Narrative:

At night, obstructions with 1 strobe or closely spaced strobes can be indistinguishable form strobe-equipped aircraft, west/O some period of observation. Because of the motion of the observer, fixed strobes appear to have motion relative to background, particularly at lower altitudes. Ironically, an aircraft on a near collision course with the observer might show little relative motion. The red and green position lights on aircraft seem to be little help in telling the difference, as they are not visible at some distance, and are overwhelmed by the strobe. When a pilot is warned of traffic by ATC, he must first determine, at night, which of the visible strobes are aircraft and which are fixed obstructions. In some cases, the delay in identing the traffic could cause serious conflict, near miss or worse. Another example: in position for takeoff at night on runway 02 at richmond, one sees a strobe that appears to be an aircraft on the extended centerline of the runway, low over the trees. Actually, it is the topmost strobe of a tower that is approximately 11 NM northeast of the airport. Some of these white strobes are quite powerful. A pilot flying in the vicinity of one of these in clouds at night could become seriously disoriented. It is recommended that pilots consider turning off their aircraft strobes at night in clouds to avoid disorientation. Of course a pilot in the area of a fixed strobe could not affect its intensity.

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Original NASA ASRS Text

Title: REPORTER PROTESTS WHITE STROBE LIGHTS ON TWRS BECAUSE OF POSSIBILITY OF CONFUSION WITH STROBE LIGHTS ON ACFT.

Narrative: AT NIGHT, OBSTRUCTIONS WITH 1 STROBE OR CLOSELY SPACED STROBES CAN BE INDISTINGUISHABLE FORM STROBE-EQUIPPED ACFT, W/O SOME PERIOD OF OBSERVATION. BECAUSE OF THE MOTION OF THE OBSERVER, FIXED STROBES APPEAR TO HAVE MOTION RELATIVE TO BACKGROUND, PARTICULARLY AT LOWER ALTS. IRONICALLY, AN ACFT ON A NEAR COLLISION COURSE WITH THE OBSERVER MIGHT SHOW LITTLE RELATIVE MOTION. THE RED AND GREEN POS LIGHTS ON ACFT SEEM TO BE LITTLE HELP IN TELLING THE DIFFERENCE, AS THEY ARE NOT VISIBLE AT SOME DISTANCE, AND ARE OVERWHELMED BY THE STROBE. WHEN A PLT IS WARNED OF TFC BY ATC, HE MUST FIRST DETERMINE, AT NIGHT, WHICH OF THE VISIBLE STROBES ARE ACFT AND WHICH ARE FIXED OBSTRUCTIONS. IN SOME CASES, THE DELAY IN IDENTING THE TFC COULD CAUSE SERIOUS CONFLICT, NEAR MISS OR WORSE. ANOTHER EXAMPLE: IN POS FOR TKOF AT NIGHT ON RWY 02 AT RICHMOND, ONE SEES A STROBE THAT APPEARS TO BE AN ACFT ON THE EXTENDED CENTERLINE OF THE RWY, LOW OVER THE TREES. ACTUALLY, IT IS THE TOPMOST STROBE OF A TWR THAT IS APPROX 11 NM NE OF THE ARPT. SOME OF THESE WHITE STROBES ARE QUITE POWERFUL. A PLT FLYING IN THE VICINITY OF ONE OF THESE IN CLOUDS AT NIGHT COULD BECOME SERIOUSLY DISORIENTED. IT IS RECOMMENDED THAT PLTS CONSIDER TURNING OFF THEIR ACFT STROBES AT NIGHT IN CLOUDS TO AVOID DISORIENTATION. OF COURSE A PLT IN THE AREA OF A FIXED STROBE COULD NOT AFFECT ITS INTENSITY.

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.