Narrative:

Deer valley airport has 2 parallel runways that are very closely spaced together. Often, during the wkdays, one controller works both runways on different frequencys. Even though different frequencys, there's a 'partly live' effect, when you can tell what's happening on the north runway even if you only hear 1/2 the tower conversation on the south tower frequency. But this was a busy wkend, where 2 controllers work each runway separately on their own frequency (no party line). I had been cleared for takeoff on runway 7R straight out to the east. Apparently, a twin had been cleared for takeoff before me on runway 7L, also straight out. No one told me about the twin, and so I wasn't really looking for him. I departed runway 7R, and because sdl class D airspace is so close to our class D airspace, I started veering about 10 degrees to the north. We have a new toy in the plane. It's a poor man's TCASII. It was going off like crazy, which is not uncommon near an airport. But I was scanning anyway, and as I looked to my lower rear left, I saw I had overtaken a twin below me. Yikes! Thanks lord. No one in the tower said anything other than 'frequency change approved' (it sounded like south tower unaware of the near hit) and they were too busy for me to query about the twin. (Frankly, I don't know if he should have been there or not.) could have been a trainee on the north tower frequency, and no coordination between tower controllers. (Trainees don't know how fast glasairs homebuilt aircraft are.) I was flying from right seat (former cfii) which made seeing twin on lower left harder. Also, even though the glasair is faster than the twin, it was one of those slow closing speed sits, where the human eye doesn't detect motion. Have resolved to scan north runway for departing aircraft as I taxi into position and to hold runway centerline better for at least 2 mi before veering off.

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Original NASA ASRS Text

Title: A GLASAIR PLT OFF RWY 7R HAS AN NMAC WITH A SENECA OFF OF RWY 7L 2 MI E OF DVT, AZ.

Narrative: DEER VALLEY ARPT HAS 2 PARALLEL RWYS THAT ARE VERY CLOSELY SPACED TOGETHER. OFTEN, DURING THE WKDAYS, ONE CTLR WORKS BOTH RWYS ON DIFFERENT FREQS. EVEN THOUGH DIFFERENT FREQS, THERE'S A 'PARTLY LIVE' EFFECT, WHEN YOU CAN TELL WHAT'S HAPPENING ON THE N RWY EVEN IF YOU ONLY HEAR 1/2 THE TWR CONVERSATION ON THE S TWR FREQ. BUT THIS WAS A BUSY WKEND, WHERE 2 CTLRS WORK EACH RWY SEPARATELY ON THEIR OWN FREQ (NO PARTY LINE). I HAD BEEN CLRED FOR TKOF ON RWY 7R STRAIGHT OUT TO THE E. APPARENTLY, A TWIN HAD BEEN CLRED FOR TKOF BEFORE ME ON RWY 7L, ALSO STRAIGHT OUT. NO ONE TOLD ME ABOUT THE TWIN, AND SO I WASN'T REALLY LOOKING FOR HIM. I DEPARTED RWY 7R, AND BECAUSE SDL CLASS D AIRSPACE IS SO CLOSE TO OUR CLASS D AIRSPACE, I STARTED VEERING ABOUT 10 DEGS TO THE N. WE HAVE A NEW TOY IN THE PLANE. IT'S A POOR MAN'S TCASII. IT WAS GOING OFF LIKE CRAZY, WHICH IS NOT UNCOMMON NEAR AN ARPT. BUT I WAS SCANNING ANYWAY, AND AS I LOOKED TO MY LOWER REAR L, I SAW I HAD OVERTAKEN A TWIN BELOW ME. YIKES! THANKS LORD. NO ONE IN THE TWR SAID ANYTHING OTHER THAN 'FREQ CHANGE APPROVED' (IT SOUNDED LIKE S TWR UNAWARE OF THE NEAR HIT) AND THEY WERE TOO BUSY FOR ME TO QUERY ABOUT THE TWIN. (FRANKLY, I DON'T KNOW IF HE SHOULD HAVE BEEN THERE OR NOT.) COULD HAVE BEEN A TRAINEE ON THE N TWR FREQ, AND NO COORD BTWN TWR CTLRS. (TRAINEES DON'T KNOW HOW FAST GLASAIRS HOMEBUILT ACFT ARE.) I WAS FLYING FROM R SEAT (FORMER CFII) WHICH MADE SEEING TWIN ON LOWER L HARDER. ALSO, EVEN THOUGH THE GLASAIR IS FASTER THAN THE TWIN, IT WAS ONE OF THOSE SLOW CLOSING SPD SITS, WHERE THE HUMAN EYE DOESN'T DETECT MOTION. HAVE RESOLVED TO SCAN N RWY FOR DEPARTING ACFT AS I TAXI INTO POS AND TO HOLD RWY CTRLINE BETTER FOR AT LEAST 2 MI BEFORE VEERING OFF.

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.