Flying into Stromboli ash cloud
 

Aerial fire fighting.
Looking at some of these photos got me wondering just how close it is safe to fly into ash, and whether it is easy to differentiate between what is ordinary forest fire and what not. (Esp. 10,11,12.)
https://www.afpbb.com/articles/-/3233535?pid=21438910

Hi, I´d think that the aircraft and engines will get inspected after a day´s work. I think it´s very difficult to distinguish those clouds.

The top of Stromboli seems to be hissing and leaking in many directions. The tourists must be important for the village and the region's economy.
Thanks for the thoughts, Klauss. I am full of admiration for the crews who risk going up in there to extinguish the lower edges of those fires.

What kind of ash?
what kind of plane?
what kind of flying?

What kind of smell/symptoms in the cockpit?

Excellent questions. 9/10

Volcanic Ash in this instance! :(

.....
How so??

Some video footage here.

*If that doesn't work, here is some good German footage from Heute ZDF. (Towards end of clip.)
https://www.zdf.de/nachrichten/heute...mboli-100.html

Aircraft and volcanic ash have a history - and the aircraft tend to come out on the loosing end.
Two examples:
Speedbird 9: https://en.wikipedia.org/wiki/British_Airways_Flight_9
KLM 867: https://en.wikipedia.org/wiki/KLM_Flight_867
While both ended happily, they were both close calls, and the aircraft damage in both cases was in the millions of dollars.

Thanks for the links. I recall both but KLM 867 particularly vividly as it happened shortly before I flew Korean (could have been KLM) via Anchorage to Europe and saw the aircraft sitting there forlornly on the tarmac. The description of what had happened to them almost defies belief.

Well, we are looking not at a passenger jet basically designed to operate in clean air, but a fire-fighting aircraft that´s very probably designed for the smoky environment it´s beeing operated in. I am thinking of special design considerations for the engines that might keep many particles away from the hot section, maybe air filters for cooling systems, for the pilots´ air... Smoke from forest fires must certainly contain a portion of dust... So, I´d say that the aircraft is just doing it´s job, should be ok - until the evening inspection. I´d guess that the engines of these aircraft don´t stay on the wing for 10.000 hr or more even with normal use. A whiff of volcanic cloud ? Well, maybe an engine change is needed earlier than expected, but that´s for the experts...

A smokey environment is one thing, volcanic ash is a whole different issue - volcanic 'ash' is a bit of a misnomer - it's really rock, not the sort of ash a fire produces.
If we're talking a piston engine, conventional air filters can do a reasonable job (although replacement would need to be very frequent, perhaps every flight). Turbine engines require very elaborate systems to filter out something like volcanic ash - some military helos use such a system - but I've never seen them on a fixed wing aircraft. Ingest a large amount of volcanic ash into a turbine engine, and you're not talking hours to potential failure, you're talking seconds...

NASA report on volcanic ash encounter in their DC-8 CFM56 engines, seven minute encounter with visually undetectable diffuse ash, hot section components predicted to likely fail if flown another 100 hours due blade erosion.

https://ntrs.nasa.gov/archive/nasa/c...0030068344.pdf

I would note that turboprops can be fitted with an inertial separator in the engine intake duct, that removes "heavier-than-air" debris (hail, ice, dust, snow, rain) from the inlet air. Common in the PT6, may be an option in the PW100 series (as on those Canadair 415s).

The duct has a sharp bend and a deflection vane, and air can follow the bend into the engine, but heavier material can't make the sharp turn and is expelled out the back by its mass.

https://aviation.stackexchange.com/q...eflectors-work

I'd also expect that pilots on the spot and directly overhead have a much better view of which "smoke" plume comes from which source, compared to someone with a telephoto lens compressing distance over several miles/kms. This over here is burning vegetation, that over there is venting rock dust.

Pattern, I agree with your comment about the pilots on the spot being able to differentiate between fire ash and volcanic ash - but they better not get it wrong.
Prior to the KLM event, the belief was that volcanic ash would react similar to rain and be centrifuged out sufficiently to avoid it being a danger to the engine. However in the aftermath we discovered that much of the volcanic ash is so fine that centrifugal designs don't work reliably.
After Mt. Saint Helens went boom 40 years ago, I saw a lot (too much, actually) volcanic ash up close and personal. The stuff is amazing yet frightening.

Having attended a presentation by a research scientist who had been flown into the area and close to a volcano to gather samples,
one major finding was that the gasses resulted into major damage to the engines.
So resuming flying because the ash seemed to have gone may be a little premature before more tests re gasses are carried out.

I think Captain Moody would have begged to differ, seven years previously.

DR, the BA event was with an earlier generation of engines - it was thought that the newer, higher bypass engines on the 747-400 would be more resistant. They weren't...

Gases?

From Laki, Iceland I can find mention of "hazardous gases (SO2, HCl and HF)"

https://link.springer.com/article/10...069-009-9415-y