TomB
Topic Author
Posts: 51
Joined: Sun Nov 12, 2006 10:17 pm

Cabin Ozone Question

Wed Jul 10, 2013 6:53 pm

A commercial pilot friend of mine has question on cabin ozone which he and his fellow pilots cannot answer. Perhaps the experts on the forum can provide an answer. Here is the question.

While flying from Iceland to Dulles, their airplane, a 757, diverted around some thunderstorms in the area, they were at a cruise altitude near 35000 feet.

A powerful electrical smell invaded the cabin, causing some alarm, but no smoke was present. (At this point I figured one of the recirculation fans for the air conditioning system burned up, it happens, they are electrical motors and can fail).

The pilots came on the PA explaining that there was nothing wrong with the plane itself, and what people were smelling was ozone from the electrical activity near the thunderstorms. The smell did go away.

I now have about 7800 hours, have flown in and around just about everything, and have never ever heard of this, not have any of my pilot friends.

I know ozone has a particular smell, but I think most aircraft have ozone scrubbers as part of their air filtration systems ( don't know about the 737...)

William the Pilot
 
320tech
Posts: 489
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RE: Cabin Ozone Question

Thu Jul 11, 2013 4:32 am

So, umm, what's your question?
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
 
Woodreau
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RE: Cabin Ozone Question

Fri Jul 12, 2013 1:38 pm

I have no idea what your question is either, but for some aircraft there are aircraft limitations as to how long they can spend at certain altitudes due to cabin ozone concentration. The limitations are based on location, altitude, and time of year. The maximum permissible flight time can be as little as 1:00hr or as long as unlimited.

I believe the maximum permissible ozone concentration by FARs is 75 parts per billion and the aircraft limitations are supposed to prevent it from getting above that limit.
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IFixPlanes
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RE: Cabin Ozone Question

Sat Jul 13, 2013 10:24 am

I think i know what the question is.   
My answer:
Yes, ozone smell can caused by nearby TS.
never tell an engineer he is wrong ;-)
 
ArmitageShanks
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RE: Cabin Ozone Question

Sat Jul 13, 2013 11:37 pm

I seem to remember this being an issue on Concorde due to the higher altitude it cruised at, no?
 
David L
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RE: Cabin Ozone Question

Fri Jul 19, 2013 12:23 pm

Quoting ArmitageShanks (Reply 4):
I seem to remember this being an issue on Concorde due to the higher altitude it cruised at, no?

There was a lot of debate about how much effect Concorde had on the ozone layer but I don't remember any discussion about ozone in the cabin. That's not to say it didn't happen.
 
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HAWK21M
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RE: Cabin Ozone Question

Tue Jul 23, 2013 10:13 am

Quoting TomB (Thread starter):
A powerful electrical smell invaded the cabin, causing some alarm, but no smoke was present. (At this point I figured one of the recirculation fans for the air conditioning system burned up, it happens, they are electrical motors and can fail).

Did a cb trip.

Also the B757 has a cataltic convertor in the PACK that will convert ozone to O2........how will it enter the Aircraft.
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