Aircraft equipment problem. Faulty first officer altimeter in normal static source. After leveloff captain's altimeter was 2000 ft higher than first officer's and when checking alternate static sources determined the first officer's normal static source erroneous.

Home

Browse by month

Random

Latest

About

Contact

Attributes
ACN	335480
Time
Date	199605
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : iiu
State Reference	KY
Altitude	msl bound lower : 35000 msl bound upper : 37000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid tower : bru
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 110 flight time total : 2000 flight time type : 250
ASRS Report	335480
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : cfi pilot : atp pilot : instrument
Experience	flight time last 90 days : 60 flight time total : 14000 flight time type : 4000
ASRS Report	335497
Events
Anomaly	aircraft equipment problem : critical altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

During climb to assigned altitude of FL350 we noticed that captain's altimeter was reading approximately 2000 ft higher than both the first officer's and standby altimeters. We tried to determine which altimeters were reading correctly. We found there was no abnormal procedure in the book to cover this situation. Since the first officer's and standby altimeters were reading the same and we were approaching leveloff altitude, we leveled off using the first officer's altimeter. We assumed the captain's altimeter was reading high since the first officer's and standby altimeters were reading the same. After leveloff (using the first officer's altimeter), the captain selected his alternate static source and his altimeter read the same as it had read in normal static (FL370). We then selected the first officer's static source to alternate and both the first officer's and standby altimeters spun up from FL350 to FL370. We immediately advised ATC of our instrument problems and requested and was given a 2000 ft descent back down to FL350. We continued on with first officer's static source in alternate position. Upon landing in shv we advised maintenance and grounded the aircraft.

Original NASA ASRS Text

Title: ACFT EQUIP PROB. FAULTY FO ALTIMETER IN NORMAL STATIC SOURCE. AFTER LEVELOFF CAPT'S ALTIMETER WAS 2000 FT HIGHER THAN FO'S AND WHEN CHKING ALTERNATE STATIC SOURCES DETERMINED THE FO'S NORMAL STATIC SOURCE ERRONEOUS.

Narrative: DURING CLB TO ASSIGNED ALT OF FL350 WE NOTICED THAT CAPT'S ALTIMETER WAS READING APPROX 2000 FT HIGHER THAN BOTH THE FO'S AND STANDBY ALTIMETERS. WE TRIED TO DETERMINE WHICH ALTIMETERS WERE READING CORRECTLY. WE FOUND THERE WAS NO ABNORMAL PROC IN THE BOOK TO COVER THIS SIT. SINCE THE FO'S AND STANDBY ALTIMETERS WERE READING THE SAME AND WE WERE APCHING LEVELOFF ALT, WE LEVELED OFF USING THE FO'S ALTIMETER. WE ASSUMED THE CAPT'S ALTIMETER WAS READING HIGH SINCE THE FO'S AND STANDBY ALTIMETERS WERE READING THE SAME. AFTER LEVELOFF (USING THE FO'S ALTIMETER), THE CAPT SELECTED HIS ALTERNATE STATIC SOURCE AND HIS ALTIMETER READ THE SAME AS IT HAD READ IN NORMAL STATIC (FL370). WE THEN SELECTED THE FO'S STATIC SOURCE TO ALTERNATE AND BOTH THE FO'S AND STANDBY ALTIMETERS SPUN UP FROM FL350 TO FL370. WE IMMEDIATELY ADVISED ATC OF OUR INST PROBS AND REQUESTED AND WAS GIVEN A 2000 FT DSCNT BACK DOWN TO FL350. WE CONTINUED ON WITH FO'S STATIC SOURCE IN ALTERNATE POS. UPON LNDG IN SHV WE ADVISED MAINT AND GNDED THE ACFT.

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.