Air carrier descended below altitude and conflicted with a fgt.

Attributes
ACN	139490
Time
Date	199003
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tlh
State Reference	FL
Altitude	msl bound lower : 22500 msl bound upper : 23000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Fighter
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 16000 flight time type : 6000
ASRS Report	139490
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 5000 flight time type : 1200
ASRS Report	139493
Events
Anomaly	altitude deviation : overshoot 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 : 3000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While inbound to tlh at about 70 or 80 mi out at FL280 ATC cleared us to descend to FL230 then pilot's discretion to 10000'. I then programmed the computer accordingly and started a slow descent to FL230. Shortly afterwards a new controller began controling traffic and he reiterated our clearance to FL230. Rather than telling him that the previous controller had already cleared us to FL230, I simply acknowledged the transmission. Just prior to leveling at FL230 the VNAV mode activated and began a descent to 10000'. As we descended through FL230 (or maybe a little lower I guess about 22500') I looked out at 11 O'clock low and saw an fgt in a right turn. The controller advised us that the fgt pilot saw our aircraft. I did not have to take evasive action. The controller then told me that I was not cleared below FL230. I then told him that our clearance to FL230 contained a 'pd' to 10000'. He advised me that the pd portion of the clearance had been invalidated. West/O further comment on the matter we were again cleared to 10000'. If a portion of our clearance had been invalidated it was totally unclr to either member of this flight crew. A terrible lack of communication between the controller and this crew and also (I believe) between controllers changing work stations.

Original NASA ASRS Text

Title: ACR DESCENDED BELOW ALT AND CONFLICTED WITH A FGT.

Narrative: WHILE INBND TO TLH AT ABOUT 70 OR 80 MI OUT AT FL280 ATC CLRED US TO DSND TO FL230 THEN PLT'S DISCRETION TO 10000'. I THEN PROGRAMMED THE COMPUTER ACCORDINGLY AND STARTED A SLOW DSCNT TO FL230. SHORTLY AFTERWARDS A NEW CTLR BEGAN CTLING TFC AND HE REITERATED OUR CLRNC TO FL230. RATHER THAN TELLING HIM THAT THE PREVIOUS CTLR HAD ALREADY CLRED US TO FL230, I SIMPLY ACKNOWLEDGED THE XMISSION. JUST PRIOR TO LEVELING AT FL230 THE VNAV MODE ACTIVATED AND BEGAN A DSCNT TO 10000'. AS WE DSNDED THROUGH FL230 (OR MAYBE A LITTLE LOWER I GUESS ABOUT 22500') I LOOKED OUT AT 11 O'CLOCK LOW AND SAW AN FGT IN A R TURN. THE CTLR ADVISED US THAT THE FGT PLT SAW OUR ACFT. I DID NOT HAVE TO TAKE EVASIVE ACTION. THE CTLR THEN TOLD ME THAT I WAS NOT CLRED BELOW FL230. I THEN TOLD HIM THAT OUR CLRNC TO FL230 CONTAINED A 'PD' TO 10000'. HE ADVISED ME THAT THE PD PORTION OF THE CLRNC HAD BEEN INVALIDATED. W/O FURTHER COMMENT ON THE MATTER WE WERE AGAIN CLRED TO 10000'. IF A PORTION OF OUR CLRNC HAD BEEN INVALIDATED IT WAS TOTALLY UNCLR TO EITHER MEMBER OF THIS FLT CREW. A TERRIBLE LACK OF COM BTWN THE CTLR AND THIS CREW AND ALSO (I BELIEVE) BTWN CTLRS CHANGING WORK STATIONS.

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.