353 AIR LEAK SOUND BOGIE 1 A SIDE UNDERF ~~~~~ 353 AIR LEAK SOUND BOGIE 1 A SIDE UNDERFRAME.  3503 A/S horn air pipe found leaking. Replaced strainer filter O-ring. Function test horn - ok. No leaks occurred. No abnormalities found.  Lee PT/Shafie/Sugu 45331