An at-6 pilot reported performing a test flight and experiencing an airborne conflict with a cessna ...

Narrative:

During a recent VFR (with flight following) test sortie in an at-6; we were conducting a test maneuver to capture 3.0 G's from a 20 degree dive. Maneuver began at 4;000 ft MSL on heading 015; and was terminated at 5;900 ft MSL shortly thereafter.we received a traffic call from ATC indicating that we had traffic directly above us; and the altitude mentioned by the controller was unreadable to us; due to intra-flight communications. We completed the maneuver at the same time of that radio call and started looking above our canopy for the traffic; and then noticed a cessna corvalis pass approximately 500 ft off of our right wing; co-altitude; westbound.I queried the controller if I had missed a previous traffic call from him; and he said that he had not personally made a traffic call to us until he advised that the VFR traffic was directly above us. This caused me to think that perhaps a controller change had just occurred and caused us to not be notified of this VFR traffic. I again asked the controller why we had not been notified of this traffic; and he gave me a phone number to call to file a near mid-air collision report with ATC. At-6's do not have TCAS installed.recommend further communication with ATC of T-6/at-6 dynamic maneuvering during test flights to notify flight crews of nearby traffic that could be potential threats.

Original NASA ASRS Text

Title: An AT-6 pilot reported performing a test flight and experiencing an airborne conflict with a Cessna Corvalis at 6000 feet after a 3 G pull up from 4000 feet. VFR flight following was in use but ATC did not report the traffic until late in the maneuver.

Narrative: During a recent VFR (with flight following) test sortie in an AT-6; we were conducting a test maneuver to capture 3.0 G's from a 20 degree dive. Maneuver began at 4;000 ft MSL on heading 015; and was terminated at 5;900 ft MSL shortly thereafter.We received a traffic call from ATC indicating that we had traffic directly above us; and the altitude mentioned by the controller was unreadable to us; due to intra-flight communications. We completed the maneuver at the same time of that radio call and started looking above our canopy for the traffic; and then noticed a Cessna Corvalis pass approximately 500 ft off of our right wing; co-altitude; westbound.I queried the controller if I had missed a previous traffic call from him; and he said that he had not personally made a traffic call to us until he advised that the VFR traffic was directly above us. This caused me to think that perhaps a controller change had just occurred and caused us to not be notified of this VFR traffic. I again asked the controller why we had not been notified of this traffic; and he gave me a phone number to call to file a near mid-air collision report with ATC. AT-6's do not have TCAS installed.Recommend further communication with ATC of T-6/AT-6 dynamic maneuvering during test flights to notify flight crews of nearby traffic that could be potential threats.

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	1402532
Time
Date	201611
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	T6A Texan II / Harvard II (Raytheon)
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	None
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict

An at-6 pilot reported performing a test flight and experiencing an airborne conflict with a cessna corvalis at 6000 feet after a 3 G pull up from 4000 feet. VFR flight following was in use but ATC did not report the traffic until late in the maneuver.