B727 miscom with ATC clearance descended 1000 ft beyond disputed clearance altitude.

Attributes
ACN	438127
Time
Date	199905
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : atl.vortac
State Reference	GA
Altitude	msl bound lower : 12000 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc tracon : atl.tracon
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	descent : approach
Route In Use	arrival star : macey two
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 4000 flight time type : 250
ASRS Report	438127
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot altitude deviation : crossing restriction not met non adherence : clearance non adherence : published procedure non adherence : far
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued alert flight crew : returned to original clearance flight crew : returned to assigned airspace
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

In a descent from FL260 to FL240, ZTL issued what I thought was the following clearance: 'air carrier X, descend to FL240, cross womac at 12000 ft, 250 KTS, atlanta altimeter 30.00.' I set 12000 ft and 30.00 in the altitude alert and pointed with company cockpit procedures. I calculated the descent rate to cross 40 DME at 12000 ft and established that descent rate. The 250 KT restr was subsequently deleted. At 12100 ft and 41 DME, atl approach inquired about womac and 13000 ft assigned. I immediately climbed to 13000 ft. The remaining approach and landing at atl was uneventful.

Original NASA ASRS Text

Title: B727 MISCOM WITH ATC CLRNC DSNDED 1000 FT BEYOND DISPUTED CLRNC ALT.

Narrative: IN A DSCNT FROM FL260 TO FL240, ZTL ISSUED WHAT I THOUGHT WAS THE FOLLOWING CLRNC: 'ACR X, DSND TO FL240, CROSS WOMAC AT 12000 FT, 250 KTS, ATLANTA ALTIMETER 30.00.' I SET 12000 FT AND 30.00 IN THE ALT ALERT AND POINTED WITH COMPANY COCKPIT PROCS. I CALCULATED THE DSCNT RATE TO CROSS 40 DME AT 12000 FT AND ESTABLISHED THAT DSCNT RATE. THE 250 KT RESTR WAS SUBSEQUENTLY DELETED. AT 12100 FT AND 41 DME, ATL APCH INQUIRED ABOUT WOMAC AND 13000 FT ASSIGNED. I IMMEDIATELY CLBED TO 13000 FT. THE REMAINING APCH AND LNDG AT ATL WAS UNEVENTFUL.

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.