"Ozone bubble" avoidance
 

Hello Fellow PPruners !

I have flown few days ago over the East coast of the US and some airliners were asking ATC to "descend to avoid a bubble/layer of Ozone" in the mid-thirties (thousands of feet).
They also said that they got the heads'up from their Operations.
We flew ourselves ABOVE (at FL430) since I (vaguely) understood that this layer was limited in altitude (let's say FL 330 to 360) and it was not exactly at our position then.

It is the first time I hear something like this....
Is it frequent ? How do Operations know about it ? Shall we pay more attention to this phenomenon ? are the pax/crew at risk or also the engines ?

Thanks a lot for your valuable inputs as always !

MERRY CHRISTMAS !!

Leo

An old article gives some background. But I have not seen much since then.
www.technology.matthey.com/article/24/3/90-94/

This may, or may not, be relevant.

Saving ozone with a no-go zone
https://www.newscientist.com/article/mg14219232-100/

Interesting one.

How are those "ozone pockets" detected in the first place?!

The data regarding localised ozone pockets can be accessed through the product portal associated with the Copernicus Sentinel-5P satellite.

Localised Ozone tracking data

Copernicus Access Hub

Build your API and fill your boots: :ok:

IG

Some aircraft have ozone scrubbers, usually the wide-bodies who have to fly through it for several hours. Many smaller types like the regional jets don't and relay on ozone forecast, they are not allowed to exceed _PPM per hour. Usually flying at a lower altitude or re-routing to avoid.

Sec. 25.832 — Cabin ozone concentration.

(a) The airplane cabin ozone concentration during flight must be shown not to exceed—

(1) 0.25 parts per million by volume, sea level equivalent, at any time above flight level 320; and

(2) 0.1 parts per million by volume, sea level equivalent, time-weighted average during any 3-hour interval above flight level 270.

(b) For the purpose of this section, “sea level equivalent” refers to conditions of 25 °C and 760 millimeters of mercury pressure.

(c) Compliance with this section must be shown by analysis or tests based on airplane operational procedures and performance limitations, that demonstrate that either—

(1) The airplane cannot be operated at an altitude which would result in cabin ozone concentrations exceeding the limits prescribed by paragraph (a) of this section; or

(2) The airplane ventilation system, including any ozone control equipment, will maintain cabin ozone concentrations at or below the limits prescribed by paragraph (a) of this section.

[Amdt. 25–50, 45 FR 3883, Jan. 1, 1980, as amended by Amdt. 25–56, 47 FR 58489, Dec. 30, 1982; Amdt. 25–94, 63 FR 8848, Feb. 23, 1998]

Some light reading. Sect. 8 lists means of compliance, e.g., flight planning:

https://www.faa.gov/documentLibrary/.../AC_120-38.pdf

https://www.gleim.com/aviation/faraim/?leafNum=121.578

Contrail detector??