Monday, December 1, 2008
For daily and breaking news in aviation maintenance, go to: www.AviationToday.com
Findings on Air Carrier Outsourcing Released
At the end of September, the Office of the Inspector General of the U. S. Department of Transportation released its most recent findings on air carriers’ outsourcing of aircraft maintenance. The inspectors’ objectives were to identify the type and quantity of maintenance performed by external repair stations and to determine whether FAA is effectively monitoring air carriers’ oversight of external repair stations’ work and verifying that safety requirements are met.
The results showed that air carriers are "increasingly outsourcing maintenance to repair stations to reduce operating costs." Nine major carriers were included: AirTran Airways, Alaska Airlines, America West Airlines, Continental Airlines, Delta Air Lines, JetBlue Airways, Northwest Airlines, Southwest Airlines and United Airlines. The study found that 71 percent of heavy airframe maintenance checks were sent to repair stations in 2007, almost doubling since 2003. Foreign repair stations did 27 percent of the outsourced heavy airframe maintenance checks, up six percent from 2003. (See chart.)
The report outlines areas of improvement for the FAA, including that the agency needs to improve its system for determining how much and where outsourced maintenance is performed. It notes that since "air carriers are only required to report their top 10 substantial maintenance providers... the system provides only limited data for FAA use in targeting inspections." The report continues that FAA needs to ensure carriers and repair stations have strong oversight systems due to the FAA’s reliance on air carriers’ own oversight. It states that the FAA needs to improve processes for documenting inspection results because FAA inspectors "did not consistently document or share inspection results." It also notes that FAA should expedite actions to ensure air carriers better define their maintenance procedures because "air carriers have not been required to have specific guidance for outsourced repairs."
The report also includes seven recommendations:
The FAA was given the draft report and concurred with all seven recommendations and provided milestones for implementing corrective actions. Five of the seven are considered resolved but the inspector general’s office requested more information about FAA’s action on recommendations 4(b) and 5 from the above list.
Airbus Starts P&W Geared Turbofan Flight Tests
Using its A340 testbed, Airbus has kicked off flight testing of the Pratt & Whitney Geared Turbofan (GTF) engine. The cooperative effort between the two companies is being conducted at the Airbus facility in Toulouse, France. It will evaluate the PW1000G technology demonstrator, which features the GTF architecture, through a series of airborne trials that will continue until the end of 2008. Airbus, which plans to carry out similar tests with other major engine manufacturers, will also validate the fuel burn and CO2 emissions from each new engine technology. Based in Toulouse, the A340-600 testbed has been used to flight test various engines. "It is imperative to us that we continuously explore all technology developments to achieve our ambitious targets," says Christian Scherer, Airbus executive VP strategy and future programs. PW1000G trials will center on design elements, such as the fan-drive gear system. Pratt & Whitney has also performed a PW1000G flight test campaign on a Boeing 747.
EASA Publishes AD for DC-9/MD-80 Family
As part of Spanish investigators’ inquiry into the Aug. 20 crash of a Spanair DC-9-82 at Barajas Intl Airport in Madrid, the European Aviation Safety Agency (EASA) has issued an airworthiness directive (AD) for the DC-9/MD-80 family. Effective Nov. 12, the AD calls for an update of the Airplane Flight Manual (AFM) to incorporate a mandatory check of the take-off warning (TOW) system before engine start, prior to every flight. The system gives a warning in the event the flaps and slats are not correctly set, alerting the crew to an improper takeoff configuration. The Joint Aviation Authorities (JAA) has also issued an operational directive (OD) to ensure that its member carriers check the TOW system before each flight. Spain’s CIAIAC has not yet established the cause of the crash, but indicated that the flaps/slats were not set for takeoff and the TOW system did not function properly in the Spanair jet.
Battelle Develops Fuel Tank Robot to Aide Inspections
Today fuel tank maintainers have to climb into these dark, forbidding and stinking enclosures to inspect for scratches, corrosion, impact damage and debris. Among the potential hazards listed in a Boeing how-to document are "fire and explosion, toxic and irritating chemicals, oxygen deficiency, and the confined nature of the fuel tank itself." In addition, inspection carries the risk of further damaging the tank by scratching the mating surfaces of the access hole and cover or the interior surfaces of the tank or, as Boeing notes, by penetrating fuel tank bladders or striking and dislodging components such as fuel pumps, fuel quantity systems, associated wiring and conduits, and sealants. Even if all the recommended precautions are taken, this work is clearly a delicate and dangerous job.
The U.S. Air Force has made a number of attempts to automate the process, but the resulting systems have been too big, too slow or too difficult to learn, according to Battelle, a research and development company. The latest contender to attack the problem, Battelle claims to have a better design, a robotic system which is affordable, efficient and operable without a lot of specialized computer training. Battelle originally developed the Multi-Use Robotic System (MURS) under an Air Force feasibility demonstration program aimed at nondestructive inspection. A MURS prototype was tested in late 2007 in an actual B-52 wing tank.
Following the conclusion of the USAF program in December 2007, the company has continued to fund the project internally in order to mature the prototype and increase the speed of the control system. Technicians want to accelerate the computation that allows the robot to navigate around the tank in seven-dimensional space without bumping into anything. Battelle envisions ways "to build a high-performance [computer] architecture that’s still very affordable, very scalable, but will make the algorithms perform much, much faster," says Tim Lastrapes, Battelle program manager.
MURS is already pretty fast. Once assembled and installed in a fuel bay — a section of the wing tank separated by the ribs — MURS can perform an inspection, document its findings and generate an automated report in 30 to 45 minutes, says Lastrapes. The bay he refers to measures 5 to 6 feet tall, about 8 feet forward-to-aft and about 3 feet across.
MURS features a six-degree-of-freedom, DENSO robotic arm mounted on a customized carriage system on a special track. This track can then be clamped to a curved surface like a wing tank. The approximately 3-foot-long arm, in its current configuration, travels along an 8-foot-long track (made of four 2-foot-long segments), enabling the robot to operate on a surface up to 14 feet long and 6 feet wide. That’s more than enough to cover the fuel bay in which it was originally demonstrated.
MURS uses a laser scanner — accurate to about 7 thousandths of an inch — to map and characterize the internal environment, forming a 3D image of a tank. The scanned data is then used to preprogram the robot’s path. The operator outside uses a computer to point and click on areas he wants the robot to inspect. A low-light-sensitive camera is mounted on the robot and an overview camera can be put into the tank to allow the operator to watch the robot. Multiple LED lights also are mounted on the robot.
But the core of the system is its software. Battelle has devoted considerable effort to developing software with motion algorithms allowing the calculation of collision-free paths from point to point. The company also mentions the idea of enhancing the software to allow the robot continuous motion, so that a maintainer could outline a trajectory for the robot to follow and monitor its progress, rather than specify a point or group of points.
Installation of the robot inside a tank bay takes less than 15 minutes, Battelle says. MURS meets the Air Force’s 32-pound, single-person lift standard: the robot arm with the plate that attaches to the carriage weighs about 27 pounds and the other components weigh 12 to 15 pounds apiece. The whole assembly comes in at about 90 pounds.
The advantages of semi-automated tank inspections are clear. A robot adapted to work in low light conditions, yet controlled by a knowledgeable individual, could permit the inspection process to be more consistent and thorough. Moreover, the approach would reduce the human maintainer’s exposure and discomfort in cramped and potentially toxic conditions by as much as 80 percent, he says. "That’s a huge thing."
If the technology ends up being adopted, there could be a sizable market. As Lastrapes points out, 90 percent or more of the Air Force fleet is 25 years or older, and the already aging B-52 fleet is expected to keep flying for another 40 years. The current MURS is also applicable to other large aircraft, such as the C-5, KC-135, E-3 or C-17, for example, the company says. Battelle is also looking at smaller, tactical aircraft, as well as at other applications such as painting and depainting. "Pretty much anything you can get a human arm to do," this robot could probably do, Lastrapes says.
— By Charlotte Adams