Air carrier flight crew reports altitude deviation in ZDC airspace.

Attributes
ACN	428990
Time
Date	199902
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : hpw.vortac
State Reference	VA
Altitude	msl bound lower : 30500 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc tower : pmp.tower
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 20000 flight time type : 10000
ASRS Report	428990
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : far
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : provided flight assist flight crew : returned to original clearance
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

ZDC had given us a climb to FL330 at FL319. They reversed and gave us a descent back to FL310. Autoplt was used and company procedures followed. The aircraft was descending back to FL310 at that point. At about the same time we were given an anticipated hold. I looked down at the map to check out the hold. When I looked up, we were descending to FL305. I immediately started a climb to FL310. At that point in the climb, ZDC called to confirm cleared to altitude. Report FL310 and called level there as we were about to leveloff. No altitude warning sounded. I feel in part this is due to work overload and late clearance given. Why autoplt dropped off is unknown.

Original NASA ASRS Text

Title: ACR FLC RPTS ALTDEV IN ZDC AIRSPACE.

Narrative: ZDC HAD GIVEN US A CLB TO FL330 AT FL319. THEY REVERSED AND GAVE US A DSCNT BACK TO FL310. AUTOPLT WAS USED AND COMPANY PROCS FOLLOWED. THE ACFT WAS DSNDING BACK TO FL310 AT THAT POINT. AT ABOUT THE SAME TIME WE WERE GIVEN AN ANTICIPATED HOLD. I LOOKED DOWN AT THE MAP TO CHK OUT THE HOLD. WHEN I LOOKED UP, WE WERE DSNDING TO FL305. I IMMEDIATELY STARTED A CLB TO FL310. AT THAT POINT IN THE CLB, ZDC CALLED TO CONFIRM CLRED TO ALT. RPT FL310 AND CALLED LEVEL THERE AS WE WERE ABOUT TO LEVELOFF. NO ALT WARNING SOUNDED. I FEEL IN PART THIS IS DUE TO WORK OVERLOAD AND LATE CLRNC GIVEN. WHY AUTOPLT DROPPED OFF IS UNKNOWN.

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.