Aircraft cabin acoustics: Approximately what is the noise level inside a jet airliner during normal cruise flight, expressed in decibels (dB)?

Introduction:
Noise exposure affects comfort and communication. Jet cabins have characteristic sound levels due to engines, airflow, and structure-borne noise.

Given Data / Assumptions:

• Normal cruise conditions.
• Modern jet airliner cabin.
• Sound pressure level in dB.

Concept / Approach:
dB is a logarithmic scale. Cabin noise typically falls in the high 70s to mid 80s dB in cruise, varying by aircraft type and seat location.

Step-by-Step Solution:
Step 1: Identify a typical cabin range of about 78 to 85 dB.Step 2: The representative choice within that band is 80 dB.Step 3: Higher options such as 125 or 145 dB indicate extreme levels not present in normal cabins.

Verification / Alternative check:
Cabin measurements in literature commonly report ~80 dB during cruise.

Why Other Options Are Wrong:
100 dB: higher than typical cabin average. 125 and 145 dB: hazardous and unrealistic for cruise. 60 dB: too quiet for jet cruise.

Common Pitfalls:
Confusing takeoff or seat near engines with average cabin levels; cruise is quieter than takeoff.

Final Answer:
80 dB