The widespread pilot use of ANR for aviation helmets is due to the enormous benefits of decreased helicopter pilot fatigue, increased situational perception. and hearing protection. Overcoming coordination problems related to a high-noise helicopter climate, and defense from double vision and two systems, were considered instances applied for CEP communications and active noise Reduction Headsets (ANR).
The CEP hearing protection consists of a small sound transducer coupled to an expandable, through ported foam earplug that is worn in combination with the standard flight helmet. The CEP’s main advantage is that it prevents unwanted sound from entering the ear canal from the outside of the helmet but permits communication signals to enter the ear without attenuation through the earplug.
The ANR for aviation helmets is composed of electronic components that transduce, condition, and reverse the phase of the “residual” noise that penetrates the headset’s ear cups and then introduce this “antinoise” inside the earcup space in a phase-inverted time relationship with the residual noise to affect its cancellation. This technology results in attenuated sound levels to the listener, more so for low-frequency signals than for high-frequency signals. This result is an advantage of ANR when it is combined with the typical flight helmet, because ANR compensates for the lack of low-frequency attenuation of the flight helmet.
The CEP hearing protection has essentially become standard issue for aviators because this device has been shown to increase speech intelligibility, reduce noise hazards, be subjectively favored by pilots over ANR, meet crashworthiness evaluations, and be less expensive than ANR systems. In the past, ANR technology has not been practical for implementation in army aviation, primarily because of the weight of the systems, crashworthiness issues, and expense to the army.
Advancements In ANR For Aviation Helmets
Recent technology developments have produced miniaturized ANR components for aviation helmets, including implementation in earplugs, as well as crashworthy earcup designs, suggesting that ANR may now be a viable alternative to CEPs for pilots. Furthermore, an aviator with high-frequency noise-induced hearing loss may benefit from the low-frequency attenuation characteristics of ANR that can reduce the amount of upward spread of ambient noise masking on speech.