Flight crew alleges altimetry in aircraft was faulty.

Attributes
ACN	192319
Time
Date	199110
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : fat
State Reference	CA
Altitude	msl bound lower : 10600 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other descent other ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 15000 flight time type : 7000
ASRS Report	192319
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 120 flight time total : 3500 flight time type : 150
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : became reoriented
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

On descent into fresno we were given a descent to 11000 ft. ATC gave us an altimeter setting of 29.80. We also got an altimeter setting from our company (which from past experience has been more current) of 29.87. Normally at around the 10000 ft altitude we set the #1 and #3 altimeters to QFE. (At fresno a conversion of .36). We used the company altimeter setting for the center altimeter and I was resetting my #1 altimeter to QFE during the level off at 11000 ft. The first officer observed me passing 10900 and called 11000 ft (a normal everyday required call). I got the clue to level at 11000 ft and began a climb from an altitude of 10850 ft. At that moment ATC told us that they observed us at 10600 ft and advised us that we were to maintain 11000 ft. Upon landing in fresno we checked out all 3 altimeters, and with the current setting all 3 altimeters were over 100 ft off. They were not in error leaving dfw so we doublechked the altimeter in fresno with the same results. The pressure was falling fairly rapidly and the setting seemed to be catching up with what we thought it should be. On return to dfw altimeters checked out ok. I think 3 things contributed to this happening. 1) lesson learned -- do not accomplish another task during level off. 2) be wary of company altimeter setting. We got the setting from ATIS which was not current. 3) there was something wrong with the settings or equipment in the fresno area since all 3 altimeters checked ok elsewhere. All 3 compounded the situation.

Original NASA ASRS Text

Title: FLC ALLEGES ALTIMETRY IN ACFT WAS FAULTY.

Narrative: ON DSCNT INTO FRESNO WE WERE GIVEN A DSCNT TO 11000 FT. ATC GAVE US AN ALTIMETER SETTING OF 29.80. WE ALSO GOT AN ALTIMETER SETTING FROM OUR COMPANY (WHICH FROM PAST EXPERIENCE HAS BEEN MORE CURRENT) OF 29.87. NORMALLY AT AROUND THE 10000 FT ALT WE SET THE #1 AND #3 ALTIMETERS TO QFE. (AT FRESNO A CONVERSION OF .36). WE USED THE COMPANY ALTIMETER SETTING FOR THE CENTER ALTIMETER AND I WAS RESETTING MY #1 ALTIMETER TO QFE DURING THE LEVEL OFF AT 11000 FT. THE FO OBSERVED ME PASSING 10900 AND CALLED 11000 FT (A NORMAL EVERYDAY REQUIRED CALL). I GOT THE CLUE TO LEVEL AT 11000 FT AND BEGAN A CLB FROM AN ALT OF 10850 FT. AT THAT MOMENT ATC TOLD US THAT THEY OBSERVED US AT 10600 FT AND ADVISED US THAT WE WERE TO MAINTAIN 11000 FT. UPON LNDG IN FRESNO WE CHKED OUT ALL 3 ALTIMETERS, AND WITH THE CURRENT SETTING ALL 3 ALTIMETERS WERE OVER 100 FT OFF. THEY WERE NOT IN ERROR LEAVING DFW SO WE DOUBLECHKED THE ALTIMETER IN FRESNO WITH THE SAME RESULTS. THE PRESSURE WAS FALLING FAIRLY RAPIDLY AND THE SETTING SEEMED TO BE CATCHING UP WITH WHAT WE THOUGHT IT SHOULD BE. ON RETURN TO DFW ALTIMETERS CHKED OUT OK. I THINK 3 THINGS CONTRIBUTED TO THIS HAPPENING. 1) LESSON LEARNED -- DO NOT ACCOMPLISH ANOTHER TASK DURING LEVEL OFF. 2) BE WARY OF COMPANY ALTIMETER SETTING. WE GOT THE SETTING FROM ATIS WHICH WAS NOT CURRENT. 3) THERE WAS SOMETHING WRONG WITH THE SETTINGS OR EQUIP IN THE FRESNO AREA SINCE ALL 3 ALTIMETERS CHKED OK ELSEWHERE. ALL 3 COMPOUNDED THE SITUATION.

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.