Narrative:

In 3/91 I experience a near miss with a helicopter. At the time the helicopter was noticed, it was at our 8-9 O'clock position and passing over the left wing about 150' above us. We were heading 360 degrees magnetic at 500' AGL and 150 KIAS. The tech and I saw the helicopter at the same time. The near miss was witnessed by another aircraft flying at 5500' MSL, who reported the near miss to las approach control, who did an ATC near miss report. I was trying to maintain a constant 500' AGL on sloping terrain, fly a constant heading or make small heading changes to remain on the flight line and maintain a constant 150 KIAS. The tech was looking at the LORAN, which is positioned on the cockpit console, so she could give me distance and direction off line in hundredth of a mile. In other words, the 2 people up front were inside the cockpit instead of outside. We were not aware that a tour helicopter operation flight route crossed our flight line. I was monitoring a las approach control frequency instead of 120.65 for tour aircraft positions. However, it was found that the positions reported by the helicopter operation were unknown to me. Both aircraft are painted with small stripes. This color blends well into the desert landscape. The helicopter pilot saw our aircraft shadow on the ground before he was us. Corrective action: the management of helicopter services and I met in 3/91 and discussed their flight rtes and altitudes along with our test lines and altitudes. We discovered several possible route and altitude conflicts. In the future, pilots or operations personnel will notify helicopter operations personnel when we plan to fly our test lines. Pilots will monitor 120.65 when they fly in airspace utilized by grand canyon tours. Pilots were briefed on chkpoint names call by the air tour operators. I will brief local air tour operators, aircraft and helicopter at a meeting convened by the local FSDO. This meeting is scheduled to take place in 3/91. Pilot will not normally conduct LORAN training while trying to fly a test line unless it is in restr airspace. The airspace was uncontrolled and perceived to be free of other aircraft. I was not aware of the vol, altitude or flight rtes of helicopter traffic in the rsl temple bar test line area. This caused me to be secure at the flight altitude and not to look around outside the aircraft as much as I normally would. I felt that trying to fly a mission profile was important, but our normal mission is in restr airspace. I took no evasive action because the helicopter was not noticed in time to take action.

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Original NASA ASRS Text

Title: NMAC.

Narrative: IN 3/91 I EXPERIENCE A NEAR MISS WITH A HELI. AT THE TIME THE HELI WAS NOTICED, IT WAS AT OUR 8-9 O'CLOCK POS AND PASSING OVER THE LEFT WING ABOUT 150' ABOVE US. WE WERE HDG 360 DEGS MAGNETIC AT 500' AGL AND 150 KIAS. THE TECH AND I SAW THE HELI AT THE SAME TIME. THE NEAR MISS WAS WITNESSED BY ANOTHER ACFT FLYING AT 5500' MSL, WHO RPTED THE NEAR MISS TO LAS APCH CTL, WHO DID AN ATC NEAR MISS RPT. I WAS TRYING TO MAINTAIN A CONSTANT 500' AGL ON SLOPING TERRAIN, FLY A CONSTANT HDG OR MAKE SMALL HDG CHANGES TO REMAIN ON THE FLT LINE AND MAINTAIN A CONSTANT 150 KIAS. THE TECH WAS LOOKING AT THE LORAN, WHICH IS POSITIONED ON THE COCKPIT CONSOLE, SO SHE COULD GIVE ME DISTANCE AND DIRECTION OFF LINE IN HUNDREDTH OF A MILE. IN OTHER WORDS, THE 2 PEOPLE UP FRONT WERE INSIDE THE COCKPIT INSTEAD OF OUTSIDE. WE WERE NOT AWARE THAT A TOUR HELI OPERATION FLT RTE CROSSED OUR FLT LINE. I WAS MONITORING A LAS APCH CTL FREQ INSTEAD OF 120.65 FOR TOUR ACFT POSITIONS. HOWEVER, IT WAS FOUND THAT THE POSITIONS RPTED BY THE HELI OPERATION WERE UNKNOWN TO ME. BOTH ACFT ARE PAINTED WITH SMALL STRIPES. THIS COLOR BLENDS WELL INTO THE DESERT LANDSCAPE. THE HELI PLT SAW OUR ACFT SHADOW ON THE GND BEFORE HE WAS US. CORRECTIVE ACTION: THE MGMNT OF HELI SVCS AND I MET IN 3/91 AND DISCUSSED THEIR FLT RTES AND ALTS ALONG WITH OUR TEST LINES AND ALTS. WE DISCOVERED SEVERAL POSSIBLE RTE AND ALT CONFLICTS. IN THE FUTURE, PLTS OR OPS PERSONNEL WILL NOTIFY HELI OPS PERSONNEL WHEN WE PLAN TO FLY OUR TEST LINES. PLTS WILL MONITOR 120.65 WHEN THEY FLY IN AIRSPACE UTILIZED BY GRAND CANYON TOURS. PLTS WERE BRIEFED ON CHKPOINT NAMES CALL BY THE AIR TOUR OPERATORS. I WILL BRIEF LCL AIR TOUR OPERATORS, ACFT AND HELI AT A MEETING CONVENED BY THE LCL FSDO. THIS MEETING IS SCHEDULED TO TAKE PLACE IN 3/91. PLT WILL NOT NORMALLY CONDUCT LORAN TRNING WHILE TRYING TO FLY A TEST LINE UNLESS IT IS IN RESTR AIRSPACE. THE AIRSPACE WAS UNCONTROLLED AND PERCEIVED TO BE FREE OF OTHER ACFT. I WAS NOT AWARE OF THE VOL, ALT OR FLT RTES OF HELI TFC IN THE RSL TEMPLE BAR TEST LINE AREA. THIS CAUSED ME TO BE SECURE AT THE FLT ALT AND NOT TO LOOK AROUND OUTSIDE THE ACFT AS MUCH AS I NORMALLY WOULD. I FELT THAT TRYING TO FLY A MISSION PROFILE WAS IMPORTANT, BUT OUR NORMAL MISSION IS IN RESTR AIRSPACE. I TOOK NO EVASIVE ACTION BECAUSE THE HELI WAS NOT NOTICED IN TIME TO TAKE ACTION.

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.