Military aircraft climbed to an occupied altitude resulting in less than standard separation.

Attributes
ACN	129845
Time
Date	198911
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tul
State Reference	OK
Altitude	msl bound lower : 26000 msl bound upper : 26500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme
Operator	other
Make Model Name	Experimental
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	government : military
Function	flight crew : captain oversight : pic
Qualification	pilot : military
Experience	flight time last 90 days : 90 flight time total : 4600
ASRS Report	129845
Person 2
Affiliation	government : military
Function	flight crew : first officer
Qualification	pilot : military
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : required legal separation non adherence : clearance
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Military spc X on climb out from tinker AFB (eastbound). Climb clearance to FL260 with ZFW. On handoff to ZME controller was very busy and initial checking was delayed by conflicting communications. PIC heard acknowledgement of initial check in with ZME, and expecting final clearance to FL270 (filed altitude), heard 'roger spc X...FL270.' PIC initiated climb from FL260 to FL270. About 20 seconds later ZME questioned our altitude. We responded, 'FL265.' ZME initiated request for 'immediate descent to FL260,' and called conflicting traffic wbound at FL270. We complied and stated, 'we mistook your initial traffic call as clearance to FL270...sorry.' controllers are overworked and task saturated. This event would have never happened if controller was working only us and the small transport, because clearance misunderstanding by pilot would not have happened. Crew coordination was poor. Copilot (side by side) should have questioned pilot when he initiated climb to FL270 from FL260. Copilot also was unclear what ZME actually said. Clearance to FL270 was never verified with center by copilot (who normally handles all communications) or pilot.

Original NASA ASRS Text

Title: MIL ACFT CLIMBED TO AN OCCUPIED ALT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: MIL SPC X ON CLBOUT FROM TINKER AFB (EBND). CLB CLRNC TO FL260 WITH ZFW. ON HDOF TO ZME CTLR WAS VERY BUSY AND INITIAL CHECKING WAS DELAYED BY CONFLICTING COMS. PIC HEARD ACKNOWLEDGEMENT OF INITIAL CHK IN WITH ZME, AND EXPECTING FINAL CLRNC TO FL270 (FILED ALT), HEARD 'ROGER SPC X...FL270.' PIC INITIATED CLB FROM FL260 TO FL270. ABOUT 20 SECS LATER ZME QUESTIONED OUR ALT. WE RESPONDED, 'FL265.' ZME INITIATED REQUEST FOR 'IMMEDIATE DSCNT TO FL260,' AND CALLED CONFLICTING TFC WBOUND AT FL270. WE COMPLIED AND STATED, 'WE MISTOOK YOUR INITIAL TFC CALL AS CLRNC TO FL270...SORRY.' CTLRS ARE OVERWORKED AND TASK SATURATED. THIS EVENT WOULD HAVE NEVER HAPPENED IF CTLR WAS WORKING ONLY US AND THE SMT, BECAUSE CLRNC MISUNDERSTANDING BY PLT WOULD NOT HAVE HAPPENED. CREW COORD WAS POOR. COPLT (SIDE BY SIDE) SHOULD HAVE QUESTIONED PLT WHEN HE INITIATED CLB TO FL270 FROM FL260. COPLT ALSO WAS UNCLEAR WHAT ZME ACTUALLY SAID. CLRNC TO FL270 WAS NEVER VERIFIED WITH CENTER BY COPLT (WHO NORMALLY HANDLES ALL COMS) OR PLT.

Data retrieved from NASA's ASRS site as of August 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.