A B737-500 crew, in descent to bos, overshot their assigned altitude.

Attributes
ACN	547061
Time
Date	200205
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : pvd.vortac
State Reference	RI
Altitude	msl single value : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw.artcc
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 6500 flight time type : 3500
ASRS Report	547061
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 200 flight time total : 14800 flight time type : 2000
ASRS Report	547063
Events
Anomaly	altitude deviation : overshoot non adherence : clearance non adherence : company policies non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Second leg return to bos from ewr. Captain flying with autoplt on, VNAV and LNAV engaged, direct to pvd VOR. ATC instructed airspeed increase to 320 KIAS or greater to cross pvd at 11000 ft. With 100 KT tailwind, captain left FL210 early on VNAV descent. Passing through FL180, in-range checklist accomplished, altimeter 29.46 with current bos ATIS. About 10 NM prior, ATC instructed us to cross pvd at 12000 ft and gave holding instructions over pvd. Captain reset altitude to 12000 ft in MCP. The captain programmed the holding pattern in the FMC with my help to make the correct entries. Took a bit longer than normal and we were rapidly approaching pvd VOR air traffic area high airspeed and rate of descent. At approximately 330 KIAS, the clacker sounded and I looked to see the airspeed high and within 100-200 ft of 12000 ft assigned altitude. I called 'altitude, altitude, we need to level.' captain was busy with FMC entries to holding pattern. I took the yoke and stopped the descent 400-500 ft below 12000 ft and immediately returning to correct altitude I then noticed both captain's altimeters set to 30.46 showing 1000 ft difference, which he then corrected. ATC did not call us about deviation. Monitoring pilot did not doublechk altimeter setting for the PF on the in-range checklist. Too much attention placed on FMC entries for a holding pattern during a critical phase.

Original NASA ASRS Text

Title: A B737-500 CREW, IN DSCNT TO BOS, OVERSHOT THEIR ASSIGNED ALT.

Narrative: SECOND LEG RETURN TO BOS FROM EWR. CAPT FLYING WITH AUTOPLT ON, VNAV AND LNAV ENGAGED, DIRECT TO PVD VOR. ATC INSTRUCTED AIRSPD INCREASE TO 320 KIAS OR GREATER TO CROSS PVD AT 11000 FT. WITH 100 KT TAILWIND, CAPT LEFT FL210 EARLY ON VNAV DSCNT. PASSING THROUGH FL180, IN-RANGE CHKLIST ACCOMPLISHED, ALTIMETER 29.46 WITH CURRENT BOS ATIS. ABOUT 10 NM PRIOR, ATC INSTRUCTED US TO CROSS PVD AT 12000 FT AND GAVE HOLDING INSTRUCTIONS OVER PVD. CAPT RESET ALT TO 12000 FT IN MCP. THE CAPT PROGRAMMED THE HOLDING PATTERN IN THE FMC WITH MY HELP TO MAKE THE CORRECT ENTRIES. TOOK A BIT LONGER THAN NORMAL AND WE WERE RAPIDLY APCHING PVD VOR ATA HIGH AIRSPD AND RATE OF DSCNT. AT APPROX 330 KIAS, THE CLACKER SOUNDED AND I LOOKED TO SEE THE AIRSPD HIGH AND WITHIN 100-200 FT OF 12000 FT ASSIGNED ALT. I CALLED 'ALT, ALT, WE NEED TO LEVEL.' CAPT WAS BUSY WITH FMC ENTRIES TO HOLDING PATTERN. I TOOK THE YOKE AND STOPPED THE DSCNT 400-500 FT BELOW 12000 FT AND IMMEDIATELY RETURNING TO CORRECT ALT I THEN NOTICED BOTH CAPT'S ALTIMETERS SET TO 30.46 SHOWING 1000 FT DIFFERENCE, WHICH HE THEN CORRECTED. ATC DID NOT CALL US ABOUT DEV. MONITORING PLT DID NOT DOUBLECHK ALTIMETER SETTING FOR THE PF ON THE IN-RANGE CHKLIST. TOO MUCH ATTN PLACED ON FMC ENTRIES FOR A HOLDING PATTERN DURING A CRITICAL PHASE.

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.