Narrative:

On oct/xx/94, I was flying a piper cub over downtown dayton, oh, taking photographs with a friend. The ground elevation varies slightly, but 950 ft is the approximately average. Due to the lack of many off-field landing sites within the city, I had been specifically monitoring my altitude, very frequently, while over the city to try and maintain 1000 ft AGL. While circling a house, I did allow the aircraft to inadvertently drop to just above 1700 ft MSL (750 ft AGL) on 1, possibly 2 occasions, but upon noticing that, I climbed back up to approximately 1950 ft MSL. After circling, we headed in a sse direction, not over any tall buildings, back towards the airport we took off from. While just south of the downtown area, and just over a major east/west running freeway, the passenger pointed out, and then I immediately saw through the overhead skylight between the wings, a small helicopter fly over us in an easterly direction. Although I had been clearing constantly throughout the flight, I did not see it approach us due to it being obscured by the right wing. While it appeared to be close, it did not appear to be making any kind of evasive maneuver. I do not remember my exact altitude at that moment, but because I was so near the downtown area where we had been circling, I am sure I was at least close to the 1000 ft AGL that I had been trying to maintain. As soon as we reached the sparsely populated areas just southeast of town, I allowed us to descend to approximately 500 ft AGL, but then climbed another hundred ft or so for the flight back to waynesville, oh, where we had departed from. Upon landing, I noticed a small 2-SEAT helicopter landing on the field beside us, and realized they were probably there to talk to me. They told me they had been at 500 ft AGL chasing a stolen car when they flew over us. They made no mention of an evasive maneuver such as a climb or a turn to avoid us. He then took down my license number and name, and stated he would report the incident to the FAA. I also noted that our aircraft altimeter indicated within 10 ft of field elevation. Besides the obvious embarrassment of being chased down by a helicopter, a couple of other things about the whole event disturb me. First, while I was not flying this aircraft precisely and by the instruments during most of the flight, on the portion of the flight where the incident occurred, I had been specifically monitoring my altitude. I realize that I dropped below 1000 ft AGL at least once inadvertently, and while a drop of 1 ft or 500 ft below that constitutes a violation, I am absolutely sure I was nowhere near the 350 ft AGL to 450 ft AGL (1300 ft MSL to 1400 ft MSL) that they claimed I was at when they overflew me at an alleged 1500 ft MSL. Though I do not question the integrity of those officers, I do believe that while I may possibly have been a little low, they, preoccupied with the chase, may have been higher than they thought, and hence the incident occurred. In that case, I would have still been in the wrong, but again, I really don't think that I was below 1000 ft AGL since I had been monitoring my altitude at the time to try and ensure that I at least maintained that altitude. I believe that problem could have been avoided had I tried to maintain an extra 100 or 200 ft altitude over the city, especially due to the low power setting, tight turns, and gusting wind. Contributing to my decision to remain right at the 1000 ft AGL level was the desire to achieve the best possible photos. In addition, although I had been clearing, banking occasionally while in straight flight would help me to see through the blind spots inherent to high wing aircraft. However, I also believe that the helicopter may have been watching the ground a little more than they should have because, from their description of the event, it seemed they didn't see me until they were right overhead. And, they may not have been paying much attention to their altimeter either. Regardless of the altitudes, it is obvious that both myself and they should have been using better clearing techniques.

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Original NASA ASRS Text

Title: PLT OF PIPER CUB FLEW BELOW MSA OVER A CITY AND HAD NMAC WITH A GOV HELI.

Narrative: ON OCT/XX/94, I WAS FLYING A PIPER CUB OVER DOWNTOWN DAYTON, OH, TAKING PHOTOGRAPHS WITH A FRIEND. THE GND ELEVATION VARIES SLIGHTLY, BUT 950 FT IS THE APPROX AVERAGE. DUE TO THE LACK OF MANY OFF-FIELD LNDG SITES WITHIN THE CITY, I HAD BEEN SPECIFICALLY MONITORING MY ALT, VERY FREQUENTLY, WHILE OVER THE CITY TO TRY AND MAINTAIN 1000 FT AGL. WHILE CIRCLING A HOUSE, I DID ALLOW THE ACFT TO INADVERTENTLY DROP TO JUST ABOVE 1700 FT MSL (750 FT AGL) ON 1, POSSIBLY 2 OCCASIONS, BUT UPON NOTICING THAT, I CLBED BACK UP TO APPROX 1950 FT MSL. AFTER CIRCLING, WE HEADED IN A SSE DIRECTION, NOT OVER ANY TALL BUILDINGS, BACK TOWARDS THE ARPT WE TOOK OFF FROM. WHILE JUST S OF THE DOWNTOWN AREA, AND JUST OVER A MAJOR E/W RUNNING FREEWAY, THE PAX POINTED OUT, AND THEN I IMMEDIATELY SAW THROUGH THE OVERHEAD SKYLIGHT BTWN THE WINGS, A SMALL HELI FLY OVER US IN AN EASTERLY DIRECTION. ALTHOUGH I HAD BEEN CLRING CONSTANTLY THROUGHOUT THE FLT, I DID NOT SEE IT APCH US DUE TO IT BEING OBSCURED BY THE R WING. WHILE IT APPEARED TO BE CLOSE, IT DID NOT APPEAR TO BE MAKING ANY KIND OF EVASIVE MANEUVER. I DO NOT REMEMBER MY EXACT ALT AT THAT MOMENT, BUT BECAUSE I WAS SO NEAR THE DOWNTOWN AREA WHERE WE HAD BEEN CIRCLING, I AM SURE I WAS AT LEAST CLOSE TO THE 1000 FT AGL THAT I HAD BEEN TRYING TO MAINTAIN. AS SOON AS WE REACHED THE SPARSELY POPULATED AREAS JUST SE OF TOWN, I ALLOWED US TO DSND TO APPROX 500 FT AGL, BUT THEN CLBED ANOTHER HUNDRED FT OR SO FOR THE FLT BACK TO WAYNESVILLE, OH, WHERE WE HAD DEPARTED FROM. UPON LNDG, I NOTICED A SMALL 2-SEAT HELI LNDG ON THE FIELD BESIDE US, AND REALIZED THEY WERE PROBABLY THERE TO TALK TO ME. THEY TOLD ME THEY HAD BEEN AT 500 FT AGL CHASING A STOLEN CAR WHEN THEY FLEW OVER US. THEY MADE NO MENTION OF AN EVASIVE MANEUVER SUCH AS A CLB OR A TURN TO AVOID US. HE THEN TOOK DOWN MY LICENSE NUMBER AND NAME, AND STATED HE WOULD RPT THE INCIDENT TO THE FAA. I ALSO NOTED THAT OUR ACFT ALTIMETER INDICATED WITHIN 10 FT OF FIELD ELEVATION. BESIDES THE OBVIOUS EMBARRASSMENT OF BEING CHASED DOWN BY A HELI, A COUPLE OF OTHER THINGS ABOUT THE WHOLE EVENT DISTURB ME. FIRST, WHILE I WAS NOT FLYING THIS ACFT PRECISELY AND BY THE INSTS DURING MOST OF THE FLT, ON THE PORTION OF THE FLT WHERE THE INCIDENT OCCURRED, I HAD BEEN SPECIFICALLY MONITORING MY ALT. I REALIZE THAT I DROPPED BELOW 1000 FT AGL AT LEAST ONCE INADVERTENTLY, AND WHILE A DROP OF 1 FT OR 500 FT BELOW THAT CONSTITUTES A VIOLATION, I AM ABSOLUTELY SURE I WAS NOWHERE NEAR THE 350 FT AGL TO 450 FT AGL (1300 FT MSL TO 1400 FT MSL) THAT THEY CLAIMED I WAS AT WHEN THEY OVERFLEW ME AT AN ALLEGED 1500 FT MSL. THOUGH I DO NOT QUESTION THE INTEGRITY OF THOSE OFFICERS, I DO BELIEVE THAT WHILE I MAY POSSIBLY HAVE BEEN A LITTLE LOW, THEY, PREOCCUPIED WITH THE CHASE, MAY HAVE BEEN HIGHER THAN THEY THOUGHT, AND HENCE THE INCIDENT OCCURRED. IN THAT CASE, I WOULD HAVE STILL BEEN IN THE WRONG, BUT AGAIN, I REALLY DON'T THINK THAT I WAS BELOW 1000 FT AGL SINCE I HAD BEEN MONITORING MY ALT AT THE TIME TO TRY AND ENSURE THAT I AT LEAST MAINTAINED THAT ALT. I BELIEVE THAT PROB COULD HAVE BEEN AVOIDED HAD I TRIED TO MAINTAIN AN EXTRA 100 OR 200 FT ALT OVER THE CITY, ESPECIALLY DUE TO THE LOW PWR SETTING, TIGHT TURNS, AND GUSTING WIND. CONTRIBUTING TO MY DECISION TO REMAIN RIGHT AT THE 1000 FT AGL LEVEL WAS THE DESIRE TO ACHIEVE THE BEST POSSIBLE PHOTOS. IN ADDITION, ALTHOUGH I HAD BEEN CLRING, BANKING OCCASIONALLY WHILE IN STRAIGHT FLT WOULD HELP ME TO SEE THROUGH THE BLIND SPOTS INHERENT TO HIGH WING ACFT. HOWEVER, I ALSO BELIEVE THAT THE HELI MAY HAVE BEEN WATCHING THE GND A LITTLE MORE THAN THEY SHOULD HAVE BECAUSE, FROM THEIR DESCRIPTION OF THE EVENT, IT SEEMED THEY DIDN'T SEE ME UNTIL THEY WERE RIGHT OVERHEAD. AND, THEY MAY NOT HAVE BEEN PAYING MUCH ATTN TO THEIR ALTIMETER EITHER. REGARDLESS OF THE ALTS, IT IS OBVIOUS THAT BOTH MYSELF AND THEY SHOULD HAVE BEEN USING BETTER CLRING TECHNIQUES.

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.