Noise Level, O2, Trip Time and fatigue

[Steve Dawson]

After just reading the thread about why someone buys a K model, the thread drifted personal O2 levels and the flying high. I'm curious if anyone has tried separating their O2 levels from noise levels in the cockpit while flying long distances?

I just went in a friends Bonanza V35 and compared the interior noise level with my "J". Using an Iphone app mine was 111db compared to his 103Db reading. Considering that amplification isn't linear but increases 3.16 fold per decibel increase means that it can be a substantially more fatiguing the nosier the interior is.

Every-time I go on a long trip of longer than a three hours I'm beat and can't help wondering if the aircraft noise on the rest of my body fatigues me also.

Anyone have any real experiences with this and their fatigue and other than ANR headsets what have you done to quiet the cockpit?

[carusoam]

Interesting thoughts.

1) that thread took a huge change...

2) Sound level really varies between the interior of planes.

I can only judge based on a feeling between the C and the R.  My R is incredibly quiet compared to my C.

There are a few reasons (guesses) for that...

1) Engine sounds/vibrations are different.

2) Insulation quality is different.

3) Windshield shape and thickness(?) are different.

4) Distance from prop to pilot's ears is very different.  

5) air density may have an effect on the measurement.  10k' the air is half as dense as lower levels..?

Should we establish an iPhone/app sound level measurement challenge?

That would be interesting.

Best regards,

-a-

[ArtVandelay]

My iPhone reports 92dB for my J, but that's at 2400 RPM. I've taken off my headphones to put on O2 and it doesn't seem that loud, so I think it's correct.

[M016576]

That was my fault on the thread drift!  I have a tendency to lob "thread drift grenades."

I did myself a favor, though, and did a quick google search IRT higher altitude flight.  I get these briefs from flight surgeons yearly, but it's nice to revisit this information.  I'm relatively young... or I think I am... I am in decent athletic shape and live at moderate altitude- so I'm used to feeling invincible!  After long-ish flights above FL180, though, I tend to feel more fatigued than what Id consider "usual."

many theories were thrown out there... I honestly am beginning to think it may be a combination of my slow breathing cycle (low resting heart rate) and my propensity to drink lots of coffee and not enough water.  I guess getting older means recognizing you need more water.... thus having to pee all the time!

heres a link to the article I was reading IRT this issue-

http://www.aeromedix.com/blog/2012/04/27/fear-and-loathing-at-the-flight-levels/

[kortopates]

1 hour ago, M016576 said:

That was my fault on the thread drift!  I have a tendency to lob "thread drift grenades."

I did myself a favor, though, and did a quick google search IRT higher altitude flight.  I get these briefs from flight surgeons yearly, but it's nice to revisit this information.  I'm relatively young... or I think I am... I am in decent athletic shape and live at moderate altitude- so I'm used to feeling invincible!  After long-ish flights above FL180, though, I tend to feel more fatigued than what Id consider "usual."

many theories were thrown out there... I honestly am beginning to think it may be a combination of my slow breathing cycle (low resting heart rate) and my propensity to drink lots of coffee and not enough water.  I guess getting older means recognizing you need more water.... thus having to pee all the time!

heres a link to the article I was reading IRT this issue-

http://www.aeromedix.com/blog/2012/04/27/fear-and-loathing-at-the-flight-levels/

Some very good points in the article cited. (and some very silly ones about losing function from lifting your mask to drink or eat which probably frightens people from keeping hydrated.) I can personally relate to the importance of hydration and sun protection. Plus I agree that cockpit noise that affects hearing also raises stress and therefore fatigue but I have always felt well insulated from that with my noise cancelling headsets. Interesting question but I don't think background noise on the body per se promotes fatigue if that's what you were getting at. But I do think cabin vibration, including the vibration we get through the cabin floors can add to our fatigue. The modern insulation materials we use today are designed to reduce both noise and vibration.

Even without flying at altitude, my experience as a flight instructor doing multiple flights per day and thus spending many hours in the cockpit shows me maintaining hydration in the cockpit is essential, so I always try to fly with water; and bring extra  when its hot on the ground. I've also found I need sun protection on the face and arms when I am flying in the mid teens and higher (i really should use it earlier). Of course, getting too much sun sure adds to fatigue. When I've had to fly without noise cancelling it was definitely more fatiguing; probably from the added stress. But although I don't have anything to back it up, I have always felt the importance of fitness is very under rated in the cockpit. I personally think being aerobically fit, including a healthy low blood pressure, is what helps us cope with the normal stress of flight with less fatigue than otherwise. But no questions many things can add to stress in flight including weather, that may have you constantly updating your best alternate due to convective weather, or strong turbulence in the clear or even a small amount of turbulence IMC and even high altitude when not entirely in the clear since alternates again need consideration. All these stressors add to our fatigue. 

I have heard of pilots, even talked to one, that claimed to be able to climb up to altitude and with the plane on AP, pull out the Sunday paper and spend a couple relaxed hours getting caught up on the news. I could never be that pilot! And maybe its just me, but I am never "relaxed" in flight - its a busy time even during long periods of otherwise boring cruise.

Edited October 15, 2016 by kortopates

[Jerry 5TJ]

I felt less tired after 3 hours in the P46T at FL270, cabin at 8,000' than after 3 hours at 8,000 in the Mooney C model I owned at the same time. I wore the same Bose X ANR type headsets in each plane.  

The workload and noise were lower in the P46T.   Seat comfort not great in either.  P46T was, ah, turbine smooth, the C had that low-level piston thrumming.  Vibration clearly adds to fatigue.  

These days flying the Ovation at 8,000' I'd say fatigue level is about as in the P46T, perhaps lower. I have more room in the Mooney, the seats are rebuilt with comfort foams, and the workload is low due to level of automation.  It is fairly smooth at cruise.  

I do try to drink water through-out long flights, especially when breathing O2.  Bottled O2 has a very low dew point & dries me out noticeably.  

I was tired after long flights 25 years ago, but somehow a bit more so now: I attribute that to climate change.  And a bit to being old.  

 

 

[Danb]

2 hours ago, M016576 said:

That was my fault on the thread drift!  I have a tendency to lob "thread drift grenades."

I did myself a favor, though, and did a quick google search IRT higher altitude flight.  I get these briefs from flight surgeons yearly, but it's nice to revisit this information.  I'm relatively young... or I think I am... I am in decent athletic shape and live at moderate altitude- so I'm used to feeling invincible!  After long-ish flights above FL180, though, I tend to feel more fatigued than what Id consider "usual."

many theories were thrown out there... I honestly am beginning to think it may be a combination of my slow breathing cycle (low resting heart rate) and my propensity to drink lots of coffee and not enough water.  I guess getting older means recognizing you need more water.... thus having to pee all the time!

heres a link to the article I was reading IRT this issue-

http://www.aeromedix.com/blog/2012/04/27/fear-and-loathing-at-the-flight-levels/

Great article Mo

[peevee]

I also don't drink enough water. I'll go all day with just a few sips so I don't have to pee. The wife will drink constantly and store it like a camel until the next stop. 

[nels]

I checked my 1978 J for sound in the cockpit while on the trip home after buying. At 5000 ft and 24 squared the decibel count on my cell phone was 95 plus or minus. I didn't get any variation when moving it from the floor to the ceiling. I will say the number never did stabilize at 95 but it was the number I saw most often as the phone would never totally make up its mind.

[Steve Dawson]

Part of the problem comparing different aircraft levels is that the meters should be calibrated to the same standard. Especially something you buy from an AP store.  I don't know if mine is actually 111 but when the same app compares two aircraft at least you know one is noisier then the other. 8 dB is a lot. 

I have aftermarket sound proofing and did try different RPM with only a change of 1 dB. 

If anybody tries this again try the same phone AP in different planes. 

[peevee]

2 hours ago, Hyett6420 said:

Every chemical reaction takes place in solution.  Your body is just millions of chemical reactions.  For every 2% drop in hydration there is a. 25% drop in performance.  Sorry peevee, but you need to pee more, drink 2 litres of water a day, you will feel so much better.  RESTOP bags are excellent in the plane to remove the pee. . 

Andrew

I drink lots most days, but on cross country days I go dry while the wife's over there just guzzling it down.