Aileron Cross-Over Cable Maintenance
Recently, while working with Trimec Aviation, I noticed they had found three aileron crossover cables thatwere worn with broken cable strands in them. No big deal, except that it just so happened to be during the last three 800-hour “C” Inspections that they accomplished. Even though bad things seem to come in threes, I still sensed that there seemed to be a trend starting here. I chatted with the one of the lead technicians, Jay Stewart, about this in much more detail. Jay gave me the rundown on his technique for inspecting the flight control cables. First and foremost, clean the cables thoroughly; there are no super mechanics with x-ray vision to see through the filth that collects all over the cables. Next, and you may note this to be a very important step, blow-dry the cables with compressed air to remove the grime stuck between the cable strands. Finally, once the cables are clean, they can be visually inspected. Areas of importance to look at are on the rear cross-over cable at the rear outboard pulleys (see detail “A”). While moving the ailerons through their full travel, look for shiny spots on the cable where it contacts the pulley assembly. A shiny spot may indicate wear, and it will need to be looked at through a magnifying lens. If wear on the cable strands is more than 40 to 50%, it will need to be replaced. What Trimec has been finding in this area is at least 50% wear with some broken strands as well.Now for the weird part – upon replacing the rear cross-over cable, Trimec has been finding broken cable strands under the other pulleys in that system. The ones that I looked at had absolutely no wear at all, but a closer inspection revealed broken strands. Chapter 27 of the Westwind Maintenance Manual states that any broken strand at a pulley necessitates replacement of that cable as well. If you have to replace the rear cable, it is always a good idea to remove the forward cross-over cable as well for a detailed inspection. It takes only a few more minutes to remove it, once you have the aft one out; so it makes good sense to take the time to look at something that, more than likely, hasn’t been thoroughly looked at in many years. As a matter of fact, every forward cable that Trimec has pulled out recently due to the rear one not passing inspection has broken strands in the pulley areas as well (see detail “B”). Those areas cannot be seen until the cable has been removed. I believe that there is no better aircraft in our industry for the money that will do what the Westwind does. It flies high, it is fast, and it has very long legs, while at the same time being comfortable and actually quite maintenance friendly. But, it “ain’t gettin’ any younger.” As the Westwind 1124/1124A continues to serve us so well, during routine inspections, we are going to find areas that need to be inspected more closely and more attention paid to them.With the help of Trimec Aviation and Worthington Aviation, I hope to be able to supply more information on issues like this in the future.
Recently, while working with Trimec Aviation, I noticed they had found three aileron crossover cables thatwere worn with broken cable strands in them. No big deal, except that it just so happened to be during the last three 800-hour “C” Inspections that they accomplished. Even though bad things seem to come in threes, I still sensed that there seemed to be a trend starting here. I chatted with the one of the lead technicians, Jay Stewart, about this in much more detail. Jay gave me the rundown on his technique for inspecting the flight control cables. First and foremost, clean the cables thoroughly; there are no super mechanics with x-ray vision to see through the filth that collects all over the cables. Next, and you may note this to be a very important step, blow-dry the cables with compressed air to remove the grime stuck between the cable strands. Finally, once the cables are clean, they can be visually inspected. Areas of importance to look at are on the rear cross-over cable at the rear outboard pulleys (see detail “A”). While moving the ailerons through their full travel, look for shiny spots on the cable where it contacts the pulley assembly. A shiny spot may indicate wear, and it will need to be looked at through a magnifying lens. If wear on the cable strands is more than 40 to 50%, it will need to be replaced. What Trimec has been finding in this area is at least 50% wear with some broken strands as well.Now for the weird part – upon replacing the rear cross-over cable, Trimec has been finding broken cable strands under the other pulleys in that system. The ones that I looked at had absolutely no wear at all, but a closer inspection revealed broken strands. Chapter 27 of the Westwind Maintenance Manual states that any broken strand at a pulley necessitates replacement of that cable as well. If you have to replace the rear cable, it is always a good idea to remove the forward cross-over cable as well for a detailed inspection. It takes only a few more minutes to remove it, once you have the aft one out; so it makes good sense to take the time to look at something that, more than likely, hasn’t been thoroughly looked at in many years. As a matter of fact, every forward cable that Trimec has pulled out recently due to the rear one not passing inspection has broken strands in the pulley areas as well (see detail “B”). Those areas cannot be seen until the cable has been removed. I believe that there is no better aircraft in our industry for the money that will do what the Westwind does. It flies high, it is fast, and it has very long legs, while at the same time being comfortable and actually quite maintenance friendly. But, it “ain’t gettin’ any younger.” As the Westwind 1124/1124A continues to serve us so well, during routine inspections, we are going to find areas that need to be inspected more closely and more attention paid to them.With the help of Trimec Aviation and Worthington Aviation, I hope to be able to supply more information on issues like this in the future.
