PointsNerd

How Quiet Are New Airplanes?

Jayce

There is often a lot of talk about how great the new aircraft from Boeing and Airbus when it comes to passenger comfort. There’s a lot of talk about how these new aircraft are better because of how they humidify their air, have mood lighting to help with sleep and are much quieter than older sister aircraft.

On our Luxury Round-the-World trip, I had the unique opportunity to actually measure the noise in a lot of different aircraft so you can get a real-world understanding of how loud or quiet a particular aircraft is.

How Do We Measure Sound?

Sound is generally measured in decibels (dB) and decibels are measured on a logarithmic scale, which differs significantly from the linear scale that everyone is used to. On a linear scale, if you were to compare 10 centimeters to 20 centimeters, you would say that 20cm is twice as long. Not so on the logarithmic scale.

On the decibel scale, a difference of 10dB equates 100x, meaning if an airplane’s interior has a noise measurement of 70dB, it is twice as loud as an airplane with a measurement of 60dB, but a noise of 80dB is four times as loud as 60dB.

This can be confusing so I’ll leave this handy scale here to help you understand how dramatically different the noise in a cabin can be between an older aircraft and the newest aircraft out there, the A350 and the 787.

Keep this in mind because while the difference in decibels may seem small, the actual difference in “loudness” is quite significant.

For those that really want to understand how decibels are measured, I’ve found a very good video about it from Techquickie that should make this easier to understand.

Methodology

This is obviously not a perfect scientific experiment but I have tried to keep the variables as consistent as possible. Here are the variables I have tried to control for:

Results will definitely vary depending on the aircraft (what we are trying to measure) as well as the particular engine power that the pilot has decided to use on the route. I’m assuming altitude will also dictate how much engine power is required and thus affect noise so I will attempt to provide the altitude measurements for each flight as well. Another aspect that may dramatically affect the decibel rating is the age of the aircraft as every year that passes, newer technologies in sound absorption are implemented into planes so, in theory, the exact same model of aircraft from different years can have different decibel ratings. As such, I have provided the date of birth (DOB) of the aircraft.

Below are the details of the flights that we took:

YYC-SEA – Embraer 175

Airline: Alaska Airlines
Flight: AS2731
DOB: April 27, 2017
Altitude: 36,000 feet
Average Noise: 74 dB

The Embraer 175 is a regional jet that first started operating in 2004 and it is quite a loud aircraft. While it is definitely better for noise than turboprops, it is the loudest jet that I’ve flown.

SEA-LAX – Boeing 737-900

Airline: Alaska Airlines
Flight: AS416
DOB: May 19, 2015
Altitude: 35,000 feet
Average Noise: 68 dB

The 737-900 is the workhorse of Alaska Airlines and services most of its medium and intercontinental flights.

LAX-HKG – Boeing 777-300ER

Airline: Cathay Pacific
Flight: CX885
DOB: January 19, 2015
Altitude: 30,000 feet
Average Noise: 69 dB

Recently, Cathay Pacific has moved towards A350s as their long-haul aircraft of choice with the 777-300ERs still servicing their major routes. The 777-300ERs feature Cathay’s true First Class cabins and while they are relatively quiet, they are noticeably louder than the A350.

HKG-AKL – Airbus A350-900

Airline: Cathay Pacific
Flight: CX199
DOB: June 2, 2017
Altitude: 29,000 feet
Average Noise: 66 dB

The Airbus A350 is the newest commercial plane in the sky and heralded as the quietest. I was actually taken aback by how quiet the plane was. Even on takeoff with the engines at 100%, I was surprised at how easily I could hear people talking 3-5 rows back.

I can’t believe I’m saying this but you might not even need noise canceling headphones for this plane because it is whisper quiet (at least in comparison to other aircraft).

AKL-SYD – Boeing 787-900

Airline: LATAM
Flight: LA801
DOB: May 14, 2016
Altitude: 40,000 feet
Average Noise: 69 dB

The noise level of the 787-900 was surprisingly high for such a new plane and something that I was not expecting. Without doing much research on the subject, I expected the 787 to be very close to the A350 but it compares more noteably to the 777-300ER.

SYD-MEL – Airbus A330-200

Airline: Qantas Airlines
Flight: QF431
DOB: August 27. 2002
Altitude: 30,000 feet
Average Noise: 70 dB

The Airbus A330-200 was quite loud in my experience but it could have something to do with the age of the aircraft. At 15 years old, this aircraft was one of the oldest we flew and it was, unfortunately, the only A330 that we flew so I did not have the ability to figure out if the age of the aircraft played a contributing factor.

MEL-CNS – Boeing 737-800

Airline: Virgin Australia
Flight: VA1291
DOB: July 12, 2010
Altitude: 36,000 feet
Average Noise: 75 dB

This was certainly a surprise because it was the loudest plane that we flew, even louder than the small Embraer 175 that services regional flights. Add that to the fact that it isn’t even the oldest plane we flew, make this quite a surprising find.

CNS-BNE – Boeing 737-800

Airline: Qantas Airlines
Flight: QF709
DOB: October 15, 2011
Altitude: 39,000 feet
Average Noise: 72dB

These next two flights are interesting in that in comparison to the Virgin Australia flight on the same aircraft, the Qantas flights were 3 decibels quieter, which is a noticeable difference. Also of interest, the BNE-SYD flight featured an aircraft that was 3 years older than the one flown by Virgin Australia but was still quieter. This could perhaps indicate that Qantas spent more money on sound dampening than their competitors, Virgin Australia.

BNE-SYD – Boeing 737-800

Airline: Qantas Airlines
Flight: QF537
DOB: January 26, 2006
Altitude: 38,000 feet
Average Noise: 72dB

SYD-AUH – Airbus A380-800

Airline: Etihad
Flight: EY451
DOB: April 25, 2015
Altitude: 30,000 feet
Average Noise: 66dB

The A380 is an absolute triumph in human engineering and features a cabin that is as quiet as it’s sister aircraft, the A350. This was surprising to me as I expected the newer A350 to be at least 1-2 dB quieter than it’s big sister. I can tell you from experience that the A380 is an incredibly comfortable aircraft to fly and suffers from the same problem as the A350 … it might just be too quiet? Scratch that … this is how quiet planes should be … we’ve just been conditioned to accept that planes are loud.

AUH-JFK – Airbus A380-800

Airline: Etihad
Flight: EY101
DOB: April 13, 2016
Altitude: 32,000 feet
Average Noise: 66dB

Interestingly, this aircraft was born just 1 year after the one servicing our SYD-AUH flight and had the same sound dampening abilities. While I did not note the cabin we were in in the details, on the SYD-AUH flight was flew in First Class and on this flight we were in Business Class but it doesn’t seem to have made a difference even though Business Class is much closer to the engines.

JFK-SEA – Boeing 737-900

Airline: Alaska Airlines
Flight: AS7
DOB: June 29, 2015
Altitude: 32,000 feet
Average Noise: 68dB

The 737-900 was the same aircraft that was flown from SEA-LAX on our outbound and both birds were delivered within a month of each other. Additionally, they were manufactured for the same airline so it is unsurprising that the sound levels were identical.

SEA-YYC – Embraer 175

Airline: Alaska Airlines
Flight: AS2718
DOB: August 29, 2017
Altitude: 35,000 feet
Average Noise: 74dB

An interesting end to our trip in that we were bookended by the same aircraft, the Embraer 175. Both planes were birthed within 2 days of each other and cruised at virtually identical altitudes so it is unsurprising that their noise levels were identical.

Sortable Table

From my limited data and what may amount to be a rudimentary analysis, it seems as though aircraft type, rather than the date of manufacturer or altitude seems to determine how loud or quiet aircraft are.

One interesting item that was culled from the data is that the same aircraft, delivered to different airlines, can have a significantly different noise level as was the case for the 737-800s operated by Virgin Australia and Qantas. It would not be too far-fetched of an idea that some airlines choose to invest money into additional sound dampening from the manufacturer (in this case Boeing).

I am going to leave you with a sortable table so that you can perhaps play with the data and come up with some of your own interesting conclusions.

Conclusion

I don’t know about you but I find it absolutely fascinating that once you get past things like the seat comfort, the food and the service levels of an aircraft, small things like how quiet the cabin is on an aircraft really can define your level of comfort. Going forward, I may just start tracking all my future flights and update the table so that you might find some patterns within the data.

I know that this is a pretty nerdy exercise but I hope you found it as interesting as I did. If you did, you might want to check out my Series on Close In Availability as we get into the guts of analytics by studying how airlines release award seats close to the date of travel.

H/T to Scott from Norebbo for his amazing plane illustrations.