Measurement flight test program with the Boeing-Vertol CH-47D helicopter. The report contains FORWARD AND AFT ROTOR SPECIFICATIONS. ROTOR S.D events. Each noise event is identified by a letter prefix, corresponding..Compliance with the provisions of military specification MIL-H-850IA was identified. The most significant of these shortcomings were the high pilot workload required 8-per-revolution vi.tion during hover, approach to a hover, and in left sideward The Boeing-Vertol Model 347 winged helicopter is a modified CH-47A..Universal Metal Marking maintains the largest marking Specification Li.ry over 1,500 AERO.E STANDARD, Identification Methods, AS478 Rev..