Altimeter in light transport jet gave erroneous reading at FL310.

Attributes
ACN	136528
Time
Date	199002
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : avl
State Reference	NC
Altitude	msl bound lower : 30200 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : atp pilot : commercial
Experience	flight time last 90 days : 150 flight time total : 25000 flight time type : 2000
ASRS Report	136582
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : undershoot other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Took off avl in light transport jet, climbing to 15000'. Got red off flag at 13600' on captain's altitude. Copilot was reading 16000'. At FL310 altimeter went off and dropped 800'. Had maintenance check. They could not find trouble although altimeter was run 0 to 45000' twice. Problem was not being able to simulate temperature and pressurization encountered normally in flight.

Original NASA ASRS Text

Title: ALTIMETER IN LTT JET GAVE ERRONEOUS READING AT FL310.

Narrative: TOOK OFF AVL IN LTT JET, CLBING TO 15000'. GOT RED OFF FLAG AT 13600' ON CAPT'S ALT. COPLT WAS READING 16000'. AT FL310 ALTIMETER WENT OFF AND DROPPED 800'. HAD MAINT CHK. THEY COULD NOT FIND TROUBLE ALTHOUGH ALTIMETER WAS RUN 0 TO 45000' TWICE. PROB WAS NOT BEING ABLE TO SIMULATE TEMP AND PRESSURIZATION ENCOUNTERED NORMALLY IN FLT.

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.