Ash clouds threaten air traffic
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Well, at this moment in time, it sounds as though we will start getting under way again at Gatwick from 19.00 tomorrow evening with, supposedly, a “normal” service from Wednesday morning. UK airports north of a line from Teesside to Blackpool are expected to reopen from 07.00 tomorrow.
VS15 Due to depart tomorrow at 1900L and VS29
due to leave at 1930L
We had Air Transat due to arrive at 1945L on a turn around
Turkish Airlines are requesting an inbound slot of 2300L for their
freighter on a turn around.
just some info ive picked up getting home from work whether it goes ahead or not who knows
VS15 Due to depart tomorrow at 1900L and VS29
due to leave at 1930L
We had Air Transat due to arrive at 1945L on a turn around
Turkish Airlines are requesting an inbound slot of 2300L for their
freighter on a turn around.
just some info ive picked up getting home from work whether it goes ahead or not who knows
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We may have dodged a bullet, but for how long? Launching our jets today without the full knowledge of what is really up there could be just short of suicide. Maybe not for a week or two, even a month or two but once the cooling in your turbine blades is clogged up engines are going to fail. I hope im wrong.
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It seems that any engine failure is highly unlikely to be immediate.
This is where us engineers come in.
I assume that after your next flight we will doubtless be asked to look at your engines, and if they are damaged, we will tell you, and not release to service.
If there is no damage then we will also tell you.
(I am probably guilty of a 'sucking eggs' analogy, but, when you are next flying, keep an eye on your TGT/ITT, FF etc. I would assume there would be an unusual increase if any damage has taken place).
This is where us engineers come in.
I assume that after your next flight we will doubtless be asked to look at your engines, and if they are damaged, we will tell you, and not release to service.
If there is no damage then we will also tell you.
(I am probably guilty of a 'sucking eggs' analogy, but, when you are next flying, keep an eye on your TGT/ITT, FF etc. I would assume there would be an unusual increase if any damage has taken place).
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Couple of things not yet discussed much here but especially relevant if any testing involving military (eg. Nimrod or fighter aircraft) is proposed.
What difference in ash vulnerability between various turbine types (straight-through, low-bypass, high-bypass)? Point being that the front fan MIGHT act as a centrifugal separator to get dust particles away from the core of the engine and outwards into the bypass area where it would do nothing. Anyone know if this happens in practice, with dust about the consistency of talcum powder?
Most of the discussion here (and news) has focused on turbine damage on the outside of the turbine / stator blades. What is the actual risk of ash getting into the cooling passages inside the blades when there is insufficient ash ppm to cause stall or failure for other reasons? In particular, is the position of the cooling plenum inlet(s) bad or good considering likely paths of heavier-than-air ash particles through the compressor stages? Clearly (?), any cooling air blockage is more likely to cause catastrophic blade failure than deposits of volcanic glass on the outside surface of the blades. Or not
. I obviously don't know enough about turbine designs.
And another thing. How long before the volcano vapourises all the ice / water present in the caldera? Once this happens, apparently the character of the eruption will change and the average ash particle size increase a lot. When THAT happens, the ash-cloud will (obviously?) sink to ground / sea much faster and therefore pose less / no threat south of Iceland, whatever the wind conditions.
What difference in ash vulnerability between various turbine types (straight-through, low-bypass, high-bypass)? Point being that the front fan MIGHT act as a centrifugal separator to get dust particles away from the core of the engine and outwards into the bypass area where it would do nothing. Anyone know if this happens in practice, with dust about the consistency of talcum powder?
Most of the discussion here (and news) has focused on turbine damage on the outside of the turbine / stator blades. What is the actual risk of ash getting into the cooling passages inside the blades when there is insufficient ash ppm to cause stall or failure for other reasons? In particular, is the position of the cooling plenum inlet(s) bad or good considering likely paths of heavier-than-air ash particles through the compressor stages? Clearly (?), any cooling air blockage is more likely to cause catastrophic blade failure than deposits of volcanic glass on the outside surface of the blades. Or not
. I obviously don't know enough about turbine designs.And another thing. How long before the volcano vapourises all the ice / water present in the caldera? Once this happens, apparently the character of the eruption will change and the average ash particle size increase a lot. When THAT happens, the ash-cloud will (obviously?) sink to ground / sea much faster and therefore pose less / no threat south of Iceland, whatever the wind conditions.
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The damage you might see would be the fan, compressor and hot section with a borescope inspection but what about the dust that will settle in the balance and signal lines, FCU's and labyrinth seals. How detailed will these inspections need to be to really give it the tick in the box safe to fly approval?
Also the airlines of course want to get up in the air again but what about the leasing companies that own the engines and airframes, are they going to let the airlines fly their equipment if their is still some doubt?
Also the airlines of course want to get up in the air again but what about the leasing companies that own the engines and airframes, are they going to let the airlines fly their equipment if their is still some doubt?
References and links:-
SKYbrary - Managing the Risk to the Safety of Aircraft in Flight Caused by Volcanic Ash
SKYbrary - Managing the Risk to the Safety of Aircraft in Flight Caused by Volcanic Ash
Taken from NATS
Statement on Icelandic volcanic eruption: Tuesday April 20, 0245
Since our last statement at 2100 yesterday, the volcano eruption in Iceland has strengthened and a new ash cloud is spreading south and east towards the UK. This demonstrates the dynamic and rapidly changing conditions in which we are working.
Latest information from the Met Office shows that the situation is variable. The information shows that Scottish airports should be available from 0700 and more airspace over England may become available from 1300 although not as far south as the main London airports.
We will continue to monitor Met Office information and the situation is likely to change during the course of the day. We will make a further statement at approximately 0900 (local time), today, Tuesday 20 April.
NATS is maintaining close dialogue with the Met Office and with the UK's safety regulator, the CAA, in respect of the international civil aviation policy we follow in applying restrictions to use of airspace.
We are working closely with Government, airports and airlines, and airframe and aero engine manufacturers to get a better understanding of the effects of the ash cloud and to seek solutions.
Since our last statement at 2100 yesterday, the volcano eruption in Iceland has strengthened and a new ash cloud is spreading south and east towards the UK. This demonstrates the dynamic and rapidly changing conditions in which we are working.
Latest information from the Met Office shows that the situation is variable. The information shows that Scottish airports should be available from 0700 and more airspace over England may become available from 1300 although not as far south as the main London airports.
We will continue to monitor Met Office information and the situation is likely to change during the course of the day. We will make a further statement at approximately 0900 (local time), today, Tuesday 20 April.
NATS is maintaining close dialogue with the Met Office and with the UK's safety regulator, the CAA, in respect of the international civil aviation policy we follow in applying restrictions to use of airspace.
We are working closely with Government, airports and airlines, and airframe and aero engine manufacturers to get a better understanding of the effects of the ash cloud and to seek solutions.
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Search of previous incidents with volcanic ash cloud addressed by NTSB reveals only one since 1962 (based on searches for volcanic and for ash). Looks like KLM should be dusting off the procedures they put in place after this event.
NTSB Identification: ANC90FA020 .
The docket is stored on NTSB microfiche number 41866.
Scheduled 14 CFR KLM ROYAL DUTCH AIRLINES
Accident occurred Friday, December 15, 1989 in ANCHORAGE, AK
Probable Cause Approval Date: 6/30/1992
Aircraft: BOEING 747-400, registration: PHBFC
Injuries: 245 Uninjured.BFR TKOF, CREW OF KLM FLT 867 ADZD OF VOLCANIC ERUPTION ABT 100 MI SW OF DESTN. EN ROUTE, FLT ADZD OF ANOTHER ERUPTION. FOR ARR, FLT CLRD TO DSCND FM FL390 AT PLT'S DISCRETION; VCTR GIVEN TO AVOID LAST KNOWN AREA OF ASH CLD. DRG DSCNT THRU FL260, FLT ENCTRD ASH CLD; ASH/SMOKE ENTERED COCKPIT/CABIN. CREW DONNED O2 MASKS; USED MAX PWR TO CLB. 1 MIN LTR, ALL ENGS LOST PWR (TO 28%-30% RPM); THERE WAS ELEC PWR INTRPN, LOSS OF AIRSPD INDCN, FIRE WARNING ALARM FOR FWD CARGO AREA. AFTER 8-9 ATMTS & DSCNT TO 13,300', ALL ENGS RESTARTED & FLT CONTD TO SAFE LDNG. DMG FND ON EXTERNAL SFCS OF ACFT & IN HI PRES TURBINES OF ALL ENGS. BOEING OMB #747-B2-4, ADZD TO AVOID VOLCANIC ACTIVITY; BUT IF ENCTRD, RETARDING THRUST TO IDLE WLD RDC BLDUP IN ENG & IMPROVE STALL MARGIN. ATC RADAR COULD ONLY DETECT VOLCANIC ASH FOR 5-10 MIN AFTER ERUPTION; ACFT RADAR NOT DESIGNED TO DETECT ASH. ASH CLD FCST TO MOV NNE AT 60 KTS; REVIEW OF SATELLITE DATA SHOWED IT ACTUALLY MOVED AT ABT 120 KTS. KLM HAD NO PROC FOR 747 ENCTR WITH ASH CLD & NO ADNL INSTRNS WERE GIVEN TO KLM CREWS.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
INADVERTENT ENCOUNTER WITH VOLCANIC ASH CLOUD, WHICH RESULTED IN DAMAGE FROM FOREIGN MATERIAL (FOREIGN OBJECT) AND SUBSEQUENT COMPRESSOR STALLING OF ALL ENGINES. A FACTOR RELATED TO THE ACCIDENT WAS: THE LACK OF AVAILABLE INFORMATION ABOUT THE ASH CLOUD TO ALL PERSONNEL INVOLVED.
NTSB Identification: ANC90FA020 .
The docket is stored on NTSB microfiche number 41866.
Scheduled 14 CFR KLM ROYAL DUTCH AIRLINES
Accident occurred Friday, December 15, 1989 in ANCHORAGE, AK
Probable Cause Approval Date: 6/30/1992
Aircraft: BOEING 747-400, registration: PHBFC
Injuries: 245 Uninjured.BFR TKOF, CREW OF KLM FLT 867 ADZD OF VOLCANIC ERUPTION ABT 100 MI SW OF DESTN. EN ROUTE, FLT ADZD OF ANOTHER ERUPTION. FOR ARR, FLT CLRD TO DSCND FM FL390 AT PLT'S DISCRETION; VCTR GIVEN TO AVOID LAST KNOWN AREA OF ASH CLD. DRG DSCNT THRU FL260, FLT ENCTRD ASH CLD; ASH/SMOKE ENTERED COCKPIT/CABIN. CREW DONNED O2 MASKS; USED MAX PWR TO CLB. 1 MIN LTR, ALL ENGS LOST PWR (TO 28%-30% RPM); THERE WAS ELEC PWR INTRPN, LOSS OF AIRSPD INDCN, FIRE WARNING ALARM FOR FWD CARGO AREA. AFTER 8-9 ATMTS & DSCNT TO 13,300', ALL ENGS RESTARTED & FLT CONTD TO SAFE LDNG. DMG FND ON EXTERNAL SFCS OF ACFT & IN HI PRES TURBINES OF ALL ENGS. BOEING OMB #747-B2-4, ADZD TO AVOID VOLCANIC ACTIVITY; BUT IF ENCTRD, RETARDING THRUST TO IDLE WLD RDC BLDUP IN ENG & IMPROVE STALL MARGIN. ATC RADAR COULD ONLY DETECT VOLCANIC ASH FOR 5-10 MIN AFTER ERUPTION; ACFT RADAR NOT DESIGNED TO DETECT ASH. ASH CLD FCST TO MOV NNE AT 60 KTS; REVIEW OF SATELLITE DATA SHOWED IT ACTUALLY MOVED AT ABT 120 KTS. KLM HAD NO PROC FOR 747 ENCTR WITH ASH CLD & NO ADNL INSTRNS WERE GIVEN TO KLM CREWS.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
INADVERTENT ENCOUNTER WITH VOLCANIC ASH CLOUD, WHICH RESULTED IN DAMAGE FROM FOREIGN MATERIAL (FOREIGN OBJECT) AND SUBSEQUENT COMPRESSOR STALLING OF ALL ENGINES. A FACTOR RELATED TO THE ACCIDENT WAS: THE LACK OF AVAILABLE INFORMATION ABOUT THE ASH CLOUD TO ALL PERSONNEL INVOLVED.
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Insurance liability
I've heard a lot of talk about the decision of the airlines to start flying again, but what about the role of the aircraft insurers in this scenario?
I would've thought that they would be wary of covering aircraft that will be flying into ash clouds, or maybe they would increase their premiums?
I would've thought that they would be wary of covering aircraft that will be flying into ash clouds, or maybe they would increase their premiums?
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We are not totally without information on plume penetration. A very special NASA DC-8 documented ash levels, sizes, and gas concentrations and the details are all there for those who have the time to read it.Here
I quote from the report on the inadvertent ash incident with the NASA DC-8, a fully instrumented airborne science research test bed.
and
I quote from the report on the inadvertent ash incident with the NASA DC-8, a fully instrumented airborne science research test bed.
More than 100 commercial aircraft have unexpectedly encountered volcanic ash in flight and at
airports in the past 20 years. Eight of these encounters caused varying degrees of in-flight loss of jet
engine power (ref. 1)
airports in the past 20 years. Eight of these encounters caused varying degrees of in-flight loss of jet
engine power (ref. 1)
Reference 5 explains
that a range of damage may occur to aircraft that fly through an eruption cloud depending on the
concentration of volcanic ash and gas aerosols in the cloud, the length of time the aircraft actually spends
in the cloud, and the actions taken by the pilots to exit the cloud
that a range of damage may occur to aircraft that fly through an eruption cloud depending on the
concentration of volcanic ash and gas aerosols in the cloud, the length of time the aircraft actually spends
in the cloud, and the actions taken by the pilots to exit the cloud
The airplane was re-engined with four CFM56-2 engines prior to delivery
to NASA.
to NASA.
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Compared with this time yesterday, the live webcam Eyjafjallajökull frá Hvolsvelli suggests a considerable weakening of the plume
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@carmel
I expect that the insurance companies don't really have much of a say.
It would be impossible for them to examine and risk-assess each and every flight every day and in all conditions, so the only practical way would be for them to cover all flights 'provided they are being operated "in accordance the regulations in force".
It's very unlikely that they have any form of veto.
If heavens forbid something went wrong they might try to recover losses from the authorities _if_ they could prove they were negligent in setting the regulations.
I expect that the insurance companies don't really have much of a say.
It would be impossible for them to examine and risk-assess each and every flight every day and in all conditions, so the only practical way would be for them to cover all flights 'provided they are being operated "in accordance the regulations in force".
It's very unlikely that they have any form of veto.
If heavens forbid something went wrong they might try to recover losses from the authorities _if_ they could prove they were negligent in setting the regulations.
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Looks pretty tame this morning from this angle too - Picasa Web Albums - eyjafjallajokull_... - Eyjafjallajok... (as it did last night ... which seems to run against the NATS statements, but presumably they know better)
Well presumeably all S UK airspace is not closed having just watched a KL 747 sail majestically along headed for AMS . Is it just certain levels or just departures? Or are we letting the cloggies do a bit of guinea pig work for us ?
As its track will take it right over London I am sure a lot of people will wonder whats going on
PB
As its track will take it right over London I am sure a lot of people will wonder whats going on
PB
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Danny: Report from 2000 - The "Diffuse" plume. How diffuse? What concentration? You are saying that we shouldn't resume flying because of the unscientific analysis of a few odd commercial flights. You are saying we should stop flying because of the unscientific wording of a single military report!
I am not saying that because you can't see it, it is safe. What I am saying is that without proper research, which is doable, we might just as well all give up and go home now. The "safe" solution is not to fly at all. The gungho solution is to say we can't see anything, or well, it's a bit grey, but hey, it's okay. Probably. The scientific solution, the sapient solution, is to properly analyse and manage the risk. It is only in the last 24 hours that Europe has come close to doing that, but even then as far as I can tell, it's not based on proper research, but on setting aside former assumptions about risk.
I am not saying that because you can't see it, it is safe. What I am saying is that without proper research, which is doable, we might just as well all give up and go home now. The "safe" solution is not to fly at all. The gungho solution is to say we can't see anything, or well, it's a bit grey, but hey, it's okay. Probably. The scientific solution, the sapient solution, is to properly analyse and manage the risk. It is only in the last 24 hours that Europe has come close to doing that, but even then as far as I can tell, it's not based on proper research, but on setting aside former assumptions about risk.
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Young Paul
check page 10 of the NASA report, there are 2 graphs, one for SO2 concentration, airborne Fourier transform infrared spectrometer , one for Aerosol data; airborne Langley condensation nuclei counter, 12 nm–1 micron.
check page 10 of the NASA report, there are 2 graphs, one for SO2 concentration, airborne Fourier transform infrared spectrometer , one for Aerosol data; airborne Langley condensation nuclei counter, 12 nm–1 micron.
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So, the KLM flew at 40,000', above the ash cloud, so their only exposure was in the climb and descent. BA spent a total of 2h45min airborne instaed of their planned 4h, and spent it at varying levels, so only a matter of minutes at the intermediate altitudes that have the highest risk. That invalidates their "tests".
No-one on here supports the apparent lack of investigation into the problem, and no-one wants the restrictions to last longer than needed. However, the continuing view from some that no engine failures means it is safe to resume normal ops is astonishing - given that the company test flights were a con trick, and that numerous military engines have been wrecked, it points to a complete cowboy attitude. Anyone supporting an immediate return to flying should have their licence permanently revoked - you're wanting to play Russian Roulette with hundreds of lives.
The simple fact is that there is not enough data to make an objective assessment whether it is safe or unsafe, and it is that research that is needed, not a resumption to ops because patience has worn out or economics are deemed more important.
No-one on here supports the apparent lack of investigation into the problem, and no-one wants the restrictions to last longer than needed. However, the continuing view from some that no engine failures means it is safe to resume normal ops is astonishing - given that the company test flights were a con trick, and that numerous military engines have been wrecked, it points to a complete cowboy attitude. Anyone supporting an immediate return to flying should have their licence permanently revoked - you're wanting to play Russian Roulette with hundreds of lives.
The simple fact is that there is not enough data to make an objective assessment whether it is safe or unsafe, and it is that research that is needed, not a resumption to ops because patience has worn out or economics are deemed more important.