B757 at FL370 receives descent from ZDC but questioned when beginning descent.

Attributes
ACN	601884
Time
Date	200312
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zdc.artcc
State Reference	VA
Altitude	msl bound lower : 36500 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : enroute altitude change
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zdc.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 90 flight time total : 6000 flight time type : 1500
ASRS Report	601884
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 15000 flight time type : 3000
ASRS Report	602100
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : published procedure non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Miss Distance	horizontal : 30000 vertical : 1500
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

ATC cleared us from FL370 to FL330. Responded on radio and began descent. As we descended through FL366, ATC questioned our altitude. We responded 'FL365' and ATC directed us to return to FL370. We climbed back to FL370 as directed.

Original NASA ASRS Text

Title: B757 AT FL370 RECEIVES DSCNT FROM ZDC BUT QUESTIONED WHEN BEGINNING DSCNT.

Narrative: ATC CLRED US FROM FL370 TO FL330. RESPONDED ON RADIO AND BEGAN DSCNT. AS WE DSNDED THROUGH FL366, ATC QUESTIONED OUR ALT. WE RESPONDED 'FL365' AND ATC DIRECTED US TO RETURN TO FL370. WE CLBED BACK TO FL370 AS DIRECTED.

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.