PA-44 pilot reported a near mid air collision with an aerobatic aircraft.

Narrative:

While climbing out and making radio calls on the appropriate practice area frequency; noticed an aerobatic aircraft doing aerobatics and taking up a large amount of space both vertical and horizontal in an area that is well known to be congested with training aircraft. Aerobatic aircraft was making no radio calls and intentions were unknown; but they were moving in a direction that would have them crossing to our right; well above us. I began to turn to the left to avoid getting any closer given the type of maneuvers they were performing and the lack of any indication/communication as to what they would be doing. While making my turn away from the flightpath of the aerobatic aircraft; it quickly changed its direction of flight towards us; and began to descend rapidly; resulting in me needing to go from what was a no threat slow turn away into an evasive action steep turn.I believe the issue could have been avoided entirely [if] radio communication was present and intentions were stated prior to performing any maneuver involving a rapid descent/ascent and/or change in direction especially given the nature of the practice area being discussed. Furthermore as soon as identifying the plane as an aerobatic I should have already been diverting my path well clear of any area they could possibly end up in as I had not appropriately anticipated how quickly separation could deteriorate.

Original NASA ASRS Text

Title: PA-44 pilot reported a Near Mid Air Collision with an aerobatic aircraft.

Narrative: While climbing out and making radio calls on the appropriate practice area frequency; noticed an aerobatic aircraft doing aerobatics and taking up a large amount of space both vertical and horizontal in an area that is well known to be congested with training aircraft. Aerobatic aircraft was making no radio calls and intentions were unknown; but they were moving in a direction that would have them crossing to our right; well above us. I began to turn to the left to avoid getting any closer given the type of maneuvers they were performing and the lack of any indication/communication as to what they would be doing. While making my turn away from the flightpath of the aerobatic aircraft; it quickly changed its direction of flight towards us; and began to descend rapidly; resulting in me needing to go from what was a no threat slow turn away into an evasive action steep turn.I believe the issue could have been avoided entirely [if] radio communication was present and intentions were stated prior to performing any maneuver involving a rapid descent/ascent and/or change in direction especially given the nature of the practice area being discussed. Furthermore as soon as identifying the plane as an aerobatic I should have already been diverting my path well clear of any area they could possibly end up in as I had not appropriately anticipated how quickly separation could deteriorate.

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	1683936
Time
Date	201909
Local Time Of Day	0601-1200
Place
Locale Reference	SDL.Airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-44 Seminole/Turbo Seminole
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	None
Flight Plan	None
Aircraft 2
Make Model Name	Aerobatic
Operating Under FAR Part	Part 91
Person 1
Function	Single Pilot
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 51 Flight Crew Total 263 Flight Crew Type 46
Events
Anomaly	Conflict NMAC Deviation - Procedural Published Material / Policy
Miss Distance	Horizontal 400 Vertical 100