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This topic comprises 9 pages: 1 2 3 4 5 6 7 8 9
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Author
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Topic: A380 - world's largest pasenger aircraft - makes maiden flight
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Will Kutler
Phenomenal Film Handler
Posts: 1506
From: Tucson, AZ, USA
Registered: Feb 2001
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posted 05-28-2005 10:48 PM
Well, here is some input (finally) from ye ole aircraft mechanic.
For many, many moons, aerospace engineers designed aircraft with the ease of maintenance being the last consideration. Consequently, certain areas that required maintenance were ignored simply because they were inaccessable for mechanics to get to. Case in point: performing post-wash lubrication on the T-tail flight control surfaces in a C-5 Galaxy. It literally takes a "small person" to fit into the access areas in order to reach the various lube fittings! At 6 ft and 160lbs, it was nearly impossible for me to perform this task!
For years, the FAA approved manufacturer's maintenance books were a total nightmare! One could literally spend 2-3 times or more researching the maintenance task than it would take to actually perform the work! Been there-done that! I personally know of several cases where, in trying to avoid a headache, mechanics would perform a task and then go back to the books to see if they did the job correctly!
Why do I not choose to currently work as a mechanic? POLITICS! The first thing out of our instructors mouth on the first day of class when I began college was about the tremendous pressure mechanics are under to pencil-whip maintenance so that the plane will take off on time! OHHHH was he right, and the personal stories I have about both civilian and military aircraft maintenance!
As far as the age/cycle time of aircraft. Not to worry about that. There are programs where a fusalage/structure can be strigently remanufactured and the airframe hours set back to "0".
Ya, I did catch that Airbus program on The Discovery Channel. That "Teflon" solution regarding the landing gear emerengcy deployment left me shaking my head! Amazing that the test-pilots accepted a repair that did not perform perfectly!
Cheers
K.
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Paul Mayer
Oh get out of it Melvin, before it pulls you under!
Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000
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posted 05-29-2005 12:02 PM
Although any given airframe can be kept airworthy indefinitely, the costs of doing so rise dramatically over time. The airlines (and the military for that matter) will not keep older airframes going if there are alternatives.
At some point it does become cheaper to invest in a new design and retire an old one. The manufacturer can drive that decision point by stopping support of an older design. That was one of the reasons Concorde was retired--BAe had given up making parts and the operators BA and AF were beginning to scavenge parts off of existing airframes.
As Ian mentioned, advancements in technology have led to huge improvements in operating efficiencies. Newer airframes are lighter and have better drag numbers. Newer engines are more powerful, burn less fuel for a pound of thrust, pollute less, and make less noise. Newer flight decks allow for 2-man crews even on long over-water flights. The newer engines are so reliable that two-engine over-water flights are now possible (before the B767 began the ETOPS era you had to have at least three engines). ETOPS: Extended Twin-Engine OPerationS or Engines Turn Or People Swim. ![[Big Grin]](biggrin.gif)
Some of these improvements can be retrofitted to older airframes or airframe designs. Some e.g.s: DC-8-60 series re-fitted with CFM-56 engines to create the DC-8-70 series, B-737-200s re-fitted with CFM-56 engines (along with other aerodynamic improvements) to become the B-737-300 and up series, hush kits for the engines on the B-727 and BAC-1-11, L-1011s fitted with "Frisbee fairings" for less drag and less cabin noise, DC-9-80/MD-80s fitted with "screwdriver" tail cones for less drag, DC-10s become MD-10s with new 2-man flight decks. But at some point it does become easier and cheaper to quit supporting design patch jobs and start with a clean slate.
Both major airliner manufacturers continue along both design and engineering paths. In new designs Airbus has flown the A380 and Boeing is proceding with the B787. In the "tweeking old designs" arena Boeing is looking at the B747 Advanced as a competitor to the A380 while Airbus is looking at a tweeked A330 to be called the A350 to compete with the B787.
As for the various "checks" each airline has their own approved maintenance program and their own mix of aircraft types so the details of the checks are different. A master list of items to be checked at each check is created by the airline for each aircraft type when that type starts operations. From that list, task cards or punch lists are created for each mechanic on the check crew to use during a given check. Mark mentioned the forums on www.airdisaster.com for more info. The forums on www.airliners.net are another source. The details of airliner checks have been discussed at both sites quite a bit. In general:
A Check: Like an oil change for your car. Can be accomplished overnight at the gate with a couple of line maintenance guys.
B Check: Like a minor tune up for your car. Requires a trip to the maintenance hangar and can take a couple of days depending on what needs to be done based on inspection results and aircraft log entries. Add a few more guys to the crew to handle the punch lists.
C Check: Like a major tune up and inspection for your car. Can take a couple of weeks and involves major inspections and parts replacements. Big crew needed.
D Check: Like a complete overhaul/restoration for your car. Can take several months. My favorite definition of a D-Check is the one for older Learjets: "Leave no part standing against any other part." The aircraft is literally disassembled down to the last nut and bolt and sometimes rivet. All parts are cleaned, inspected, re-painted, and replaced if necessary. You practically have a new aircraft after a D-Check. You're gonna need a bigger crew.
Many airlines combine A and B check items together and do them in phases to minimize down time and shorten the C checks. Many airlines also combine the items of a D check into phased C checks so that they don't have to ever do full D checks. When an aircraft is sold or returned from a lease, full checks have to be done since phase programs are all different. Again each airline has its own way of doing things. In the US the FAA must approve each airline's maintenance and engineering support programs.
When you've won the Lotto and are shopping around for a private airliner (like Arnold Palmer and his B-737-700 or John Travolta and his B-707-138) you'll want to know how many hours have accrued on an aircraft since the last C and D checks. Same thing with engines--look at the time since the last "hot section" was done. Gives you some bargaining power if the aircraft is coming up on any of those since they are frighteningly expensive.
Old aviation joke:
Q: How do you make a small fortune in aviation?
A: Start with a big one.
[ 06-03-2005, 09:46 PM: Message edited by: Paul Mayer ]
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Will Kutler
Phenomenal Film Handler
Posts: 1506
From: Tucson, AZ, USA
Registered: Feb 2001
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posted 05-29-2005 01:00 PM
Thank you, Paul! Kept me from lots of typing!
So Mark, when was the last time you turned a wrench on an aircraft?
The difference between how civilian and military maintenance is performend is like day and night!
Civilian aviation mechanics can be licensed via an FAA rated school, like what I attended, or by serving a strictly documented and regulated "apprenticship" of sorts.
Attending a college as I did was VERY strict. Actually, I attended as soon as I graduated high school, and took my FAA exams when I turned legal age to do so, so I've been at it a while.
The big differneces between civilian and military maintenance is that a civilian mechanic is required to understand the generic in-and-outs of an aircraft system, regardless of what it is. For example, lets look at hydraulic systems(pumps). A civilain mechanic will know that there are: single and dual action manual hand pumps, gear driven, centrifugal and cam-piston type pumps. While a specific type pump may be designed for a particular aircraft, the basic way in which the pump is put together is similar between designs. The civilian mechanic will be able to: 1)troubleshoot the system (including documentation research), 2)remove the bad hydraulic pump, 3)remanufacture the the pump, 4)test the pump on a test bench system, 5) reinstall the pump, 6) ops check the hydraulic system, 7) complete all necessary paperwork.
On the other hand, USAF maintenance is task oriented. The flightline hydraulic specialist will know how to ops check a system by following a grade-school level flow chart, known as TO's and TM's. That USAF hydraulic specialist will have no understanding of the pumps innards, or what makes the system tic! In-shop maintenance will be responsible fo remanufacturing and pre-testing the pump, before sending it back to the flight-line. All in all, the USAF mechanic will have a fraction of the knowledge that a person who has attended an FAA rated school will have.
Civilian mechanics cannot legally ground an aircraft due to maintenance. They can simply write up the maintenance discrepency within the log book. Should a pilot or aircraft owner choose to fly an unairworthy aircraft, legal responsibility is on him/her. Consequently, there is often a lot of pressure put onto mechanics to pencil-whip maintenance. A notorious case happened a few years ago in Tucson at Hamilton Aviation. A mechanic refused to pencil-whip maintenance and was subsequently disciplined by the employeer. Luckily, the mechanic had the entire incident documented and consequently wone a mult-million $$ settlement against Hamilton.
USAF maintenance is really a Catch-22 NIGHTMARE ! Because the USAF coordinates various military operations with other branches of the US Armed Forces, on-time take off-reliability is ALL IMPORTANT! And this is even more evident at a high-profile base like Travis, where officers come for promotion. Not having a TO opened to the specific page and being able reference the specific "step" you are on is a Court-Marshall offense. But that on-time take-off is all important! And if that on-time take-off fails, then the mechanics annula evaluation report might not look good, if ya get my drift. So, one needs to deviate from the TO w/o getting cought!
Here is one of my favorite C-5 maintenance story at Travis that directly involved me. Myself and a fellow Airman were assigned to a C-5 that was due to leave on a mission later that day. As it turned out, the pre-flight inspection (which was usually good for 48hrs) needed to be updated. So, we began our inspection. We called our immediate supervisor to request a safety harness so that I could inspect the upper fusalage/wing surfaces. The supervisor told us that a safety harness was not available and that we should pencil-whip the maintenance. We refused, and a major pissing-match ensued. Our Line-Chief was then called, and subsequently sided with us two Airman over the TSgt supervisor. As soon as I got onto the uper fusalage surface, WHAT DID I FIND? A major pannel that required approximately 100 screws was held on with just 3! The pannel had previously been removed for maintenance, and only 3 of the 100 had been reinstalled! To make matters worse, the aircraft had flown a whopping 3 TIMES that month in this condition, with all those previous preflight inspections having been pencil-whipped. By this time the flight-crew had arrived on-scene when I called down that the aircraft was unairworthy! So, I went with our Line Chief all over Travis trying to locate the needed screws. As it was, all shops on base were out of the required hardware! So, the Line Chief grabbed whatever hardware he could find that would fill the holes! I refused to install the hardware or sign my name to the aircraft logs! I did recieve a Letter of Appreciation for my efforts, but my annual EPR did suffer for jeopardizing the on-time take-off. BTW, the aircraft did fly.
Going back to civilian maintenance, an A&P is legally allowed to work on everything on an aircraft with the exception of instruments and propellers. The A & P can ops check and remove/replace an instrument, but is not allowed to open it up. This is done by a spcially licensed FAA instrument repair station. DITTO with props, but there are a few thins a mechanic can do, like blending out a leading-edge that has been lightly damaged by FOD or the like.
And besides A,B,C,and D checks, and other "heavy" maintenance, all systems on an aircraft are maintained at time intervals, so, there may be maintenance done while the aircraft is a the boarding gate between flights!
Cheers
K.
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Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 05-29-2005 03:16 PM
Paul & Will - many thanks for the explanation.
quote: Paul Mayer
The manufacturer can drive that decision point by stopping support of an older design.
Or going bust, like Fokker.
quote: Paul Mayer
That was one of the reasons Concorde was retired--BAe had given up making parts and the operators BA and AF were beginning to scavenge parts off of existing airframes.
I guess that part of the problem there was that very few Concordes were ever built in the first place, and so maintaining a parts supply service would be far more difficult and expensive. Therefore, would it be fair to say that it's easier and cheaper to keep an older aircraft in service, the more of them were built in the first place? That would, I guess, create a bigger demand for new parts and a bigger supply of old ones (i.e. recycled from scrapped planes) than if you only build 10-20 to start with; not to mention a larger pool of engineers and pilots qualified to work on them.
quote: Paul Mayer
D Check: Like a complete overhaul/restoration for your car. Can take several months. My favorite definition of a D-Check is the one for older Learjets: "Leave no part standing against any other part." The aircraft is literally disassembled down to the last nut and bolt and sometimes rivet. All parts are cleaned, inspected, re-painted, and replaced if necessary. You practically have a new aircraft after a D Check. You're gonna need a bigger crew.
I'd further guess that when one of these comes due is the moment an operator has to make the realistic decision between investing in a D-check or a new plane. Presumably in some cases it must make economic sense to do the D-check and keep a plane in service, or else D-checks would never happen.
I must declare a personal interest here - I'm off to California for a couple of weeks in September. As this is on Northwest, presumably the transatlantic leg will be on one of their venerable DC-10s, like my trip to Minneapolis was last year. I take it these planes will have had a D-check or two by now...
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