What is the average sound for light air craft cockpit:
A) 80-100 db
40-60 db
C) 20-30 db
D) 30-40 db

That you ask this question suggests that you haven't read up on noise engineering at all and, in particular, typical sound pressure levels (ie those dB numbers). Plenty of net references, such as

www.noisehelp.com/noise-level-chart.html
en.wikipedia.org/wiki/Noise_control

Generally, you will see SPL values assigned with a particular weighting scale (eg dB(A)) to match up better with hearing physiology. Some information here - en.wikipedia.org/wiki/A-weighting

It is important to keep in mind that the dB scales are logarithmic, not linear. This link gives some background - geoffthegreygeek.com/understanding-decibels/

Looking at the first link and the question's answer options, only option (a) makes any sense at all. Even then, those figures are a bit undercooked - see www.faa.gov/data_research/research/med_h...0s/media/am68-21.pdf

It is important to note that, for workplace OHS (WHS, these days) if you are exposed to noise levels above (generally) 80 dB you are required to wear hearing protection (ear muffs or the like) to minimise the likelihood of cumulative hearing damage.

That is to say, when you go flying, please do wear good quality, noise attenuating headsets .. else you will pay a dreadful penalty many years down the track, like so many of us who trod our careers in the less enlightened days of old. Some information here - www.defence.gov.au/whs/_Master/docs/Safe...Noise-Management.pdf

Thank you very much sir..Im asking because my answer was (A) but got it wrong on my KDR..confusing..I read the book and understand the light A/C is from 75db-94db which from take-off to landing..

Thanks alot sir..just wanted to confirm what I put on exam and got it wrong

I can't comment on whether you have transcribed the question correctly or your KDR.

However, ONLY option (a), as you have posted it, can be correct. I suggest that it is very important that folk read the FAA link I provided to get an idea of just what sort of range you might be looking at in a light aircraft.

Main thing is, PLEASE do wear earphones with a Class 5 attenuation capability. If you don't, and you fly a lot over the years, you probably will have a significant hearing deficit later on and have to wear hearing aids.

Thank you very much sir for making it more clearly