Narrative:

This happened during preflight. I have been checking the power control units hydraulic lines for over two years for rubbing and chaffing. The last being aircraft X in march 2009. During my preflight I was looking in the left wheel well at the power control units on the forward wall and noticed that the one hydraulic line was rubbing on a bracket that supports the pivot points of both 'a' and 'B' systems. This has been a recurring issue I've been dealing with for over two years. There was an engineering order issued back in 2007 for chaffing but nothing else. The order; I believe; was issued in june of 2007 and complies by october of 2007. This bracket wear is directly related to the rubbing of the lines and is the second aircraft in four months that canceled due to my preflight inspections. Also not related to this; aircraft Y had a hydraulic leak on the aft left wheel well wall that maintenance said was fixable. Maintenance was advised on both problems and I made sure that they saw the problem. Not being followed up at later date on a daily check or any other checks. I suggested as before that a follow up after the engineering order should be done so that I shouldn't find the problem again on a future preflight. I sometimes find it hard to convince maintenance that there is a problem and no one else finds it. I also carry around the engineering order and the official boeing drawings.callback conversation with reporter revealed the following information: reporter stated one of the hydraulic hoses from the upper aileron power control unit was frayed and had a flat spot on the hose lower surface; from wearing against an aluminum support bracket for the power control units. He has found hydraulic hoses misrouted in the bracket area. Reporter stated mechanics are not checking these hoses for known wear issues. The seriousness of his carrier's engineering order; issued back in 2007 doesn't seem to be understood by their mechanics.

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Original NASA ASRS Text

Title: During a preflight check on a B737; a First Officer noticed one of the Aileron Power Control Units hydraulic lines was rubbing on a bracket that supports the pivot points of both 'A' and 'B' systems in the left main gear forward wheel well.

Narrative: This happened during preflight. I have been checking the Power Control Units hydraulic lines for over two years for rubbing and chaffing. The last being Aircraft X in March 2009. During my preflight I was looking in the left wheel well at the Power Control Units on the forward wall and noticed that the one hydraulic line was rubbing on a bracket that supports the pivot points of both 'A' and 'B' systems. This has been a recurring issue I've been dealing with for over two years. There was an Engineering Order issued back in 2007 for chaffing but nothing else. The order; I believe; was issued in June of 2007 and complies by October of 2007. This bracket wear is directly related to the rubbing of the lines and is the second aircraft in four months that canceled due to my preflight inspections. Also not related to this; Aircraft Y had a hydraulic leak on the aft left wheel well wall that maintenance said was fixable. Maintenance was advised on both problems and I made sure that they saw the problem. Not being followed up at later date on a daily check or any other checks. I suggested as before that a follow up after the Engineering Order should be done so that I shouldn't find the problem again on a future preflight. I sometimes find it hard to convince Maintenance that there is a problem and no one else finds it. I also carry around the Engineering Order and the official Boeing drawings.Callback conversation with Reporter revealed the following information: Reporter stated one of the hydraulic hoses from the upper Aileron Power Control Unit was frayed and had a flat spot on the hose lower surface; from wearing against an aluminum support bracket for the Power Control Units. He has found hydraulic hoses misrouted in the bracket area. Reporter stated mechanics are not checking these hoses for known wear issues. The seriousness of his carrier's Engineering Order; issued back in 2007 doesn't seem to be understood by their mechanics.

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.