An air carrier medium large transport failed to cross a fix on descent at the proper altitude.

Attributes
ACN	259643
Time
Date	199312
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 12700 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : anc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : atl
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 11000 flight time type : 1800
ASRS Report	259643
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 5000 flight time type : 2000
ASRS Report	259443
Events
Anomaly	altitude deviation : undershoot altitude deviation : crossing restriction not met 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:

Descending into atl after multiple heading and speed changes for spacing. First officer was using vertical speed or IAS descent mode approaching womac. Approach controller gave us clearance to 10000 ft cross womac 13000. When 10000 ft was set in altitude window, we lost altitude arming for 13000 ft. Passing 12700 ft approach stated he wanted womac 13000 ft, but continue to 10000 ft. No conflicts existed. Factors: 1) too much reliance on automation on our part. 2) ATC consideration. Why give 10000 if you don't want it now? Especially in busy phase of flight. 3) misunderstanding on our part of clearance. We interpreted clearance at or below womac at 13000 ft. Supplemental information from acn 259443: approaching womac on the macey 1 arrival. At around 15000 ft on the descent, we were 'cleared to 10000 ft, cross womac at or below 13000 ft'.

Original NASA ASRS Text

Title: AN ACR MLG FAILED TO CROSS A FIX ON DSCNT AT THE PROPER ALT.

Narrative: DSNDING INTO ATL AFTER MULTIPLE HDG AND SPD CHANGES FOR SPACING. FO WAS USING VERT SPD OR IAS DSCNT MODE APCHING WOMAC. APCH CTLR GAVE US CLRNC TO 10000 FT CROSS WOMAC 13000. WHEN 10000 FT WAS SET IN ALT WINDOW, WE LOST ALT ARMING FOR 13000 FT. PASSING 12700 FT APCH STATED HE WANTED WOMAC 13000 FT, BUT CONTINUE TO 10000 FT. NO CONFLICTS EXISTED. FACTORS: 1) TOO MUCH RELIANCE ON AUTOMATION ON OUR PART. 2) ATC CONSIDERATION. WHY GIVE 10000 IF YOU DON'T WANT IT NOW? ESPECIALLY IN BUSY PHASE OF FLT. 3) MISUNDERSTANDING ON OUR PART OF CLRNC. WE INTERPRETED CLRNC AT OR BELOW WOMAC AT 13000 FT. SUPPLEMENTAL INFO FROM ACN 259443: APCHING WOMAC ON THE MACEY 1 ARR. AT AROUND 15000 FT ON THE DSCNT, WE WERE 'CLRED TO 10000 FT, CROSS WOMAC AT OR BELOW 13000 FT'.

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.