how high do you fly?

[wingtip777]

hi
do you all really fly at the optimum FL? most of us don`t. because we think that is harmfull to our health. any thoughts? thanks!

[18-Wheeler]

I try to.
I worked out that the radiation for 600 hours at 35,000' is roughly equal to four chest x-rays per year - No big deal, especially as that doesn't include the airframe protection. (such as it may be)

[MarkD]

I would have thought the difference in exposure between FL370/390 and say FL 350 would be pretty marginal. If you're that scared of the cosmic rays, go work on a boat - plenty of protective air between you and space then!

[wingtip777]

I worked out that the radiation for 600 hours at 35,000' is roughly equal to four chest x-rays per year
18-wheeler: how did you work out this? and too many chest x-ray is harmful too.
do the campany pay you for saving fuel?

[dolly737]

...do the campany pay you for saving fuel?

Yes. And some will sack you for not doing so.

Somewhere in any FOM you’ll find something like „...economic operation...“ and “...the commander is responsible for the ...economic... conduct of the flight...”.

Until there’s a regulatory limit on exposure (which we'll see probably in another 10 or 20 years), flying eco-levels is the best way to avoid seeing the Director of Operations too frequently.

[Notso Fantastic]

I've flown with a pilot who had his own geiger counter on a trip to Australia. Taking regular readings in the climb and cruise, it seems that each 4000' increase in altitude roughly up to doubles radiation exposure in the 30k' levels. Heavily dependant on latitude and other factors. To chart radiation levels for the world at altitude would lead to charts as complicated as isobaric (lines of magnetic force?) charts. I ws surprised that the geiger counter going off every 6 seconds at ground level was reading c 360/minute at cruise altitude. Flying 1/10 year per year, you are getting more radiation than nuclear power station workers and you are just within the legal limits for radiation.

[Whisky]

Here you can do your own calculation: http://www.cami.jccbi.gov/aam-600/610/600radio.html

Greetings,
Whisky

[McD]

Whisky, thanks for the link to a very useful website! It's really good for comparing high-latitude vs low-latitude flights, and "low-30s" cruise altitude radiation vs "high-30s" radiation. Just to show some sample comparison data, here are some trips with a flight time duration of approx. 8 hours, using the month of January 2002, and using FL330 as a "lower altitude" sample, and FL370 as a "higher altitude" sample. Flight times are Takeoff to Landing, not gate-to-gate and reflect typical January cruise wind conditions :

Miami – Madrid (Flight time 7+55)
FL 330 entire cruise – 23.72
FL 330/FL 370 split – 27.48
FL 370 entire cruise – 31.53

London – Chicago (Flight time 8+10)
FL 330 entire cruise – 31.62
FL 330/FL 370 split – 37.23
FL 370 entire cruise – 42.71

Miami – Rio de Janeiro (Flight time 8+00)
FL 330 entire cruise – 16.53
FL 330/FL 370 split – 19.20
FL 370 entire cruise – 21.43

London – Barbados (Flight time 8+10)
FL 330 entire cruise – 22.10
FL 330/FL 370 split – 25.01
FL 370 entire cruise – 29.10


Interesting information !

[Techman]

Are there any regulations that require companies to monitor and keep records of individual crew members exposure?. And are there any yearly accumulated limits?.

[dolly737]

1. No
2. No

Flight crews would have to be officially categorized as "exposed" first (like workers in a nuclear powerplant), which presently is not the case.

happy landings

[Techman]

Oh yes there is!. Found this in the JAR's after a bit of digging.

JAR-OPS 1.390 Cosmic Radiation

(a) An operator shall take account of the in-flight exposure to cosmic radiation of all crew members while on duty (including positioning) and shall take the following measures for those crew liable to be subject to exposure of more than 1 mSv per year (See ACJ OPS 1.390(a)(1):

(1) Assess their exposure

(2) Take into account the assessed exposure when organising working schedules with a view to reduce the doses of highly exposed crew members (See ACJ OPS 1.390(a)(2));

(3) Inform the crew members concerned of the health risks their work involves (See ACJ OPS 1.390(a)(3));

(4) Ensure that working schedules for female crew members, once they have notified the operator that they are pregnant, keep the equivalent dose to the foetus as low as can reasonably be achieved and in any case ensure that the dose does not exceed 1mSv for the remainder of the pregnancy.

(5) Ensure that individual records are kept for those crew members who are liable to high exposure. There exposures are to be notified to the individual on an annual basis, and also upon leaving the operator.

(b) (1) An operator shall not operate an aeroplane above 15 000m (49 000ft) unless the equipment specified in JAR-OPS 1.680(a)(1) is serviceable, or the procedure prescribed in JAR-OPS 1.680(a)(2) is complied with.

(2) The commander or the pilot to whom conduct of the flight has been delegated shall initiate a descent as soon as practicable when the limit values of cosmic radiation dose rate specified in the Operations Manual are exceeded
(See JAR-OPS 1.680(a)(1))


JAR-OPS 1.680 Cosmic radiation detection equipment

(a) An operator shall not operate an aeroplane above 15 000 m (49 000 ft) unless:

(1) It is equipped with an instrument to measure and indicate continuously the dose rate of total cosmic radiation being received (i.e. the total of ionizing and neutron radiation of galactic and solar origin) and the cumulative dose on each flight, or

(2) A system of on-board quarterly radiation sampling acceptable to the authority is established (See AMC OPS 1.680(a)(2)).

[Sheep Guts]

I suppose this question is steered towards the Jet guys. But heres my 2 bobs worth. Not cosmic related

I used to fly King Airs at Levels between FL200 AND FL240, on oxygen for 5-6 hours legs. The Aircraft was an A90 not pressurised. It was the optimum altitude though used to get a fuel burn of 350lbs/hr.

The only minus for me was the extended lengths of time on Oxy, it took its tolls, headaches afterwards etc. Ive been told that WW2 Bomber PILOTS used to get enlarged hearts due to prolonged high alt oxy use.

Regads
Sheep
Merry Xmas

[Wino]

McD

One of the issues of Flightline dealt with this issue as well, everyone started cruising lower when they read it <G>...

It was around the same time we did the proving runs on the polar routes. Freezing fuel was not the only concern.

Cheers
Wino

[surtyp]

I saw some data from a company that showed the actual, not statistical, radiation differs a lot from day to day but the airlines do not check although it is a JAR requirement.

[strake]

From The World Health Organisation specific to Flight Crews and Frequent Flyers......:

http://www.who.int/ionizing_radiation/env/cosmic/en/

[keithl]

Ive been told that WW2 Bomber PILOTS used to get enlarged hearts due to prolonged high alt oxy use.

Unlikely, I think. WW2 lasted 6 years, the altitudes were, what, not much more than 30K' (and that only in the later years) how much O2 use could there have been?

Compare that with blokes like me spending 32 years in unpressurised, or partially pressurised, military aircraft, pressure breathing above 40K' (IIRC) and no sign of enlarged hearts.

Also, no extra arms or legs from cosmic radiation. Half my flying was done in Victors and Canberras, well above F400 and often above F500. Not so many hours as you commercial chaps, I admit, but that's counterbalanced by the considerably less protected environment.

So what am I supposed to be suffering from?

[LRdriver II]

what about us poor bizjet pilots who spend our time at FL400 and above? Makes me wonder when I had the Lear31 upto FL510

The danish medical branch do keep tabs on this by observing a crosssection of pilots who operate up there.

[izatrue]

Cosmic radiations exposure.

Thank you Techman, for your very useful contribution: very helpful to "bully off" the subject with management on regulatory grounds

i found this site here to do your own calculations on a date/departure-arrival airports/time of day etc...

and to me it looks far from marginal year on year, something like 3-5 mSv/yr depending on altitude/lattitude when a total of 100mSv equals to generalised cancer...

or to be more accurate, after 25-30years on jets, you're 100% more prone to cancers than the average non-flying person.

scary huh?

well, airliner pilots' life is also made of this, short lifespan...but what a life!!

happy flights

[seat 0A]

Well, I guess I work for a pretty nice airline. Every month they state the radiation numbers I have been exposed to on my flight hours log. That way I can track my exposure throughout the year. It`s a comforting thought that I never come close to legal maximum. Although the legal maximum is open to discussion.

All according to the JAR`s, really.

[virginpaul]

My atirline (well, not actually mine!) carries a cosmic radiation monitor on selected sectors to monitor such exposure.