Narrative:

I was scheduled to fly aircraft out of an out station. When the aircraft arrived; the inbound first officer told my first officer that they had written up a hydraulic leak at the previous maintenance station which had been signed off as no leak found. He seemed to be uncomfortable with the sign off. My first officer examined the area and found hydraulic fluid dripping from the aircraft near the APU non ram door. Contract maintenance was called; and they began to look for the leak under the direction of maintenance control. The mechanic examined the right thrust reverser control valve and did not find any fluid leaking from that location. Then; at the direction of maintenance control he signed off the log book as no leaks noted; ok for service. I pointed out the fluid that was still dripping from the bottom of the aircraft; as well as that just because he did not find a leak the first place he looked; did not mean that there was no leak; and that were still other possible sources. The mechanic's reply was that he could only do what maintenance control told him to do even though he acknowledged the fact that fluid was still dripping from the bottom of the aircraft. By that time; we had already been assigned to fly another aircraft. I called maintenance and spoke to a technician. I told him the same thing that I told the mechanic and pointed out that they were just setting themselves up for the next crew to refuse the aircraft; and should pursue the leak further. As it turned out; our second aircraft had its own maintenance issues; and we were assigned back to previous aircraft. I refused the aircraft as promised. We later departed on the second aircraft. Several days later; I checked the maintenance entry in the computer and saw that a hydraulic leak was found and repaired in the rudder shutoff valve. It was unclear to me where that repair had taken place. On my next trip; I was again assigned (same) aircraft. I checked the logbook to see where the repair had been made and was surprised to find that there was no entry anywhere in the logbook about the repair of the leak at the rudder shut off valve. My entry refusing the aircraft (the third; for the same leak) had again been signed off as no leaks noted; ok for service. The aircraft had flown 5 legs on the next day; none on the second day after my maintenance entry and began flying again on the third day; again; with no mention of any hydraulic repair. I then called maintenance control and again talked to the technician; who remembered our original conversation the previous week. He explained that the leak was discovered during a daily check at a maintenance station on the night of the night after I refused the aircraft. All of the repair work was done as a result of the daily check and therefore would not show up in the log book. This scenario brings up a number of questions in my mind. How can three different mechanics look at dripping hydraulic fluid and insist that no leak exists just because the source was not found the first place they looked? What are the chances that a leak would be found the next day; in the exact same place; by a mechanic doing a daily check at night? Is it just a coincidence that when the leak was discovered; the aircraft was at a major maintenance station; a much more convenient location to make repairs. Why does a contract mechanic feel that he could only do what maintenance control told him to do; and not continue looking for a leak that he knows exists. How can a significant repair be made to the aircraft without showing up in the logbook other than daily check complete? I find this especially disturbing given that it was directly related to 3 consecutive write ups that had been signed of with no action taken. I rely on the aircraft logbook to give an accurate picture of the aircraft's maintenance history. How many times can an item be written up with no action taken; before someone digs further into the problem? Given this situation and the abovequestions; I cannot help but wonder if there was not a deliberate attempt to whitewash the write ups in order to move the aircraft to a location which was more convenient for repairs. I have no problem taking an aircraft if I know what the problem is; and that it meets safety criteria. However; I will not take an aircraft with an unknown problem (i.e. Source of a hydraulic leak) just so I can get it to a more convenient location. We had hydraulic fluid leaking in the area of the APU which is extremely hot; not to mention hydraulic fluid in the APU inlet area being a source of smoke in the cabin. There are many possible dangerous consequences of a hydraulic leak in this area; and we did not know the source of the leak. I am submitting this through because I would like [an] answers to my questions. I have found this happening with increasing frequency; where I feel that maintenance write ups have been signed off with no action taken; when there is clearly a problem. I believe this is being done to keep aircraft moving until a more convenient time can be found to do repairs. I would like to be clear on one issue. I mentioned the maintenance control technician because he was the person who I talked to. I do not mean to accuse him personally of any wrongdoing. In fact I found him to be very helpful. This report was formally submitted in order to avoid it disappearing into the system 'black hole.'

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Original NASA ASRS Text

Title: A MD80 Captain reported refusing an aircraft with a repeat maintenance log hydraulic leak entry which was signed off even as hydraulic fluid dripped. Days later a rudder hydraulic shutoff valve was found leaking.

Narrative: I was scheduled to fly aircraft out of an out station. When the aircraft arrived; the inbound First Officer told my First Officer that they had written up a hydraulic leak at the previous maintenance station which had been signed off as no leak found. He seemed to be uncomfortable with the sign off. My First Officer examined the area and found hydraulic fluid dripping from the aircraft near the APU non ram door. Contract Maintenance was called; and they began to look for the leak under the direction of Maintenance Control. The mechanic examined the right thrust reverser control valve and did not find any fluid leaking from that location. Then; at the direction of Maintenance Control he signed off the log book as no leaks noted; OK for service. I pointed out the fluid that was still dripping from the bottom of the aircraft; as well as that just because he did not find a leak the first place he looked; did not mean that there was no leak; and that were still other possible sources. The Mechanic's reply was that he could only do what Maintenance Control told him to do even though he acknowledged the fact that fluid was still dripping from the bottom of the aircraft. By that time; we had already been assigned to fly another aircraft. I called Maintenance and spoke to a Technician. I told him the same thing that I told the mechanic and pointed out that they were just setting themselves up for the next crew to refuse the aircraft; and should pursue the leak further. As it turned out; our second aircraft had its own maintenance issues; and we were assigned back to previous aircraft. I refused the aircraft as promised. We later departed on the second aircraft. Several days later; I checked the maintenance entry in the computer and saw that a hydraulic leak was found and repaired in the rudder shutoff valve. It was unclear to me where that repair had taken place. On my next trip; I was again assigned (same) aircraft. I checked the logbook to see where the repair had been made and was surprised to find that there was no entry anywhere in the logbook about the repair of the leak at the rudder shut off valve. My entry refusing the aircraft (the third; for the same leak) had again been signed off as no leaks noted; OK for service. The aircraft had flown 5 legs on the next day; none on the second day after my maintenance entry and began flying again on the third day; again; with no mention of any hydraulic repair. I then called Maintenance Control and again talked to the Technician; who remembered our original conversation the previous week. He explained that the leak was discovered during a daily check at a maintenance station on the night of the night after I refused the aircraft. All of the repair work was done as a result of the daily check and therefore would not show up in the log book. This scenario brings up a number of questions in my mind. How can three different mechanics look at dripping hydraulic fluid and insist that no leak exists just because the source was not found the first place they looked? What are the chances that a leak would be found the next day; in the exact same place; by a mechanic doing a daily check at night? Is it just a coincidence that when the leak was discovered; the aircraft was at a major maintenance station; a much more convenient location to make repairs. Why does a contract mechanic feel that he could only do what Maintenance Control told him to do; and not continue looking for a leak that he knows exists. How can a significant repair be made to the aircraft without showing up in the logbook other than daily check complete? I find this especially disturbing given that it was directly related to 3 consecutive write ups that had been signed of with no action taken. I rely on the aircraft logbook to give an accurate picture of the aircraft's maintenance history. How many times can an item be written up with no action taken; before someone digs further into the problem? Given this situation and the abovequestions; I cannot help but wonder if there was not a deliberate attempt to whitewash the write ups in order to move the aircraft to a location which was more convenient for repairs. I have no problem taking an aircraft if I know what the problem is; and that it meets safety criteria. However; I will not take an aircraft with an unknown problem (i.e. source of a hydraulic leak) just so I can get it to a more convenient location. We had hydraulic fluid leaking in the area of the APU which is extremely hot; not to mention hydraulic fluid in the APU inlet area being a source of smoke in the cabin. There are many possible dangerous consequences of a hydraulic leak in this area; and we did not know the source of the leak. I am submitting this through because I would like [an] answers to my questions. I have found this happening with increasing frequency; where I feel that maintenance write ups have been signed off with no action taken; when there is clearly a problem. I believe this is being done to keep aircraft moving until a more convenient time can be found to do repairs. I would like to be clear on one issue. I mentioned the Maintenance Control Technician because he was the person who I talked to. I do not mean to accuse him personally of any wrongdoing. In fact I found him to be very helpful. This report was formally submitted in order to avoid it disappearing into the system 'Black Hole.'

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.