Helicopters and Volcanic Ash?
Joined: Jul 1999
Posts: 3,931
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From: Warrington, UK
Seems to be a fair bit of flying in the ash at the moment:
http://www.radarvirtuel.com/#
http://www.radarvirtuel.com/#
Joined: Dec 2006
Posts: 1,303
Likes: 23
From: UK and MALTA
Crab - If a turbine blade/stator vane is allowed to heat up beyond its melting temperature I very much doubt that you will much time to worry about its design life. The thing will eventually fail - probably with catastrophic results.
Thats why the powers that be are soooo cautious. The worst that can happen....is just BAD.
The NASA aircraft flew in the cloud for 7 minutes. A cloud that was not detected by the operating crew, just the boffins in the back.
I think you optimism is commendable but flawed.
Thats why the powers that be are soooo cautious. The worst that can happen....is just BAD.
The NASA aircraft flew in the cloud for 7 minutes. A cloud that was not detected by the operating crew, just the boffins in the back.
I think you optimism is commendable but flawed.
Joined: Mar 2008
Posts: 582
Likes: 1
From: Where I'm pointing...
I have not read anything where someone has claimed the fan blades will melt; they will overheat, and become brittle, increasing their rate of natural wear.
This is not something that will happen in one flight, and with the right inspection procedures can be monitored with a good degree of reliability.
Your maintenance bills will go up, and you will be down for more service periods; I don't believe anyone claims this is something that will happen in the midst of a single flight in 8/8 skies.
This is not something that will happen in one flight, and with the right inspection procedures can be monitored with a good degree of reliability.
Your maintenance bills will go up, and you will be down for more service periods; I don't believe anyone claims this is something that will happen in the midst of a single flight in 8/8 skies.
Joined: May 2003
Posts: 1,032
Likes: 7
From: OS SX2063
ASHTAM web site
Folks,
I've started to put together a site on Volcanic ash and info about it for us as pilots, its not detailed enough to be of great use yet but its a start. There is nothing on it you couldn't get from Google info wise, with the exception of some tools that come straight from my in house collection.
You can find it at
ASHTAM Home :: ASHTAM The Aviation, Volcanic Information Site
There is Google Earth Plotter of the volcanic ash Advisories that you can play with the different layers in, it gives I believe a reasonable picture of where the models say the ash cloud is or will be at a point in time, the folder names should give away what you are looking at.
If you just want the latest KML file without having to visit the site it can be found at http://www.ashtam.co.uk/VACloud.KML
Before anyone says it, I know I need to get out more.
Gary
I've started to put together a site on Volcanic ash and info about it for us as pilots, its not detailed enough to be of great use yet but its a start. There is nothing on it you couldn't get from Google info wise, with the exception of some tools that come straight from my in house collection.
You can find it at
ASHTAM Home :: ASHTAM The Aviation, Volcanic Information Site
There is Google Earth Plotter of the volcanic ash Advisories that you can play with the different layers in, it gives I believe a reasonable picture of where the models say the ash cloud is or will be at a point in time, the folder names should give away what you are looking at.
If you just want the latest KML file without having to visit the site it can be found at http://www.ashtam.co.uk/VACloud.KML
Before anyone says it, I know I need to get out more.
Gary
Heathrow zone closed - why?
Joined: Dec 2008
Posts: 843
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From: N/A
Only 2 ways out (3)
One: Find scapegoat , ICAO? Metoffice? NATS? Brown? Adonis? CAA?
(A knighthood for whichever chairman takes the blame .... hurry.)
Two: "We (the government) can't say yes it's up to you private industry to make your own decision" ("here is the data we have collected using your tax funded equipment")
(Three: Dammage will happen ... "told you so")
Maybe the other European countries will stop blindly following the UK on aviation matters - too late I guess....
(A knighthood for whichever chairman takes the blame .... hurry.)
Two: "We (the government) can't say yes it's up to you private industry to make your own decision" ("here is the data we have collected using your tax funded equipment")
(Three: Dammage will happen ... "told you so")
Maybe the other European countries will stop blindly following the UK on aviation matters - too late I guess....
Joined: Dec 2006
Posts: 1,303
Likes: 23
From: UK and MALTA
THE FOLLOWING TAKEN FROM THE NASA REPORT
NASA are all Astronauts so they should know.
Not a good read if you are keen to go flying.
Engine Damage to a NASA DC-8-72
Airplane From a High-Altitude Encounter
With a Diffuse Volcanic Ash CloudAirplane From a High-Altitude Encounter
In the early morning hours of February 28, 2000, the National Aeronautics and Space Administration (NASA) DC-8 Airborne Sciences research airplane inadvertently flew through a diffuse plume of volcanic ash from the Mt. Hekla volcano. There were no indications to the flight crew, but sensitive onboard instruments detected the 35-hr-old ash plume. Upon landing there was no visible damage to the airplane or engine first-stage fan blades; later borescope inspection of the engines revealed clogged
turbine cooling air passages.
The engines were removed and overhauled at a cost of $3.2 million. Satellite data analysis of the volcanic ash plume trajectory indicated the ash plume had been transported further north than predicted by atmospheric effects. Analysis of the ash particles collected in cabin air heat exchanger filters showed strong evidence of volcanic ash, most of which may have been ice-coated (and therefore less damaging to the airplane) at the time of the encounter. Engine operating temperatures at the time of the encounter were sufficiently high to cause melting and fusing of ash on and inside high-pressure turbine blade cooling passages.
There was no evidence of engine damage in the engine trending results, but some of the turbine blades had been operating partially uncooled and may have had a remaining lifetime of as little as 100 hr.
There are currently no fully reliable methods available to flight crews to detect the presence of a diffuse, yet potentially damaging volcanic ash cloud.
turbine cooling air passages.
The engines were removed and overhauled at a cost of $3.2 million. Satellite data analysis of the volcanic ash plume trajectory indicated the ash plume had been transported further north than predicted by atmospheric effects. Analysis of the ash particles collected in cabin air heat exchanger filters showed strong evidence of volcanic ash, most of which may have been ice-coated (and therefore less damaging to the airplane) at the time of the encounter. Engine operating temperatures at the time of the encounter were sufficiently high to cause melting and fusing of ash on and inside high-pressure turbine blade cooling passages.
There was no evidence of engine damage in the engine trending results, but some of the turbine blades had been operating partially uncooled and may have had a remaining lifetime of as little as 100 hr.
There are currently no fully reliable methods available to flight crews to detect the presence of a diffuse, yet potentially damaging volcanic ash cloud.
Not a good read if you are keen to go flying.
Joined: Jan 2005
Posts: 1,529
Likes: 2
From: yorkshire uk
Well DB , i,m going flying now . Beautiful day , people to fly ...perfect . Now you have a nice day sitting at home alright ?? 
And the cheryl Cole one is .....whats the difference between Cheryl and the Volcano .......the Volcano is still blowing ash .
And the cheryl Cole one is .....whats the difference between Cheryl and the Volcano .......the Volcano is still blowing ash .
Joined: Sep 2001
Posts: 741
Likes: 0
From: UK
Parachuting / ..sending / .. sailing etc. all OK in Scotland :-)
Re the "Still no risk to health" quotes - This appears to be backed up by NATS @ 0245 today :
The information shows that Scottish airsports should be available from 0700
Joined: Dec 2006
Posts: 1,303
Likes: 23
From: UK and MALTA
Hi NigelH,
Good one. Any more volcano jokes out there.
Went to work this morning ready to go flying. No IFR flight permitted. Sitting on arse all day AGAIN!!
Went to Iceland (Supermarket) for something nice for tea. Cashier asked me "Would you like some Ash-back"...................the whole place erupted!!
NigelH enjoy your day and if you are brave enough to do some VFR out over the NS there are plenty of passengers who are gaggin for it.
DB
Good one. Any more volcano jokes out there.
Went to work this morning ready to go flying. No IFR flight permitted. Sitting on arse all day AGAIN!!
Went to Iceland (Supermarket) for something nice for tea. Cashier asked me "Would you like some Ash-back"...................the whole place erupted!!
NigelH enjoy your day and if you are brave enough to do some VFR out over the NS there are plenty of passengers who are gaggin for it.
DB
Joined: Apr 2000
Aviation Qualifications: ATP+Mil
Posts: 10,959
Likes: 1,814
From: EGDC
DB - as birddog says there is no threat of turbine failure, just increased wear and decreased service life - they are not being operated above their melting point, just their designed operating temperature which will have been calculated so the engine makes its TBOs.
See Nick Lappos' old thread re engines and beans
See Nick Lappos' old thread re engines and beans
Joined: Jul 2000
Posts: 1,735
Likes: 21
From: Used to be God's own County
Sea King Heathrow Zone.....
Sunday 830pm local
Sea King requesting to drop-off med team into Regents Park......refused as wasn't Cat1......
Intrigued to hear if your plea to ATC work?
Sea King requesting to drop-off med team into Regents Park......refused as wasn't Cat1......
Intrigued to hear if your plea to ATC work?
Last edited by EESDL; 20th April 2010 at 09:18.
Joined: May 2003
Posts: 1,032
Likes: 7
From: OS SX2063
Seems common sense (from an airspace point of view) is beginning to prevail
I am lead to believe other bits of similarly classed airspace are soon to follow .
WITH IMMEDIATE EFFECT THE CHANNEL ISLANDS CONTROL ZONE (CICZ) WILL NOT PRECLUDE SPECIAL VFR WI THE CICZ CLASS A AIRSPACE. THE REGULATOR IS MAKING NO JUDGEMENTS AS TO THE SUITABILITY OF THE ENVIRONMENT FOR FLIGHTS AND IT IS THE RESPONSIBILITY OF THE INDIVIDUAL OPERATOR TO CARRY OUT THEIR OWN RISK ASSESSMENT PRIOR TO FLIGHT AND SHOULD BE AWARE THAT THEY ARE FLYING INTO AIRSPACE WHERE THERE IS A KNOWN RISK TO AVIATION DUE TO VOLCANIC ASH. PILOTS SHOULD BRIEF THEMSELVES BEFORE FLIGHT ON THE ATC SERVICES AVBL FM ADJACENT ATC UNITS ON LEAVING THE CICZ AND ON CROSSING THE ZONE BOUNDARY, PILOTS MUST ENSURE THAT THEY ARE ABLE TO CONTINUE VFR.
.
Joined: May 2003
Posts: 1,032
Likes: 7
From: OS SX2063
Heathrow Zone is back open SVFR
Special VFR now back in action in CTRs in the UK and Channel Isles.
http://www.caa.co.uk/docs/7/20100419...licyLetter.pdf
http://www.caa.co.uk/docs/7/20100419...licyLetter.pdf
Joined: Dec 2006
Posts: 1,303
Likes: 23
From: UK and MALTA
CRAB, I think you are rather missing the point. The design temperature limits for rotable components within a gas turbine hot end section are critical. That is exactly why tertiary air is used within the engine to maintain a stable temperature environment within which the components will survive.
Operating the engine in conditions, such as with airways and internal pathways blocked, especially within turbine blade and hub tree components does not simply mean that the TBO is compromised. What it means is that the inherent properties of the material, proven at a design temperature range, are entirely different when operated outside that design temperature range.
With turbine blades in particular, elasticity and thus "creep" tends to be the first indications of prolonged operation beyond the designed range (and by prolonged I do not mean weeks, but several minutes).
Thus there are no methods by which TBO can be reduced, simply due to operation beyond designed temperature ranges, and the real issue here is if such operations occurred unforeseen and undetected, catastrophic failure of the hot end is the most probable result.
That is precisley why hot end temperature limits are defined in Flight Manuals down to single degrees. The criteria and acceptable operating ranges are that critical.
The temperature we measure (and view in the cockpit) bears only a limited relationship with the critical temperatures experienced in the business bits of the hot end. Thus start temperatures and operating temperatures may differ with engine speed, as this is a function of total air mass available through the engine, the majority of which is used for flame shaping and tertiary cooling. Only a fraction of the sucked in the intake is actually used for conbustion.
Blocked air passageways within a turbine engine are an extermely serious condition, thus the immediate $3.2m overhaul of all 4 of the NASA aircraft engines.
I am not an expert in this field, far from it but I do have an aerospace engineering background to draw upon. I think it is very foolish to think that these issues are not important.
Taken as a whole this very subject is the meat and two veg of the current European policy for flight within Volcanic ash/dust environments. Modern turbine engines simply cannot endure prolonged operation in certain types of particulate atmosphere especially those emanating from volcanos.
Do you really believe that the entire European Aviation Indistry is currently being compromised by regulators who simply devise policy on a whim or the back of a fag packet.
The problem with this thread, and those who post one dimensional devil may care posts is that such individuals will never have to suffer the consequences of what they post.
I am an operational NS pilot and although I can appreciate the reasons behind the extreme caution of the European Governments I will not hesitate to start flying as soon as the restrictions are lifted, cos also taken as a whole, my expertise lies in flying helicopters and not the in depth risk assessment and decision making process necessary to ensure that we can operate safely within the current volcanic conditions.
As an aside, we have had one catstrophic engine failure (in my time) on the NS. Due to an overspeed but the results were horrific and there was not much life left in the PAX or crew long before the aircraft hit the sea.
Its all very nice and dandy to feel that what we are experiencing is overkill or just plain daft. But the days of thinking there will just be a bit of a bang down the back, and no bother we've got two engines are long gone. Modern helicopter engines let go with a spectacular bang when a catastrophic failure occurs.
That is a grown-ups explanation - just for you. My reference to the blades "melting" in my earlier posts is a bit of poetic licence............but, actually the results are about the same.
I will wait until a grown up says it is OK to fly.
Operating the engine in conditions, such as with airways and internal pathways blocked, especially within turbine blade and hub tree components does not simply mean that the TBO is compromised. What it means is that the inherent properties of the material, proven at a design temperature range, are entirely different when operated outside that design temperature range.
With turbine blades in particular, elasticity and thus "creep" tends to be the first indications of prolonged operation beyond the designed range (and by prolonged I do not mean weeks, but several minutes).
Thus there are no methods by which TBO can be reduced, simply due to operation beyond designed temperature ranges, and the real issue here is if such operations occurred unforeseen and undetected, catastrophic failure of the hot end is the most probable result.
That is precisley why hot end temperature limits are defined in Flight Manuals down to single degrees. The criteria and acceptable operating ranges are that critical.
The temperature we measure (and view in the cockpit) bears only a limited relationship with the critical temperatures experienced in the business bits of the hot end. Thus start temperatures and operating temperatures may differ with engine speed, as this is a function of total air mass available through the engine, the majority of which is used for flame shaping and tertiary cooling. Only a fraction of the sucked in the intake is actually used for conbustion.
Blocked air passageways within a turbine engine are an extermely serious condition, thus the immediate $3.2m overhaul of all 4 of the NASA aircraft engines.
I am not an expert in this field, far from it but I do have an aerospace engineering background to draw upon. I think it is very foolish to think that these issues are not important.
Taken as a whole this very subject is the meat and two veg of the current European policy for flight within Volcanic ash/dust environments. Modern turbine engines simply cannot endure prolonged operation in certain types of particulate atmosphere especially those emanating from volcanos.
Do you really believe that the entire European Aviation Indistry is currently being compromised by regulators who simply devise policy on a whim or the back of a fag packet.
The problem with this thread, and those who post one dimensional devil may care posts is that such individuals will never have to suffer the consequences of what they post.
I am an operational NS pilot and although I can appreciate the reasons behind the extreme caution of the European Governments I will not hesitate to start flying as soon as the restrictions are lifted, cos also taken as a whole, my expertise lies in flying helicopters and not the in depth risk assessment and decision making process necessary to ensure that we can operate safely within the current volcanic conditions.
As an aside, we have had one catstrophic engine failure (in my time) on the NS. Due to an overspeed but the results were horrific and there was not much life left in the PAX or crew long before the aircraft hit the sea.
Its all very nice and dandy to feel that what we are experiencing is overkill or just plain daft. But the days of thinking there will just be a bit of a bang down the back, and no bother we've got two engines are long gone. Modern helicopter engines let go with a spectacular bang when a catastrophic failure occurs.
That is a grown-ups explanation - just for you. My reference to the blades "melting" in my earlier posts is a bit of poetic licence............but, actually the results are about the same.
I will wait until a grown up says it is OK to fly.
Joined: Apr 2000
Aviation Qualifications: ATP+Mil
Posts: 10,959
Likes: 1,814
From: EGDC
DB - thankyou for the egg-sucking lesson on engines 101, one doesn't need an 'aerospace background' to know this stuff
You really are a 'glass half empty' sort of fellow.
My 'one-dimensional devil may care' attitude seems to be reflected by the carriers who are desperate to get back in the air - the European policy, whilst not quite 'back of a fag packet' stuff, is a typical EU 'one size fits all' approach which gives little flexibility in such a variable and rapidly changing situation.
Increased inspections, especially borescoping, will show signs of creep and allow the increased wear to be assessed appropriately rather than the knee jerk 'flown through ash - scrap the engines' approach.
Not quite sure what the catastrophic failure in the NS has to do with this thread or maybe you think you have to amplify the dangers of an engine failure (more eggs methinks).
You really are a 'glass half empty' sort of fellow.My 'one-dimensional devil may care' attitude seems to be reflected by the carriers who are desperate to get back in the air - the European policy, whilst not quite 'back of a fag packet' stuff, is a typical EU 'one size fits all' approach which gives little flexibility in such a variable and rapidly changing situation.
Increased inspections, especially borescoping, will show signs of creep and allow the increased wear to be assessed appropriately rather than the knee jerk 'flown through ash - scrap the engines' approach.
Not quite sure what the catastrophic failure in the NS has to do with this thread or maybe you think you have to amplify the dangers of an engine failure (more eggs methinks).