Evaluation of Aircrew Whole-Body Vibration Exposure Levels on a Canadian CH-147F Chinook Helicopter

Flight testing has been performed on a Royal Canadian Air Force (RCAF) CH-147F Chinook helicopter to investigate aircrew whole-body vibration (WBV) exposure levels in accordance with ISO 2631-1 or MIL-STD-1472G standard. Results showed that the helicopter cabin vibration was dominated at the N/rev harmonics of the three-bladed tandem rotor speed. The aircrew WBV levels varied significantly depending on flight conditions and aircraft load configurations while the highest levels of WBV occurred at high speed level flight maneuver conditions. With reference to the guidelines in the standards, the aircrew WBV exposure level in the entire tested flight profile was qualitatively rated as "uncomfortable", and the maximum duration of such missions should be limited to ensure compliance with the limit of the "Vibration Health Risks Guideline Caution Zone". The aircrew subjective perception survey for this flight profile also confirmed an increase of personnel ride discomfort.