Sticking altimeter causes error at level off.

Attributes
ACN	325520
Time
Date	199601
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : hto
State Reference	NY
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 280 flight time total : 10000
ASRS Report	325520
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 21000 flight time type : 500
ASRS Report	325521
Events
Anomaly	altitude deviation : undershoot non adherence : far non adherence other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On level off, at assigned FL350 noticed discrepancy between captain's and first officer's altimeter approximately 740 ft (captain's low). Crosschecked with ATC and they concurred. Captain disconnected autoplt and climbed to FL350 on first officer's altimeter. On climbing captain's altimeter jumped, and read within 150 ft of first officer's altimeter. Log entry made. Supplemental information from acn 325521: after tapping on captain's altimeter it jumped up and read within 150 ft of first officer's. On landing in dca we made maintenance aware of the situation and put an entry in the aircraft logbook.

Original NASA ASRS Text

Title: STICKING ALTIMETER CAUSES ERROR AT LEVEL OFF.

Narrative: ON LEVEL OFF, AT ASSIGNED FL350 NOTICED DISCREPANCY BTWN CAPT'S AND FO'S ALTIMETER APPROX 740 FT (CAPT'S LOW). XCHKED WITH ATC AND THEY CONCURRED. CAPT DISCONNECTED AUTOPLT AND CLBED TO FL350 ON FO'S ALTIMETER. ON CLBING CAPT'S ALTIMETER JUMPED, AND READ WITHIN 150 FT OF FO'S ALTIMETER. LOG ENTRY MADE. SUPPLEMENTAL INFO FROM ACN 325521: AFTER TAPPING ON CAPT'S ALTIMETER IT JUMPED UP AND READ WITHIN 150 FT OF FO'S. ON LNDG IN DCA WE MADE MAINT AWARE OF THE SIT AND PUT AN ENTRY IN THE ACFT LOGBOOK.

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.