Narrative:

On nov/xa/99 aircraft xyz had to abort takeoff due to #2 airspeed (first officer) reading drastically different than the captain. Upon troubleshooting, the mechanic found #2 air data computer pitot stall lines disconnected. This aircraft was just released from ZZZ heavy maintenance. The reason for the visit was to install the sync localizer modification on the thrust reverser system. Since this aircraft was not in for a full blown quality check, the floors were not removed to gain access to a splice joint that was required in the airworthiness directive and engineering order. Originally, I thought I would be accessing this area from the forward cargo bay, forward wall (bulkhead) on the right side. I found that because of the oxygen bottle being in the way that it would make accessibility difficult. I decided I could do it by removing the #1 and #2 IRU's and sliding my body in that way. This was successful and all work was accomplished. By this time the end of shift had come and I decided to leave the IRU's out and leave a turn over with the last sentence stating left and right IRU's removed to facilitate maintenance on an OM26-1 (now many times the #2 air data computer pitot-static lines are disconnected to allow removal of the #1 (left) IRU. When IRU's were reinstalled they were not written up as reinstalling and no operations check was performed (R5 card). This is where I believe someone removed the #2 pitot static lines.

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Original NASA ASRS Text

Title: A B737-300 REJECTED A TKOF DUE TO DIFFERENCES BTWN THE CAPT'S AND FO'S AIRSPD INDICATORS CAUSED BY DISCONNECTED PITOT AND STATIC LINES.

Narrative: ON NOV/XA/99 ACFT XYZ HAD TO ABORT TKOF DUE TO #2 AIRSPD (FO) READING DRASTICALLY DIFFERENT THAN THE CAPT. UPON TROUBLESHOOTING, THE MECH FOUND #2 ADC PITOT STALL LINES DISCONNECTED. THIS ACFT WAS JUST RELEASED FROM ZZZ HVY MAINT. THE REASON FOR THE VISIT WAS TO INSTALL THE SYNC LOC MODIFICATION ON THE THRUST REVERSER SYS. SINCE THIS ACFT WAS NOT IN FOR A FULL BLOWN QUALITY CHK, THE FLOORS WERE NOT REMOVED TO GAIN ACCESS TO A SPLICE JOINT THAT WAS REQUIRED IN THE AIRWORTHINESS DIRECTIVE AND ENGINEERING ORDER. ORIGINALLY, I THOUGHT I WOULD BE ACCESSING THIS AREA FROM THE FORWARD CARGO BAY, FORWARD WALL (BULKHEAD) ON THE R SIDE. I FOUND THAT BECAUSE OF THE OXYGEN BOTTLE BEING IN THE WAY THAT IT WOULD MAKE ACCESSIBILITY DIFFICULT. I DECIDED I COULD DO IT BY REMOVING THE #1 AND #2 IRU'S AND SLIDING MY BODY IN THAT WAY. THIS WAS SUCCESSFUL AND ALL WORK WAS ACCOMPLISHED. BY THIS TIME THE END OF SHIFT HAD COME AND I DECIDED TO LEAVE THE IRU'S OUT AND LEAVE A TURN OVER WITH THE LAST SENTENCE STATING L AND R IRU'S REMOVED TO FACILITATE MAINT ON AN OM26-1 (NOW MANY TIMES THE #2 ADC PITOT-STATIC LINES ARE DISCONNECTED TO ALLOW REMOVAL OF THE #1 (L) IRU. WHEN IRU'S WERE REINSTALLED THEY WERE NOT WRITTEN UP AS REINSTALLING AND NO OPS CHK WAS PERFORMED (R5 CARD). THIS IS WHERE I BELIEVE SOMEONE REMOVED THE #2 PITOT STATIC LINES.

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.