Bali Flights Cancelled due to Lewotobi Volcano Nov. 2024

[Himeno]

So the Darwin VACC envelopes appear to be some 'call' on the density of the ash plume, but they don't say what the criteria is; probably includes infra-red and other spectra to determine a 'safe' level. Never-the-less you can tell from FR24 that any plane flying into or out of DPS will encounter some ash.

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If anyone has info on the methodology of the Darwin VAAC, particularly on what they use to define their envelopes, it would be interesting to know.

Following the 2010 Iceland volcanic disruption in Europe, the UK CAA decided that 4 milligrams of ash per cubic metre of air was "safe". Not sure if that determination has spread past the UK.

 

[Quickstatus]

Yes

Likely lots of passengers trying to rebook

 

[RooFlyer]

Following the 2010 Iceland volcanic disruption in Europe, the UK CAA decided that 4 milligrams of ash per cubic metre of air was "safe". Not sure if that determination has spread past the UK.

IF I understand the concept of 'mass flow rate' in kg/sec being the mass of air that passes through a compressor/engine per second (will vary a lot of course) and a GE-90 engine (largest in use? on B777) has a max MFR of 1,350kg/sec source (opens a PDF) , and the density of air is 1.3 kg/m3 at sea level and 0.55 at 25,000 ft (so 2,450m3/sec ) then it will ingest about 9kg of ash per second using the smaller figure. Hmmm ..that doesn't sound right; as if 6kg/sec would be OK? That's a lot of potential melt to adhere to the turbine blades etc.

@jb747 would you care to tell me where I'm going wrong or what are the relevant factors that would determine safe levels of ash in the air?

Note - I'm not suggesting any VAAC guidance is wrong, just trying to figure out some of the physical parameters of ash Vs engine.

 

[Saab34]

Envelope is increasing again. Not sure what the deciding factor is for the airlines to stop again, certainly any breach past 117E would seem probable. We shall see what the winds do overnight and tomorrow mornings update will be interesting.

 

[MooTime]

Anyone tracking eruptions from Lewotobi?

Is there a website tracking this?
Obviously further eruptions will provide more sky high ash.