saikojer Posted November 16, 2014 Share Posted November 16, 2014 Hi guys, we are looking for solution to verify on the problem with "Pilot ADI"s Computer and Gyro Flag inview while select on "INS ATT" mode (Satisfactory while put to "GYRO Mode"). Accompanied with "AP Failed" and "Computer Fail" light illuminate.Pilot had been reported, it happen inflight.While, One of the symptoms, it only happen in flight but sometimes happen on ground and after remove and refitted a few component, it dissappeared on ground.But its happen again inflight. We already swapped most of the major component related to the system with No.2/Co-Pilot but after come back from flying its still happen at Pilot side. The component had been swapped and sometime we had replaced with a new one : - Vertical Gyro - Autopilot Amplifier - Initial Navigation Unit - Flight Computer - Air Data Control - Nav INS switching relay - CDU/INU switching Unit - Mode Coupler - Directional Gyro - INU Battery Unit Anyone ever had this problem? Any help would be great. Many Thanks. :) Quote Link to comment Share on other sites More sharing options...
tinyclark Posted November 16, 2014 Share Posted November 16, 2014 The year and model/serial number might help, if I have any info on it. Quote Link to comment Share on other sites More sharing options...
saikojer Posted November 18, 2014 Author Share Posted November 18, 2014 The year and model/serial number might help, if I have any info on it. LAC s/no : 4866. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted November 18, 2014 Share Posted November 18, 2014 Does the INU ATT mode lamp come on? Have you tried the Pilot's ATT relay on the Nav switching relay panel? What was done to the aircraft before it started doing this? Was any ISO work done, or a component replaced before this started? Are there any ACTION codes and FAULT codes displayed on the INU control? Quote Link to comment Share on other sites More sharing options...
saikojer Posted November 19, 2014 Author Share Posted November 19, 2014 Does the INU ATT mode lamp come on? Have you tried the Pilot's ATT relay on the Nav switching relay panel? What was done to the aircraft before it started doing this? Was any ISO work done, or a component replaced before this started? Are there any ACTION codes and FAULT codes displayed on the INU control? Yes , while selected to INS ATT the mode switch illuminate. The relay on the switching panel already try and error with swapped among each other, but the result was still the same. According to our record its had been reported since 2010, so the exact record on the initially on the problem not so clear. There are also no ACTION code display on the INS's CDU. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted November 20, 2014 Share Posted November 20, 2014 Wow. I wish I could help you more. There is probably a broken wire somewhere. But, I would suggest looking at all of the connectors on the Nav relay panel and flight director computer to make sure no pins are bent. I would almost suggest swapping the relay panel out with another aircraft, but there is no guarantee the panels would be identical. Quote Link to comment Share on other sites More sharing options...
saikojer Posted November 21, 2014 Author Share Posted November 21, 2014 Wow. I wish I could help you more. There is probably a broken wire somewhere. But, I would suggest looking at all of the connectors on the Nav relay panel and flight director computer to make sure no pins are bent. I would almost suggest swapping the relay panel out with another aircraft, but there is no guarantee the panels would be identical. We also had swapped the Nav switching Relay assembly with other aircraft AND RELEASE FOR FLYING BUT ITS STILL THE SAME.. Yes, a broken wire probably might be the main cause of the problem but to check on the wiring its quiet complicated.. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted November 21, 2014 Share Posted November 21, 2014 Well, it looks like the problem is between the INU and the Nav switching panel, since gyro mode works. I know how complicated it can be, especially if it is a signal wire intermittently shorting to the shield. Maybe one of the 26VAC excitation voltages is bad. There are quite of few splices that are tied together. Maybe you could try to duplicate the problem by removing a 26VAC excitation signal from the INU connector, or removing an X,Y or Z signal wire from the Heading, Pitch & Roll outputs of the INU. I know this would be a lot of work, but I think you have to see what may cause the fault to be able to find it. My diagram probably doesn't match yours, but it is all I have. By the way, where are you located? . Quote Link to comment Share on other sites More sharing options...
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