An S80 flight crew descends and overshoots their assigned altitude while north of bos, ma.

Attributes
ACN	436420
Time
Date	199904
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : bos.airport
State Reference	MA
Altitude	msl bound lower : 5650 msl bound upper : 6000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tracon : a90.tracon tower : cle.tower
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	436420
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : instrument pilot : commercial
ASRS Report	435573
Events
Anomaly	altitude deviation : overshoot inflight encounter : weather non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : radar other controllera other flight crewa
Resolutory Action	controller : issued advisory flight crew : returned to original clearance
Supplementary
Problem Areas	Weather Flight Crew Human Performance Environmental Factor
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Location: north of bos about 15 mi. Received clearance to turn right heading 150 degrees. First officer was the PF. He started the turn, but also began a descent. I noticed the descent at about 5750 ft, our altitude went to 5650 ft. Bos approach told us to maintain 6000 ft. I acknowledged with no other conversation on the matter. We have no excuse for descending other than possibly fatigue. It was the 4TH leg of a 5 leg day. At night. In the WX. High density airport #3 for the day. Today's threat obviously was fatigue. I will brief the threat. Supplemental information from acn 435573: inadvertently rolled thumbwheel through 00 and directed descent to a lower altitude. Corrected back to 6000 ft. This was leg #4 of a 5 leg day through aus-dfw-ord-bos and jfk. Approach directed a heading change at the same time autoplt was leveling at 6000 ft. First officer anticipated a heading and altitude change, even though no altitude change was given.

Original NASA ASRS Text

Title: AN S80 FLC DSNDS AND OVERSHOOTS THEIR ASSIGNED ALT WHILE N OF BOS, MA.

Narrative: LOCATION: N OF BOS ABOUT 15 MI. RECEIVED CLRNC TO TURN R HDG 150 DEGS. FO WAS THE PF. HE STARTED THE TURN, BUT ALSO BEGAN A DSCNT. I NOTICED THE DSCNT AT ABOUT 5750 FT, OUR ALT WENT TO 5650 FT. BOS APCH TOLD US TO MAINTAIN 6000 FT. I ACKNOWLEDGED WITH NO OTHER CONVERSATION ON THE MATTER. WE HAVE NO EXCUSE FOR DSNDING OTHER THAN POSSIBLY FATIGUE. IT WAS THE 4TH LEG OF A 5 LEG DAY. AT NIGHT. IN THE WX. HIGH DENSITY ARPT #3 FOR THE DAY. TODAY'S THREAT OBVIOUSLY WAS FATIGUE. I WILL BRIEF THE THREAT. SUPPLEMENTAL INFO FROM ACN 435573: INADVERTENTLY ROLLED THUMBWHEEL THROUGH 00 AND DIRECTED DSCNT TO A LOWER ALT. CORRECTED BACK TO 6000 FT. THIS WAS LEG #4 OF A 5 LEG DAY THROUGH AUS-DFW-ORD-BOS AND JFK. APCH DIRECTED A HDG CHANGE AT THE SAME TIME AUTOPLT WAS LEVELING AT 6000 FT. FO ANTICIPATED A HDG AND ALT CHANGE, EVEN THOUGH NO ALT CHANGE WAS GIVEN.

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.