Sikorsky S-58/S-58T and S-61/H-3 Tail Rotor Blade Erosion
Aviation Blade Services has received a number of tail rotor blades with tip cap and abrasion strip damage. Upon detailed inspection we found that the tip cap mount landing had been severely eroded, as illustrated in the following picture. This damage is the reason many blades have been removed from service; they were determined to be SCRAP. Sikorsky only allows repairs to this area if the erosion has not exceeded .125”, which in many tail rotor blades is the case.
Aviation Blade Services received authorization to increase the amount of repairable erosion thus saving numerous blades. The main point to operators is, maintain your abrasion strip and tip cap. Many blades exhibit this damage to some degree. The cause of tip caps which are severely eroded or improperly fit is severe erosion to the abrasion strip. If the tip cap and abrasion strip do not make firm contact with each other in this area there will be a problem. Some of the blades received at ABS came in presumed repairable condition but after removing the tip cap and abrasion strip the more severe problem was uncovered.
The picture below is a tail blade purchased by an operator and installed on the aircraft in ‘as is’ condition. When the abrasion strip was found to be voided ABS was contracted for the repairs. The previous owner had replaced the tip cap and did a good job, but did not address the erosion thus the hidden damage was covered up.
This notice is for information purposes only and does not condemn any blade without a more detailed inspection.