Citabria pilot reported taking evasive action to avoid a mid-air collision.

Narrative:

I flew and encountered a near miss. I felt I needed maximized evasive action. Weather was not a factor. This was the very first day of the new clearance delivery system. After getting clearance I taxied to the runway. No need to contact ground but monitored ground anyway and held short and contacted tower. Got cleared and took off as cleared with a left downwind departure to the east. Saw a beechcraft on the downwind turn base as advertised (no factor) and kept flying and climbing east as cleared while monitoring tower.tower advised of an aircraft westbound that tower asked to keep south. I responded '... Looking' and after some delay saw the aircraft. I continued looking for traffic for good measure; as I always do. Tower then called and I saw the suspected aircraft ahead of me very slightly above and to my left very close and in a 45degree right bank; aimed right at me in direct collision course. I immediately jabbed the stick full forward and to the right and thus rolled 90degree while in a negative G max dive. While this was going tower continued '...traffic; less than a mile; ahead!' this must have been the aircraft (I think) that they cleared to transition the airspace. I did acknowledge to tower 'thanks for the late warning...' and felt very scared about it yet blessed to be alive. Contacted tower on clearance delivery to give an initial report on the incident.

Original NASA ASRS Text

Title: Citabria pilot reported taking evasive action to avoid a mid-air collision.

Narrative: I flew and encountered a near miss. I felt I needed maximized evasive action. Weather was not a factor. This was the very first day of the new Clearance delivery system. After getting clearance I taxied to the runway. No need to contact ground but monitored ground anyway and held short and contacted tower. Got cleared and took off as cleared with a left downwind departure to the East. Saw a Beechcraft on the downwind turn base as advertised (no factor) and kept flying and climbing east as cleared while monitoring Tower.Tower advised of an aircraft westbound that Tower asked to keep south. I responded '... Looking' and after some delay saw the aircraft. I continued looking for traffic for good measure; as I always do. Tower then called and I saw the suspected aircraft ahead of me very slightly above and to my left VERY close and in a 45degree right bank; aimed right at me in direct collision course. I immediately jabbed the stick full forward and to the right and thus rolled 90degree while in a negative G max dive. While this was going Tower continued '...Traffic; less than a mile; ahead!' This must have been the aircraft (I think) that they cleared to transition the Airspace. I did acknowledge to Tower 'Thanks for the late warning...' and felt very scared about it yet blessed to be alive. Contacted Tower on Clearance delivery to give an initial report on the incident.

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.

Attributes
ACN	1344837
Time
Date	201604
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Champion Citabria Undifferentiated
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	None
Flight Plan	None
Aircraft 2
Make Model Name	Cessna 180 Skywagon
Flight Phase	Cruise
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 15 Flight Crew Total 1900 Flight Crew Type 900
Events
Anomaly	ATC Issue All Types Conflict NMAC
Miss Distance	Horizontal 100 Vertical 10