Flight crew of B727 on descent goes below assigned altitude.

Attributes
ACN	408760
Time
Date	199807
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : slc
State Reference	UT
Altitude	msl bound lower : 16650 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc tracon : slc
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 230 flight time total : 2500 flight time type : 460
ASRS Report	408760
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Last leg of a 4 day rotation. Flying from boise to salt lake city, captain flying. Center cleared us to descend to 17000 ft. We were running our descent checklist passing 18000 ft. At 17500 ft, ZLC passed us off to salt lake approach. As the first officer changed to the new frequency and tried to contact approach, I took that opportunity to finish up my flight engineer items on the panel. The first officer while talking to approach signaled to the captain that we were only cleared to 17000 ft. He did this about 250 ft below 17000 ft. The captain advanced power and climbed back up to 17000 ft, but the aircraft bottomed out about 350 ft low (16650 ft MSL). Remainder of flight uneventful.

Original NASA ASRS Text

Title: FLC OF B727 ON DSCNT GOES BELOW ASSIGNED ALT.

Narrative: LAST LEG OF A 4 DAY ROTATION. FLYING FROM BOISE TO SALT LAKE CITY, CAPT FLYING. CTR CLRED US TO DSND TO 17000 FT. WE WERE RUNNING OUR DSCNT CHKLIST PASSING 18000 FT. AT 17500 FT, ZLC PASSED US OFF TO SALT LAKE APCH. AS THE FO CHANGED TO THE NEW FREQ AND TRIED TO CONTACT APCH, I TOOK THAT OPPORTUNITY TO FINISH UP MY FE ITEMS ON THE PANEL. THE FO WHILE TALKING TO APCH SIGNALED TO THE CAPT THAT WE WERE ONLY CLRED TO 17000 FT. HE DID THIS ABOUT 250 FT BELOW 17000 FT. THE CAPT ADVANCED PWR AND CLBED BACK UP TO 17000 FT, BUT THE ACFT BOTTOMED OUT ABOUT 350 FT LOW (16650 FT MSL). REMAINDER OF FLT UNEVENTFUL.

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.