First officer of medium large transport flying descended below assigned altitude.

Attributes
ACN	178612
Time
Date	199105
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bwi
State Reference	MD
Altitude	msl bound lower : 13600 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 190 flight time total : 13000 flight time type : 3700
ASRS Report	178612
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 24000 vertical : 600
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

The first officer was flying. I was getting the ATIS. I saw the first officer pick up his microphone and change the altitude in the alerter from 14000' to 11000'. At 13600' I saw him pick up his microphone again. I could tell by his body language that something was wrong. I turned up the volume on ATC and realized we were below our assigned altitude of 14000'. The first officer was making no effort to stop our descent. I took control and brought us back to 14000'. A few seconds later I saw another aircraft pass under us.

Original NASA ASRS Text

Title: FO OF MLG FLYING DESCENDED BELOW ASSIGNED ALT.

Narrative: THE F/O WAS FLYING. I WAS GETTING THE ATIS. I SAW THE F/O PICK UP HIS MIC AND CHANGE THE ALT IN THE ALERTER FROM 14000' TO 11000'. AT 13600' I SAW HIM PICK UP HIS MIC AGAIN. I COULD TELL BY HIS BODY LANGUAGE THAT SOMETHING WAS WRONG. I TURNED UP THE VOLUME ON ATC AND REALIZED WE WERE BELOW OUR ASSIGNED ALT OF 14000'. THE F/O WAS MAKING NO EFFORT TO STOP OUR DSNT. I TOOK CTL AND BROUGHT US BACK TO 14000'. A FEW SECS LATER I SAW ANOTHER ACFT PASS UNDER US.

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.