Potential conflict after altitude deviation altitude excursion.

Attributes
ACN	284938
Time
Date	199410
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : tul
State Reference	OK
Altitude	msl bound lower : 9000 msl bound upper : 10500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : tul
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other cruise other
Flight Plan	None
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : flight engineer pilot : instrument pilot : atp
Experience	flight time last 90 days : 200 flight time total : 19000 flight time type : 1500
ASRS Report	284938
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Required maintenance flight after gear box teardown (nts check) negative torque system check. Told approach control needed 10500 ft MSL for future flight checks. Accomplishing nts check right engine test failed (excessive drag on windmilling propeller lost approximately 1500 ft altitude. Feathered engine. Declared emergency, returned to airport. During altitude loss approach control told me to make immediate turn to 360 degrees -- may have been conflict with airline jet. They said they received a TCASII alert. Better communication with approach control would help prevent this in the future.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT AFTER ALTDEV ALT EXCURSION.

Narrative: REQUIRED MAINT FLT AFTER GEAR BOX TEARDOWN (NTS CHK) NEGATIVE TORQUE SYS CHK. TOLD APCH CTL NEEDED 10500 FT MSL FOR FUTURE FLT CHKS. ACCOMPLISHING NTS CHK R ENG TEST FAILED (EXCESSIVE DRAG ON WINDMILLING PROP LOST APPROX 1500 FT ALT. FEATHERED ENG. DECLARED EMER, RETURNED TO ARPT. DURING ALT LOSS APCH CTL TOLD ME TO MAKE IMMEDIATE TURN TO 360 DEGS -- MAY HAVE BEEN CONFLICT WITH AIRLINE JET. THEY SAID THEY RECEIVED A TCASII ALERT. BETTER COM WITH APCH CTL WOULD HELP PREVENT THIS IN THE FUTURE.

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.