Air carrier medium large transport overshoots assigned altitude in descent.

Attributes
ACN	140502
Time
Date	199003
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ard
State Reference	PA
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute airway : j51
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 2000
ASRS Report	140502
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were given a clearance to cross somto intersection at 11000'. I placed 11000' in the altitude alert window, but I must have been thinking 10000' all along because I descended right down to 10000'. The captain noticed that we were at 10000' and asked what altitude I was showing on my side. I stated 10000' and was surprised that he asked. I felt sure in my mind that we were cleared to 10000', but when I looked at the altitude alert window and saw 11000', I immediately initiated a climb to 11000'. The altitude warning was on low, so it was difficult to hear and the light difficult to see. ARTCC handed us off to approach ZNY wishing us a good day and apparently did not notice we were not at the correct altitude. On the handoff to approach we were asked our altitude, which at that time was 11000', and we reported level at 11000'. There was no mention of any problem from ATC.

Original NASA ASRS Text

Title: ACR MLG OVERSHOOTS ASSIGNED ALT IN DESCENT.

Narrative: WE WERE GIVEN A CLRNC TO CROSS SOMTO INTXN AT 11000'. I PLACED 11000' IN THE ALT ALERT WINDOW, BUT I MUST HAVE BEEN THINKING 10000' ALL ALONG BECAUSE I DSNDED RIGHT DOWN TO 10000'. THE CAPT NOTICED THAT WE WERE AT 10000' AND ASKED WHAT ALT I WAS SHOWING ON MY SIDE. I STATED 10000' AND WAS SURPRISED THAT HE ASKED. I FELT SURE IN MY MIND THAT WE WERE CLRED TO 10000', BUT WHEN I LOOKED AT THE ALT ALERT WINDOW AND SAW 11000', I IMMEDIATELY INITIATED A CLB TO 11000'. THE ALT WARNING WAS ON LOW, SO IT WAS DIFFICULT TO HEAR AND THE LIGHT DIFFICULT TO SEE. ARTCC HANDED US OFF TO APCH ZNY WISHING US A GOOD DAY AND APPARENTLY DID NOT NOTICE WE WERE NOT AT THE CORRECT ALT. ON THE HDOF TO APCH WE WERE ASKED OUR ALT, WHICH AT THAT TIME WAS 11000', AND WE RPTED LEVEL AT 11000'. THERE WAS NO MENTION OF ANY PROB FROM ATC.

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.