Narrative:

There is a 'phantom' green light at salina ATCT that appears just like a normal green light would given by a controller. This light has been seen for some 10 yrs and never formally reported. I would estimate that 10-15 runway incursions have occurred due to this light. The cause is unknown, however, we have taken 2 safety measures: 1) cover the light guns with black felt to insure light is not somehow bouncing around and causing a green to appear from the lights guns. 2) we are giving a steady red light prior to a steady green. This is not adequate because a 'phantom' light could appear after a steady red anyway. We have spotted the light since these safety measures have been taken. This eliminates the theory that the light guns are part of the problem. Most of the controllers and maintenance personnel have VHF radios to cross the runway, however, many people cross without radio contact. I am not sure what is causing this problem but have a few ideas: 1) the sun is causing a reflection of the windows somehow. 2) the sun is causing a reflection off of the windows and the shades. 3) the CRT used for our fdio is green but does not face the window that the light is visible from. I think a sign that prohibits runway xings via the tower light guns is in order and all personnel should be given an adequate radio for direct 2-WAY radio contact with the tower. The radios we have are very old and do not hold a charge for any length of time, most of them are falling apart. Callback conversation with reporter revealed the following information: reporter states that runway incursions involve vehicles only, no aircraft. He said that there are many no radio vehicles crossing the runway on a daily basis. When they look at the tower for a green light gun signal to cross, they see a green reflection, possibly from the tower windows and the tinted glass. There are approximately 15-30 vehicles that cross the runway a day and some of these vehicles do not have radios. Many of them are not familiar with airport operations, i.e., janitors, window cleaners, etc. The runway incursions have impacted aircraft departing and landing. Facility management aware of problem. Reporter not sure if tower is owned and maintained by airport or FAA. Reporter called back to advise that the facility and airport management have implemented a plan that will hopefully take care of inadvertent runway xings by vehicle drivers due to the 'phantom green light' reflecting problem at the tower cabin attendant. He said that the policy now is that all vehicles must have a radio and in direct communications with the tower before crossing the runway. Vehicle drivers without radios are being instructed to stop by the WX office to pick up a small hand-held transceiver radio before proceeding out to the runway intersection. The reporter believes that requiring all vehicles to establish 2-WAY communications with the tower will eliminate runway incursions. The reporter also mentioned that the tower structure is owned by the FAA and that any replacement or cleaning of windows is the FAA's responsibility. They have just recently signed a janitorial contract to have the windows cleaned on a regular basis.

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Original NASA ASRS Text

Title: RWY INCURSIONS CAUSED BY VEHICLE DRIVERS MISTAKENLY SEEING A GREEN REFLECTION IN THE TWR CAB AND XING RWY WITHOUT AUTHORIZATION.

Narrative: THERE IS A 'PHANTOM' GREEN LIGHT AT SALINA ATCT THAT APPEARS JUST LIKE A NORMAL GREEN LIGHT WOULD GIVEN BY A CTLR. THIS LIGHT HAS BEEN SEEN FOR SOME 10 YRS AND NEVER FORMALLY RPTED. I WOULD ESTIMATE THAT 10-15 RWY INCURSIONS HAVE OCCURRED DUE TO THIS LIGHT. THE CAUSE IS UNKNOWN, HOWEVER, WE HAVE TAKEN 2 SAFETY MEASURES: 1) COVER THE LIGHT GUNS WITH BLACK FELT TO INSURE LIGHT IS NOT SOMEHOW BOUNCING AROUND AND CAUSING A GREEN TO APPEAR FROM THE LIGHTS GUNS. 2) WE ARE GIVING A STEADY RED LIGHT PRIOR TO A STEADY GREEN. THIS IS NOT ADEQUATE BECAUSE A 'PHANTOM' LIGHT COULD APPEAR AFTER A STEADY RED ANYWAY. WE HAVE SPOTTED THE LIGHT SINCE THESE SAFETY MEASURES HAVE BEEN TAKEN. THIS ELIMINATES THE THEORY THAT THE LIGHT GUNS ARE PART OF THE PROB. MOST OF THE CTLRS AND MAINT PERSONNEL HAVE VHF RADIOS TO CROSS THE RWY, HOWEVER, MANY PEOPLE CROSS WITHOUT RADIO CONTACT. I AM NOT SURE WHAT IS CAUSING THIS PROB BUT HAVE A FEW IDEAS: 1) THE SUN IS CAUSING A REFLECTION OF THE WINDOWS SOMEHOW. 2) THE SUN IS CAUSING A REFLECTION OFF OF THE WINDOWS AND THE SHADES. 3) THE CRT USED FOR OUR FDIO IS GREEN BUT DOES NOT FACE THE WINDOW THAT THE LIGHT IS VISIBLE FROM. I THINK A SIGN THAT PROHIBITS RWY XINGS VIA THE TWR LIGHT GUNS IS IN ORDER AND ALL PERSONNEL SHOULD BE GIVEN AN ADEQUATE RADIO FOR DIRECT 2-WAY RADIO CONTACT WITH THE TWR. THE RADIOS WE HAVE ARE VERY OLD AND DO NOT HOLD A CHARGE FOR ANY LENGTH OF TIME, MOST OF THEM ARE FALLING APART. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT RWY INCURSIONS INVOLVE VEHICLES ONLY, NO ACFT. HE SAID THAT THERE ARE MANY NO RADIO VEHICLES XING THE RWY ON A DAILY BASIS. WHEN THEY LOOK AT THE TWR FOR A GREEN LIGHT GUN SIGNAL TO CROSS, THEY SEE A GREEN REFLECTION, POSSIBLY FROM THE TWR WINDOWS AND THE TINTED GLASS. THERE ARE APPROX 15-30 VEHICLES THAT CROSS THE RWY A DAY AND SOME OF THESE VEHICLES DO NOT HAVE RADIOS. MANY OF THEM ARE NOT FAMILIAR WITH ARPT OPS, I.E., JANITORS, WINDOW CLEANERS, ETC. THE RWY INCURSIONS HAVE IMPACTED ACFT DEPARTING AND LNDG. FACILITY MGMNT AWARE OF PROB. RPTR NOT SURE IF TWR IS OWNED AND MAINTAINED BY ARPT OR FAA. RPTR CALLED BACK TO ADVISE THAT THE FACILITY AND ARPT MGMNT HAVE IMPLEMENTED A PLAN THAT WILL HOPEFULLY TAKE CARE OF INADVERTENT RWY XINGS BY VEHICLE DRIVERS DUE TO THE 'PHANTOM GREEN LIGHT' REFLECTING PROB AT THE TWR CAB. HE SAID THAT THE POLICY NOW IS THAT ALL VEHICLES MUST HAVE A RADIO AND IN DIRECT COMS WITH THE TWR BEFORE XING THE RWY. VEHICLE DRIVERS WITHOUT RADIOS ARE BEING INSTRUCTED TO STOP BY THE WX OFFICE TO PICK UP A SMALL HAND-HELD TRANSCEIVER RADIO BEFORE PROCEEDING OUT TO THE RWY INTXN. THE RPTR BELIEVES THAT REQUIRING ALL VEHICLES TO ESTABLISH 2-WAY COMS WITH THE TWR WILL ELIMINATE RWY INCURSIONS. THE RPTR ALSO MENTIONED THAT THE TWR STRUCTURE IS OWNED BY THE FAA AND THAT ANY REPLACEMENT OR CLEANING OF WINDOWS IS THE FAA'S RESPONSIBILITY. THEY HAVE JUST RECENTLY SIGNED A JANITORIAL CONTRACT TO HAVE THE WINDOWS CLEANED ON A REGULAR BASIS.

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.