An large transport air carrier crew departed an assigned altitude without clearance.

Attributes
ACN	213547
Time
Date	199206
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lgc airport : atl
State Reference	GA
Altitude	msl bound lower : 23000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival 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 : 200 flight time total : 16400 flight time type : 300
ASRS Report	213547
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 4500 flight time type : 1200
ASRS Report	213534
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were at cruise altitude of FL350 outside of lgc VOR into atl for 9R. We received clearance to descend to FL290 now and FL240 our discretion. We set FL290 into the altitude reminder window and programmed our descent to FL240 into the FMS. We started down to FL290. Reaching FL290 we started to perform checklist and preapch briefings. My first officer was on another frequency talking to company. During this time, I was programming the FMS to cross honie at 12000/250 KTS. We then received clearance to 'descend now slow to 250 KTS.' when the controller said descend now, I reached over and put 12000 into the altitude reminder and started the descent. As we passed through 22800 ATC asked our altitude. I said out of 22800 for 12000. He reminded us that our clearance limit was FL240 and asked us to level at FL230 which we did. I feel we should have had our clearance limit altitude of FL240 in the altitude reminder from the beginning as it was, we had no reference of FL240 in front of us. As we became busy the only altitude that I was thinking about at the time was in anticipation of crossing honie at 12000/250 KTS. I also feel that if the controller had said descend now to FL240, we would have been able to see our error.

Original NASA ASRS Text

Title: AN LGT ACR CREW DEPARTED AN ASSIGNED ALT WITHOUT CLRNC.

Narrative: WE WERE AT CRUISE ALT OF FL350 OUTSIDE OF LGC VOR INTO ATL FOR 9R. WE RECEIVED CLRNC TO DSND TO FL290 NOW AND FL240 OUR DISCRETION. WE SET FL290 INTO THE ALT REMINDER WINDOW AND PROGRAMMED OUR DSCNT TO FL240 INTO THE FMS. WE STARTED DOWN TO FL290. REACHING FL290 WE STARTED TO PERFORM CHKLIST AND PREAPCH BRIEFINGS. MY FO WAS ON ANOTHER FREQ TALKING TO COMPANY. DURING THIS TIME, I WAS PROGRAMMING THE FMS TO CROSS HONIE AT 12000/250 KTS. WE THEN RECEIVED CLRNC TO 'DSND NOW SLOW TO 250 KTS.' WHEN THE CTLR SAID DSND NOW, I REACHED OVER AND PUT 12000 INTO THE ALT REMINDER AND STARTED THE DSCNT. AS WE PASSED THROUGH 22800 ATC ASKED OUR ALT. I SAID OUT OF 22800 FOR 12000. HE REMINDED US THAT OUR CLRNC LIMIT WAS FL240 AND ASKED US TO LEVEL AT FL230 WHICH WE DID. I FEEL WE SHOULD HAVE HAD OUR CLRNC LIMIT ALT OF FL240 IN THE ALT REMINDER FROM THE BEGINNING AS IT WAS, WE HAD NO REF OF FL240 IN FRONT OF US. AS WE BECAME BUSY THE ONLY ALT THAT I WAS THINKING ABOUT AT THE TIME WAS IN ANTICIPATION OF XING HONIE AT 12000/250 KTS. I ALSO FEEL THAT IF THE CTLR HAD SAID DSND NOW TO FL240, WE WOULD HAVE BEEN ABLE TO SEE OUR ERROR.

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.