Narrative:

I was cleared for takeoff on runway 28R for an eastbound VFR departure. (This departure calls for a westbound takeoff followed by a climbing right turn to the downwind; remaining south of california route 52; and exiting the pattern eastbound.) on takeoff; I began my climb; maintaining visual separation from a slower airplane in the upwind from runway 28L. Upon reaching california route 163; I began a climbing right turn. At approximately the crosswind point of the turn; a cirrus crossed my flight path from my left to right (east to west); approximately 300 ft horizontally and between 50 and 100 ft vertically from me; requiring me to take evasive action to avoid what appeared to be a collision course with that airplane. No traffic advisories were reported from the tower prior to; or during; the takeoff; and it's possible the tower was not aware the aircraft was there. (During my run-up; my wife; also a pilot; recalled hearing the tower clear a cirrus over mt. Soledad for landing on runway 28L. If that's correct and the subject plane was that cirrus; then he would have entered the pattern from the incorrect side of the field; and north of the tower. The controllers would have been looking for him to pass south of the tower from the controllers' right to left.) once clear of the cirrus; I returned to my climbing turn and continued downwind in the pattern; maintaining visual separation from that airplane. As I cleared the pattern eastbound; I observed him descend; and it appeared he began to cross over the runway environment at which point I lost sight of him. I reported the event to the tower and continued my flight with no further issues.

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Original NASA ASRS Text

Title: M20 pilot departing MYF reports a NMAC with a Cirrus entering the pattern. Evasive action is taken and the event reported to the Tower.

Narrative: I was cleared for takeoff on Runway 28R for an eastbound VFR departure. (This departure calls for a westbound takeoff followed by a climbing right turn to the downwind; remaining south of California Route 52; and exiting the pattern eastbound.) On takeoff; I began my climb; maintaining visual separation from a slower airplane in the upwind from Runway 28L. Upon reaching California Route 163; I began a climbing right turn. At approximately the crosswind point of the turn; a Cirrus crossed my flight path from my left to right (east to west); approximately 300 FT horizontally and between 50 and 100 FT vertically from me; requiring me to take evasive action to avoid what appeared to be a collision course with that airplane. No traffic advisories were reported from the Tower prior to; or during; the takeoff; and it's possible the Tower was not aware the aircraft was there. (During my run-up; my wife; also a pilot; recalled hearing the Tower clear a Cirrus over Mt. Soledad for landing on Runway 28L. If that's correct and the subject plane was that Cirrus; then he would have entered the pattern from the incorrect side of the field; and north of the Tower. The controllers would have been looking for him to pass south of the Tower from the Controllers' right to left.) Once clear of the Cirrus; I returned to my climbing turn and continued downwind in the pattern; maintaining visual separation from that airplane. As I cleared the pattern eastbound; I observed him descend; and it appeared he began to cross over the runway environment at which point I lost sight of him. I reported the event to the Tower and continued my flight with no further issues.

Data retrieved from NASA's ASRS site as of July 2013 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.