Narrative:

Our flight houston direct harlingen was cleared for takeoff on runway 30L by hou tower. After takeoff, we saw that a beechcraft bonanza was taking off from runway 35 without clearance and was on a potential collision course. We continued to climb and turned right to a 360 degree heading to avoid a conflict. After the bonanza was no longer a factor, we turned back to runway heading. Supplemental information from acn 418867: on nov/xa/98 approximately XA30 local, I was at hou airport preparing for a CFI training flight. I was holding short of runway 35 ready for takeoff. Another grumman cheetah was in position on runway 35 waiting for release and a B737 was taxiing into position on runway 30L. When the grumman cheetah in front of me was released, I was told to 'position and hold, runway 35' by hou tower. I taxied into position and waited for clearance to take off. While taxiing into position, I noted an airliner on about a 5 mi final. Noting that airplane, I was primed for an immediate takeoff clearance. The following is what I heard and did in the mins that followed: (tower) -- '(garble)...cleared for immediate takeoff runway 35.' I assumed this clearance was for me and while starting my takeoff role answered: (me) -- 'grumman n-number cleared for immediate takeoff runway 35, what heading do you want after takeoff?' (tower) -- 'fly runway heading.' (me) -- 'north-number, fly runway heading.' I continued my takeoff roll, lifted off starting my climb and noticed the B737 lifting off on runway 30L. It became clear very quickly we were on intersecting paths and I started altering course to the west (left) at the same time the B737 started altering course to the north(right). I believe that the 2 aircraft never got closer than 1500 ft horizontal distance. Shortly after turning, an unidented voice, which I believe was the airline pilot asking hou tower if 'that grumman' had been cleared for takeoff. The question was asked 3 times before hou tower answered no. Tower then contacted me and repeated that I had not been cleared for takeoff, that clearance was for the B737. I apologized for the miscoms explaining that I thought the clearance issued was for me and asked what the tower needed me to do. I was given a heading of 270 degrees and flew that heading until clear of the class B airspace. The remainder of the flight continued without incident. This problem arose because of the fast delivery of clrncs. Hou airport was very busy at that time and hou tower was dealing with a large number of aircraft. Contributing factors include the slight garble of communications in the beginning, the improper runway given in the clearance to the B737, and the failure of all involved to maintain clear communications. Clarification of the clearance should have been obtained by both myself and the airliner, and hou tower should have caught the mistake when I read back a faulty clearance.

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Original NASA ASRS Text

Title: A GA AA-5A CHEETAH PERFORMS AN UNAUTH TKOF FROM RWY 35 AT HOU. IN THE PROCESS THE ACFT CREATES A POTENTIAL CONFLICT WITH A DEP B737 ON RWY 30L. BOTH ACFT TURN AWAY TO AVOID EACH OTHER.

Narrative: OUR FLT HOUSTON DIRECT HARLINGEN WAS CLRED FOR TKOF ON RWY 30L BY HOU TWR. AFTER TKOF, WE SAW THAT A BEECHCRAFT BONANZA WAS TAKING OFF FROM RWY 35 WITHOUT CLRNC AND WAS ON A POTENTIAL COLLISION COURSE. WE CONTINUED TO CLB AND TURNED R TO A 360 DEG HDG TO AVOID A CONFLICT. AFTER THE BONANZA WAS NO LONGER A FACTOR, WE TURNED BACK TO RWY HDG. SUPPLEMENTAL INFO FROM ACN 418867: ON NOV/XA/98 APPROX XA30 LCL, I WAS AT HOU ARPT PREPARING FOR A CFI TRAINING FLT. I WAS HOLDING SHORT OF RWY 35 READY FOR TKOF. ANOTHER GRUMMAN CHEETAH WAS IN POS ON RWY 35 WAITING FOR RELEASE AND A B737 WAS TAXIING INTO POS ON RWY 30L. WHEN THE GRUMMAN CHEETAH IN FRONT OF ME WAS RELEASED, I WAS TOLD TO 'POS AND HOLD, RWY 35' BY HOU TWR. I TAXIED INTO POS AND WAITED FOR CLRNC TO TAKE OFF. WHILE TAXIING INTO POS, I NOTED AN AIRLINER ON ABOUT A 5 MI FINAL. NOTING THAT AIRPLANE, I WAS PRIMED FOR AN IMMEDIATE TKOF CLRNC. THE FOLLOWING IS WHAT I HEARD AND DID IN THE MINS THAT FOLLOWED: (TWR) -- '(GARBLE)...CLRED FOR IMMEDIATE TKOF RWY 35.' I ASSUMED THIS CLRNC WAS FOR ME AND WHILE STARTING MY TKOF ROLE ANSWERED: (ME) -- 'GRUMMAN N-NUMBER CLRED FOR IMMEDIATE TKOF RWY 35, WHAT HDG DO YOU WANT AFTER TKOF?' (TWR) -- 'FLY RWY HDG.' (ME) -- 'N-NUMBER, FLY RWY HDG.' I CONTINUED MY TKOF ROLL, LIFTED OFF STARTING MY CLB AND NOTICED THE B737 LIFTING OFF ON RWY 30L. IT BECAME CLR VERY QUICKLY WE WERE ON INTERSECTING PATHS AND I STARTED ALTERING COURSE TO THE W (L) AT THE SAME TIME THE B737 STARTED ALTERING COURSE TO THE N(R). I BELIEVE THAT THE 2 ACFT NEVER GOT CLOSER THAN 1500 FT HORIZ DISTANCE. SHORTLY AFTER TURNING, AN UNIDENTED VOICE, WHICH I BELIEVE WAS THE AIRLINE PLT ASKING HOU TWR IF 'THAT GRUMMAN' HAD BEEN CLRED FOR TKOF. THE QUESTION WAS ASKED 3 TIMES BEFORE HOU TWR ANSWERED NO. TWR THEN CONTACTED ME AND REPEATED THAT I HAD NOT BEEN CLRED FOR TKOF, THAT CLRNC WAS FOR THE B737. I APOLOGIZED FOR THE MISCOMS EXPLAINING THAT I THOUGHT THE CLRNC ISSUED WAS FOR ME AND ASKED WHAT THE TWR NEEDED ME TO DO. I WAS GIVEN A HDG OF 270 DEGS AND FLEW THAT HDG UNTIL CLR OF THE CLASS B AIRSPACE. THE REMAINDER OF THE FLT CONTINUED WITHOUT INCIDENT. THIS PROB AROSE BECAUSE OF THE FAST DELIVERY OF CLRNCS. HOU ARPT WAS VERY BUSY AT THAT TIME AND HOU TWR WAS DEALING WITH A LARGE NUMBER OF ACFT. CONTRIBUTING FACTORS INCLUDE THE SLIGHT GARBLE OF COMS IN THE BEGINNING, THE IMPROPER RWY GIVEN IN THE CLRNC TO THE B737, AND THE FAILURE OF ALL INVOLVED TO MAINTAIN CLR COMS. CLARIFICATION OF THE CLRNC SHOULD HAVE BEEN OBTAINED BY BOTH MYSELF AND THE AIRLINER, AND HOU TWR SHOULD HAVE CAUGHT THE MISTAKE WHEN I READ BACK A FAULTY 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.