|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : zzz.airport|
|Operator||common carrier : air carrier|
|Make Model Name||B737-200|
|Operating Under FAR Part||Part 121|
|Flight Phase||climbout : takeoff|
ground : maintenance
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Qualification||technician : powerplant|
technician : airframe
|Experience||maintenance technician : 13|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Anomaly||aircraft equipment problem : critical|
maintenance problem : improper maintenance
non adherence : company policies
non adherence : published procedure
|Independent Detector||aircraft equipment other aircraft equipment : adc failure flags|
other flight crewa
other flight crewb
|Resolutory Action||none taken : detected after the fact|
While troubleshooting the first officer's flight director, the #1 and #2 air data computers were swapped. After running test and determining the air data computer was not the problem, they were swapped back to original position. #1 air data computer was secured in rack and attention turned to #2 air data computer rack cannon plugs. After examining plugs, #2 air data computer was installed and the electronic equipment door closed. Troubleshooting continued for about 1 hour and then problem (flight director) was continued on MEL. Aircraft was released and flight attempted. After takeoff, the captain's air data instruments were inoperative with no failure flags and first officer's air data instruments were inoperative with failure flags. Aircraft made air turn back. After returning to gate maintenance found that pitot and static hoses to #1 air data computer were not installed. #2 air data computer had failure flags on previous 2 legs with the air data computers replaced on both occasions. The pitot and static lines for #1 air data computer were inadvertently left disconnected during troubleshooting. Lines would have been discovered before electric door closed if time was taken to rechk air data computer installation. Personal problems at home were a factor during troubleshooting and maintenance. Mind should have been on work and not on other problems.
Original NASA ASRS Text
Title: B737-200 ACFT MECH NEGLECTS TO REATTACH THE PITOT STATIC LINES TO THE AIR DATA COMPUTERS AND RELEASES THE ACFT FOR FLT.
Narrative: WHILE TROUBLESHOOTING THE FO'S FLT DIRECTOR, THE #1 AND #2 AIR DATA COMPUTERS WERE SWAPPED. AFTER RUNNING TEST AND DETERMINING THE AIR DATA COMPUTER WAS NOT THE PROB, THEY WERE SWAPPED BACK TO ORIGINAL POS. #1 AIR DATA COMPUTER WAS SECURED IN RACK AND ATTN TURNED TO #2 AIR DATA COMPUTER RACK CANNON PLUGS. AFTER EXAMINING PLUGS, #2 AIR DATA COMPUTER WAS INSTALLED AND THE ELECTRONIC EQUIP DOOR CLOSED. TROUBLESHOOTING CONTINUED FOR ABOUT 1 HR AND THEN PROB (FLT DIRECTOR) WAS CONTINUED ON MEL. ACFT WAS RELEASED AND FLT ATTEMPTED. AFTER TKOF, THE CAPT'S AIR DATA INSTS WERE INOP WITH NO FAILURE FLAGS AND FO'S AIR DATA INSTS WERE INOP WITH FAILURE FLAGS. ACFT MADE AIR TURN BACK. AFTER RETURNING TO GATE MAINT FOUND THAT PITOT AND STATIC HOSES TO #1 AIR DATA COMPUTER WERE NOT INSTALLED. #2 AIR DATA COMPUTER HAD FAILURE FLAGS ON PREVIOUS 2 LEGS WITH THE AIR DATA COMPUTERS REPLACED ON BOTH OCCASIONS. THE PITOT AND STATIC LINES FOR #1 AIR DATA COMPUTER WERE INADVERTENTLY LEFT DISCONNECTED DURING TROUBLESHOOTING. LINES WOULD HAVE BEEN DISCOVERED BEFORE ELECTRIC DOOR CLOSED IF TIME WAS TAKEN TO RECHK AIR DATA COMPUTER INSTALLATION. PERSONAL PROBS AT HOME WERE A FACTOR DURING TROUBLESHOOTING AND MAINT. MIND SHOULD HAVE BEEN ON WORK AND NOT ON OTHER PROBS.
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.