Corporate aircraft takes evasive action, descending into climbing aircraft. Potential conflict.

Attributes
ACN	295396
Time
Date	199502
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mia
State Reference	FL
Altitude	msl bound lower : 6680 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mia tower : mex
Operator	general aviation : corporate
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 4000 flight time type : 1200
ASRS Report	295396
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 750 vertical : 1500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

After famin intersection assigned to altitude 8000 ft heading 360 degrees -- we observed a boeing 767 at our 2 O'clock position and climbing. -- From our present position it appeared that our courses would cross based on the boeing continuing to climb. I was not advised of the boeing's assigned altitude. As an evasive action I descended to 6600 ft to avoid the other aircraft. The controller reprimanded me for descending from my assigned altitude. We were not aware of this but, the boeing had been assigned to maintain 7000 ft. -- Our reaction was based on the appearance of the boeing being our altitude and heading straight for us. As PIC, I deviated and acted in a responsible way to avoid a situation that appeared to be unsafe and imminent.

Original NASA ASRS Text

Title: CORPORATE ACFT TAKES EVASIVE ACTION, DSNDING INTO CLBING ACFT. POTENTIAL CONFLICT.

Narrative: AFTER FAMIN INTXN ASSIGNED TO ALT 8000 FT HDG 360 DEGS -- WE OBSERVED A BOEING 767 AT OUR 2 O'CLOCK POS AND CLBING. -- FROM OUR PRESENT POS IT APPEARED THAT OUR COURSES WOULD CROSS BASED ON THE BOEING CONTINUING TO CLB. I WAS NOT ADVISED OF THE BOEING'S ASSIGNED ALT. AS AN EVASIVE ACTION I DSNDED TO 6600 FT TO AVOID THE OTHER ACFT. THE CTLR REPRIMANDED ME FOR DSNDING FROM MY ASSIGNED ALT. WE WERE NOT AWARE OF THIS BUT, THE BOEING HAD BEEN ASSIGNED TO MAINTAIN 7000 FT. -- OUR REACTION WAS BASED ON THE APPEARANCE OF THE BOEING BEING OUR ALT AND HEADING STRAIGHT FOR US. AS PIC, I DEVIATED AND ACTED IN A RESPONSIBLE WAY TO AVOID A SIT THAT APPEARED TO BE UNSAFE AND IMMINENT.

Data retrieved from NASA's ASRS site as of July 2007 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.