37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 1008901 |
Time | |
Date | 201205 |
Local Time Of Day | 0001-0600 |
Place | |
Locale Reference | ZZZ.Airport |
State Reference | US |
Aircraft 1 | |
Make Model Name | B747-400 |
Operating Under FAR Part | Part 121 |
Flight Phase | Parked |
Component | |
Aircraft Component | Cockpit Window |
Person 1 | |
Function | Pilot Flying Captain |
Qualification | Flight Crew Air Transport Pilot (ATP) |
Experience | Flight Crew Last 90 Days 240 Flight Crew Total 19000 Flight Crew Type 5000 |
Events | |
Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural MEL |
Narrative:
B747-400 L3 cockpit window crack and vinyl deformation. During preflight; I noticed what appeared to be a crack in the upper right hand corner of cockpit windshield L3. The crack appeared to be .75 inches in length; approximately 1 inch out from the corner. It appeared to have sub-fractures emanating from the main crack. There were also signs of some delamination; but that was not of concern to me. We reported this defect to maintenance by ACARS and radio. A mechanic and a maintenance supervisor came out and inspected the window. They both determined the crack to be located in one of the fail-safe layers and needed to be replaced. About 30 minutes later; the mechanic supervisor returned to tell me that he had inspected the window from the outside and determined it to be a simple deferrable delamination. They offered to let me see it from the outside; to which I agreed. My observation from the outside revealed even more damage to the window than originally observed; some of which could not be seen from the cockpit. There were obvious signs of vinyl deformation at the window edge (pictures to be forwarded to engineering by email). The mechanic was adamant that it was a simple delamination but I disagreed; referring him to the boeing definition of delamination. A delamination is defined by boeing as being flat; smooth; and with a circular edge. This defect was neither flat; smooth; or with a circular edge. The damage was similar to photographic examples provided by flight operations detailing unacceptable window defects. The vinyl deformation visible from the outside of the window also appears to be very similar to what is shown in boeing fleet team digest 747-400-ftd-56-05001; in which boeing indicates such a defect requires a window change. My knowledge of window defects is fairly extensive and is the result of my long history as a safety representative and my work as the current fleet safety coordinator. After a good bit of discussion; the mechanic supervisor advised me that they would be continuing with replacing the window. It's unfortunate that this defect caused the delay of our flight; but what is more disappointing is that we could have avoided the delay entirely had maintenance properly inspected the windows prior to departure when the aircraft arrived hours earlier. The window replacement took about 3 hours once the work was started. We arrived in our destination approximately 5 hours late. The maintenance supervisor did advise me that he had asked a mechanic to inspect the cockpit windows prior to our arrival at the cockpit. However; the mechanic performing the inspection failed to note the defect. It is my experience that; generally speaking; our mechanics do not have a good grasp on what constitute's notable window defects or what is contained in the maintenance manual with respect to cockpit windows. On many occasions; I have had mechanics attempt to defer or simply brush off nogo window defects. In one recent situation; both the mechanic and the mechanic supervisor attempted to defer a nogo window until a line engineer from the maintenance base advised them of its nogo status. Problem with the crew desk; crew rest rooms not offered I made several calls to operations to try to find out when the flight would depart. I was concerned about a lengthy delay and its potential detrimental effect on fatigue. Our original departure was supposed to be at noon; with a crew check-in of two hours prior. I could not get any information from operations. They kept saying that they would get back to me; which didn't happen. I tried to call the crew desk several times but my calls went unanswered. Finally; I was able to contact the crew desk who informed me that they had posted a departure; some 4:43 minutes late. My crew would now be pushing 19 hours on duty. This; to me; appeared to be an intentional act by the crew desk to avoid having to give us hotel rooms for the over 5 hour delay prior to an 11 hour-plus flight; with our dutyperiod exceeding 19:30. We should have been offered crew rest rooms immediately when the crew desk knew that this would be a lengthy delay or when the new departure time was posted.
Original NASA ASRS Text
Title: A B747 Captain discovered a delaminated L3 cockpit window during his preflight which Maintenance reluctantly changed causing a nearly five hour departure delay.
Narrative: B747-400 L3 COCKPIT WINDOW CRACK AND VINYL DEFORMATION. During preflight; I noticed what appeared to be a crack in the upper right hand corner of cockpit windshield L3. The crack appeared to be .75 inches in length; approximately 1 inch out from the corner. It appeared to have sub-fractures emanating from the main crack. There were also signs of some delamination; but that was not of concern to me. We reported this defect to Maintenance by ACARS and radio. A Mechanic and a Maintenance Supervisor came out and inspected the window. They both determined the crack to be located in one of the fail-safe layers and needed to be replaced. About 30 minutes later; the Mechanic Supervisor returned to tell me that he had inspected the window from the outside and determined it to be a simple deferrable delamination. They offered to let me see it from the outside; to which I agreed. My observation from the outside revealed even more damage to the window than originally observed; some of which could not be seen from the cockpit. There were obvious signs of vinyl deformation at the window edge (pictures to be forwarded to Engineering by email). The Mechanic was adamant that it was a simple delamination but I disagreed; referring him to the Boeing definition of delamination. A delamination is defined by Boeing as being flat; smooth; and with a circular edge. This defect was neither flat; smooth; or with a circular edge. The damage was similar to photographic examples provided by Flight Operations detailing unacceptable window defects. The vinyl deformation visible from the outside of the window also appears to be very similar to what is shown in Boeing Fleet Team Digest 747-400-FTD-56-05001; in which Boeing indicates such a defect requires a window change. My knowledge of window defects is fairly extensive and is the result of my long history as a safety representative and my work as the current Fleet Safety Coordinator. After a good bit of discussion; the Mechanic Supervisor advised me that they would be continuing with replacing the window. It's unfortunate that this defect caused the delay of our flight; but what is more disappointing is that we could have avoided the delay entirely had Maintenance properly inspected the windows prior to departure when the aircraft arrived hours earlier. The window replacement took about 3 hours once the work was started. We arrived in our destination approximately 5 hours late. The Maintenance Supervisor did advise me that he had asked a Mechanic to inspect the cockpit windows prior to our arrival at the cockpit. However; the Mechanic performing the inspection failed to note the defect. It is my experience that; generally speaking; our mechanics do not have a good grasp on what constitute's notable window defects or what is contained in the Maintenance Manual with respect to cockpit windows. On many occasions; I have had mechanics attempt to defer or simply brush off NOGO window defects. In one recent situation; both the Mechanic and the Mechanic Supervisor attempted to defer a NOGO window until a Line Engineer from the Maintenance Base advised them of its NOGO status. Problem with the crew desk; crew rest rooms not offered I made several calls to Operations to try to find out when the flight would depart. I was concerned about a lengthy delay and its potential detrimental effect on fatigue. Our original departure was supposed to be at noon; with a crew check-in of two hours prior. I could not get any information from Operations. They kept saying that they would get back to me; which didn't happen. I tried to call the crew desk several times but my calls went unanswered. Finally; I was able to contact the crew desk who informed me that they had posted a departure; some 4:43 minutes late. My crew would now be pushing 19 hours on duty. This; to me; appeared to be an intentional act by the crew desk to avoid having to give us hotel rooms for the over 5 hour delay prior to an 11 hour-plus flight; with our dutyperiod exceeding 19:30. We should have been offered crew rest rooms immediately when the crew desk knew that this would be a lengthy delay or when the new departure time was posted.
Data retrieved from NASA's ASRS site as of July 2013 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.