Narrative:

I (aircraft X) was told by smo tower to taxi into position and hold for my IFR tower en route departure to lgb. I complied. After a few seconds holding (a plane had just taken off in front of me), I thought I saw a green light signal from the tower. But since I was unaware my radio (communication #1) was not receiving, I didn't realize at first that the light was for me. Within seconds, I saw a red light. I then returned, there was something wrong with my receiver. I tried transmitting to tower, asking them to blink the light if they heard me. I did not know if they wanted me to taxi off the runway or continue holding in place. I believe the red light was steady, indicating that I should hold. I switched to communication #2 and re-established contact with smo tower. I was told another plane (aircraft Y) had to go around and I was told I was now cleared for takeoff. The flight to lgb was uneventful, except the #1 communication worked on and off. I flew using #2 communication. When I returned to smo, I, on my own, called the tower. I was told 2 planes had to go around and that I should've noticed the light guns. I told them my attention was focused on my plane's instruments in preparation for takeoff and not the tower, and by the time I noticed the lights, the message they were sending was confusing. I believe a blinking red light means taxi clear of runway, not a steady one. In any event, maybe yet another light signal or color needs to be used to indicate to a plane already on the runway waiting for takeoff clearance, that it should quickly exit the runway.

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Original NASA ASRS Text

Title: C172 PLT ENCOUNTERS EQUIP PROB WHILE IN TKOF POS ON RWY. TWR LIGHT GUN SIGNALS ARE MISINTERPED. PLT REGAINS COM WITH TWR, BUT TFC ON FINAL IS REQUIRED TO EXECUTE A MISSED APCH.

Narrative: I (ACFT X) WAS TOLD BY SMO TWR TO TAXI INTO POS AND HOLD FOR MY IFR TWR ENRTE DEP TO LGB. I COMPLIED. AFTER A FEW SECONDS HOLDING (A PLANE HAD JUST TAKEN OFF IN FRONT OF ME), I THOUGHT I SAW A GREEN LIGHT SIGNAL FROM THE TWR. BUT SINCE I WAS UNAWARE MY RADIO (COM #1) WAS NOT RECEIVING, I DIDN'T REALIZE AT FIRST THAT THE LIGHT WAS FOR ME. WITHIN SECONDS, I SAW A RED LIGHT. I THEN RETURNED, THERE WAS SOMETHING WRONG WITH MY RECEIVER. I TRIED XMITTING TO TWR, ASKING THEM TO BLINK THE LIGHT IF THEY HEARD ME. I DID NOT KNOW IF THEY WANTED ME TO TAXI OFF THE RWY OR CONTINUE HOLDING IN PLACE. I BELIEVE THE RED LIGHT WAS STEADY, INDICATING THAT I SHOULD HOLD. I SWITCHED TO COM #2 AND RE-ESTABLISHED CONTACT WITH SMO TWR. I WAS TOLD ANOTHER PLANE (ACFT Y) HAD TO GO AROUND AND I WAS TOLD I WAS NOW CLRED FOR TKOF. THE FLT TO LGB WAS UNEVENTFUL, EXCEPT THE #1 COM WORKED ON AND OFF. I FLEW USING #2 COM. WHEN I RETURNED TO SMO, I, ON MY OWN, CALLED THE TWR. I WAS TOLD 2 PLANES HAD TO GO AROUND AND THAT I SHOULD'VE NOTICED THE LIGHT GUNS. I TOLD THEM MY ATTN WAS FOCUSED ON MY PLANE'S INSTS IN PREPARATION FOR TKOF AND NOT THE TWR, AND BY THE TIME I NOTICED THE LIGHTS, THE MESSAGE THEY WERE SENDING WAS CONFUSING. I BELIEVE A BLINKING RED LIGHT MEANS TAXI CLR OF RWY, NOT A STEADY ONE. IN ANY EVENT, MAYBE YET ANOTHER LIGHT SIGNAL OR COLOR NEEDS TO BE USED TO INDICATE TO A PLANE ALREADY ON THE RWY WAITING FOR TKOF CLRNC, THAT IT SHOULD QUICKLY EXIT THE RWY.

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.