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A DC-10 Passenger Plane Is Perfect At Fighting Wildfires
Daniel_Stuckey writes: Friday night in Southern California's Silverado Valley, relief flew in on an old airliner. In this summer of drought and fire, the DC-10, an airplane phased out of passenger service in February, has been spotted from Idaho to Arizona delivering up to 12,000 gallons of fire retardant in a single acrobatic swoop.
The three-engine DC-10 entered service in 1970 as a passenger jet, and the last airplane working in that capacity, operated by Biman Bangladesh Airlines, made its final flight on February 24. But some designs defy obsolescence. The DC-10 had already been converted to function as a mid-air refueling airplane for the Air Force, and in 2006, the first fire-fighting DC-10 was unleashed on the Sawtooth fire in San Bernardino County, California.
The three-engine DC-10 entered service in 1970 as a passenger jet, and the last airplane working in that capacity, operated by Biman Bangladesh Airlines, made its final flight on February 24. But some designs defy obsolescence. The DC-10 had already been converted to function as a mid-air refueling airplane for the Air Force, and in 2006, the first fire-fighting DC-10 was unleashed on the Sawtooth fire in San Bernardino County, California.
one incident occured because it was possible to close the door and make it appear fully seated and locked without it actually being so. after it was redesigned it was no longer possible to do so. they also added vents between the cargo and passenger holds, to allow the air pressure to equalize (you see them on almost all airliners now). they fixed that problem. engineering wise, the problem was fixed and it was deemed safe*. what they couldnt fix was ground personel. who would ignore the safety indicator indicating that the door wasnt fully seated and properly locked. i know we talk about idiot proofing, but ground personel are responsible for several things that can crash a bird if done improperly. we trust them everyday.
but generally, once it was fixed, the DC-10 was considered safe and airworthy, even if the public perception wasnt so trusting of it.
and if you really want to feel safe, dont think about how they work long high tempo hours outdoors for an average of 9 bucks an hour (typical low wage physical labor job).
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(*if you really want to get into it, explosive decompression is generally not even a concern on aircraft, partly because of the DC-10 (if it hadnt beent eh DC-10, another plane would have eventually taught engineers the same lessons), being more of a hollywood thing (people getting sucked out windows, planes dinintergrating, etc.....).
I dont know when air vents between the two halves of the pressure vessel became common (they are now though, because of this...), but at the time the DC-10 did not have them. so if one half decompressed, and the other is still airtight, but the floor/ceiling seperating them isnt designed to contain the prssure...it buckles. because of how the DC-10 was structurally designed, what would happen is, if the cargo hold decompresses it was possible for the floor seperating the hold from the passenger cabin to buckle, because the floor acted as an air tight membrane. this buckling would cause damage to the control system running the length of the fuseleage, because of where the control system component were located as they traveled the length of the plane. the end result was a loss of control, that would cause the crash. this problem was a potential problem on many aircraft, if they ever experienced decompression in either half of the pressure vessel.
any of several things could have improved this: relocate the control components, improve/redesign the floor structural supports, and so on. Those options are really expensive, add weight, reduce capacity, etc.
So on a large plane that needs two usable cargo holds to be profitable......air vents.
Air vents allow the pressure to equalize between the two halves, so that if either half should lose pressure (for any reason...not just a door malfunction), the pressure can equalize, the floor doesnt buckle, the control system isnt impaired, and the plane remains flyable.)
...and the DC-10 can deliver as much water as five of the largest water scoopers.
Also bear in mind that a water scooper has to "land and refill" too...it just does that on a body of water instead of an airport. That could be closer than the nearest airport, or it could be farther.
I looked them up: the scooper scoops 6,137 litres of water during a 12-second 410 metres (1,350 ft) long run on the water at 70 knots. 12 seconds to refill sounds pretty amazing, but apparently the DC-10 can be filled (45000 L) in 15-20 minutes, which is not too bad.
"For every expert, there is an equal and opposite expert"
There's a reason why the DC-10 isn't used anymore.
Explosive Decompression
Incorrect. DC-10s were perfectly safe aircraft that flew millions of miles. They weren't explosively decompressing left right and center.
DC-10s aren't flying passengers any more because they don't have the efficiency of modern airliners like the 787. They're heavier, have more drag, and burn more fuel - Particularly due to the their three engines.
FedEx still operates a whack of 'em hauling cargo.
But some designs defy obsolescence
This isn't about obsolescence or a design that stands the test of time. This is about simple economics. The main reason airliners phase out old airplanes is that their operating costs are too high - their older engines are too fuel consuming compared to newer designs, and may not meet newer noise regulations for most commercial airports. Maintenance also becomes difficult to source with no new spare parts being produced.
Fire fighting aircraft fly under a different set of economics. They fly short flights, and only seasonally, so their fuel expenses are a smaller proportion of their expenses. They don't have to worry about noise regulations, because they don't fly out of commercial airports. And an older model that was produced in large volumes like the DC-10 means there is a large source of cheap junkyard parts to maintain these aircraft.
This isn't about the DC-10 being a good or bad design - it's just simple economics. What's expensive for a commercial airliner can be economical for a fire-fighting operation.