Clearance confusion. Flight began descent without clearance.

Attributes
ACN	114157
Time
Date	198906
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : rmg
State Reference	GA
Altitude	msl bound lower : 27000 msl bound upper : 33000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl tower : crw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent 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 : 170 flight time total : 10150 flight time type : 500
ASRS Report	114157
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

We had been doing some deviating for WX plus were being vectored for sequence clearance. I had to be 'slow to 250 KIAS then descend to FL270'. I did this. ATC called us to verify our altitude, which at that time was (and we said) passing FL275 for FL270. They told us to level off at FL270 and that no clearance to descend was given. Our clearance, according to ATC was 'slow to 250 KIAS and turn to 070 degree heading'. ATC said there was no conflict with any other plane. This was the last leg of a duty day that started exactly 10 hours earlier. We were about 140 mi from hartsfield (atl) where we normally get a clearance to descend from our cruising altitude of FL330. I believe that it was a clearance to descend and the copilot during this descent acted as if everything was alright. However, after ATC questioned us, he could not remember the descent clearance. Workload, long duty days, WX and vectoring all added to this situation.

Original NASA ASRS Text

Title: CLRNC CONFUSION. FLT BEGAN DESCENT WITHOUT CLRNC.

Narrative: WE HAD BEEN DOING SOME DEVIATING FOR WX PLUS WERE BEING VECTORED FOR SEQUENCE CLRNC. I HAD TO BE 'SLOW TO 250 KIAS THEN DSND TO FL270'. I DID THIS. ATC CALLED US TO VERIFY OUR ALT, WHICH AT THAT TIME WAS (AND WE SAID) PASSING FL275 FOR FL270. THEY TOLD US TO LEVEL OFF AT FL270 AND THAT NO CLRNC TO DSND WAS GIVEN. OUR CLRNC, ACCORDING TO ATC WAS 'SLOW TO 250 KIAS AND TURN TO 070 DEG HDG'. ATC SAID THERE WAS NO CONFLICT WITH ANY OTHER PLANE. THIS WAS THE LAST LEG OF A DUTY DAY THAT STARTED EXACTLY 10 HRS EARLIER. WE WERE ABOUT 140 MI FROM HARTSFIELD (ATL) WHERE WE NORMALLY GET A CLRNC TO DSND FROM OUR CRUISING ALT OF FL330. I BELIEVE THAT IT WAS A CLRNC TO DSND AND THE COPLT DURING THIS DSCNT ACTED AS IF EVERYTHING WAS ALRIGHT. HOWEVER, AFTER ATC QUESTIONED US, HE COULD NOT REMEMBER THE DSCNT CLRNC. WORKLOAD, LONG DUTY DAYS, WX AND VECTORING ALL ADDED TO THIS SITUATION.

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.