When cleared to descend to 11000' captain readback 10000 and they descended to 10000'.

Attributes
ACN	154844
Time
Date	199008
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : chd airport : phx
State Reference	AZ
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 210 flight time total : 13000 flight time type : 10000
ASRS Report	154844
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Received clearance to cross arlin intersection. I read back 'arlin, 10000, at 250 KTS'. When we reach 10000', center said 'say your altitude. You were cleared to 11000!' first officer was giving P/a so he didn't hear what clearance I read back. Fatigue a factor. Had flown a 4 day trip, then 2 days of training in dallas, 1 day off, then another 4 day trip. Lots of time zone and body clock changes. Callback conversation with reporter revealed the following: reporter readily admitted mistake. He read back the wrong altitude and ATC did not notice the mistake. He described the causes of the fatigue he claims contributed to this incident.

Original NASA ASRS Text

Title: WHEN CLEARED TO DESCEND TO 11000' CAPT READBACK 10000 AND THEY DESCENDED TO 10000'.

Narrative: RECEIVED CLRNC TO CROSS ARLIN INTXN. I READ BACK 'ARLIN, 10000, AT 250 KTS'. WHEN WE REACH 10000', CTR SAID 'SAY YOUR ALT. YOU WERE CLRED TO 11000!' F/O WAS GIVING P/A SO HE DIDN'T HEAR WHAT CLRNC I READ BACK. FATIGUE A FACTOR. HAD FLOWN A 4 DAY TRIP, THEN 2 DAYS OF TRAINING IN DALLAS, 1 DAY OFF, THEN ANOTHER 4 DAY TRIP. LOTS OF TIME ZONE AND BODY CLOCK CHANGES. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR READILY ADMITTED MISTAKE. HE READ BACK THE WRONG ALT AND ATC DID NOT NOTICE THE MISTAKE. HE DESCRIBED THE CAUSES OF THE FATIGUE HE CLAIMS CONTRIBUTED TO THIS INCIDENT.

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.