Helicopter Inside Cabin Acoustic Evaluation: A Case Study-IAR PUMA 330

Area of Science:

• Acoustics
• Aviation Engineering
• Noise Control

Background:

• Helicopter cabin noise significantly impacts passenger and crew comfort and safety.
• Understanding noise sources and propagation is crucial for effective noise reduction strategies.

Purpose of the Study:

• To conduct an inside-cabin acoustic evaluation of the IAR PUMA 330 helicopter.
• To identify areas with high noise levels and pinpoint major noise sources within the cabin.
• To assess acoustic leaks and structural attenuation.

Main Methods:

• Acoustic measurements were performed following the ISO 5129 standard.
• Ground tests involved generating pink noise with engines off to identify acoustic leaks through the door area using an intensity probe.
• In-flight tests utilized 16 microphones placed at head level in seven zones to map cabin noise levels during hovering and flight maneuvers.

Main Results:

• Acoustic leaks were identified in the door area.
• The transmission gear and door area were identified as the primary sources of high cabin noise.
• Noise spectral components were detailed for seven cabin zones.

Conclusions:

• High noise levels were confirmed inside the IAR PUMA 330 helicopter cabin.
• Noise reduction measures are necessary to mitigate passenger and crew exposure.
• Targeted interventions at the transmission gear and door area are recommended.