Narrative:

I planned a departure from cys in a PA28R arrow. The first waypoint was the mbw VOR. There was a NOTAM for military airdrop activity 9000 ft and below and 3 mi either side of a line from CYS349027 to CYS256012 to CYS216014. Since this blocked a direct departure to the northwest to mbw; I planned to depart to the north; remain east of the cys 360 degree radial; and climb to a safe altitude above 9000 ft before turning northwest. I requested a north departure when I contacted cheyenne ground. ATIS information reported wind 180 degrees at 6 KTS and ground sent me to runway 13. When cheyenne tower cleared me for takeoff; they stated left turnout approved. After takeoff; I climbed on runway heading until I was at about 600 ft AGL then began a turn to the north. I set up for a vy climb at 90 KIAS. As I approached the extended centerline for runway 27 and about 0.5 NM east of the runway 27 threshold; a king air reported entering right downwind for runway 27. The tower did not respond to the king air instead talked to a beech 1900 on the ground. I lowered the nose for better visibility and began scanning for the king air. I glanced at the altimeter and saw 7100. Traffic pattern is 7200 ft MSL. I leveled off and initiated a gradual descent. Once the frequency cleared; the king air again called right downwind for runway 27. During that transmission; I spotted the king air at my 10:30 O'clock position; slightly above me; at about 1/4 mi and closing. I immediately pushed the nose down. At that time tower acknowledged the king air and added traffic is an arrow. At about the same instant tower completed the transmission; I passed directly beneath the king air with less than 200 ft vertical separation. Then tower called; sorry about that arrow xyz; traffic is a king air on downwind. The track node at that time shows a ground speed of 122 KTS; which I assume was due to the rapid descent to avoid the king air. The king air pilot likely did not see me. I would have been at his 1 or 2 O'clock position and slightly below. This may have put me below his glare shield. I did not notice that he took any evasive action and he landed about 1 min later on runway 27. He did not comment on frequency about the near miss. Once I heard the king air announce on right downwind; I did recognize the situation that was developing and I should have reacted sooner by immediately checking altitude and staying well below pattern altitude. Changing course would have also been an option; but even now I don't know which direction would have been the better choice. Perhaps the single most important reason that I failed to act sooner was my assumption that the tower controller would provide TA's. I do recall thinking to myself; why isn't tower resolving this? I think this assumption is a function of my inexperience; in general; but also from complacency based on the experience that I do have. My home field is in class D airspace and I have grown accustomed to my local controllers being very cautious and providing pilots with ample traffic callouts. I now have a better understanding that traffic avoidance under VFR is ultimately the pilot's responsibility and not the controller's. Having said that; I do believe another link was that the tower controller did not recognize the situation developing. If the king air had called up before I took off and was expected on a right downwind for runway 27; tower should probably not have cleared me for a left turn and departure to the north. Similarly; the concern over the beech 1900 on the ground suggests that tower was unaware of the situation developing in the air.

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Original NASA ASRS Text

Title: PA28 PLT DESCRIBED NMAC DEPARTING RWY 13 AT CYS CONFLICTING WITH KING AIR ENTERING DOWNWIND FOR RWY 27 AT 7200 FT; NO TFC ISSUED BY ATC.

Narrative: I PLANNED A DEP FROM CYS IN A PA28R ARROW. THE FIRST WAYPOINT WAS THE MBW VOR. THERE WAS A NOTAM FOR MIL AIRDROP ACTIVITY 9000 FT AND BELOW AND 3 MI EITHER SIDE OF A LINE FROM CYS349027 TO CYS256012 TO CYS216014. SINCE THIS BLOCKED A DIRECT DEP TO THE NW TO MBW; I PLANNED TO DEPART TO THE N; REMAIN E OF THE CYS 360 DEG RADIAL; AND CLB TO A SAFE ALT ABOVE 9000 FT BEFORE TURNING NW. I REQUESTED A N DEP WHEN I CONTACTED CHEYENNE GND. ATIS INFO RPTED WIND 180 DEGS AT 6 KTS AND GND SENT ME TO RWY 13. WHEN CHEYENNE TWR CLRED ME FOR TKOF; THEY STATED L TURNOUT APPROVED. AFTER TKOF; I CLBED ON RWY HDG UNTIL I WAS AT ABOUT 600 FT AGL THEN BEGAN A TURN TO THE N. I SET UP FOR A VY CLB AT 90 KIAS. AS I APCHED THE EXTENDED CTRLINE FOR RWY 27 AND ABOUT 0.5 NM E OF THE RWY 27 THRESHOLD; A KING AIR RPTED ENTERING R DOWNWIND FOR RWY 27. THE TWR DID NOT RESPOND TO THE KING AIR INSTEAD TALKED TO A BEECH 1900 ON THE GND. I LOWERED THE NOSE FOR BETTER VISIBILITY AND BEGAN SCANNING FOR THE KING AIR. I GLANCED AT THE ALTIMETER AND SAW 7100. TFC PATTERN IS 7200 FT MSL. I LEVELED OFF AND INITIATED A GRADUAL DSCNT. ONCE THE FREQ CLRED; THE KING AIR AGAIN CALLED R DOWNWIND FOR RWY 27. DURING THAT XMISSION; I SPOTTED THE KING AIR AT MY 10:30 O'CLOCK POS; SLIGHTLY ABOVE ME; AT ABOUT 1/4 MI AND CLOSING. I IMMEDIATELY PUSHED THE NOSE DOWN. AT THAT TIME TWR ACKNOWLEDGED THE KING AIR AND ADDED TFC IS AN ARROW. AT ABOUT THE SAME INSTANT TWR COMPLETED THE XMISSION; I PASSED DIRECTLY BENEATH THE KING AIR WITH LESS THAN 200 FT VERT SEPARATION. THEN TWR CALLED; SORRY ABOUT THAT ARROW XYZ; TFC IS A KING AIR ON DOWNWIND. THE TRACK NODE AT THAT TIME SHOWS A GND SPD OF 122 KTS; WHICH I ASSUME WAS DUE TO THE RAPID DSCNT TO AVOID THE KING AIR. THE KING AIR PLT LIKELY DID NOT SEE ME. I WOULD HAVE BEEN AT HIS 1 OR 2 O'CLOCK POS AND SLIGHTLY BELOW. THIS MAY HAVE PUT ME BELOW HIS GLARE SHIELD. I DID NOT NOTICE THAT HE TOOK ANY EVASIVE ACTION AND HE LANDED ABOUT 1 MIN LATER ON RWY 27. HE DID NOT COMMENT ON FREQ ABOUT THE NEAR MISS. ONCE I HEARD THE KING AIR ANNOUNCE ON R DOWNWIND; I DID RECOGNIZE THE SITUATION THAT WAS DEVELOPING AND I SHOULD HAVE REACTED SOONER BY IMMEDIATELY CHKING ALT AND STAYING WELL BELOW PATTERN ALT. CHANGING COURSE WOULD HAVE ALSO BEEN AN OPTION; BUT EVEN NOW I DON'T KNOW WHICH DIRECTION WOULD HAVE BEEN THE BETTER CHOICE. PERHAPS THE SINGLE MOST IMPORTANT REASON THAT I FAILED TO ACT SOONER WAS MY ASSUMPTION THAT THE TWR CTLR WOULD PROVIDE TA'S. I DO RECALL THINKING TO MYSELF; WHY ISN'T TWR RESOLVING THIS? I THINK THIS ASSUMPTION IS A FUNCTION OF MY INEXPERIENCE; IN GENERAL; BUT ALSO FROM COMPLACENCY BASED ON THE EXPERIENCE THAT I DO HAVE. MY HOME FIELD IS IN CLASS D AIRSPACE AND I HAVE GROWN ACCUSTOMED TO MY LCL CTLRS BEING VERY CAUTIOUS AND PROVIDING PLTS WITH AMPLE TFC CALLOUTS. I NOW HAVE A BETTER UNDERSTANDING THAT TFC AVOIDANCE UNDER VFR IS ULTIMATELY THE PLT'S RESPONSIBILITY AND NOT THE CTLR'S. HAVING SAID THAT; I DO BELIEVE ANOTHER LINK WAS THAT THE TWR CTLR DID NOT RECOGNIZE THE SITUATION DEVELOPING. IF THE KING AIR HAD CALLED UP BEFORE I TOOK OFF AND WAS EXPECTED ON A R DOWNWIND FOR RWY 27; TWR SHOULD PROBABLY NOT HAVE CLRED ME FOR A L TURN AND DEP TO THE N. SIMILARLY; THE CONCERN OVER THE BEECH 1900 ON THE GND SUGGESTS THAT TWR WAS UNAWARE OF THE SITUATION DEVELOPING IN THE AIR.

Data retrieved from NASA's ASRS site as of January 2009 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.