Narrative:

I and another mechanic were assigned aircraft xyz, an A320. We were assigned 2 tasks -- variable stator vanes lube on #1 engine, and troubleshoot and repair a #2 engine high pressure bleed message. We assisted each other in opening the left and right fan and reverser cowls on #1 engine and the left fan and reverser cowl on #2 engine. I began work on the #2 engine write-up while he began the variable stator vanes lube. When the variable stator vanes lube was accomplished, I assisted the mechanic in closing the cowls. We closed and latched the reverser cowl together, and I closed and latched the fan cowls, while the other mechanic left the area for a moment. He returned as I was completing the latching of the cowl. We then both began working the #2 engine fault. Upon completing this task, we closed up #2 engine and performed an idle run check on the engine. After completing paperwork and turning in equipment, I returned to the aircraft and performed a FOD check around both engines, looking at the security of the cowls (visually) and to make sure the area was clear of tools and equipment. A few hours later, during takeoff, the #1 engine fan cowls departed the aircraft during rotation. The fan cowls damaged the pylon, #1, #2, and #3 slats, the fuselage over the wing, and the l-hand horizontal stabilizer. After the maintenance was completed, the aircraft was taxied to the gate. The taxi crew, the gate captain, and the flight crew all did walkarounds prior to aircraft departure. None noted anything abnormal (latches hanging down or cowls not flush). The night after the incident, during the investigation, fan cowls on several aircraft were checked for latch tension. Approximately 1/2 the latches were found to be 5-15 pounds under tension per the maintenance manual. The investigation is continuing. Callback conversation with reporter revealed the following information: the reporter stated the cowling was latched when the aircraft was delivered to the terminal and checked by the taxi crew, captain and gate mechanic and nothing abnormal found. The reporter said the next night after the incident several aircraft were checked for latch tension and about 1/2 were found 5-15 pounds under the tension required by the maintenance manual. The reporter said this incident was still under investigation. The reporter stated this is a recurring event as 2 previous incidents of loss of cowling are known to the reporter.

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Original NASA ASRS Text

Title: AN AIRBUS A320 ON TKOF HAD THE L ENG FAN COWLING DEPART THE ACFT INCURRING DAMAGE TO THE LEADING EDGE SLATS, PYLON, FUSELAGE AND THE L HORIZ STABILIZER CAUSE UNDER INVESTIGATION.

Narrative: I AND ANOTHER MECH WERE ASSIGNED ACFT XYZ, AN A320. WE WERE ASSIGNED 2 TASKS -- VARIABLE STATOR VANES LUBE ON #1 ENG, AND TROUBLESHOOT AND REPAIR A #2 ENG HIGH PRESSURE BLEED MESSAGE. WE ASSISTED EACH OTHER IN OPENING THE L AND R FAN AND REVERSER COWLS ON #1 ENG AND THE L FAN AND REVERSER COWL ON #2 ENG. I BEGAN WORK ON THE #2 ENG WRITE-UP WHILE HE BEGAN THE VARIABLE STATOR VANES LUBE. WHEN THE VARIABLE STATOR VANES LUBE WAS ACCOMPLISHED, I ASSISTED THE MECH IN CLOSING THE COWLS. WE CLOSED AND LATCHED THE REVERSER COWL TOGETHER, AND I CLOSED AND LATCHED THE FAN COWLS, WHILE THE OTHER MECH LEFT THE AREA FOR A MOMENT. HE RETURNED AS I WAS COMPLETING THE LATCHING OF THE COWL. WE THEN BOTH BEGAN WORKING THE #2 ENG FAULT. UPON COMPLETING THIS TASK, WE CLOSED UP #2 ENG AND PERFORMED AN IDLE RUN CHK ON THE ENG. AFTER COMPLETING PAPERWORK AND TURNING IN EQUIP, I RETURNED TO THE ACFT AND PERFORMED A FOD CHK AROUND BOTH ENGS, LOOKING AT THE SECURITY OF THE COWLS (VISUALLY) AND TO MAKE SURE THE AREA WAS CLR OF TOOLS AND EQUIP. A FEW HRS LATER, DURING TKOF, THE #1 ENG FAN COWLS DEPARTED THE ACFT DURING ROTATION. THE FAN COWLS DAMAGED THE PYLON, #1, #2, AND #3 SLATS, THE FUSELAGE OVER THE WING, AND THE L-HAND HORIZ STABILIZER. AFTER THE MAINT WAS COMPLETED, THE ACFT WAS TAXIED TO THE GATE. THE TAXI CREW, THE GATE CAPT, AND THE FLC ALL DID WALKAROUNDS PRIOR TO ACFT DEP. NONE NOTED ANYTHING ABNORMAL (LATCHES HANGING DOWN OR COWLS NOT FLUSH). THE NIGHT AFTER THE INCIDENT, DURING THE INVESTIGATION, FAN COWLS ON SEVERAL ACFT WERE CHKED FOR LATCH TENSION. APPROX 1/2 THE LATCHES WERE FOUND TO BE 5-15 LBS UNDER TENSION PER THE MAINT MANUAL. THE INVESTIGATION IS CONTINUING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE COWLING WAS LATCHED WHEN THE ACFT WAS DELIVERED TO THE TERMINAL AND CHKED BY THE TAXI CREW, CAPT AND GATE MECH AND NOTHING ABNORMAL FOUND. THE RPTR SAID THE NEXT NIGHT AFTER THE INCIDENT SEVERAL ACFT WERE CHKED FOR LATCH TENSION AND ABOUT 1/2 WERE FOUND 5-15 LBS UNDER THE TENSION REQUIRED BY THE MAINT MANUAL. THE RPTR SAID THIS INCIDENT WAS STILL UNDER INVESTIGATION. THE RPTR STATED THIS IS A RECURRING EVENT AS 2 PREVIOUS INCIDENTS OF LOSS OF COWLING ARE KNOWN TO THE RPTR.

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.