Flappenstein
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Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 4:25 am

Good evening everybody,

I fly everything from a King Air E90 to a G550 and everything in between as pilot; and then all flavors of Boeing, Airbus, MD-s, the Dash 8, Fokker series, CRJ, Bombardier Regional Jet as a passenger.
I feel I know my fair share about aviation and airframe and power plants.

So today, I had my first ride ever on a B717-200. I was eager to see what Boeing had done to the good old MD-concept with the rear mounted engines and modern technology.
Everything was fine until the engines spooled up on the ground. It was not the engines that upset me though - it was the bleed air noise.

Now I can't say I would have familiarized myself with the pressurization system of the B717, other than I know there is no air recycling going on. In my case, it should not matter - the hissing air noise was unbearable.
It started right from when the engines spooled up; but the noise was even there with just the APU on. I sat in a first class seat on the right, and flight attendants could not hear drink orders. That's how bad it was.

The weird thing is that the noise had occasional relation with engine rpm, but would also drastically change level from annoying super loud hissing to almost being quiet for a few seconds, only to spool up the hissing again. This started right on the ground as soon as the engines started and continued throughout the flight. There was no discernible change in the irregular hissing noise throughout the flight, and differential pressure had absolutely no bearing on the noise. It was exactly the same at FL 370 as it was taxiing to the runway.

It sounded like when you have an old car vent blower fan randomly change fan speeds for no apparent reason. But the noise was several magnitudes louder. In order to be louder than jet engine noise, it has to be quite significant, but that's what it was.

I know it was not a leak - the noise seemed strongest from just the overhead bin - where no exit or door could have a leaky seal.

I did a few quick searches and people seem to praise the B717 as one of the quietest airliners every - are they perhaps talking about exterior noise signature? Because the interior, and I am not kidding you, was so loud that my short 2:30 hr flight seemed to never end I am seriously considering filing a report with the FAA and the NTSB as the sustained noise level on that flight was certainly above the legal limits and potentially damaging to hearing.

So what's the damage? There is no way a plane could have been certified as transport category with that noise I had encountered today. It was deafening.
Pressurization was not the issue - differential pressure was maintained and the cabin alt never climbed above 6700 ft.
It also was not an obvious acute defect, as the crew seemed entirely indifferent to the noise levels.

I am still surprised and at a loss to explain what could have caused this horrendous noise. Short of a pressurized hose leaking I have no explanation, but for that to be the case the variations in the noise seemed to be too 'controlled' to some extent.

Two final thoughts I'd like to add to my random rants: When a main door seal rolled out on my G-IV at FL430 once, the resulting hissing noise was several orders of magnitude lower than the one on that B717 today.
AND: also on the G-IV, the temperature control system responds erratically to changes in the cabin temperature selector knob, sometimes resulting in a momentary hiss - again, several orders of magnitude less significant AND over in half a second.

What I experienced today on a B717 was in no way compromising the safety of the flight. But it was putting the auditory acuity of every passenger on that flight at risk, and most certainly the flight crew's hearing if they had to endure that horrendous noise on several flights.

The PIC has the ultimate authority to determine whether his craft is airworthy. Airworthy, as it turns out, the craft may be, even when it gives you sound trauma.

For me, I will never set foot on a Boeing 717 ever again. I value my hearing too much. I don't care if there is no recycled air. I don't care if the exterior noise signature is low. If the cabin is screaming loud, there is no need for me to be on that plane.
 
kengo
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 6:56 am

Not in the front of the cabin but did fly HA 717 several times between the Hawaiian islands but never noticed the hissing air noise as you described. Too bad your first ride in the 717 did not come out as you've expected. Hope your hearing is fine. Cheers....
 
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OA940
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 7:13 am

I've never flown it myself, but a family member did recently with Volotea, and they were at the back too. They said in fact it was a relatively quiet aircraft. And that's what I've heard in general. Maybe it was a problem with that particular aircraft? I mean there's a reason crews and passengers alike love the 717.
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Max Q
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 7:44 am

Sounds like a problem with
that particular aircraft
The best contribution to safety is a competent Pilot.


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WN732
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 7:52 am

I've flown the 717 before on HA and I did not notice that noise. I recently flew on an MD88 at DL a few weeks ago and I did notice a slight noise with the bleed air, but it was not overbearing by any means.
 
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Peeter
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 8:49 am

I used to fly the 717 frequently with Blue1 (I think theirs are with Delta now?) and I never noticed the bleed-air noise you're describing. I hope you give it another chance, it's a great aircraft.
 
soyuz
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 9:53 am

I've flown on Qantaslink's 717's several times. Most recent flight was BNE-CNS last week. I've sat right next to the engines and forward of the wings and never have I encountered the noise you speak of. It can get pretty loud on takeoff at the rear of the aircraft but I'd say overall it's probably the quietest Boeing I've flown on, certainly quieter than the 737 and 777, particularly when sitting up the front. Give it another go. I think the noise you described must've been a fault on that particular aircraft.
 
masi1157
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 10:04 am

I work in cabin acoustics since more than 30 years, so I usally listen quite well to whatever I hear from an aircraft, aspecially if it is new to me. So far I had just one flight on a B717, that was PER-AYQ on Qantas a few years ago. I don't remember any special noise from that flight, in fact it was rather quiet.

Cabin noise btw is not a certification item, not even cockpit noise is in itself, as long as communication and VDR work. An extremely noisy cabin would not be accepted by the customers and passengers, but the A/C could still be certified.


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stratocruiser
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 10:15 am

The noisiest cabin award has got to go to the Shorts 360!
 
ILUV767
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 1:47 pm

I've always found it to be a loud airplane in the cabin.
 
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ElroyJetson
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 2:37 pm

Flew on 717's many times with Air Tran. I never noticed a loud cabin.
707 717 727 72S 737 733 737-700 747 757 753 767-300 764 A319 A320 DC-9-10 DC-9-30 DC-9-50, MD-82 MD-88 MD-90 DC-10-10 DC-10-40 F-100
 
ryan78
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 3:23 pm

I've had 3 flights on a 717 in the last year, one with Volotea and two with Delta. The first two flights I was seated around rows 8-10 and I found the cabin to be extremely quiet due to the rear mounted engines. However, my last flight with Delta I was in the back of the airplane right next to the engine inlet cowl and I definitely did hear the hissing/bleed air/air conditioning sound you described. It was pretty bad and seemed to change pitch with the engine spooling up/down. I took a walk up to the front of the cabin mid-flight and the noise completely went away. Next time I fly a 717 I'm paying extra for seat selection so I don't get stuck in the back again.
 
PA12
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 4:22 pm

Maybe a faulty door seal caused the whistling/ hissing noise.
 
stratclub
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 4:45 pm

In the cabin it would not be bleed air as such all though bleed air is a component of conditioned air that is processed by the ECS system (packs etc) and then distributed to the cabin.Was the noise localized or pretty much everywhere in the cabin? The F/A should have squawked the noise on the cabin report.

Most definitely something in the ECS system need attention. I flew on and MD80 many years ago sitting in front of the wings and It was probably the quietest cabin I've ever flown in. It was dead silent except for the slight sound of the airstream flowing past the outside of the airframe. I would imagine that the B717 version of the MD80 is pretty close to identical as far as most systems are designed and built.
 
flyboy80
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 8:20 pm

I've worked in the cabin on many of these airplanes, including 717s, the forward galley is incredibly loud (like MD80s/90s/DC9s) and I've always believed it to be "air noise" It starts shortly after takeoff when the plane picks up speed I've noticed. It's actually hard to hear other flight attendants speaking in the galley on this place. That said, I do notice when a passenger, even as close as first-row main cabin, it's considerably quieter, so I would imagine there must be more insulation between the interior and fuselage than the forward galley. I can't wait to try out the A220- I've heard the cabin is very quiet at cruise...
 
WPvsMW
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 9:20 pm

Flappenstein, welcome to a.nut.

I fly on HA's 712s frequently, and there is a sharp noise gradient from the 1L boarding door/galley to Row 2 of F. There's a similar noise gradient on A333's from the 1L door aft to about row 4 of F. My sound level meter agrees (I used to work in recording studio design and still have my tools.). Turning to the OP's report, I think the problem is with that particular a/c, and probably something vibrating in the bleed air path in the air supply and cabin pressure system ... with the noise being transmitted downstream.
 
BravoOne
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Sep 29, 2018 10:04 pm

The OP hit the nail on the head. Haven't a clue regarding what DL may have done to their 717 but they are by far the noisiest airliners in the sky today. The FA's can't even hear the pax when they are talking. Sounds as if some baffeling has been removed or fallen out of place. I would rather fly on an RJ in the last rown than any of Delta's 717. Really hard to imagine MD delivering an airplane with these sound qualities, so I suspect Delta has done something to cause this.
 
DeltaMD95
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Re: Boeing 717 - loudest interior cabin noise level ever!

Mon Oct 01, 2018 6:45 am

I had the recent pleasure of two DL 717s: LGA-BOS, LGA-ORD. From 21A, the aircraft was noticeably quieter than the 737NG/A32X in the mid/aft cabin. Engine noise and air ventilation system were pretty consistent in volume throughout cruise and descent. In 17A, some of the engine and hydraulic characteristics during takeoff are less audible to even notice. Overall the 717 is generally pleasant from a volume standpoint in at least 85% of the cabin. But the front of an MD90 is still quieter than the front of a 717.
Did you know that a Boeing 717-200 is really a McDonnell Douglas MD95-30? ;-)
 
Alias1024
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Re: Boeing 717 - loudest interior cabin noise level ever!

Mon Oct 01, 2018 2:26 pm

The 717 is usually a comfortable and quiet ride unless you are seated at the very back, but I've experienced this once before where it was VERY loud. I don't know if perhaps a duct in my part of the aircraft had come loose or had a leak, but I've flown as a passenger on the 717 many times and never heard anything nearly as loud as that.

A couple thoughts based on what the OP described besides a loose air duct:

1) The 717 has a gasper booster fan that can add some noise but is very necessary to keep the aircraft cool on the ground in warm conditions. It's possible the pilots forgot to turn it off after takeoff. While not a safety issue it would add a little extra noise from the air vents overhead.

2) WPvsMW is correct that there is a pretty steep sound gradient at the front of the cabin. There's a huge air vent overhead right as you enter the aircraft. Drives flight attendants nuts during boarding in the summer because the air is blasting out ice cold to keep the cabin cool and they're freezing as they stand under the vent to greet passengers. Then add in any noise if a door seal isn't perfect.

3) The surging sounds like possibly an issue with the flow control valve switching between the normal and high flow schedules. Not sure what would cause that, but it would explain the airflow sound from overhead increasing and decreasing.
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DocLightning
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Re: Boeing 717 - loudest interior cabin noise level ever!

Mon Oct 01, 2018 2:58 pm

I was just on an AA MD-80 on Friday and I noticed a few things:

1) Flow from my gasper vent definitely varied with engine RPM.

2) I didn't hear a lot of engine noise up in the bulkhead row of Y, but man was the slipstream loud once we got up to speed. By contrast, on approach it was almost like we were flying a glider.

3) I took an MD-90 yesterday and it was a similar experience, but I didn't notice such variation in the airflow from the gasper vent.
-Doc Lightning-

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bpat777
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Oct 06, 2018 4:42 am

I've flown the 717 with both FL and DL (mostly up front) and I agree its extremely noisy. I remember the rear being pretty quiet however.
 
bpat777
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Re: Boeing 717 - loudest interior cabin noise level ever!

Sat Oct 06, 2018 4:43 am

I've flown the 717 with both FL and DL (mostly up front) and I agree its extremely noisy. I remember the rear being pretty quiet however.
 
oldannyboy
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Re: Boeing 717 - loudest interior cabin noise level ever!

Tue Oct 16, 2018 2:02 pm

I suppose (strongly) that it was a specific issue of the aircraft in question....
 
mikeinatlanta
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Re: Boeing 717 - loudest interior cabin noise level ever!

Tue Oct 16, 2018 2:17 pm

Impossible to know without investigating the particular aircraft.
External repair/mod not properly faired or sealed
Area of insulation not restored during mtc.
Defect in the air conditioning system
If near a lav or galley, faulty repair to a drain causing excess flow.

Hard to say, but plenty of possibilities.
Aircraft Maintenance Professional since 1979.
 
SteelChair
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Re: Boeing 717 - loudest interior cabin noise level ever!

Wed Oct 17, 2018 12:33 pm

DocLightning wrote:
I was just on an AA MD-80 on Friday and I noticed a few things:

1) Flow from my gasper vent definitely varied with engine RPM.

2) I didn't hear a lot of engine noise up in the bulkhead row of Y, but man was the slipstream loud once we got up to speed. By contrast, on approach it was almost like we were flying a glider.

3) I took an MD-90 yesterday and it was a similar experience, but I didn't notice such variation in the airflow from the gasper vent.


MD88/90 do not have a dedicated gasper fan. The air coming out of be gaspers is just bleed air, and does vary somewhat with engine rpm (see below). Not sure why you would feel the constant eyeball air on the 90 unless some airplanes have been modified to include gasper fans.

One of the "upgrades" that the 717 has is the inclusion of a gasper fan.

WRT the OP concerns, that level of noise seems very abnormal and should have been reported by the crew to mtc to have it checked out. Perhaps a blown duct somewhere or some other abnormality. I have never experienced that level of noise on a 717, and in fact at the rear of the cabin near the engines the 717 is quite a bit quieter than a DC9.

WRT to the report of the air noise changing, yes it does fluctuate. This is to to "high stage switchover." There are 2 air bleeds on the engine and when the high pressure bleed opens, there is often a rush of air for a short time. When it closes, there is a monentaty decrease in air flow. The outflow valve should modulate to keep the changes in he pressurization smooth, but you can still hear the changeover audibly. All transport category jets have this system. If you are in airborne holding, or do a lot of intermediate level offs during climb or descent, you will hear the changeover frequently as a result of the frequent power changes. The 757 will actually sometimes fly in cruise with one HP open and one closed due to the tolerances in the system and wear, but this is usually undetectable in the cabin.
 
AA737-823
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Re: Boeing 717 - loudest interior cabin noise level ever!

Mon Nov 26, 2018 2:49 am

BravoOne wrote:
The OP hit the nail on the head. Haven't a clue regarding what DL may have done to their 717 but they are by far the noisiest airliners in the sky today. The FA's can't even hear the pax when they are talking. Sounds as if some baffeling has been removed or fallen out of place. I would rather fly on an RJ in the last rown than any of Delta's 717. Really hard to imagine MD delivering an airplane with these sound qualities, so I suspect Delta has done something to cause this.


THIS.
I flew on Delta's N938AT (the penultimate 717 ever built!) last Sunday and it was UNBELIEVABLE.
I've flown in many MD-80s and related types. But this thing was unreal.
As soon as the packs came on at the gate, using APU bleed, it was like a hurricane.
I was seated at the overwing exit, and the noise from the pack air flow was louder than any other event in flight, including gear doors opening, noisy slats whooshing in the breeze, etc etc.
During transition from high stage bleed to low stage bleed, the noise would go silent for 2-4 seconds.
But it was present from gate to gate, while sitting still, flying, descending, everything except engine start (packs off).
And it was really awful- I put ear plugs in, and still couldn't sleep through it.
Flight attendants couldn't hear my drink order, and I couldn't hear them, either.

And I've never noticed it before on any of my 717 flights, MD-80 flights, MD-90 flights, or DC-9 flights.
 
BravoOne
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Re: Boeing 717 - loudest interior cabin noise level ever!

Mon Nov 26, 2018 11:04 am

Thanks for confirming what I was hearing. It almost becomes a safety of flight issue as you cannot hear the PA or FA verbal instructions. I'm confident that is NOT the way MD delivered this airplane when it was new.
 
DaveFly
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Re: Boeing 717 - loudest interior cabin noise level ever!

Thu Nov 29, 2018 3:15 pm

I’m sort of dumbfounded by many of the comments because I’ve flown on the 717 many times (AirTran, Delta, Hawaiian), the MD-90 (Delta), and countless DC-9/MD-80s. I never noticed any excessive noise from the air conditioning on any of them, nor did I hear excessive slipstream noise. We all know that the rear rows are subject to engine noise, but I’ve always found the MDs to be very quiet otherwise. I’m really flummoxed on this one, sorry!
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evank516
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Re: Boeing 717 - loudest interior cabin noise level ever!

Thu Nov 29, 2018 7:23 pm

I flew on multiple 717s with DL this year. All of them had that noise.
 
spacecadet
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Re: Boeing 717 - loudest interior cabin noise level ever!

Fri Nov 30, 2018 4:48 am

OP says he flew in first class. The only time I ever flew on a 717 was in first class (on DL) and it was one of the quietest flights I've ever had. I was able to speak in whispers to my wife sitting next to me.

This had to be a problem with this particular plane. Could be a common issue, which might be why others have heard it, but probably not a safety-related one or those planes wouldn't fly. But these planes definitely can (and should) be very quiet up front.
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BravoOne
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Re: Boeing 717 - loudest interior cabin noise level ever!

Fri Nov 30, 2018 2:12 pm

spacecadet wrote:
OP says he flew in first class. The only time I ever flew on a 717 was in first class (on DL) and it was one of the quietest flights I've ever had. I was able to speak in whispers to my wife sitting next to me.

This had to be a problem with this particular plane. Could be a common issue, which might be why others have heard it, but probably not a safety-related one or those planes wouldn't fly. But these planes definitely can (and should) be very quiet up front.




Sorry but I fly on this aircraft twice a week and it is LOUD. The crews all acknowledge that its the noiest airplane in their fleet.
 
evank516
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Re: Boeing 717 - loudest interior cabin noise level ever!

Fri Nov 30, 2018 4:24 pm

BravoOne wrote:
spacecadet wrote:
OP says he flew in first class. The only time I ever flew on a 717 was in first class (on DL) and it was one of the quietest flights I've ever had. I was able to speak in whispers to my wife sitting next to me.

This had to be a problem with this particular plane. Could be a common issue, which might be why others have heard it, but probably not a safety-related one or those planes wouldn't fly. But these planes definitely can (and should) be very quiet up front.




Sorry but I fly on this aircraft twice a week and it is LOUD. The crews all acknowledge that its the noiest airplane in their fleet.


I mean I've been in 10E which is the bulkhead row right behind First Class and I still heard it.
 
BravoOne
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Re: Boeing 717 - loudest interior cabin noise level ever!

Fri Nov 30, 2018 4:43 pm

Well that's better than getting knee capped in 10C:) 1st class is just a little less noisy than mid-ship as far a AC pack noise is concerned.

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