Cleared to descend, changed altitude alert to 11000', but aircraft climbed 1000' before noticed.

Attributes
ACN	156015
Time
Date	199009
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : dqo
State Reference	DE
Altitude	msl bound lower : 21000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 4300 flight time type : 450
ASRS Report	156015
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Cruising at FL210 we were cleared to 11000'. The altitude alerter was changed to 11000'. The autoplt altitude hold was on and subsequently kicked off with the change to 11000'. The aircraft then climbed to FL220 before being noticed, just seconds before the controller called it out. Maintenance failure was duplicated once and written up. Contributing factors: first officer was in the process of the approach brief, the captain was on the P/a. Human considerations: first officer's reliance on altitude hold. First officer distracted by the frequency and longevity of captain's use of the P/a and lack of attention to aircraft performance (F/east concurred). First officer failed to xfer verbally controls of the aircraft to the captain (because of his passenger announcements) as is company SOP. First officer and F/east not being more assertive with the captain (re: his frequent/long passenger announcements). We flew the same aircraft the next day and were unable to duplicate.

Original NASA ASRS Text

Title: CLEARED TO DESCEND, CHANGED ALT ALERT TO 11000', BUT ACFT CLIMBED 1000' BEFORE NOTICED.

Narrative: CRUISING AT FL210 WE WERE CLRED TO 11000'. THE ALT ALERTER WAS CHANGED TO 11000'. THE AUTOPLT ALT HOLD WAS ON AND SUBSEQUENTLY KICKED OFF WITH THE CHANGE TO 11000'. THE ACFT THEN CLBED TO FL220 BEFORE BEING NOTICED, JUST SECONDS BEFORE THE CTLR CALLED IT OUT. MAINT FAILURE WAS DUPLICATED ONCE AND WRITTEN UP. CONTRIBUTING FACTORS: F/O WAS IN THE PROCESS OF THE APCH BRIEF, THE CAPT WAS ON THE P/A. HUMAN CONSIDERATIONS: F/O'S RELIANCE ON ALT HOLD. F/O DISTRACTED BY THE FREQ AND LONGEVITY OF CAPT'S USE OF THE P/A AND LACK OF ATTN TO ACFT PERFORMANCE (F/E CONCURRED). F/O FAILED TO XFER VERBALLY CTLS OF THE ACFT TO THE CAPT (BECAUSE OF HIS PAX ANNOUNCEMENTS) AS IS COMPANY SOP. F/O AND F/E NOT BEING MORE ASSERTIVE WITH THE CAPT (RE: HIS FREQUENT/LONG PAX ANNOUNCEMENTS). WE FLEW THE SAME ACFT THE NEXT DAY AND WERE UNABLE TO DUPLICATE.

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.