Many people who write into the Plane Answers column have questions about what it takes to become a pilot. Little did they know, the answer lies in the genius of the online comic XKCD. Perhaps this is how the venerable Kent Wien reached the pointy end of the plane.
[Via XKCD]
Nearly a week into the volcanic ash crisis plaguing swaths of Europe, passengers and airlines alike are starting to tire of the restricted airspace. The haunting cloud drifting thousands of feet above Earth’s surface is often invisible to the naked eye both at ground level and high into the reaches of the troposphere, causing many to wonder how this material could impact a flight. Could all of these microscopic particles of ash really be that big of problem?
Yes, and in many ways.
Large volumes of volcanic ash have an obvious effect on flight performance. Any particulate getting into cooling holes will cause the engine pressure and temperature to increase, dropping efficiency and potentially causing serious issues inside of the engine. This failure mechanisms poses an immediate and large threat to aircraft safety and is the primary situation that airlines are trying to avoid.
But even small volumes — parts per million of the material — can have a long-term detrimental effect on engine performance.
Typical engine combustors operate at extremely high temperatures — hot enough to melt most metals — and the materials used in each component are specially designed to withstand this heat. The single-crystal turbine blades used in the fabrication of commercial engines often are exposed to temperatures well over 2500°F, and because of this are coated with a special Thermal Barrier Coating (TBC) to prevent overheating. In short, the TBCs prevent the turbine blades from melting.Part of what helps the TBCs do their job is their microstructure. Instead of being fully crystalline, solid materials like the compressor blades, most coatings are porous and less dense, preventing them from transferring too much heat. But this also subjects them to infiltration by foreign particles like calcium magnesium alumino silicate (aka CMAS, formed in and near sand particles) or volcanic ash.
Over time, these embedded particles fill in the pores of the TBC, and they remain in the microstructure as the engine gets hot and cold over and over again. Each time the engine heats and cools, this thermal cycling creates strain between the two materials, and like a sealed bottle of water in the freezer, the container eventually will burst. And once the TBC breaks down, heat can flow freely to the compressor blades, potentially melting a section and causing a catastrophic failure.
Depending on the volume of ash or particle ingested, this can happen quickly over several engine cycles or over a long term of repeated use. But the result is the same: failure during operation.
TBC degradation is only one mechanism for long term failure. Engineers also need to consider abrasion, creep and a host of other materials problems that can result from interaction between volcanic ash and highly specialized engine components.
As you can probably guess, this is partially why the European Aviation Safety Agency is being so cautious with easing restrictions on airspace — many of the long term effects of volcanic ash (which varies in composition by geographic location) on engine components are unknown. Only with time, testing and weeks of analysis will the full impact of these materials be know. Until then, we’re going to have to wait for the skies to clear.
Read more about the short term effects of volcanic ash at popsci.
Check out Alaska Airlines’ operating procedure near ash here.
Boeing’s comprehensive study on engine performance in ash clouds can be found here.
A bill introduced in the U.S. Senate last week would ban airlines from charging for carry-on luggage, according to Reuters. Two senators rightly point out that carry-ons often contain items that are “important for the safety and health” of travelers, including medication and eyewear.
But can we please keep in mind that Spirit Airlines’ now infamous decision to charge for carry-on luggage only applies to items too large to fit in the seat in front of the passenger? You can still carry on personal items for free, and that would include a large purse, brief case, or backpack into which you can stuff whatever essentials or valuables you desire. Coats, strollers, cameras, and certain other items are also carried in-cabin for free.
Let’s get real here. To avoid looking disingenuous, Spirit should simply ban carry on bags altogether rather than making them a profit center. And the US Congress should let airlines conduct business as they see fit, and if it really cares about airline passengers, instead legislate a solution to the real safety risks of carry-on luggage.
Spirit’s CEO, Ben Baldanza, with some justification, claims that the overhead bin fee will discourage carry-on overcrowding and lead to safer air travel, both for flight attendants and passengers, who are sometimes injured when lifting heavy bags into the bins and by bags falling out of the bins, despite the airlines’ constant “bags do tend to shift in flight” PA announcements.
But most likely, safety isn’t the real issue here, at least not for an airline CEO. Baldanza also suggests that the airline will be able to board and deplane their aircraft faster, which implies that Spirit will profit by faster airport turnarounds, and thus be able to complete more flights per day and earn more revenue per plane (or fly more passengers with fewer multi-million dollar jets).
Is safety the real issue here?But if safety is really the issue, then the airline should ban large carry-ons altogether, rather than charging for them. Is a carry-on that is charged $45 any safer than one riding for free? Of course not. Indeed, in the infancy of commercial aviation, there were no overhead bins at all, just hat racks into which it was forbidden to place even the smallest flight bag or other hard object. Everything else went under the seat. (OK, OK, the seats were spaced farther apart, granted.)
In any case, the US Congress should back off. If Spirit or any other airline decides to ban larger-sized carry-ons for safety reasons or to charge for them for revenue-enhanhcement reasons or to discourage passengers from using the overhead bins altogether, then that’s their business. If the government were really consumer focused, they should recognize the health hazards of large carry-on luggage and encourage airlines to ban the practice altogether, following Spirit’s model of only permitting smaller carry-ons that fit under the seat.
And there are about a thousand other things Congress should focus on when it comes to air travel, such as fixing the air traffic control system.
Then we could go back to the old model of free checked baggage, or not. But that should be the airlines’ decision. Or maybe passengers will finally “get it” that the airlines don’t want to be carrying their luggage in the first place, and they’d learn the pleasures of 5-day FedEx Ground delivery service, at least on domestic flights.
Airlines could save millions, and offer free checked baggage once again.
Although putting an end to large carry-on bags, whether free or paid, would require the airlines to hire more baggage handlers and check in staff, who are paid relatively modest wages, most likely the carriers would come out ahead by boarding and deplaning planes far faster than currently possible. It doesn’t take an airline CEO with an MBA to figure out that if every one of the thousands of flights flown in the US each day could shave 30 or 45 minutes off of their schedules by turning around quicker at the airport, then the airlines would save millions in equipment, fuel and the more expensive salaries paid to pilots, who often sit around doing nothing while passengers attempt to stuff bags in the overhead bins, blocking other passengers from reaching their seats.
With the money they save, airlines could once again offer free checked bags, just like in the good old days, when flying was fun.
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Recently on a flight a passenger took the empty seat beside me. He had an assigned seat that he left behind. If by luck of the draw I had an empty seat (true not paid for), then it seems to me that as a beneficiary of said luck that I have inherited certain rights. If the other guy had stayed in his OWN seat, I would have had the enjoyment of more space. His moving AFFECTED me. The only reason I point this out is because while my situation was benign, I know that sometimes these little irritations or frictions on flights escalate into real on board conflicts (fights), and while I am describing out a pretty subtle point here, I think that it is better for the flight crew to mediate between passengers using preventive practices (etiquette, courtesies, “rules” etc.) rather than letting passengers resolve them themselves, in those cases where we are dealing with seat assignments at least. – Trevor
I’m going to tell you what 90% of the flight attendants I know would say. You paid for a seat. One seat. Not two seats. Not an entire row. Just a single seat. So if a passenger wants to switch seats, that’s okay. The passenger is allowed to sit in “your” row. While at my airline passengers are free to move to any open seat available in their ticketed cabin, other airlines (regional carriers dealing with weight and balance issues and airlines who charge extra for certain seats in the same cabin), require passengers to ask a flight attendant before swapping seats. If the flight attendant says it’s okay, it’s okay, the passenger can move.
Just because you were lucky enough to to score an entire row to yourself does not mean you have “inherited certain rights.” Oh sure it’s annoying when someone who already has a seat invades your space, but imagine you are the one stuck in an undesirable seat and there are two open seats in the row behind you, wouldn’t you move? Should a passenger have to suffer just because someone else is the “beneficiary of said luck” when there is plenty of room for both passengers to stretch out and relax?
In the future, if you’d rather not sit next to anyone, try making your row a little less appealing. The most popular seat on the airplane is the aisle seat. Take it! Otherwise someone will plop down beside you. Then, after takeoff, spread out. Pull the tray table down and place something on top of it. Put a bag, coat, or book in the seat beside you. Pretend to sleep. Not many people are ballsy enough to wake a sleeping passenger. Try traveling with a packet of Kleenex. No one wants to sit next to the sick guy. Or better yet, travel with a child. Works for me. Passengers avoid kids like the plague. That said, if someone still wants to sit in your row, they can. So be prepared to move your things out of the way.Airlines are charging for exit row seats and I have been on two flights where they have remained empty and flight attendants required payment from passengers who requested to switch to them. My question is what happens in case of an emergency landing? Do you think it is safer to have an able bodied person willing to open the door sitting there? I can visualize pandemonium as people rush to the door. I think gate agents or flight attendants should be able to offer these seats to qualified passengers! – Laura
While it makes sense to have willing and able bodied passengers who meet the exit row criteria seated in an exit row in case of an emergency evacuation opposed to leaving those seats vacant, FAA does not deem it necessary. I could tell you why I think this is, but it doesn’t matter what I think, or what you think for that matter. It is what it is. My question to you is, if flight attendants and agents working for an airline charging an extra fee for the exit row could move passengers to the vacant seats for free, how would they determine which lucky passengers to choose without creating the same type of pandemonium? With all that leg room, the exit row is the most sought after row on the airplane! That said, I understand why some airlines, mostly discount carriers, are charging the extra fee. They have to stay in business somehow!
At my airline we do not charge a fee for the exit row, but our ticket prices are higher than most discount carriers and the exit row is often blocked just for frequent fliers. Nine times out of ten the most elite frequent fliers occupy the exit row and bulkhead seats. So while my airline isn’t charging a fee for the row, they are asking for something even more – passenger loyalty. It comes in the form of miles. So what’s worse, an airline charging a small price to anyone willing to pay for the extra space, or an airline who only rewards a select few? Wouldn’t you rather be able to purchase the seat than not even have a shot at it?
An Indonesian 737 operated by Merpati Nusantara Airlines skidded off of a runway in the eastern Paupa province early yesterday, coming to rest over a canal and subsequently breaking in two right through the fuselage.
Initial reports indicate that the incident was weather related and had nothing to do with the aircraft or its operator.
Miraculously, nobody was killed during the incident although scores were injured. The crash does, however, bring the safety records for many Indonesian carriers back into the limelight, many of which have been recently scrutinized for being below international standard. MSNBC has footage from the crash site below:
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