us departed on runway 36. Copilot called the tower ready to depart. We got no response from the tower and the copilot attempted to call again. At this time the customer got out of his seat in the cabin and came forward to ask his chief pilot in the jumpseat a question about the aircraft. The copilot attempted to call the tower and once again got no response. I called the tower ready to depart. The tower responded and I turned around to ask the passenger to take his seat. Once lined up on the runway, checklists complete, I asked the copilot, 'are we cleared to go?' he replied, 'yes.' tower said, 'cleared for takeoff, contact oakland center leaving 10000'.' I saw the light single engine aircraft that had departed before us approximately 2-2 1/2 mi off the departure end of the runway on the centerline. When I saw the other aircraft I was still over the runway airborne so I immediately moved to the right of centerline to keep it in sight during climb out. Never losing sight of the traffic, I climbed to an altitude of approximately 1000' above it, then initiated a turn to join the standard instrument departure. We did not receive any communication from the tower from thetime we started our takeoff roll before reaching 10000', so the copilot attempted to call ZOA as instructed. After 2 unsuccessful attempts by the copilot to call center, I picked up my microphone, called ZOA and got an immediate response. At this time we realized that the copilot was having difficulty transmitting. We traded mics and that did not clear up the problem. The copilot then wiggled his microphone plug and called center again. This time they said they heard him loud and clear. To our knowledge, at no time did was have a problem receiving. On each frequency at the time it was selected (ground control, tower and center) we were able to hear controllers and other aircraft. The following morning I spoke with south lake tower chief. He informed me that they believe we had taxied and taken off west/O clearance. I asked him if at any time while we were operating on or around tvl, did the tower receive or record any xmissions of carrier signals with no voice. He replied negative. I asked him if we were taxiing west/O clearance to do so, why did not ground control question our activity. He had no response. I asked him why, if when we contacted the tower holding short of the runway, the tower did not question what we were doing there west/O clearance from ground control. He replied that he did know, however, our clearance at the runway was into position and hold, not a clearance to depart. I asked him why, if the tower saw our aircraft begin a takeoff roll west/O clearance to depart, and the tower saw a possible conflict with the previously departed aircraft, did not the tower tell us to stop. He told me he would not discuss it at that time. I asked him why we did not hear from the tower before we contacted ZOA. He said that our IFR clearance was to contact center out of 10000'. I believe the problem arose from a problem with the copilot's transmitter. I believe the problem was compounded by: my confirming the clearance to taxi and takeoff with the copilot west/O requesting that he call the controller if I had a doubt, ambient noise levels inside the aircraft, inappropriate passenger activity inside the aircraft, lack of comment by ground control that we may have copiedanother aircraft's clearance to taxi--we would have most likely found the radio problem at that time, and inaction by the tower controller when we initiated our takeoff roll and he saw what could be a possible traffic conflict. I believe this situation could have been avoided by more complete and better communication between the controllers and the aircraft.

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Original NASA ASRS Text

Title: GA-LTT UNAUTH TAXI TKOF CLOSE PROX WITH GA-SMA THAT HAD DEPARTED PREVIOUSLY.

Narrative: THIS WAS A DEMONSTRATION FLT FOR OUT COMPANY SALES DEPT. IN THE JUMPSEAT WAS THE CHIEF PLT FOR THE CUSTOMER. LOCATED IN THE CABIN WAS THE CUSTOMER. AFTER THE BRIEFING AND FIELDING SEVERAL QUESTIONS ABOUT THE ACFT, I RETURNED TO THE COCKPIT AND REVIEWED THE DEP CLRNC WITH THE COPLT. WE STARTED AND PREPARED TO TAXI. THE COPLT CALLED GND CTL AT THE SAME TIME THE PROSPECTIVE BUYER'S CHIEF PLT ATTEMPTED TO QUESTION ME ABOUT THE ACFT. MY ATTN WAS GIVEN TO THE LINE PERSONNEL'S DIRECTION OUT OF PARKING AND ONCE CLR OF OTHER ACFT, I CAME TO A FULL STOP ON THE RAMP. I ASKED THE COPLT IF WE HAD RECEIVED CLRNC TO TAXI AND HE REPLIED YES, GND SAID TAXI TO RWY 36. FROM LEAVING THE RAMP TO THE TIME WE CHANGED FROM GND CTL FREQ TO TWR CTL FREQ AT THE APCH END OF RWY 36, WE DID NOT RECEIVE ANY COM FROM GND CTL. WE CAME TO A STOP BEHIND A LIGHT HIGH WING SINGLE ENG ACFT HOLDING FOR DEP AND BEGAN OUR PRETKOF CHKLISTS. THE ACFT AHEAD OF US DEPARTED ON RWY 36. COPLT CALLED THE TWR READY TO DEPART. WE GOT NO RESPONSE FROM THE TWR AND THE COPLT ATTEMPTED TO CALL AGAIN. AT THIS TIME THE CUSTOMER GOT OUT OF HIS SEAT IN THE CABIN AND CAME FORWARD TO ASK HIS CHIEF PLT IN THE JUMPSEAT A QUESTION ABOUT THE ACFT. THE COPLT ATTEMPTED TO CALL THE TWR AND ONCE AGAIN GOT NO RESPONSE. I CALLED THE TWR READY TO DEPART. THE TWR RESPONDED AND I TURNED AROUND TO ASK THE PAX TO TAKE HIS SEAT. ONCE LINED UP ON THE RWY, CHKLISTS COMPLETE, I ASKED THE COPLT, 'ARE WE CLRED TO GO?' HE REPLIED, 'YES.' TWR SAID, 'CLRED FOR TKOF, CONTACT OAKLAND CENTER LEAVING 10000'.' I SAW THE LIGHT SINGLE ENG ACFT THAT HAD DEPARTED BEFORE US APPROX 2-2 1/2 MI OFF THE DEP END OF THE RWY ON THE CENTERLINE. WHEN I SAW THE OTHER ACFT I WAS STILL OVER THE RWY AIRBORNE SO I IMMEDIATELY MOVED TO THE RIGHT OF CENTERLINE TO KEEP IT IN SIGHT DURING CLBOUT. NEVER LOSING SIGHT OF THE TFC, I CLBED TO AN ALT OF APPROX 1000' ABOVE IT, THEN INITIATED A TURN TO JOIN THE STANDARD INSTRUMENT DEP. WE DID NOT RECEIVE ANY COM FROM THE TWR FROM THETIME WE STARTED OUR TKOF ROLL BEFORE REACHING 10000', SO THE COPLT ATTEMPTED TO CALL ZOA AS INSTRUCTED. AFTER 2 UNSUCCESSFUL ATTEMPTS BY THE COPLT TO CALL CENTER, I PICKED UP MY MIC, CALLED ZOA AND GOT AN IMMEDIATE RESPONSE. AT THIS TIME WE REALIZED THAT THE COPLT WAS HAVING DIFFICULTY XMITTING. WE TRADED MICS AND THAT DID NOT CLR UP THE PROB. THE COPLT THEN WIGGLED HIS MIC PLUG AND CALLED CENTER AGAIN. THIS TIME THEY SAID THEY HEARD HIM LOUD AND CLEAR. TO OUR KNOWLEDGE, AT NO TIME DID WAS HAVE A PROB RECEIVING. ON EACH FREQ AT THE TIME IT WAS SELECTED (GND CTL, TWR AND CENTER) WE WERE ABLE TO HEAR CTLRS AND OTHER ACFT. THE FOLLOWING MORNING I SPOKE WITH SOUTH LAKE TWR CHIEF. HE INFORMED ME THAT THEY BELIEVE WE HAD TAXIED AND TAKEN OFF W/O CLRNC. I ASKED HIM IF AT ANY TIME WHILE WE WERE OPERATING ON OR AROUND TVL, DID THE TWR RECEIVE OR RECORD ANY XMISSIONS OF CARRIER SIGNALS WITH NO VOICE. HE REPLIED NEGATIVE. I ASKED HIM IF WE WERE TAXIING W/O CLRNC TO DO SO, WHY DID NOT GND CTL QUESTION OUR ACTIVITY. HE HAD NO RESPONSE. I ASKED HIM WHY, IF WHEN WE CONTACTED THE TWR HOLDING SHORT OF THE RWY, THE TWR DID NOT QUESTION WHAT WE WERE DOING THERE W/O CLRNC FROM GND CTL. HE REPLIED THAT HE DID KNOW, HOWEVER, OUR CLRNC AT THE RWY WAS INTO POS AND HOLD, NOT A CLRNC TO DEPART. I ASKED HIM WHY, IF THE TWR SAW OUR ACFT BEGIN A TKOF ROLL W/O CLRNC TO DEPART, AND THE TWR SAW A POSSIBLE CONFLICT WITH THE PREVIOUSLY DEPARTED ACFT, DID NOT THE TWR TELL US TO STOP. HE TOLD ME HE WOULD NOT DISCUSS IT AT THAT TIME. I ASKED HIM WHY WE DID NOT HEAR FROM THE TWR BEFORE WE CONTACTED ZOA. HE SAID THAT OUR IFR CLRNC WAS TO CONTACT CENTER OUT OF 10000'. I BELIEVE THE PROB AROSE FROM A PROB WITH THE COPLT'S XMITTER. I BELIEVE THE PROB WAS COMPOUNDED BY: MY CONFIRMING THE CLRNC TO TAXI AND TKOF WITH THE COPLT W/O REQUESTING THAT HE CALL THE CTLR IF I HAD A DOUBT, AMBIENT NOISE LEVELS INSIDE THE ACFT, INAPPROPRIATE PAX ACTIVITY INSIDE THE ACFT, LACK OF COMMENT BY GND CTL THAT WE MAY HAVE COPIEDANOTHER ACFT'S CLRNC TO TAXI--WE WOULD HAVE MOST LIKELY FOUND THE RADIO PROB AT THAT TIME, AND INACTION BY THE TWR CTLR WHEN WE INITIATED OUR TKOF ROLL AND HE SAW WHAT COULD BE A POSSIBLE TFC CONFLICT. I BELIEVE THIS SITUATION COULD HAVE BEEN AVOIDED BY MORE COMPLETE AND BETTER COM BTWN THE CTLRS AND THE ACFT.

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.