If you've been anywhere near a television or Web enabled device in the last week (and you must have been), you know that a volcanic eruption in Iceland has grounded airline flights across Europe and even halted a few flights into the northeastern-most areas of Canada. What you probably don't know is how to pronounce the name of the volcano (Eyjafjallajökull) or why an eruption in Iceland is grounding flights in London, Madrid and Berlin.
After all, planes fly through lightning storms, heavy fog and the occasional flock of geese and come out fine on the other side with amazing consistency. But a volcanic ash cloud presents it's own unique set of problems, particularly to an aircraft engine's working parts. A group of Finnish F-16s are currently circling the area to see just how bad the air quality is for jet engines, and some airlines are conducting their own tests to see just what kind of damage this ash cloud might exact on their hardware.
Luckily for us, NASA already performed an ash cloud test on an airliner a full decade ago, albeit unintentionally. In February of 2000, a NASA DC-8 bound for Sweden flew right through an ash plume produced by Icelandic volcano Mt. Hekla. The flight crew couldn't see the plume, and in a stroke of good fortune they landed their plane at their destination without incident. In fact, no visible damage was detected upon arrival, but a closer inspection turned up some harrowing clues to just how devastating volcanic ash can be on an airplane in flight.
The fan blades where deeply gouged (see below), the critical cooling components were clogged with a sooty gunk, and the engine's innards were coated with a glassy, silicate material (see above). The in-flight data showed that the engine hit nearly 2,000 degrees Fahrenheit, enough to melt silicate rocks. That's lava in your jet engine, not ideal for longevity.
Interestingly – and quite fortunately for the crew on board – the relatively low dose of hot ash the DC-8 received temporarily turbocharged the engine by polishing the engine parts and letting air move more freely through the components. But make no mistake; too much more of that kind of performance enhancing would have led to engine failure, and at 30,000 feet all engine failure is a serious issue.
Of course, this is all in addition to the fact that hot ash plumes can degrade aircraft windows to the point of failure ro compromise the integrity of an aircraft's skin. But the fact that these plumes can be hard to detect from the flight deck explains why no one is leaving the ground in Europe; there's no flying under or around the ash cloud because in some cases pilots can't distinguish exactly what they're trying to avoid.
Oh, and for the record, it's "AY-uh-fyat-luh-YOE-kuutl-uh." And if you want to know how you get that pronunciation from Eyjafjallajökull, you'll have to ask elsewhere.
This is perhaps nitpicking, but Finland doesn't have f-16s. They used f/a-18s.
perhaps? uuhuh just a bit ;)
...they could be using F16's instead of their pricey FA18's, I know I would! I didnt google or anything, I'm just saying :)
Ashclouds arent good for jetengines for pretty much the same reason why wet/damp cement mix isnt good for your vacuum cleaner. ...Except your vacuum doesnt hit its melting point as quickly when it accidentally sucks up something it doesnt necessarily like, and it's not carrying you 30K feet above the rocky ground either O_O
I checked, and Finland doesn't have F-16s.
I loaned them a few of my F-16s. They didn't say anything about flying them around in ash clouds when they asked to borrow them though.. I wish I had gotten some sort of deposit now. :(
"failure ro compromise"???? Please read over your articles before posting them! No wonder people are continuing to read less.
I was stationed at Mountain Home AFB in Idaho in 1980 when Mount St. Helen's blew. We had F-111's and one was on static display in Portland at an air-show. As soon as the mountain erupted, the crew took off and headed back to Idaho within 30 minutes . The Aircraft declared an emergency and had to be escorted back to base by a wingman as the Ash ( Barely visible to the aircrew) had sandblasted the canopies of both pilot and WSO and the pilot had a small area about 8.5X 11" out his left side with which to see the wingman who flew him to the ground and a Barrier landing( wire stretched across the runway- like a Naval Carrier). Both engines were damaged by FOD (Foreign object damage) to the tune of only producing approx. 60-70% thrust in each. Additionally, the swing wing pivot mechanism had volcanic ash in it as well as all flight control surfaces and pivot points. which had to be removed . This aircraft did not fly again for many months and a whole lot of Tax payer dollars, and the important thing to remember here is they did not fly through the visible cloud. I know that the folks in Europe are frustrated at delays and groundings, but the risks to man and machine far outweigh the benefits of getting home without due diligence and caution.
"...it's own unique set of problems"?? IT'S = IT IS.
"The fan blades where deeply gouged"? This is pathetic. Try a little proofreading next time.
If people commenting here would be a bit more informed, would know that in fact the airplanes used to test fly were NATO F-16 planes. The pilots were Finns and although Finland is not a member of NATO, they cooperate on security operations based on a partnership they signed in 1994!
These engines routinely have parts (like the 1st stage turbine blades) that operate at 2000 deg F. The 3rd photo is of a high pressure turbine blade (probably a 1st stage), not a fan blade. Notice all the cooling holes. Fan blades are in the front of the engine and don't require cooling holes. The cooling holes produce a film of relatively cooler air along the surface of the blade. Beyond that film of air are the 2000 deg temps; hot enough to actually melt the blade if not for the thin film of cooling air. That is another reason you don't want your engine sucking up that ash; it clogs the cooling holes and degrades the film cooling. That is what you are seeing in the very first photo.
Jetengineer is correct, the bottom 2 photos are from the high pressure turbine (HPT). The top photo from BA looks like a HPT nozzle. Having just read the NASA technical report that this article was based on, the NASA DC-8 had 4 GE CFM56-2 engines. The CFM56 single stage HPT blades are the only rotating component that has cooling holes, which are shown in the pictures. Other static parts, like the combustor, high press turbine nozzle and low pressure turbine nozzle, are also cooled. The report also mentioned that the life of the pictured HPT blades was reduced to 100 hours. This means that after that time period, the blades could crack and catastrophically fail.
A 4-engine British Airways 747 encountered an ash cloud in SE Asia a number of years ago. The ash caused all 4 engines to flameout. The crew did an amazing job to glide the plane to a safe landing.
Fluid dynamics ftl!
Oh, and Wikipedia doesn't count as a resource for nations and their military equipment :)
Is Popular Science really a professional journalism organization?
"...presents it’s own unique set of problems..." There's no apostrophe in "its" because it is a possessive. WTF!!!!!! Learn how to write.