An afterburner is exceptionally loud, generating noise levels that can be as high as 130 decibels (dB) when observed from a distance of 50 feet, particularly during a military jet aircraft take-off from an aircraft carrier. This extreme noise level is comparable to or even exceeds some of the loudest sounds naturally occurring or produced by human activity, making afterburners one of the most powerful sources of noise.
What Makes an Afterburner So Loud?
An afterburner is an additional combustion component used on some jet engines, primarily military supersonic aircraft, to provide a temporary increase in thrust. It works by injecting fuel into the hot exhaust gases flowing from the jet engine's turbine, where it ignites and creates additional thrust. This process significantly increases the exhaust velocity and temperature, resulting in a dramatic surge in both power and noise output. The sheer volume of hot, high-velocity gases being expelled creates immense acoustic energy.
Understanding Decibel Levels and Noise Comparison
Decibels are a logarithmic unit used to measure sound intensity. A small increase in decibels represents a large increase in sound energy. For context, normal conversation is around 60 dB, while a rock concert might be around 110 dB. The 130 dB produced by an afterburner is well within the range that can cause immediate and permanent hearing damage without proper protection.
To put the loudness of an afterburner into perspective, consider the following noise comparisons:
| Noise Source | Decibel Level (dB) | Notes |
|---|---|---|
| Military Jet Afterburner (50 ft) | 130 | Extremely loud; immediate danger to unprotected hearing. |
| Thunderclap | 120+ | Varies, but often exceeds 120 dB, particularly close to the strike. |
| Chain Saw | 100-120 | Typical operating noise, requires hearing protection. |
| Oxygen Torch | 121 | Intense, focused sound; requires specialized hearing protection. |
| Ambulance Siren (10 ft) | 110-120 | Very loud, can cause discomfort and potential hearing damage over time. |
| Normal Conversation | 60 | Comfortable listening level. |
(Note: Decibel levels can vary based on distance, environment, and specific equipment.)
Impact on Hearing and Safety
Exposure to sounds at 130 dB is considered immediate danger to hearing. Even brief exposure can lead to temporary or permanent hearing loss, tinnitus (ringing in the ears), or other auditory issues. This is why personnel working near afterburner-equipped aircraft, such as those on aircraft carriers or at air bases, are required to wear advanced hearing protection, often consisting of both earplugs and earmuffs, to mitigate the risk of noise-induced hearing loss.
The sheer power of the sound waves at these levels can also cause physical vibrations and discomfort, highlighting the necessity of strict safety protocols in environments where afterburners are operated.
