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A B757-200 rejected takeoff due to #1 airspeed indication inoperative caused by air data computer pitot static quick disconnect connectors.
| Attributes | |
| ACN | 483017 |
| Time | |
| Date | 200008 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : apc.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : parked ground : maintenance |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : inspector |
| Qualification | technician : powerplant technician : airframe |
| ASRS Report | 483017 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper maintenance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : capt. airspeed indicator other flight crewa |
| Resolutory Action | flight crew : rejected takeoff |
| Consequence | other other |
| Factors | |
| Maintenance | contributing factor : manuals contributing factor : work cards performance deficiency : testing performance deficiency : repair performance deficiency : installation performance deficiency : inspection |
| Supplementary | |
| Problem Areas | Chart Or Publication Company Flight Crew Human Performance Maintenance Human Performance Aircraft |
| Primary Problem | Chart Or Publication |
| Situations | |
| Publication | MNTC MANUAL |
Narrative:
During preflight test of aircraft after letter check, l-hand half of overspd light came on. Avionics swapped air data computers and problem followed air data computers. New air data computer was installed in l-hand position and problem was corrected. However, on the first flight, pilot's airspeed indicator was inoperative. Logbook was signed off that l-hand air data computer pitot static connectors were reseated. These are quick disconnect type couplings. Per the B757 maintenance manual, quick disconnect couplings do not require a pitot static test. As the inspector on this aircraft, I physically checked the l-hand and r-hand air data computers for installation in their racks, and checked the installation of the pitot static lines on both boxes. Recommendation: change maintenance manual to perform a pitot static leak test any time connectors are disturbed.
Original NASA ASRS Text
Title: A B757-200 REJECTED TKOF DUE TO #1 AIRSPD INDICATION INOP CAUSED BY AIR DATA COMPUTER PITOT STATIC QUICK DISCONNECT CONNECTORS.
Narrative: DURING PREFLT TEST OF ACFT AFTER LETTER CHK, L-HAND HALF OF OVERSPD LIGHT CAME ON. AVIONICS SWAPPED AIR DATA COMPUTERS AND PROB FOLLOWED AIR DATA COMPUTERS. NEW AIR DATA COMPUTER WAS INSTALLED IN L-HAND POS AND PROB WAS CORRECTED. HOWEVER, ON THE FIRST FLT, PLT'S AIRSPD INDICATOR WAS INOP. LOGBOOK WAS SIGNED OFF THAT L-HAND AIR DATA COMPUTER PITOT STATIC CONNECTORS WERE RESEATED. THESE ARE QUICK DISCONNECT TYPE COUPLINGS. PER THE B757 MAINT MANUAL, QUICK DISCONNECT COUPLINGS DO NOT REQUIRE A PITOT STATIC TEST. AS THE INSPECTOR ON THIS ACFT, I PHYSICALLY CHKED THE L-HAND AND R-HAND AIR DATA COMPUTERS FOR INSTALLATION IN THEIR RACKS, AND CHKED THE INSTALLATION OF THE PITOT STATIC LINES ON BOTH BOXES. RECOMMENDATION: CHANGE MAINT MANUAL TO PERFORM A PITOT STATIC LEAK TEST ANY TIME CONNECTORS ARE DISTURBED.
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.