TAVIS FAILURE ANALYSIS

HOME PAGE Web Site Contents Mars Report Contents Mars Report Abstract CV for Dr. David Roffman Diplomas PhD Thesis PhD Thesis Powerpoint Mars PowerPoint MSL Weather Reports MSL Yr 3 Winter Weather MSL Fall Yr 3 Weather MSL Yr. 3 Summer Weather MSL Yr. 3 Spring Weather Martian plume March 25 2017 MSL Ultraviolet Desai, EDL, Parachutes & ExoMars Mars winter vs. summer temps Sea at Utopia Planitia, Mars Tree Stump at MSL? Spherical life on Mars? Mars Report Abstract, 1-1.2 Mars Report Sec.2-2.1 Report 2.2-2.4 Report 2.5-2.5.2 Report 2.5.3-2.7 Report 3-4.1.2 Report 5 to 6 Report  7-7.2.1 Report 8 Report 9 Report 10-11 Report  12-12.2 Report 12.3-12.5 Report 12.6 Report 13-14 Report 14.1 Report 14.2-14.3 Report 14.4-14.6.2 Report 14.6.3-14.7 Report 15-19 Report References Report Afterword Rebuttal of REMS Report Running water on Mars MSL Year 0 Weather MSL Yr 2 Winter-Spring Weather MSL Yr 2 Summer Weather MSL Yr 2 Fall Weather MSL Yr 2-3 Winter Weather Adiabatics MSL Hi Temps MSL Low Temps Organic Chem found by MSL Oxygen in Mars Air MSL Day length & Temp Warm winter ground temps 155-Mile High Mars Plume Radiation Diurnal Air Temp Variation Mars Temps Fahrenheit Beagle found JPL/NASA Pressure Mistakes Enter MarsCorrect Sol 370, 1160 & 1161 Histories Mars-Radio-Show JPL Fudges Pressure Curves MSL Temp. ∆ Mast to Ground High & Low Pressures Normalized Mars soil 2% water Moving rock Mars MAVEN MSL Relative Humidity Claim Ashima Concedes Original MSL Weather Record Old MSL Weather Record MSL Summer Weather Pressure Estimate REMS Wind MSL Pressures REMS Reports Curiosity Geology CERN-2013-pics Daylight Math MSL Errors P1 MSL Errors P2 MSL-Chute-Flap MSL daylight Ashima Sols 15 to 111 Ashima Sol 112 to 226 Ashima Sol 227 on New Ashima Sols 270+ MSL Summer to Sol 316 Updated Secrets of Mars Weather Forecast Wind Booms MSL Credibility MSL Temp. Swings MSL Temperatures Sample Analysis at Mars (SAM) VL2 - MSL Ls Comparson Ashima MIT Mars GCM Dust Storm Nonsense Mars Slideshow Moving Sand & Martian Wind 3 DEC12 Press Conf. MSL Press Conf. 15NOV2012 Sol Numbering MSL Pressure Graph to Ls 218.8 MSL Sky Color Mars Sky Color DATA DEBATE! Zubrin's Letter Phoenix Vaisala Vaisala Pressure Sensors Phoenix &MSL Flawed MSL REMS Viking pressure sensors failed MSL landing site Mars Landings Phobos Grunt Martian Air Supersaturation Mars & CH4 Mars and MSL Time Viking Pressure Audit Links Mars Society 2008 Quant Finance Frontiers Home Front. Preface Frontiers Ch. 1 Frontiers Ch. 2 Antimatter Lightning Frontiers Ch. 3 Frontiers Ch. 4 Frontiers Ch. 5 Frontiers Ch. 6 Frontiers Ch. 7 Frontiers Ch. 8 Frontiers Ch. 9 Frontiers Ch 10 Frontiers Ch 11 Frontiers Ch 12 Frontiers Ch 13 Frontiers Ch 14 Frontiers Ch 15 Frontiers Ch 16 Frontiers Ch 17 Frontiers Ch 18 Frontiers Ch 19 Frontiers Ch 20 Frontiers Ch 21 Frontiers Ch 22 World Tour Spring-Break -13 Other Travels Asteroid Impact? ExoMars data Unit Issues Viking Pressures Tavis CADs Landing Long Scale Heights LS of Max/Min Pressures Tavis Report Tavis Failures Lander Altitude Martian Trees? Code Experiment Gedanken Report Mars Nuke? Martian Flares Mach Numbers MOLA (altitude) Original Mars Report Mariner 9 & Pressure Mars  Temps MSL Time MPF Pressure Blog Debates Spring Pendulum Plasma Model Reporting Errors Orbital Parameters Anderson Localization P. 1 Anderson Localization P. 2 Moving rock old Navigating Mars Mars Report Section Links Mars Report Figure Link Gillespie Lake rock outcrop MSL Sol 200 Anomaly Sol 1300&1301 Anomalies Gilbert Levin & Labeled Release Brine on Mars Ceres Lights Yr 1 Table 1 amfivan Missing data Mitchell Report Old Mars Report All MPF Temps ExoMars fails Did Spirit find past life? MSL ground temps go haywire Seasonal Pressure Altitude Calculations OPACITY AT MSL



Note: while most Tavis transducers did not fail, the point of including this report on my web site is that nothing in the report refers to dust, which I believe is a major source for failure of transducers on Mars.

 

Source: found on-line in conjunction with foia.msfc.nasa.gov/docs/praca/A15483.doc.

 

MSFC Problem Reporting and Corrective Action (PRACA) System

WHOLE RECORD REPORT( + ADDENDUM)


 

MSFC Record #
A15483

In-Flight Anomaly Number
--

Contractor Report Number
E-152

JSC#
--

KSC#
--

Problem Title
LOX ULLAGE PRESSURE TRANSDUCER FAILED OUTPUT VOLTAGE TEST AT MAF

EICN#
--

ELEMENT
ET

Contractor
MMMSS

FSCM#
--

FCRIT
3

HCRIT
--

Sys_Lvl
N

Misc Codes
A B C D E F G H I J K L M N O

HARDWARE
EIM

NOMENCLATURE
--

PART#
--

SER/LOT#
--

MANUFACTURER
--

HARDWARE
LRU

NOMENCLATURE
--

PART#
--

SER/LOT#
--

MANUFACTURER
--

HARDWARE
NCA

NOMENCLATURE
LOX PRESS TRANSDUCER

PART#
80931003731-009

SER/LOT#
0000028

MANUFACTURER
TAVIS CORP

Test/Operation
A - ATP

Prevailing Condtion
F - FUNCTIONAL

F / U
F

Fail Mode
EG - SIG HI OR LO

Cause
MAW - MFG-ASY-WORK

System
ELECTRICAL

Defect
MW - MISWIR

Material
C - EEE

Work Contact
JOHN ADAMS

Fail Date
08/17/1992

Received at MSFC
06/24/1993

Date Isolated
08/17/1992

FMEA Reference
3.2.1.1C & 3.2.1.2C

IFA: Mission Phase
--

Mission Elapsed Time
--

Location
MAF

Symptom
EG - SIG HI OR LO

Time Cycle
--

Effectivity Text
--

Vehicle Effectivity Codes

Vehicle 1
--

Vehicle 2
--

Vehicle 3
--

Vehicle 4
--

Vehicle 5
--

Mission Effectivity Codes

Mssn 1
--

Mssn 2
--

Mssn 3
--

Mssn 4
--

Mssn 5
--

Estimated Completion Dates

MSFC Approved Defer Until Date
01/17/1994

Contractor Req Defer Until Date
02/08/1994

LVL 3 Close
--

Remark / Action
02/08/1994

Investigation / Resolution Summary

 

Last MSFC Update
02/09/1995

CN RSLV SBMT
02/09/1994

Defer Date
--

Add Date
06/24/1993

R/C Codes
2 - MFG -- --

Assignee

Design
R. MOYE

Chief Engineer
M. PESSIN

S & MA
R. JACKSON

Project
--

Project MGR
P. COUNTS

Approval

Design
R. MOYE

Chief Engineer
M. PESSIN

S & MA
R. JACKSON

Project
--

Project MGR
P. COUNTS

PAC Assignee
B. HURST

PAC Review Complete
BH

MSFC Closure Date
02/23/1994

Status
C - CLOSED

F/A Completion
06/15/1993

Problem Type
--

SEV
--

Program Name
--

REVL
--

OPRINC
--

FUNC MOD
--

Software Effectivity
-- -- -- -- --

Software Fail CD
--

SUBTYPE
--

Software Closure CD
--

RES PERSON L2
--

Approval Signature L3
--

Related Document Type
--

Related Document ID
T-123647

Related Document Title
--

Related Document Type
--

Related Document ID
--

Related Document Title
--

Related Document Type
--

Related Document ID
--

Related Document Title
--

Contractor Status Summary

 

Reliability/Quality Assurance Concerns, Recommendations:

 

Problem Description

 
A LOX ULLAGE PRESSURE TRANSDUCER FAILED A TEST OF OUTPUT VOLTAGE
VERSUS APPLIED PRESSURE DURING ACCEPTANCE TESTING OF ET-65/LWT-58
FAILURE ANALYSIS OF THE TRANSDUCER, COMPLETED JUNE 15, 1993,
IDENTIFIED THE ROOT CAUSE OF THE FAILURE AS A DEFECTIVE TRANSISTOR
THE NATURE OF THE TRANSISTOR DEFECT INDICATES A LOT RELATED PROBLEM
THE TRACING OF ALL USES OF THE DEFECTIVE LOT OF TRANSISTORS WAS
RECEIVED ON JUNE 17, 1993
CRITICALITY: THE PD7400239-009 TRANSDUCERS ARE USED ON ET-64/
SUBSEQUENT AND ARE CRIT. 3; FMEA ITEM CODE 3.2.1.1C, "FAILS WITH HIGH
READING;" AND FMEA ITEM CODE 3.2.1.2C, "FAILS WITH LOW READING."
NOTE: THE TRANSDUCERS ARE LIMITED LIFE CONTROLLED
PREVIOUS CAPS: CAPS E-132, E-133, AND E-141 ADDRESSED UNRELATED
PROBLEMS WITH PD7400239 TRANSDUCERS
REVISION "E" CLOSES ALL TASKS. SEE ASTERISKS FOR CHANGES

Contractor Investigation/Resolution

 
GENERAL:
A LOX ULLAGE PRESSURE TRANSDUCER INSTALLED ON ET-65/LWT-58 FAILED A
TEST OF THE ACCURACY OF THE OUTPUT VOLTAGE PRESSURE VERSUS THE APPLIED
PRESSURE. THE TEST, TP7C201-AT, WAS BEING PERFORMED IN THE MAF
BUILDING 420, FINAL ACCEPTANCE AND TEST WORK AREA
THE TRANSDUCER WAS A PART NUMBER 80931003731-009, SERIAL NUMBER 28,
INSTALLED ON THE ET IN THE REFERENCE DESIGNATOR 327A04 POSITION. AT
AN APPLIED PRESSURE OF 21.006 PSIG, THE OUTPUT VOLTAGE WAS 3.581 VDC
THE MAXIMUM ALLOWABLE OUTPUT VOLTAGE AT THAT PRESSURE IS 3.560 VDC
THE 0.021 VDC OUT-OF-TOLERANCE CONDITION IS EQUIVALENT TO AN ERROR OF
0.4% OF FULL SCALE. THE 80931003731-009 TRANSDUCER IS AN ASSEMBLY OF A
PD4800280-019 METAL SCREEN FILTER INSTALLED ON THE REFERENCE PORT OF A
PD7400239-009 PRESSURE TRANSDUCER. THE PD7400239 TRANSDUCER, SERIAL
NUMBER 85, USED IN THIS ASSEMBLY HAD AN OUTPUT VOLTAGE THAT WAS LOWER
BY 0.9% AT 21 PSIG DURING THE ORIGINAL SUPPLIER ACCEPTANCE TEST
THE TRANSDUCER WAS RETURNED TO THE SUPPLIER, TAVIS CORPORATION, FOR
FAILURE ANALYSIS. THE TRANSDUCER IS A HERMETICALLY SEALED DESIGN
WITH A TUBULAR STAINLESS STEEL CASE. ANALYSIS PROVED DIFFICULT AS
THE FAILURE WAS INTERMITTENT AND VARIABLE IN NATURE. THE ANALYSIS
AT TAVIS CONCLUDED IN APRIL 1993, BY IDENTIFYING A DEFECTIVE
TRANSISTOR. THE DEFECTIVE TRANSISTOR WAS SENT TO THE MARTIN
MARIETTA ASTRONAUTICS GROUP IN DENVER, COLORADO,FOR FURTHER
ANALYSIS
THE DEFECTIVE TRANSISTOR WAS A 2N2946A JANTXV, PRODUCED BY TELEDYNE
CRYSTALONICS, LOT CODE 8619. IT WAS FOUND TO HAVE EXCESSIVE
ELECTRICAL LEAKAGE AT ALL TEMPERATURES; THE GREATEST OUT OF
TOLERANCE CONDITION OCCURRED AT 75 DEGREE F. TESTING FOUND THE
TRANSISTOR CASE HERMETICITY WAS WITHIN SPECIFICATION. RESIDUAL GAS
ANALYSIS (RGA) OF THE CONTENTS OF THE HERMETICALLY SEALED CASE
FOUND THE MOISTURE CONTENT WAS 6.79%; THE MAXIMUM ALLOWABLE VALUE
IS 0.5%. FOLLOWING RGA, WITH THE MOISTURE HAVING BEEN REMOVED, THE
TRANSISTOR NO LONGER HAD EXCESSIVE ELECTRICAL LEAKAGE. EXCESSIVE
INTERNAL MOISTURE INDICATES LOSS OF CONTROL DURING THE
MANUFACTURING PROCESS AND BRINGS INTO QUESTION THE RELIABILITY OF
THE ASSOCIATED PRODUCTION LOT
TAVIS CORPORATION IDENTIFIED ALL PARTS PRODUCED FOR MARTIN MARIETTA
MANNED SPACE SYSTEMS WHICH USED THE SAME LOT OF TELEDYNE
CRYSTALONICS TRANSISTORS AS THAT IN THE ORIGINAL FAILURE; LOT CODE
8619. A TOTAL OF TWENTY-SEVEN PD7400239-009/80931003731-009 LOX ULLAGE
PRESSURE TRANSDUCERS ARE AFFECTED. A TOTAL OF THIRTY PD7400239-019 LH2
ULLAGE PRESSURE TRANSDUCERS ARE AFFECTED. THE LH2 TRANSDUCERS WERE
DEVELOPED TO REPLACE THE EXISTING PD7400098-089 PARTS BUT HAVE NEVER
BEEN QUALIFIED FOR FLIGHT
TASK I. FAILURE INVESTIGATION
    A ENGINEERING IS REVIEWING THE LOX ULLAGE PRESSURE
      TRANSDUCER TEST DATA TAKEN IN MAF BLDG. 420 ON THE ETS WHICH
      HAVE THE 80931003731-009 TRANSDUCERS. THE DATA WILL BE COMPARED
      WITH THE LAST SUPPLIER CALIBRATION TESTS TO DETERMINE IF THE
      TRANSDUCERS HAVE CHANGED
      RESPONSIBILITY: L. COLON/4120--J. COOL/4120
      COMPLETE: JUNE 28, 1993
      CLOSURE STATEMENT
      SEVERAL OF THE EIGHTEEN INSTALLED AND TESTED TRANSDUCERS HAD
      MINOR CHANGES IN THE OUTPUT VOLTAGE AS COMPARED TO THE SUPPLIER
      ATP. ANY ACTIONS NECESSARY WILL BE ADDRESSED FOLLOWING THE
      COMPLETION OF THE OTHER FAILURE INVESTIGATION TASKS
   B  PURCHASING IS OBTAINING FROM TAVIS CORPORATION THE TRACEABILITY
      DATA ON THE 2N2946A TRANSISTORS USED IN ALL TRANSDUCERS OTHER
      THAN THOSE INVOLVED WITH THE SUSPECT LOT
      RESPONSIBILITY: G. PICHON/3830  M. COMBS/3830
      COMPLETE: JUNE 28, 1993
      CLOSURE STATEMENT
      TWENTY-FOUR PD7400239-009/80931003731-009 LOX ULLAGE PRESSURE
      TRANSDUCERS AND TWENTY-TWO PD7400239-019 LH2 ULLAGE PRESSURE
      TRANSDUCERS WERE IDENTIFIED WITH THE LOT CODES OF TRANSISTORS
   C  ALL PD7400239 LOX AND LH2 ULLAGE PRESSURE TRANSDUCERS IN MAF
      STORES WERE DOCUMENTED ON MARS AS BEING SUSPECT OF BEING
      INACCURATE AND WILL BE RETURNED TO TAVIS FOR TESTING. THIRTY LOX
      TRANSDUCERS WERE DOCUMENTED ON MARS T-127791. FIFTY-TWO LH2
      TRANSDUCERS WERE DOCUMENTED ON MARS T-127790
      RESPONSIBILITY: J. ADAMS/3741--D. WESTPHAL/3740
      COMPLETE: JUNE 28, 1993
   D  TESTING OF THE PD7400239 LOX AND LH2 ULLAGE PRESSURE TRANSDUCERS
      AT TAVIS WILL CONSIST OF THE POST-VIBRATION PORTION OF THE
      SUPPLIER ATP
      RESPONSIBILITY: G. PICHON/3830--M. COMBS/3830
                      L. COLON/4120--J. COOL/4120
      COMPLETE:  NOVEMBER 30, 1993
     CLOSURE STATEMENT
      1. THIRTY LOX PRESSURE TRANSDUCERS WERE TESTED AT TAVIS
         CORPORATION:
         A. TEN TRANSDUCERS WERE FOUND TO HAVE SMALL ERRORS IN OUTPUT
            VOLTAGE AND WERE DOCUMENTED ON MARS T-121303 AND T- 121304
            THE TRANSDUCERS HAVE BEEN DISPOSITIONED TO BE READJUSTED
            AND RETURNED TO MAF
         B. ONE TRANSDUCER HAD GALLED THREADS ON THE REFERENCE PORT
            FITTING, AS A RESULT OF FILTER REMOVAL FOR TESTING, AND
            WAS DOCUMENTED ON MARS T-121306. THE TRANSDUCER WAS
            DISPOSITIONED "USE-AS-IS."
         C. ONE TRANSDUCER HAD AN OUTPUT VOLTAGE ERROR SIMILAR TO THAT
            OF THE ORIGINAL FAILURE WHICH OPENED THIS CAPS. THE
            TRANSDUCER WAS DOCUMENTED ON MARS T-121302 AND
            DISPOSITIONED FOR FAILURE ANALYSIS TO BE PERFORMED; SEE
            TASK I.G. BELOW
      2. FIFTY TWO LH2 PRESSURE TRANSDUCERS WERE TESTED AT TAVIS
         CORPORATION:
         A. TWO TRANSDUCERS WERE FOUND TO HAVE SMALL ERRORS IN OUTPUT
            VOLTAGE AND WERE DOCUMENTED ON MARS T-121305.THE
            TRANSDUCERS WILL BE READJUSTED AND RETURNED TO MAF
         B. ONE TRANSDUCER HAD AN OUTPUT VOLTAGE ERROR AND WAS
            DOCUMENTED ON MARS T121307. THE MARS WAS DISPOSITIONED
            FOR FAILURE ANALYSIS; SEE TASK I.I BELOW
  E   NINETEEN TELEDYNE CRYSTALONICS TRANSISTORS FROM TAVIS STOCK ARE
      BEING TESTED TO DETERMINE THEIR CONDITION. THE TRANSISTORS ARE
      NEW UNITS WHICH HAVE BEEN UPGRADED BY TEST TO LEVEL "S" FOR
      USE IN THE PD7400239 TRANSDUCERS. EIGHTEEN OF THE TRANSISTORS
      ARE FROM THE SAME LOT CODE AS THE ORIGINAL FAILURE. THE TESTING
      IS BEING PERFORMED AT THE MARTIN MARIETTA ASTRONAUTICS GROUP IN
      DENVER, COLORADO
      RESPONSIBILITY: G. PICHON/3830--M. COMBS/3830
                      L. COLON/4120-- J. COOL/4120
      COMPLETE: AUGUST 12. 1993
      CLOSURE STATEMENT
      ALL NINETEEN TRANSISTORS PASSED THE ELECTRICAL PERFORMANCE
      TESTS. RESIDUAL GAS ANALYSIS OF FOURTEEN TRANSISTORS FOUND ONE
      UNIT THAT WAS NOT HERMETICALLY SEALED AND TWO WHICH HAD
      EXCESSIVE LEVELS OF MOISTURE. ONE OF THE TWO TRANSISTORS WITH
      EXCESSIVE MOISTURE WAS THE LOT CODE 8611 PART. THE GIDEP ALERT
      WAS REVISED TO INCLUDE THE ADDITIONAL INFORMATION AND LOT CODE;
      SEE TASK II.A
  F   ELECTRICAL ENGINEERING DEPT. 4120, WILL RECOMMEND A COURSE OF
      ACTION FOR THE TRANSDUCER PROBLEMS BASED ON AN EVALUATION OF THE
      DATA FROM THE TRANSDUCERS IN TASK I.D., THE TRANSISTORS IN
      TASK I.E., AND THE RESULTS OF THE FAILURE ANALYSES IN TASK I.G
      AND TASK I.I
      RESPONSIBILITY: G. PICHON/3830--M. COMBS/3830
                      L. COLON/4120-- J. COOL/4120
 *    COMPLETED: JANUARY 17, 1994
  CLOSURE STATEMENT
  1. REVIEW OF THE TRANSDUCER TEST DATA FROM THIRTY LOX AND FIFTY-TWO
     LH2 PRESSURE TRANSDUCERS, OBTAINED AS PART OF I.D., FOUND NO
     INDICATION OF PROBLEMS ASSOCIATED WITH AN INDIVIDUAL LOT
     OF TRANSISTORS
 *2. REVIEW OF THE TEST DATA FROM TASK I.D., FOUND THAT THE
     TRANSDUCERS HAD SMALL, BUT UNEXPECTED, CHANGES IN THE
     CALIBRATION DATA WHEN COMPARED WITH THE ORIGINAL ATP DATA. AS A
     RESULT, TEN LH2 PRESSURE TRANSDUCERS WERE SELECTED BY ELECTRICAL
     ENGINEERING TO BE TESTED FOR LONG TERM (LIFE) STABILITY OF THE
     PD7400239 DESIGN. SEE TASK I.H
 *3. THE FAILURES COVERED BY TASK I.G. AND TASK I.I. WERE THE RESULT
     OF WORKMANSHIP/QUALITY ESCAPES AND WERE JUDGED TO HAVE NO EFFECT
     ON THE OVERALL PERFORMANCE OF THE TRANSDUCERS
 G. FAILURE ANALYSIS T-121302 IS IN PROGRESS AT TAVIS CORPORATION
    THE FAILED PART IS A LOX TRANSDUCER, P/N 80931003731-009,
    S/N 0000020, AND UTILIZES TRANSISTORS WITH THE SAME LOT CODE THAT
    WAS ASSOCIATED WITH THE ORIGINAL FAILURE
    RESPONSIBILITY: G. PICHON/3830--M. COMBS/3830
                   J. ADAMS/3741--D. WESTPHAL/3740
    COMPLETE: NOVEMBER 9, 1993
    CLOSURE STATEMENT
    ANALYSIS FOUND THE CAUSE OF THE FAILURE TO BE A DEFECTIVE SOLDER
    JOINT BETWEEN A CIRCUIT BOARD TERMINAL AND ONE OF THE LEADS TO A
    DIAPHRAGM POSITION SENSING INDUCTOR. THE WIRE HAD BEEN WRAPPED
    ONTO THE TERMINAL BUT HAD NOT BEEN SOLDERED. THE MANUFACTURING
    PROCESSES INSPECT THE SOLDER JOINTS. THE DEFECT IS THE RESULT OF
    A QUALITY CONTROL ESCAPE AT TAVIS CORP
  H.AN ENGINEERING TEST PROGRAM TO DETERMINE THE LONG TERM STABILITY
    OF THE TRANSDUCERS HAS BEEN ESTABLISHED. TEN LH2 ULLAGE PRESSURE
    TRANSDUCERS, PART NUMBER PD7400239-019, WERE SELECTED BY
    ENGINEERING FROM AMONG THE FIFTY-TWO PARTS NOW EXISTING. THE
    TRANSDUCERS ARE TO BE TESTED FOR ACCURACY AT 90 DAY INTERVALS
    UNTIL THE FIRST FLIGHT OF AN ET WITH PD7400239-009 TRANSDUCERS
    THEREAFTER, THE TEN TRANSDUCERS WILL BE TESTED AT 180 DAY
    INTERVALS UNTIL THE PARTS ARE FIVE YEARS OLD (I.E. DECEMBER 1996)
    THE TESTING IS CONTROLLED BY OPERATIONS DIRECTIVE 93-OD-0643
 I. A PD7400239-019 LH2 ULLAGE PRESSURE TRANSDUCER, SERIAL NUMBER
    0000065, FAILED THE TESTS AT TAVIS CORP DOCUMENTED IN TASK I.D
    THE TRANSDUCER OUTPUT WAS 676MV REGARDLESS OF APPLIED PRESSURE,
    AT AN OPERATING TEMPERATURE OF 150 DEGREES FAHRENHEIT. THE
    TRANSDUCER WILL BE DOCUMENTED ON MARS T-121307 AND DISPOSITIONED
    FOR FAILURE ANALYSIS
        RESPONSIBILITY: G. PICHON/3830--M. COMBS/3830
                        J. ADAMS/3741--D. WESTPHAL/3740
  *     COMPLETE: JANUARY 17, 1994
  * CLOSURE STATEMENT
    ANALYSIS FOUND THAT THE INSULATION ON A WIRE HAD BEEN DAMAGED AND
    WAS CAUSING A SHORT CIRCUIT BETWEEN TRANSDUCER COMPONENTS. THE
    DAMAGE WAS THE RESULT OF A WORKMANSHIP/QUALITY ESCAPE WHICH
    IMPROPERLY POSITIONED THE WIRE IN THE ASSEMBLY
    TASK CLOSED
CAUSE
ORIGINAL FAILURE - THE TRANSISTOR WAS DEFECTIVE AS SUPPLIED FROM THE
                   MANUFACTURER
PROBLEMS DISCOVERED DURING THE TASK I INVESTIGATION - SEE TASK II
                   CORRECTIVE ACTION FOR DETAILS
TASK II. CORRECTIVE ACTION
  A. THE CORRECTIVE ACTIONS FOR THE DEFECTIVE TRANSISTORS ARE LISTED
     BELOW. REVIEW BY ELECTRICAL ENGINEERING, TASK I,F.1., DID NOT
     RECOMMEND FURTHER ACTIONS
     1. GIDEP ALERT 9Q-A-93-03 WAS ORIGINALLY RELEASED BY THE GIDEP
        SYSTEM AND WAS BASED ON THE SINGLE ORIGINAL DEFECTIVE
        TRANSISTOR. THE ALERT WAS SUBSEQUENTLY REVISED TO 9Q-A-93-03A
        TO INCLUDE INFORMATION ON OTHER FAILURES DISCOVERED AS PART OF
        TASK I.E
        RESPONSIBILITY: B. CORNAY/3742  D. WESTPHAL/3740
        COMPLETE: SEPTEMBER 9, 1993
     2. SCAD 92-132 WAS ISSUED TO TAVIS CORP
        RESPONSIBILITY: T. PASTORET/3742--D. WESTPHAL/3740
        COMPLETE: JULY 29, 1993
 *B.   CORRECTIVE ACTION FOR THE CHANGES IN THE TRANSDUCER
       CALIBRATIONS, IDENTIFIED DURING ELECTRICAL ENGINEERING REVIEW
       OF TEST DATA IN TASK I.F.2., WAS ADDRESSED BY INSTITUTING A
       LONG TERM TEST OF TRANSDUCER PERFORMANCE. REFERENCE: TASK I.H
       AND OPERATION DIRECTIVE 93-OD-0643. SHOULD THE TEST RESULTS
       INDICATE THAT FURTHER ACTION IS NECESSARY, IT WILL BE ADDRESSED
       BY ENGINEERING CHANGES
 *C.   CORRECTIVE ACTIONS FOR THE FAILURE CAUSED BY A WIRE CONNECTION
       WHICH HAD NOT BEEN SOLDERED WERE TO REVISE THE SOLDER
       INSPECTION CRITERIA OF THE MANUFACTURING TRAVELERS AT THE
       APPLICABLE STAGE OF ASSEMBLY. REFERENCE: TAVIS CORPORATION
       TEST TRAVELER 10345-1, STEP 340, FOR THE
       PD7400239-009; AND TAVIS CORPORATION PRODUCTION TEST TRAVELER
       10346-1, STEP 330, FOR THE PD7400239-019
  *D   CORRECTIVE ACTIONS FOR THE FAILURE CAUSED BY DAMAGED WIRE
       INSULATION WERE TO REVISE THE MANUFACTURING TRAVELERS,
       ENGINEERING DRAWINGS, AND TO CREATE A TOOL TO CONTROL THE
       ASSEMBLY AND PREVENT NICKED WIRES
       1. PD7400239-009 LOX TRANSDUCER; TAVIS CORPORATION PRODUCTION
          TEST TRAVELER 10345-1, STEP 240, ALIGNMENT TOOL #T0215;
          TAVIS CORPORATION PRODUCTION TEST TRAVELER 10345-1, STEP
          350, WIRE ROUTING; AND TAVIS CORPORATION ENGINEERING DRAWING
          18131, REVISION C., DOCUMENTATION ACCOUNTABILITY SHEET (DAS)
          BBE-061
       2. PD7400239-019 LH2 TRANSDUCER: TAVIS CORPORATION PRODUCTION
          TEST TRAVELER 10346-1, STEP 230, ALIGNMENT TOO #T0215; TAVIS
          CORPORATION PRODUCTION TEST TRAVELER 10346-1, STEP 340, WIRE
          ROUTING; AND TAVIS CORPORATION ENGINEERING DRAWING 18913,
          REVISION B., DOCUMENTATION ACCOUNTABILITY SHEET (DAS) BBG-056
TASK CLOSED
TASK III. CLEARANCE OF EFFECTIVITIES
 ALL ETS CLEARED. TESTING OF THE EIGHTY-TWO PD7400239 TRANSDUCERS, NOT
 INSTALLED ON ETS, FOUND NO INDICATION OF A TRANSISTOR LOT RELATED
 PROBLEM.  REVIEW OF THE TEST DATA FROM TRANSDUCERS INSTALLED ON ETS
 FOUND NO INDICATION OF A TRANSISTOR LOT RELATED PROBLEM. REVIEW OF
 THE TEST DATA FROM TRANSDUCERS INSTALLED ON ETS FOUND NO INDICATION
 OF A TRANSISTOR LOT RELATED PROBLEM. THERE ARE SUFFICIENT TESTS OF
 TRANSDUCER PERFORMANCE AT THE SUPPLIER, MAF, AND KSC TO ASSURE
 PERFORMANCE DURING PROPELLANT LOADING AND FLIGHT
 ETS 64 AND SUBSEQUENT HAVE THREE ACTIVE PD7400239-009 LOX ULLAGE
 PRESSURE TRANSDUCERS CONNECTED TO THE ORBITER AT A TIME. THE LAUNCH
 COMMIT CRITERIA (LSS) REQUIRES THAT TWO OF THE THREE BE FUNCTIONING
 THROUGH THE PRE-PRESS EVENT OF PROPELLANT LOADING.  NONE ARE
 REQUIRED FOR FLIGHT
TASK CLOSED
*TASK IV. CAPS CLOSURE SUMMARY
A FAILURE OF A PD7400239 LOX ULLAGE PRESSURE TRANSDUCER WAS TRACED TO
A DEFECTIVE TRANSISTOR. A GIDEP ALERT WAS ISSUED AGAINST THE
TRANSISTOR LOT AND WAS BACKED BY TESTS OF OTHER TRANSISTORS FROM THE
SAME LOT. THE MAF TEST DATA FOR ALL INSTALLED TRANSDUCERS WAS REVIEWED
ALONG WITH TEST DATA OBTAINED BY RETURNING ALL UNINSTALLED PARTS TO
THE SUPPLIER FOR CALIBRATION TESTING. NO DEFINITE LINK COULD BE FOUND
BETWEEN THE TRANSISTOR LOTS AND THE PERFORMANCE OF THE COMPLETED
TRANSDUCERS
DURING THE INVESTIGATION ASSOCIATED WITH THE FIRST FAILURE, THREE
OTHER PROBLEMS OCCURRED. THE FIRST WAS CALIBRATION SHIFTS NOTED IN THE
TRANSDUCERS RETURNED TO THE SUPPLIER. AS A RESULT OF SHIFTS, A LONG
TERM TEST HAS BEEN INITIATED TO VERIFY TRANSDUCER STABILITY. THE
SECOND AND THIRD PROBLEMS WERE TWO SEPARATE TRANSDUCER FAILURES
RESULTING FROM WORKMANSHIP ESCAPES DURING TRANSDUCER MANUFACTURE
THESE FAILURES WERE ADDRESSED BY PLACING ADDITIONAL CONTROLS IN THE
SUPPLIERS MANUFACTURING TRAVELERS AND DRAWINGS
TASK CLOSED
THIS CAPS IS CLOSED. NO FURTHER ACTION IS REQUIRED

MSFC Response/Concurrence

 

MSFC Problem Reporting and Corrective Action (PRACA) System

ASSESSMENT ADDENDUM REPORT


 

MSFC Report#
A15483

IFA#
--

Contractor RPT#
E-152

JSC#
--

KSC#
--

EICN#
--

Asmnt Part#
80931003731-009

Asmnt Part Name
LOX PRES TRANSDUCER

Asmnt Serial/Lot#
0000028

HCRIT CD
--

FCRIT CD
3

CAUSE CD
MAW - MFG-ASY-WORK

FAIL MODE
EG - SIG HI OR LO

Asmnt FMEA
3.2.1.1C

Asmnt FM
1C

FMEA CSE
E

FMEA SCSE
4

Asmnt FMEA
--

Asmnt FM
--

FMEA CSE
--

FMEA SCSE
--

Asmnt FMEA
--

Asmnt FM
--

FMEA CSE
--

FMEA SCSE
--

Correlated Part#
--

Correlated Part#
--

Correlated Part#
--

Associated LRU#
--

Associated LRU#
--

Associated LRU#
--

MAJOR DESIGN CHANGES

APRV DATE
--

DESCRIPTION OF CHANGES
--

ASSESSMENT TEXT