GA flight crew reported taking evasive action due to low climb rate of another aircraft.

Attributes
ACN	1678770
Time
Date	201908
Local Time Of Day	0601-1200
Place
Locale Reference	TOA.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	None
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Person 1
Function	Pilot Not Flying
Qualification	Flight Crew Flight Instructor Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 220 Flight Crew Total 9967 Flight Crew Type 86
Events
Anomaly	Conflict NMAC Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance Deviation - Track / Heading All Types
Miss Distance	Horizontal 100 Vertical 209

Narrative:

After departing runway 29R; stearman executed a VFR box climb within class D airspace. The aircraft was on a right downwind approaching 1;500 feet when ATC advised it to level off and issued a traffic alert. Conflicting traffic; a white and green cessna 177; was at the aircraft's 1 o'clock high position; almost directly over the stearman. Position was initially obscured by the stearman's upper right wing. Less than 300 feet of separation was estimated. The cessna 177 was also executing a box climb; however; its rate of climb was minimal.stearman leveled off; and continued an easterly track at 1;500 feet to gain separation with the conflicting traffic. Once sufficient separation was gained; a climb was resumed while maintaining visual separation with the cessna 177. An uneventful climb out of class D followed.the ATC who assigned me to level off had a distinctly different voice from the controller working local control and could have been a supervisor. The crew of debriefed this incident; and feel the conflict was mainly the result of the cessna 177's very low rate of climb. Our crew is very grateful for the hard work and diligence of ATC.replay of the incident on an ads-B out monitoring website confirmed visual indications of less than 300 feet of separation. At the closest point of approach; the two aircraft tracks indicated 219 feet apart. After their initial climb on downwind; cessna turned over toa airport at 1;286 feet MSL. Had that aircraft made this turn at a higher altitude; a traffic conflict might not have occurred on its second climbing downwind leg.

Original NASA ASRS Text

Title: GA flight crew reported taking evasive action due to low climb rate of another aircraft.

Narrative: After departing Runway 29R; Stearman executed a VFR box climb within Class D airspace. The aircraft was on a right downwind approaching 1;500 feet when ATC advised it to level off and issued a traffic alert. Conflicting traffic; a white and green Cessna 177; was at the aircraft's 1 o'clock high position; almost directly over the Stearman. Position was initially obscured by the Stearman's upper right wing. Less than 300 feet of separation was estimated. The Cessna 177 was also executing a box climb; however; its rate of climb was minimal.Stearman leveled off; and continued an easterly track at 1;500 feet to gain separation with the conflicting traffic. Once sufficient separation was gained; a climb was resumed while maintaining visual separation with the Cessna 177. An uneventful climb out of Class D followed.The ATC who assigned me to level off had a distinctly different voice from the Controller working local control and could have been a supervisor. The crew of debriefed this incident; and feel the conflict was mainly the result of the Cessna 177's very low rate of climb. Our crew is very grateful for the hard work and diligence of ATC.Replay of the incident on an ADS-B Out monitoring website confirmed visual indications of less than 300 feet of separation. At the closest point of approach; the two aircraft tracks indicated 219 feet apart. After their initial climb on downwind; Cessna turned over TOA airport at 1;286 feet MSL. Had that aircraft made this turn at a higher altitude; a traffic conflict might not have occurred on its second climbing downwind leg.

Data retrieved from NASA's ASRS site 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.