Sympoms of volcanic ash in Jet engines
Thread Starter
Join Date: Aug 2003
Location: Londinium village
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
Sympoms of volcanic ash in Jet engines
Other than the obvious of them stopping.....what could could be expected?
Rise in ITT?
Rollback?
Sudden flameout?
Increased FF?
Compressor stall?
What about those 747 incidents, how did it all happen?
Rise in ITT?
Rollback?
Sudden flameout?
Increased FF?
Compressor stall?
What about those 747 incidents, how did it all happen?
......careful now specialbrew with those questions.....i asked similar sorts of things a day or two ago and was deleted by the mod. (Rumour & News forum) !!
Apparently asking for opinions and answers to questions of your peers is a big "no no" - for what reasons i have no idea ! so, i just decided to bury my head in the sand....sorry, ash !
Apparently asking for opinions and answers to questions of your peers is a big "no no" - for what reasons i have no idea ! so, i just decided to bury my head in the sand....sorry, ash !
Join Date: Jun 2000
Location: Wherever I lay my hat
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
In the BA009 incident the only warning the crew got was St Elmo's Fire round the windshield, just before flameout.
There are two problems the engines would see - one is blockage of turbine air film cooling holes due to sand melting in the combustion chamber and re-solidifying on the front edge of the HPT blades, and the other is simple erosion of compressor blades leading to core surge. In either case I doubt you would get much warning.
If the LH and KL test flights are anything to go by the concentration of ash is not as bad as the situation that caused the BA incident. Trouble is, nobody really knows.
There are two problems the engines would see - one is blockage of turbine air film cooling holes due to sand melting in the combustion chamber and re-solidifying on the front edge of the HPT blades, and the other is simple erosion of compressor blades leading to core surge. In either case I doubt you would get much warning.
If the LH and KL test flights are anything to go by the concentration of ash is not as bad as the situation that caused the BA incident. Trouble is, nobody really knows.
Join Date: Jan 1997
Location: UK
Posts: 7,737
Likes: 0
Received 0 Likes
on
0 Posts
Oooh look,
I can use google if the advice isn't in my ops manual, its supplements or my manufacturer's training material. So for those who need spoonfeeding.
Aero 09 - Volcanic Ash Avoidance
It's a very good article but here are the essentials:
Recognition.
Indicators that an airplane is penetrating volcanic ash are related to
odor, haze, changing engine conditions, airspeed, pressurization, and
static discharges.
* Odor. When encountering a volcanic ash cloud, flight crews
usually notice a smoky or acrid odor that can smell like
electrical smoke, burned dust, or sulfur.
* Haze. Most flight crews, as well as cabin crew or passengers,
see a haze develop within the airplane. Dust can settle on
surfaces.
* Changing engine conditions. Surging, torching from the tailpipe,
and flameouts can occur. Engine temperatures can change
unexpectedly, and a white glow can appear at the engine inlet.
* Airspeed. If volcanic ash fouls the pitot tube, the indicated
airspeed can decrease or fluctuate erratically.
* Pressurization. Cabin pressure can change, including possible
loss of cabin pressurization.
* Static discharges. A phenomenon similar to St. Elmo?s fire or
glow can occur. In these instances, blue-colored sparks can
appear to flow up the outside of the windshield or a white glow
can appear at the leading edges of the wings or at the front of
the engine inlets.
[Let's take a break from the difficult stuff shall we?] Some displays of St Elmos Fire on Youtube at
YouTube - St. Elmos Fire in a A319 from cockpit - Now we return to the bits where you have to think.
Procedures.
The following nine procedures are general recommendations. Each
operator's flight operations manuals will include more specific
directions.
1. Reduce thrust to idle immediately. By reducing thrust, engines
may suffer less buildup of molten debris on turbine blades and
hot-section components. Idle thrust allows engines to continue
producing electrical power, bleed air for pressurization, and
hydraulic power for airplane control.
2. Turn the autothrottles off. This prevents the engines from
increasing thrust above idle. Ash debris in the engine can
result in reduced surge margins, and limiting the number of
thrust adjustments improves the chances of engine recovery.
3. Exit the ash cloud as quickly as possible. A 180-deg turn out of
the ash cloud using a descending turn is the quickest exit
strategy. Many ash clouds extend for hundreds of miles, so
assuming that the encounter will end shortly can be false.
Climbing out of the ash could result in increased engine debris
buildup as the result of increased temperatures. The increased
engine buildup can cause total thrust loss.
4. Turn on engine and wing anti-ice devices and all
air-conditioning packs. These actions improve the engine stall
margins by increasing the flow of bleed air.
5. If possible, start the auxiliary power unit (APU). The APU can
power systems in the event of a multiple-engine power loss. It
can also be used to restart engines through the use of APU bleed
air.
6. If volcanic dust fills the flight deck, the crew may need to use
oxygen. Use flight deck oxygen at the 100 percent setting.
Manual deployment of the passenger oxygen system is not required
because it will deploy automatically if the cabin altitude
exceeds 14,000 ft.
7. Turn on the continuous ignition. Confirm that autostart is on,
if available. In the event that the engines flame out or stall,
use appropriate procedures to restart the engines. During
restart, the engines may take longer than normal to reach idle
thrust due to the combined effects of high altitude and volcanic
ash ingestion. If an engine fails to start, try restarting it
again immediately. Flight crews should remember that the
airplane may be out of the airstart envelope if the encounter
occurs during cruise.
8. Monitor engine exhaust gas temperature (EGT). Because of
potential engine debris buildup, the EGT can climb excessively.
The flight crew should prevent EGT exceedances. Shut down the
engine and restart it if the EGT is approaching limits similar
to a hung start.
9. Fly the airplane by monitoring airspeed and pitch attitude. If
necessary, follow the procedure for flight with unreliable
airspeed.
Finally, click here to see photos of F18 engine parts following test flights on Thursday 15th before any of Finnish airspace was declared unsafe.
(Puolustusvoimat - Frsvarsmakten - The Finnish Defence Forces)
Rob
I can use google if the advice isn't in my ops manual, its supplements or my manufacturer's training material. So for those who need spoonfeeding.
Aero 09 - Volcanic Ash Avoidance
It's a very good article but here are the essentials:
Recognition.
Indicators that an airplane is penetrating volcanic ash are related to
odor, haze, changing engine conditions, airspeed, pressurization, and
static discharges.
* Odor. When encountering a volcanic ash cloud, flight crews
usually notice a smoky or acrid odor that can smell like
electrical smoke, burned dust, or sulfur.
* Haze. Most flight crews, as well as cabin crew or passengers,
see a haze develop within the airplane. Dust can settle on
surfaces.
* Changing engine conditions. Surging, torching from the tailpipe,
and flameouts can occur. Engine temperatures can change
unexpectedly, and a white glow can appear at the engine inlet.
* Airspeed. If volcanic ash fouls the pitot tube, the indicated
airspeed can decrease or fluctuate erratically.
* Pressurization. Cabin pressure can change, including possible
loss of cabin pressurization.
* Static discharges. A phenomenon similar to St. Elmo?s fire or
glow can occur. In these instances, blue-colored sparks can
appear to flow up the outside of the windshield or a white glow
can appear at the leading edges of the wings or at the front of
the engine inlets.
[Let's take a break from the difficult stuff shall we?] Some displays of St Elmos Fire on Youtube at
YouTube - St. Elmos Fire in a A319 from cockpit - Now we return to the bits where you have to think.
Procedures.
The following nine procedures are general recommendations. Each
operator's flight operations manuals will include more specific
directions.
1. Reduce thrust to idle immediately. By reducing thrust, engines
may suffer less buildup of molten debris on turbine blades and
hot-section components. Idle thrust allows engines to continue
producing electrical power, bleed air for pressurization, and
hydraulic power for airplane control.
2. Turn the autothrottles off. This prevents the engines from
increasing thrust above idle. Ash debris in the engine can
result in reduced surge margins, and limiting the number of
thrust adjustments improves the chances of engine recovery.
3. Exit the ash cloud as quickly as possible. A 180-deg turn out of
the ash cloud using a descending turn is the quickest exit
strategy. Many ash clouds extend for hundreds of miles, so
assuming that the encounter will end shortly can be false.
Climbing out of the ash could result in increased engine debris
buildup as the result of increased temperatures. The increased
engine buildup can cause total thrust loss.
4. Turn on engine and wing anti-ice devices and all
air-conditioning packs. These actions improve the engine stall
margins by increasing the flow of bleed air.
5. If possible, start the auxiliary power unit (APU). The APU can
power systems in the event of a multiple-engine power loss. It
can also be used to restart engines through the use of APU bleed
air.
6. If volcanic dust fills the flight deck, the crew may need to use
oxygen. Use flight deck oxygen at the 100 percent setting.
Manual deployment of the passenger oxygen system is not required
because it will deploy automatically if the cabin altitude
exceeds 14,000 ft.
7. Turn on the continuous ignition. Confirm that autostart is on,
if available. In the event that the engines flame out or stall,
use appropriate procedures to restart the engines. During
restart, the engines may take longer than normal to reach idle
thrust due to the combined effects of high altitude and volcanic
ash ingestion. If an engine fails to start, try restarting it
again immediately. Flight crews should remember that the
airplane may be out of the airstart envelope if the encounter
occurs during cruise.
8. Monitor engine exhaust gas temperature (EGT). Because of
potential engine debris buildup, the EGT can climb excessively.
The flight crew should prevent EGT exceedances. Shut down the
engine and restart it if the EGT is approaching limits similar
to a hung start.
9. Fly the airplane by monitoring airspeed and pitch attitude. If
necessary, follow the procedure for flight with unreliable
airspeed.
Finally, click here to see photos of F18 engine parts following test flights on Thursday 15th before any of Finnish airspace was declared unsafe.
(Puolustusvoimat - Frsvarsmakten - The Finnish Defence Forces)
Rob
Join Date: Sep 2005
Location: Norfolk UK
Age: 80
Posts: 1,200
Likes: 0
Received 0 Likes
on
0 Posts
Engine damage
PICTURES: Finnish F-18 engine check reveals effects of volcanic dust-16/04/2010-London-Flightglobal.com
I'm a humble PPL but at least I flew yesterday,sorry
The above link may be of interest,it came from a vintage car site of all places!
Lister
I'm a humble PPL but at least I flew yesterday,sorry
The above link may be of interest,it came from a vintage car site of all places!
Lister
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Wea are a liability driven society. We are a media panic driven society.
Many of us are loosing confidence in the so called science.
Take the Mexican flu. 2 £Billion spent on Tamiflu we would all drop down like flies with an estimated 65000 deaths.
Reality 340 deaths (less than a normal flu) and so much Tamiflu they cannot give it away.
We all sit in our Gardens and think what a lovely flying day with clear blue skies, superb conditions and no sign of thick dense black clouds full of choking volcanic dust.
No one has taken into account of dispersion and the very low levels in the air.
Ok the airlines have put up with it for a couple of days but as they loose a fortune will they question the science? I think so.
Maybe the Government should give some of the Carbon tax back as this volcano has made a mockery of the whole man made global warming theory.
Pace
Many of us are loosing confidence in the so called science.
Take the Mexican flu. 2 £Billion spent on Tamiflu we would all drop down like flies with an estimated 65000 deaths.
Reality 340 deaths (less than a normal flu) and so much Tamiflu they cannot give it away.
We all sit in our Gardens and think what a lovely flying day with clear blue skies, superb conditions and no sign of thick dense black clouds full of choking volcanic dust.
No one has taken into account of dispersion and the very low levels in the air.
Ok the airlines have put up with it for a couple of days but as they loose a fortune will they question the science? I think so.
Maybe the Government should give some of the Carbon tax back as this volcano has made a mockery of the whole man made global warming theory.
Pace
Join Date: Jan 1997
Location: UK
Posts: 7,737
Likes: 0
Received 0 Likes
on
0 Posts
As a post scientific sceptic Pace which of the Finnish Airforce pictures from 4 days ago are beyond you?
Have you run the text through a translator or are we just reading a fashionable growl from you?
Rob
Have you run the text through a translator or are we just reading a fashionable growl from you?
Rob
Look at the NASA year 2000 incident report
This Nasa Report on the year 2000 DC8 incident should give you some information.
The interesting fact is, that they used the engines 69 hours after passing the ash cloud without any overt symptoms.
The detailed analysis showed severe damage to the engines.
Sorry for my bad, german influenced grammar.
Save flight
Thomas
PS: Short summary of the report (with highlights on relevant points)
SUMMARY
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.
The interesting fact is, that they used the engines 69 hours after passing the ash cloud without any overt symptoms.
The detailed analysis showed severe damage to the engines.
Sorry for my bad, german influenced grammar.
Save flight
Thomas
PS: Short summary of the report (with highlights on relevant points)
SUMMARY
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.
Last edited by krohmie; 19th Apr 2010 at 17:57.
Join Date: Mar 2006
Location: n / a
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
why would anyone decide to fly in that? I am amazed that ANY operator would even consider it. Not a rumor just a fact (at the end of the page)
Experts: Why planes should stay grounded - CNN.com
Pedersen
Experts: Why planes should stay grounded - CNN.com
Pedersen
Join Date: Mar 2004
Location: schermoney and left front seat
Age: 57
Posts: 2,438
Received 0 Likes
on
0 Posts
I tried to squeeze some info out of Cessna and Pratt, but no real new stuff there. No guidelines, no ash concentration or anything
The MM for our P&W306C says:
9. Aircraft Flown Through a Cloud of Volcanic Ash
A. Procedure
(1) Do a compressor and turbine wash (Ref. 71-00-00, CLEANING).
(2) Drain and refill oil system with new oil (Ref. 72-00-00, SERVICING).
(3) Replace oil filter (Ref. 72-00-00, SERVICING).
(4) Do a boroscope inspection of the compressor (Ref. 72-00-00, INSPECTION).
(5) Do a boroscope inspection of the HP turbines (Ref. 72-00-00, INSPECTION) and check for glass-like deposits on turbine blades.
If found, do a hot section inspection.
(6) Return engine to service if no unsatisfactory conditions are found.
(7) Drain and refill oil system with new oil (Ref. 72-00-00, SERVICING),
50 +/-10 flight hours after original oil change done at step 2.
I venture a guess, its about the same for all jet/TP engines. There is no definition of "ash cloud" though.
I just wonder what the boss says IF we´d catch same Ash and we´ll be grounded for 2 HSI´s way before they are due in normal ops...
When they lift the ban with particles still in the air, then the ball is in our garden and I frankly have no experience whatsoever with that stuff. Annoying to say the least.
The MM for our P&W306C says:
9. Aircraft Flown Through a Cloud of Volcanic Ash
A. Procedure
(1) Do a compressor and turbine wash (Ref. 71-00-00, CLEANING).
(2) Drain and refill oil system with new oil (Ref. 72-00-00, SERVICING).
(3) Replace oil filter (Ref. 72-00-00, SERVICING).
(4) Do a boroscope inspection of the compressor (Ref. 72-00-00, INSPECTION).
(5) Do a boroscope inspection of the HP turbines (Ref. 72-00-00, INSPECTION) and check for glass-like deposits on turbine blades.
If found, do a hot section inspection.
(6) Return engine to service if no unsatisfactory conditions are found.
(7) Drain and refill oil system with new oil (Ref. 72-00-00, SERVICING),
50 +/-10 flight hours after original oil change done at step 2.
I venture a guess, its about the same for all jet/TP engines. There is no definition of "ash cloud" though.
I just wonder what the boss says IF we´d catch same Ash and we´ll be grounded for 2 HSI´s way before they are due in normal ops...
When they lift the ban with particles still in the air, then the ball is in our garden and I frankly have no experience whatsoever with that stuff. Annoying to say the least.
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Rob
Strangely last night on the news a big question was raised on dispersion and how large the safety umbrella should be from the core of the Eruption. The "expert" opinion was that the umbrella was far to large.
No one is going to argue the fact that if you fly into thick black volcanic clouds you are in serious trouble but at the point that the ash is so dispersed that it is barely visible that is where the question lies.
We now have further eruptions! What are we going to do close a large proportion of European airspace for weeks or even months.
At that rate there will be no point in reopening the airspace as there will be no airlines still existing!
The science is not complete and there lies the problem as no one dares take the risk on the unknown.
While everyone accepts a couple of days the longer this goes on the more arguements there will be as the costs bite harder and harder.
I feel very sorry for the aviation industry with all the Carbon taxes, the recession all the security costs and now this.
Maybe the governement should redirect its carbon tax back towards helping the aviation businesses survive
Pace
Strangely last night on the news a big question was raised on dispersion and how large the safety umbrella should be from the core of the Eruption. The "expert" opinion was that the umbrella was far to large.
No one is going to argue the fact that if you fly into thick black volcanic clouds you are in serious trouble but at the point that the ash is so dispersed that it is barely visible that is where the question lies.
We now have further eruptions! What are we going to do close a large proportion of European airspace for weeks or even months.
At that rate there will be no point in reopening the airspace as there will be no airlines still existing!
The science is not complete and there lies the problem as no one dares take the risk on the unknown.
While everyone accepts a couple of days the longer this goes on the more arguements there will be as the costs bite harder and harder.
I feel very sorry for the aviation industry with all the Carbon taxes, the recession all the security costs and now this.
Maybe the governement should redirect its carbon tax back towards helping the aviation businesses survive
Pace
Last edited by Pace; 20th Apr 2010 at 12:38.
