Aircraft descended through cleared altitude.

Attributes
ACN	105170
Time
Date	198902
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : boi
State Reference	ID
Altitude	msl bound lower : 12300 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Night
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 : j517
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : commercial pilot : atp pilot : instrument
Experience	flight time last 90 days : 170 flight time total : 10000 flight time type : 500
ASRS Report	105170
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : detected after the fact other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Flying first officer on an large transport I was descending to 12000' en route to boi from geg. When passing 13000' both the captain and I called out '1 to go.' the captain called center and reported 'out of 12-5 for 13, looking for lower.' center responded we were assigned 13000'. I stopped the descent at 12300' and started a climb. The captain responded that he read back 12000'. At 12700' center cleared us to a lower altitude and gave us a frequency change to boi approach. The captain, second officer, a jump seat rider and myself all agreed we heard 12000'. The jump seat rider (a new hire and former commuter pilot in that area) said he made note of the 12000' call because he was used to 13000'. Extra effort should be made to encourage the jump seat rider to mention anything unusual. Also, I should be more aware of the appropriate altitude for that direction of flight (east uses odd thousands). If a controller assigns a wrong altitude we need all the input we can get to cause us to question the controller. Also, the controller needs to listen carefully for the proper response from crews receiving his clrncs.

Original NASA ASRS Text

Title: ACFT DESCENDED THROUGH CLEARED ALT.

Narrative: FLYING F/O ON AN LGT I WAS DSNDING TO 12000' ENRTE TO BOI FROM GEG. WHEN PASSING 13000' BOTH THE CAPT AND I CALLED OUT '1 TO GO.' THE CAPT CALLED CENTER AND RPTED 'OUT OF 12-5 FOR 13, LOOKING FOR LOWER.' CENTER RESPONDED WE WERE ASSIGNED 13000'. I STOPPED THE DSCNT AT 12300' AND STARTED A CLB. THE CAPT RESPONDED THAT HE READ BACK 12000'. AT 12700' CENTER CLRED US TO A LOWER ALT AND GAVE US A FREQ CHANGE TO BOI APCH. THE CAPT, S/O, A JUMP SEAT RIDER AND MYSELF ALL AGREED WE HEARD 12000'. THE JUMP SEAT RIDER (A NEW HIRE AND FORMER COMMUTER PLT IN THAT AREA) SAID HE MADE NOTE OF THE 12000' CALL BECAUSE HE WAS USED TO 13000'. EXTRA EFFORT SHOULD BE MADE TO ENCOURAGE THE JUMP SEAT RIDER TO MENTION ANYTHING UNUSUAL. ALSO, I SHOULD BE MORE AWARE OF THE APPROPRIATE ALT FOR THAT DIRECTION OF FLT (E USES ODD THOUSANDS). IF A CTLR ASSIGNS A WRONG ALT WE NEED ALL THE INPUT WE CAN GET TO CAUSE US TO QUESTION THE CTLR. ALSO, THE CTLR NEEDS TO LISTEN CAREFULLY FOR THE PROPER RESPONSE FROM CREWS RECEIVING HIS CLRNCS.

Data retrieved from NASA's ASRS site as of August 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.