Narrative:

July 2009; ZZZ to ZZZZ1 (international station); flying B747-400. (Issue of) window defects inappropriately deferred. Enroute to ZZZZ1; we reported writeups to maintenance via ACARS. I noticed later that all of these defects were deferred per amm chapters 56-11-00 or 56-12-01. First officer's fixed side-window visibility is affected by defects; light brown-green defect 6 inches down from upper left corner; 2 inches from edge. Captain's windshield (L-1) visibility is affected by defects at right edge; with 24-inch by .5-inch delamination and crazed on upper 6-inch section near bus bar; with 2-inch light brown discoloration. Captain's L-1 also has 18-inch by .5-inch delamination across top edge. It is my understanding from reading amm 56-11-00; that these defects are 'no-go' items requiring a window change. Regarding the first officer's fixed side window (R-2); this appeared to be a small round discolored burned delamination in the middle layer in the body of window R2. Amm 56-11 is specific about the requirement to replace the window with this condition. Regarding the captain's forward windshield (L-1); there was brown discoloration at the bus bar and quite a bit of evidence of possible overheating. Also; the lead mechanic in ZZZZ1 looked at it when we arrived and stated to me that it appeared to be damage due to overheating. Again; amm 56-11 is quite specific about this being a replacement issue. Yet; both of these reported defects were deferred and the aircraft allowed to continue in service. I believe that amm 56-11 required a window replacement for both of these conditions. I called maintenance control from the layover hotel in ZZZZ1 to discuss the issue. The aircraft is scheduled to depart ZZZZ1-ZZZ2. I expressed my concerns that these items had been inappropriately deferred. He checked the amm and agreed that such defects could require a window replacement. However; he could not make a definitive judgment on these specific writeups because he could not examine them. He stated that he would advise them. I remain concerned that critical safety issues are being inappropriately deferred or cleared in the interest of dispatch reliability. Window defects seem to be on the increase. Many mechanics seem to lack a good understanding of which window defects are serious and which are not. Pilots; who have not been provided guidance on evaluating window defects tend to ignore all but the most obvious defects (such as large cracks). I believe that mechanics and pilots alike need to be better educated on how to assess window defects and their potential impact upon flight safety.

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Original NASA ASRS Text

Title: A Captain flying a B747-400 reports the Captain's L-1 Forward windshield and the First Officer's R-2 window; both with delaminations and light brown burn areas near the window heat Bus Bars were deferred at an International Station contrary to requirements.

Narrative: July 2009; ZZZ to ZZZZ1 (International Station); flying B747-400. (Issue of) Window defects inappropriately deferred. Enroute to ZZZZ1; we reported writeups to Maintenance via ACARS. I noticed later that all of these defects were deferred per AMM Chapters 56-11-00 or 56-12-01. First Officer's Fixed Side-Window visibility is affected by defects; light brown-green defect 6 inches down from upper left corner; 2 inches from edge. Captain's Windshield (L-1) visibility is affected by defects at right edge; with 24-inch by .5-inch delamination and crazed on upper 6-inch section near Bus Bar; with 2-inch light brown discoloration. Captain's L-1 also has 18-inch by .5-inch delamination across top edge. It is my understanding from reading AMM 56-11-00; that these defects are 'NO-GO' items requiring a window change. Regarding the First Officer's Fixed Side Window (R-2); this appeared to be a small round discolored burned delamination in the middle layer in the body of window R2. AMM 56-11 is specific about the requirement to replace the window with this condition. Regarding the Captain's Forward Windshield (L-1); there was brown discoloration at the Bus Bar and quite a bit of evidence of possible overheating. Also; the Lead Mechanic in ZZZZ1 looked at it when we arrived and stated to me that it appeared to be damage due to overheating. Again; AMM 56-11 is quite specific about this being a replacement issue. Yet; both of these reported defects were deferred and the aircraft allowed to continue in service. I believe that AMM 56-11 required a window replacement for both of these conditions. I called Maintenance Control from the layover hotel in ZZZZ1 to discuss the issue. The aircraft is scheduled to depart ZZZZ1-ZZZ2. I expressed my concerns that these items had been inappropriately deferred. He checked the AMM and agreed that such defects could require a window replacement. However; he could not make a definitive judgment on these specific writeups because he could not examine them. He stated that he would advise them. I remain concerned that critical safety issues are being inappropriately deferred or cleared in the interest of dispatch reliability. Window defects seem to be on the increase. Many Mechanics seem to lack a good understanding of which window defects are serious and which are not. Pilots; who have not been provided guidance on evaluating window defects tend to ignore all but the most obvious defects (such as large cracks). I believe that Mechanics and Pilots alike need to be better educated on how to assess window defects and their potential impact upon flight safety.

Data retrieved from NASA's ASRS site as of April 2012 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.