A C550 flight crew leveled off 1000 ft below assigned altitude.

Attributes
ACN	581658
Time
Date	200305
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : slc.airport
State Reference	UT
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla.artcc tracon : s56.tracon tower : grr.tower
Operator	general aviation : corporate
Make Model Name	Citation II S2/Bravo
Operating Under FAR Part	Part 91
Flight Phase	descent : intermediate altitude descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
ASRS Report	581658
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued advisory
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were handed off from ZLC to salt lake approach. We were given clearance to descend to 11000 ft. We complied. My copilot then misunderstood a clearance given to another aircraft to descend and maintain 10000 ft. He then set 10000 ft in the pre-select box, and told me I was good to descend to 10000 ft. I was at the time slowing to 210 KTS, as instructed by ATC, and never did hear the false clearance that my copilot thought was for us. I then descended to 10000 ft. Upon reaching 10000 ft, approach contacted us and asked to verify our altitude. I contacted them (via land line) on the ground. They played the tapes back, and verified that we indeed went through our assigned altitude of 11000 ft. They said that no conflicts occurred, and that they also should have noticed our readback to descend to 10000 ft. They concluded that they will further train for listening to read back clrncs. I and our pilots will discuss better procedures for training on communication skills.

Original NASA ASRS Text

Title: A C550 FLT CREW LEVELED OFF 1000 FT BELOW ASSIGNED ALT.

Narrative: WE WERE HANDED OFF FROM ZLC TO SALT LAKE APCH. WE WERE GIVEN CLRNC TO DSND TO 11000 FT. WE COMPLIED. MY COPLT THEN MISUNDERSTOOD A CLRNC GIVEN TO ANOTHER ACFT TO DSND AND MAINTAIN 10000 FT. HE THEN SET 10000 FT IN THE PRE-SELECT BOX, AND TOLD ME I WAS GOOD TO DSND TO 10000 FT. I WAS AT THE TIME SLOWING TO 210 KTS, AS INSTRUCTED BY ATC, AND NEVER DID HEAR THE FALSE CLRNC THAT MY COPLT THOUGHT WAS FOR US. I THEN DSNDED TO 10000 FT. UPON REACHING 10000 FT, APCH CONTACTED US AND ASKED TO VERIFY OUR ALT. I CONTACTED THEM (VIA LAND LINE) ON THE GND. THEY PLAYED THE TAPES BACK, AND VERIFIED THAT WE INDEED WENT THROUGH OUR ASSIGNED ALT OF 11000 FT. THEY SAID THAT NO CONFLICTS OCCURRED, AND THAT THEY ALSO SHOULD HAVE NOTICED OUR READBACK TO DSND TO 10000 FT. THEY CONCLUDED THAT THEY WILL FURTHER TRAIN FOR LISTENING TO READ BACK CLRNCS. I AND OUR PLTS WILL DISCUSS BETTER PROCS FOR TRAINING ON COM SKILLS.

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.