Narrative:

I was assigned an aircraft for a turn from one foreign airport to another. The maintenance history showed that on the two preceding days the aircraft had a failure of the slat primary hydraulic system which resulted in the flaps operating in the secondary (electrical) mode. This was associated with several caution messages. Upon arrival at the aircraft; I learned that this failure had occurred a third time upon arrival into this airport. The mechanics were working on the aircraft. As we waited for them to finish I expected that they would either fix the aircraft or defer whatever was causing this problem. To my surprise the mechanics signed it off as 'primary system test; FSEU1 carried out; satis.' I had a discussion with maintenance control; dispatch; and the duty manager and expressed my concern that there clearly was a problem; which resulted in a degraded aircraft flight control state on three occasions in the last three days. I inquired as to how there could be a presumption of nothing being wrong with the aircraft; and how they could just keep ground testing it as 'satisfactory.' I learned that there was a logbook write up calling for a solenoid to be replaced. Thus there clearly was something wrong; something was going to be replaced; but yet there was no 'deferral' associated with the problem. I asked why they couldn't just defer the item so that I could see that it was legal; and so that I could have all of the associated potential considerations available to me in making a good decision about the airworthiness of the aircraft and how it might be affected by the conditions of my flight. The answer I received was that this aircraft condition was 'not deferrable.'thus it seemed to me that we would have been operating in a murky area of legality between a clean aircraft and a deferred degraded aircraft. None of this seemed right; quite legal; or ultimately very smart. As I did not have enough information at this point; and since all I could do was take maintenance control's word for the situation as being legal and that the aircraft was airworthy; I offered to fly the aircraft to our first destination with the stipulation that if the slats failed on arrival to our next foreign airport that I would not fly it back unless and until it was properly fixed. A decision to cancel the round trip flight. The aircraft sat on the ground for about seven hours and then returned to a domestic airport. No further maintenance action was taken in the foreign airport. At the end of the day my question is; was this a proper and legal method of operating this aircraft? Can a malfunction that occurs in the air be ignored over and over because it 'ground tests' okay? If a defect is not deferrable; shouldn't that be an indication that it is foolish to fly the aircraft on the assumption that something that has happened three times won't happen again? I would appreciate feedback on this matter.

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Original NASA ASRS Text

Title: An air carrier Maintenance Personnel knew the B777 SLAT PRIMARY HYDRAULIC system had a recurring fault; but had mechanics sign it off as 'Primary System Test FSEU1 Carried Out; SATIS;' but when the Captain threatened to ground the aircraft at a foreign station; the flight was canceled.

Narrative: I was assigned an aircraft for a turn from one foreign airport to another. The maintenance history showed that on the two preceding days the aircraft had a failure of the SLAT PRIMARY HYDRAULIC system which resulted in the flaps operating in the SECONDARY (ELECTRICAL) Mode. This was associated with several caution messages. Upon arrival at the aircraft; I learned that this failure had occurred a third time upon arrival into this airport. The mechanics were working on the aircraft. As we waited for them to finish I expected that they would either fix the aircraft or defer whatever was causing this problem. To my surprise the mechanics signed it off as 'Primary System Test; FSEU1 Carried Out; Satis.' I had a discussion with Maintenance Control; Dispatch; and the Duty Manager and expressed my concern that there clearly was a problem; which resulted in a degraded aircraft flight control state on three occasions in the last three days. I inquired as to how there could be a presumption of nothing being wrong with the aircraft; and how they could just keep ground testing it as 'satisfactory.' I learned that there was a logbook write up calling for a solenoid to be replaced. Thus there clearly was something wrong; something was going to be replaced; but yet there was no 'deferral' associated with the problem. I asked why they couldn't just defer the item so that I could see that it was legal; and so that I could have all of the associated potential considerations available to me in making a good decision about the airworthiness of the aircraft and how it might be affected by the conditions of my flight. The answer I received was that this aircraft condition was 'not deferrable.'Thus it seemed to me that we would have been operating in a murky area of legality between a clean aircraft and a deferred degraded aircraft. None of this seemed right; quite legal; or ultimately very smart. As I did not have enough information at this point; and since all I could do was take Maintenance Control's word for the situation as being legal and that the aircraft was airworthy; I offered to fly the aircraft to our first destination with the stipulation that if the slats failed on arrival to our next foreign airport that I would not fly it back unless and until it was properly fixed. A decision to cancel the round trip flight. The aircraft sat on the ground for about seven hours and then returned to a domestic airport. No further maintenance action was taken in the foreign airport. At the end of the day my question is; was this a proper and legal method of operating this aircraft? Can a malfunction that occurs in the air be ignored over and over because it 'ground tests' okay? If a defect is not deferrable; shouldn't that be an indication that it is foolish to fly the aircraft on the assumption that something that has happened three times won't happen again? I would appreciate feedback on this matter.

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.