Potential conflict evolves into an unauthorized formation flight.

Attributes
ACN	204620
Time
Date	199203
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : den
State Reference	CO
Altitude	agl bound lower : 600 agl bound upper : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 17500 flight time type : 3500
ASRS Report	204620
Person 2
Affiliation	Other
Function	flight crew : single pilot
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation non adherence : far other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 6000 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While patrolling pipeline (15 NM, 046 degree, den VOR), I was flying south observing pipeline. I observed traffic (an small aircraft Y) 12 O'clock 2 mi approximately 200 ft above. My reaction was to descend and reverse course. After reversing course, I was in a position to patrol a pipeline that goes east from that location. I continued east on that pipeline. By raising my right wing, I could look over my right shoulder and keep other aircraft in sight. The other aircraft turned in my direction and was approaching me from the 4 O'clock position. I continued my patrol east until the other aircraft was about 500 ft to my rear and 50 ft below. At that time I initiated a climb in an attempt to evade the other aircraft. The climb caused the other aircraft to fly past. I continued to climb and departed area. I did not see other aircraft after he passed below. The greatest potential for an accident in this situation is while patrolling pipeline. The patrol pilot may make sudden turns in either direction -- in this case, a right turn would have probably caused a midair. I thing the other aircraft was trying to get my aircraft number. In so doing he put both aircraft in danger.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT EVOLVES INTO AN UNAUTHORIZED FORMATION FLT.

Narrative: WHILE PATROLLING PIPELINE (15 NM, 046 DEG, DEN VOR), I WAS FLYING S OBSERVING PIPELINE. I OBSERVED TFC (AN SMA Y) 12 O'CLOCK 2 MI APPROX 200 FT ABOVE. MY REACTION WAS TO DSND AND REVERSE COURSE. AFTER REVERSING COURSE, I WAS IN A POS TO PATROL A PIPELINE THAT GOES E FROM THAT LOCATION. I CONTINUED E ON THAT PIPELINE. BY RAISING MY R WING, I COULD LOOK OVER MY R SHOULDER AND KEEP OTHER ACFT IN SIGHT. THE OTHER ACFT TURNED IN MY DIRECTION AND WAS APCHING ME FROM THE 4 O'CLOCK POS. I CONTINUED MY PATROL E UNTIL THE OTHER ACFT WAS ABOUT 500 FT TO MY REAR AND 50 FT BELOW. AT THAT TIME I INITIATED A CLB IN AN ATTEMPT TO EVADE THE OTHER ACFT. THE CLB CAUSED THE OTHER ACFT TO FLY PAST. I CONTINUED TO CLB AND DEPARTED AREA. I DID NOT SEE OTHER ACFT AFTER HE PASSED BELOW. THE GREATEST POTENTIAL FOR AN ACCIDENT IN THIS SITUATION IS WHILE PATROLLING PIPELINE. THE PATROL PLT MAY MAKE SUDDEN TURNS IN EITHER DIRECTION -- IN THIS CASE, A R TURN WOULD HAVE PROBABLY CAUSED A MIDAIR. I THING THE OTHER ACFT WAS TRYING TO GET MY ACFT NUMBER. IN SO DOING HE PUT BOTH ACFT IN DANGER.

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.