How Much Safety?

I recommend that safety be left to the experts judgment. Risk assessment is a difficult job for anyone taking on the responsibility. Their decisions/recommendations can impact the life (or lives) of people. Money savings and convenience have NO value.... compared to ONE life.

Well......maybe

Yet the safest aircraft are those that don't leave the ground. So working safety in an industry that has large inherent risks means we cannot use so absolute a measure even back in the design stages.

But these apparent contradictions are a natural part of our industry.

As the op mentioned, the travellers and the airlines industry second guessing the decision to not fly, due to the extremely adverse conditions (ash in the sky) is a good sign there is a real concern and disserves a close evaluation. Assessing this 'natural' risk in the industry is just good business. If it were my airline, I would defer to legitimate experts in airline safety! The balance between a human life and the costs of doing business (holding flights until the air is clear) is not an easy one to make. How much money can be made with it's planes on the ground?

The airlines certainly should not decide! Europe has shown that all they are worried about is their bottom lines. Let the government agancies do it. Politicians will keep the heat on them if they go astray.

The airlines have to balance between safety and service, but are in a generally better position than a politician.

The regulatory industry for aviation in the US is robust, responsible, and quite careful. Having worked with their counterparts in many countries I will generally say the same, especially in Europe.

I'm not sure who you refer to russ123, but I would point out that in dealing with a difficult problem like a volcano the European airlines and regulatory agencies have passengers moving without losing any aircraft.

The regulatory agencies did - the airlines were whining about how a little ash wouldn' hurt anything

Perhaps an unfair characterization, but in fact no one had ever done studies on just how much ash becomes dangerous to engines.

While I think the airlines would agree they don't want to fly through ash plumes, zero is also not a very effective allowance.

Complicating the problem, I don't know of an effective ash erosion monitoring system other than engine inspection after landing.

Perhaps engine vibration monitoring, which we do now....

The news was full of the reports here - probably far more so than in the US. There has been some earlier experience with ash in jet engines before (limited) and it was not good. Air Force planes had engines damaged flying out of the UK this time. At high temperatures the ash can become very nasty and very corrosive as well as being abrasive.

The only real way to measure the effects of ash on engine performance is a UL type test. Of course, this type of testing environment may be able to simulate conditions close to that such as flying through ash and would probably be cost prohibitive?

Just imagine, a very large airplane hangar designed to test the engines in a variety of atmospheres and conditions. Where would the money come from to conduct the tests? It would be worth while if some philanthropist spent his spare millions to improve safety in the skies.....just some thoughts.

A big point against the airlines statements - much of their whining was to try to get reimbursement from the governments since they were not permitted to fly. Don't think that went far though.

Under our system it is the airlines job to push to fly and the agencies job to check them.

But if you look at the numbers from any recent strike, the airlines start losing staggering sums the day they have to cease operations even though the planes are parked.