Narrative:

Aircraft had a previous un-commanded transfer of fuel from the left wing to the center tank. Mechanics on board that flight were consulted and signed off the problem after the transfer was stopped. No repairs were made. I do not believe further troubleshooting was accomplished. During flight the fuel configuration light and warning came on. 1400 pounds of fuel were in the center tank even though there was much less in the tank earlier. The left wing tank had less fuel than the right wing. We burned the fuel from the center tank to re balance the load; but the problem recurred several more times during the flight. I wrote the problem in the logbook and discussed it with contract maintenance people. I was later called by a company maintenance supervisor who asked me to ferry the aircraft to a mx base. He told me that the outbound crew had refused to fly the airplane. I asked if they had figured out the problem. He told me they did not know; but that if I made it okay over the ocean that I should be able to fly it back. I pointed out that if they did not know the problem; they could not promise me it would not get worse. I refused the ferry flight. The discrepancy received inadequate attention after the first occurrence. The imbalance on that flight was reported as 1300 pounds. That is significant enough to affect safety. But apparently; no further work was done to identify the cause. Second problem: I have had problems in the past with maintenance people trying to convince me to accept a ferry permit for a plane with a problem of unknown cause. I do not think it is proper; and I know it is unsafe to fly an aircraft with unknown problems in major systems. However; I have been told that 'we do it all the time'. I did not think it was possible to get a ferry permit unless the problem could be identified. Otherwise it is impossible to know if the problem will progress; or if it is the result of some other hidden problem. Regardless; maintenance control is issuing permits for ferry flights with unknown problems. Third problem: I felt that some pressure was being applied to change my decision; and that of the other captain who also refused the ferry flight. I think that a conservative decision should not be challenged without a really good reason. In this case; I think the only reason was cost savings. There was no justification for second guessing two experienced crews. Fourth problem: we were asked to take flight attendants along with us on the ferry. I do not believe it is appropriate to take 'non-essential' passengers on a flight with problems in major mechanical systems. I believe that if a line pilot is uncomfortable with a maintenance ferry; they should have an absolute right to refuse. If supervisory pilots choose to accept the ferry flights; that is up to them. But pressure should never be brought to bear on a line crew. That is one of our last safety barriers and should not be compromised. An aircraft should not be moved unless the problem is identified and everyone involved believes there is still a sufficient safety margin for the flight. It would not even be an issue except that we already know there is some degradation in safety. If we do not know the problem; we can not know the degree of degradation or the potential for progressively worse failure. I believe that the company needs to examine; and change; the philosophy behind approving ferry flights. A lot of 'safety of flight' items cannot be placed on MEL. If it is not in the MEL; then it is obviously a safety issue and should not be taken casually. It should only be ferried if the aircraft manufacturer; or the engineering department can assure that no further degradation will occur during flight. They cannot do that unless they know the cause of the problem. The attitude that it is 'probably okay' is very dangerous and should be changed. Summary. Do not ferry a plane if you do not know exactly what is wrong with it.

Google
 

Original NASA ASRS Text

Title: B767 Captain accepts aircraft with history of fuel transferring from left tank to center tank uncommanded; which reoccurs on transoceanic flight. When asked to ferry aircraft on return he declines.

Narrative: Aircraft had a previous un-commanded transfer of fuel from the left wing to the center tank. Mechanics on board that flight were consulted and signed off the problem after the transfer was stopped. No repairs were made. I do not believe further troubleshooting was accomplished. During flight the FUEL CONFIG light and warning came on. 1400 pounds of fuel were in the center tank even though there was much less in the tank earlier. The left wing tank had less fuel than the right wing. We burned the fuel from the center tank to re balance the load; but the problem recurred several more times during the flight. I wrote the problem in the logbook and discussed it with contract maintenance people. I was later called by a company maintenance supervisor who asked me to ferry the aircraft to a MX Base. He told me that the outbound crew had refused to fly the airplane. I asked if they had figured out the problem. He told me they did not know; but that if I made it okay over the ocean that I should be able to fly it back. I pointed out that if they did not know the problem; they could not promise me it would not get worse. I refused the ferry flight. The discrepancy received inadequate attention after the first occurrence. The imbalance on that flight was reported as 1300 pounds. That is significant enough to affect safety. But apparently; no further work was done to identify the cause. Second problem: I have had problems in the past with maintenance people trying to convince me to accept a ferry permit for a plane with a problem of unknown cause. I do not think it is proper; and I know it is unsafe to fly an aircraft with unknown problems in major systems. However; I have been told that 'we do it all the time'. I did not think it was possible to get a ferry permit unless the problem could be identified. Otherwise it is impossible to know if the problem will progress; or if it is the result of some other hidden problem. Regardless; Maintenance control is issuing permits for ferry flights with unknown problems. Third problem: I felt that some pressure was being applied to change my decision; and that of the other captain who also refused the ferry flight. I think that a conservative decision should not be challenged without a really good reason. In this case; I think the only reason was cost savings. There was no justification for second guessing two experienced crews. Fourth problem: We were asked to take flight attendants along with us on the ferry. I do not believe it is appropriate to take 'non-essential' passengers on a flight with problems in major mechanical systems. I believe that if a line pilot is uncomfortable with a maintenance ferry; they should have an absolute right to refuse. If supervisory pilots choose to accept the ferry flights; that is up to them. But pressure should never be brought to bear on a line crew. That is one of our last safety barriers and should not be compromised. An aircraft should not be moved unless the problem is identified and everyone involved believes there is still a sufficient safety margin for the flight. It would not even be an issue except that we already know there is some degradation in safety. If we do not know the problem; we can not know the degree of degradation or the potential for progressively worse failure. I believe that the company needs to examine; and change; the philosophy behind approving ferry flights. A lot of 'safety of flight' items cannot be placed on MEL. If it is not in the MEL; then it is obviously a safety issue and should not be taken casually. It should only be ferried if the aircraft manufacturer; or the engineering department can assure that no further degradation will occur during flight. They cannot do that unless they know the cause of the problem. The attitude that it is 'PROBABLY okay' is very dangerous and should be changed. Summary. Do not ferry a plane if you do not know exactly what is wrong with it.

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.