Avionics, fatigue, vibration, materials and flight, engine, non-destructive…all of these areas require specialist products, software and training. And they are all intertwined into aviation and the manufacturing and maintenance of the aircraft operated in this industry where it is imperative to be ready for anything at any time. We will be exploring the latest technological advances in aerospace testing as well as the tried and true products already here.
Rolls-Royce has started testing the first elements of the most powerful hybrid-electric aero power and propulsion system in aerospace at a newly-renovated testbed.
The tests are part of the 2.5 megawatt (MW) Power Generation System 1 (PGS1) demonstrator program, for future regional aircraft.
Rolls-Royce has begun testing the AE2100 engine element and specialist controls and thermal management system, supported by a system integration generator, at their Testbed 108 in Bristol, UK.
Later this year a fully operational generator and a 3,000-volt power electronics system, currently completing testing at our facility in Trondheim, Norway, will be brought together to start full PGS1 system testing. The generator can be used either for hybrid-electric propulsion systems or as part of a “more-electric” system for larger aircraft.
Rolls-Royce says PGS1 forms an important element of their sustainability strategy, which includes developing innovative electrical power and propulsion systems, as well as further improving gas turbine performance and promoting the use of Sustainable Aviation Fuels.
“This is an important milestone for us all at Rolls-Royce. We are bringing together a system that promises to be truly ground-breaking in the world of aviation,” said Alan Newby, director Aerospace Technology and Future Programs, Rolls-Royce. “We know that in a post COVID-19 world people will want to connect but do so more sustainably. Electrification offers a new way to power short-haul aircraft and we want to be at the forefront of pioneering this technology.”
“Our PGS1 tests will lead the way in finding out what this new generation of hybrid-electric propulsion system is capable of delivering. For example, our generator is about the size of a beer keg but it needs to produce enough electricity to power around 2,500 homes and do so continuously. By doing these tests we will be able to validate our digital modelling and find out precisely what is physically and technically possible.”
Once ground tested, PGS1 will then provide a technology basis for any future hybrid aircraft program requiring MW power.
The company says both Testbed 108 and PGS1 have been supported by the UK Aerospace Technology Institute’s MegaFlight project, while the 2.5MW electrical generator, motor and power electronics design, make and testing in Trondheim has been supported by the EU Clean Sky 2 program.
Testbed 108 has a history that relates to a number of iconic aircraft engines. They include:
1960s /’70s – Hercules and Centaurus engines which powered the Bristol Beaufighter, Bristol Brabazon and Hawker Sea Fury aircraft. Olympus engine that powered the Concorde supersonic jet aircraft and the Avro Vulcan. 1970s/’80s – Pegasus and RB199 engines, powering the Harrier and Tornado.
1990s – Gem and RTM322 that power the Lynx, Army Air Corps Apache and Royal Navy Merlin helicopters.
The testbed, which had been used as a storage facility from 2008, was completely renovated to accommodate hybrid-electric testing.
Rolls-Royce has officially opened Testbed 80, the world’s largest and smartest indoor aerospace testbed, in a ceremony with the Rt Hon Kwasi Kwarteng, Secretary of State for the Department of Business Energy & Industrial Strategy, in Derby, UK.
The completion of the project is a major milestone after almost three years of construction and a £90m investment. With an internal area of 7,500m2, making it larger than a Premiership football pitch, Testbed 80 was designed with distinctive technologies and systems which are more capable and complex than any of our other testbeds. The testbed conducted its first run on a Rolls-Royce Trent XWB engine at the test facility in Derby, UK earlier this year.
“Testbed 80 is the largest facility of its type in the world. However, it is not only big, it is also smart and features the most advanced testing technology we have ever used,” Warren East, chief executive, Rolls-Royce, said. “As the new global hub of our testing capability, it will support the next stage of our UltraFan programme as we begin ground testing the first demonstrator in 2022. This incredible piece of infrastructure is a very visible sign of our commitment to this site and secures the future of Derby as the home of large engine development, continuing a history that began in the late 1960s with the RB211.”
Business Secretary Kwasi Kwarteng, said: “This testbed here in Derby shows that the UK remains a global leader in aeroengine technology. I’m proud that we’re supporting Rolls-Royce’s development of the highly-efficient UltraFan engine, as well as investment in green and cutting-edge aerospace technology here in the UK that will create high-skilled, well-paid jobs for decades to come. As the civil aviation market recovers, the innovation of great British companies such as Rolls-Royce and the entire aerospace sector are central to our plans to build back better from the pandemic and end our contribution to climate change by 2050.”
Testbed 80 will support all three pillars of the company’s sustainability strategy. Firstly, they say they will be continuing to improve the efficiency of the gas turbine. The facility has been designed to test a range of engines, including the Trent XWB and the Trent 1000, but will also have the capability to test the UltraFan demonstrator, the blueprint for our next generation of engines. UltraFan will be 25% more efficient than the first Trent engine, and ground testing of the demonstrator at the testbed will begin in 2022.
Secondly, Rolls-Royce says they are committed to promoting the use of Sustainable Aviation Fuels (SAFs), which can already be used as “drop-in” fuels in our existing engines. Testbed 80 has been designed to support this commitment – it is equipped with a 140,000-litre fuel tank (you could fill a car up almost 3,000 times with this amount of fuel) for different fuel types, including SAFs. Next year, Rolls-Royce says they also plan to run their first UltraFan demonstrator test using 100% SAF.
Finally, in line with Roll’s Royce’s ambition to pioneer novel, more sustainable technologies, they say the testbed is designed to have the capability to test the hybrid or all-electric flight systems of the future.
Part of the new technology development for Testbed 80 has been supported by the ATI’s PACE project, specifically for the UltraFan.
Rolls-Royce partnered with MDS Aero Support Corporation of Ottawa, Canada, for the design and construction of the facility.
AMADA WELD TECH announced the availability of the Jupiter series of modular systems for precision joining, available for laser welding, laser marking, resistance welding, micro arc welding, and hot bar bonding applications. Jupiter modular systems can be equipped with all joining process modules available from AMADA WELD TECH to provide solutions to customers.
With the Jupiter series, customers receive intensive process development support in AMADA WELD TECH application development centers. Joint early stage process development in AMADA WELD TECH labs ensures that customers receive the ideal system solution for years of high-quality production. Any welding, soldering, bonding, brazing, laser micromachining, and laser marking application can be handled by equipment in the Jupiter series.
The Jupiter modular system platform is a flexible system that comes in four sizes, so it is adaptable to specific production requirements. The stable platform enables connections of very high quality and accuracy. The modular design is configurable to fit all process components and modules. The Jupiter models feature an ergonomic system design with high quality components, designed for 24/7 continuous production. All models are equipped with a human-machine interface (HMI) with touchscreen for easy programming and standard safety features.
Control systems, based upon a programmable logic controller (PLC) or industrial PC, collect all available process parameters and process data into one control system. The data can be stored in local and remote storage areas, all engineered to seamlessly integrate with an Industry 4.0 factory concept.
Optional features for the Jupiter systems include a combustion suppression unit (CSU) for battery pack welding; a transport system with two individual belts that can be configured for a wide range of product carriers, including transfer systems; an automatic cleaning station for electrodes and thermodes; a “Not OK” bin to separate products outside the control limits from those within control limits; and a range of water cooling options. Also available are upgraded data collection and traceability functionalities, including a barcode reader or a label printer; and interfaces for a variety of robotic systems.
AMADA WELD TECH offers its expertise to all of its customers to correctly match any welding, soldering, bonding, brazing, laser micromachining and laser marking application inside the Jupiter series.
The Measuring Division of Kaman Precision Products announced the KD-5100+, an upgraded higher reliability version of Kaman’s legacy KD-5100 measuring system. The KD-5100+ retains the proven performance of the KD-5100 system while incorporating upgrades to the circuit layout, ground connections, and sensor connectors. The upgraded system also features higher reliability diodes and capacitors.
The KD-5100+ is used for laser communications, satellite and ground station applications, as well as directed energy (ground, shipboard, and airborne), and image stabilization systems.
Two precisely matched sensors of a measuring channel are positioned opposite each other on the back of a fast steering mirror (FSM) in two axes at 90 degrees to each other. As the FSM actuators drive the mirror about the center flexure, the mirror moves away from one sensor of an axis and toward the other sensor an equal amount. The KD-5100+ output signal is used to actively control mirror position.
At the heart of the upgraded KD-5100+ is a Mil-PRF-38534 Class H proprietary hybrid microcircuit. The system also features dual channel signal conditioner with two precisely matched sensors per channel.
Designed for thermal and long term stability, radiation tolerant, and suitable for vacuum applications, the KD-5100+ offers a small package size and low power consumption. It features isolated signal and chassis grounds and low outgassing components.
Signal conditioning electronics are available in the identical low profile enclosure as the KD-5100. Enclosure finish can be either black paint for low reflectivity or bright nickel finish for lower outgassing. Sensor and signal conditioner packaging can be customized for unique requirements.
Kaman offers high-precision, electro-mechanical contract manufacturing at its 215,000 square foot facility, with assembly to IPC-A-610 Class III and component traceability. Complete end-item data package (EIDP) development is available upon request. The Measuring Division of Kaman Precision Products follows rigorous aerospace quality systems. The manufacturing facility is certified to AS9100 and ISO 9001:2000 and features a class 100 clean room.
Jamco America highlights its extensive machining capabilities that enable the company to meet rapid turnaround times and extensive customization needs. In addition to internal product development and fabrication projects for its aerospace customers, the Jamco America machine shop is available for contract projects from the aerospace industry.
In nearly 30 years of operation, the Jamco machine shop has expanded its capabilities from basic machining to extensive, cutting edge equipment. The shop’s capabilities include: sheet metal bending, profiling, and forming; countersinking, dimpling, riveting, and other preparations for sub-assembly; large 4-axis Horizontal milling and machining; smaller 3- and 4-axis Vertical machining; and lathe turning for round components. The large 4-axis machine centers hold 240 tools each, and are accompanied by an automated 36 pallet cell, for highly flexible, efficient milling 24/7, ensuring rapid turnaround time.
One of the shop’s most unique capabilities is delivered by its freeform CNC tube bender, installed in summer 2020. This machine forms a round tube into a unique tubing frame, and is used to produce Jamco’s industry-leading Venture business class seats with embedded aluminum edge trim. The shop also houses a digital cutter/router for composite materials, open cell core, textiles, and more. Used traditionally in the sign-making industry, Jamco has adapted this technology for aircraft seating and other innovative projects.
Thanks to its extensive machining capabilities, Jamco America is able to deliver products in unrivaled rapid lead times. This rapid turnaround enables fast-paced product development, a necessity in aerospace and other highly demanding industries. What’s more, the machine shop’s extensive capabilities enable Jamco to offer ultimate customizability, helping customers to differentiate their products from competitors.
On April 29th, 2021, ZeroAvia’s R&D aircraft made an off-airport landing just outside Cranfield airport perimeter during a routine pattern test flight (logged as ZeroAvia Test 86, and the 6th flight in this flight testing segment). The aircraft landed normally on its wheels in a flat grass field and almost came to a stop, but was damaged as it caught the left main gear and wing in the uneven terrain at the end of the field at low speed. Everybody involved is safe, and without injury. The incident was immediately reported to the Air Accidents Investigation Branch (AAIB), and the Fire Service attended on the ground, as is the standard procedure.
The facts as they stand now are as follows: the flight conformed to the approved test route over the airport; the structural integrity of ZeroAvia systems was maintained throughout the incident sequence and there were no unintended hydrogen or electrical releases and no fire; after the landing, the crew were able to safeguard the battery and safely release hydrogen from the onboard tanks, following ZeroAvia safety protocol; no fluid leaks were observed at the time; and full data logs were preserved and will be used in our investigation.
Following the flight test incident, ZeroAvia appointed a team of experts to conduct the internal investigation. These individuals, led by Dominic Cheater, ZeroAvia’s Head of Airworthiness, are independent from the design and operation of the HyFlyer I program. Dominic holds extensive expertise in airworthiness, flight test engineering and air safety. He has past experience with major industry names such as Babcock International as Chief of the Office of Airworthiness.
Vibrant has received FAA Part 145 repair station certification for its Albuquerque, New Mexico facility. The certification makes it easier for Vibrant to support OEMs, airlines, and independent MROs with its revolutionary process compensated resonance testing (PCRT) services. PCRT provides unparalleled nondestructive testing for worldwide aerospace, automotive, and power generation industries.
“For more than 30 years, Vibrant’s innovative nondestructive testing services have helped industries cost-effectively test every part, ensuring higher quality and reliability while reducing costly incidents caused by undiscovered faults deep inside parts,” said Lem Hunter, president, Vibrant. “FAA Part 145 repair station certification delivers yet another level of integrity to our services, guaranteeing Vibrant meets the FAA’s high standards in quality and accountability.”
As a part of receiving the certification, Vibrant hired Greg Sullivan to serve as the repair station’s accountability manager. A licensed airframe and powerplant mechanic with inspector authorization and a former American Airlines Boeing heavy airliner captain, Sullivan brings real-world experience to Vibrant, including experience in interpreting, meeting, and documenting processes and procedures as per FAA regulations.
Carlisle Interconnect Technologies announced that it is now offering vibration and mechanical shock testing. These services provide original equipment manufacturers (OEM) insight into how a product will behave while in vibration environments found in helicopters, turboprop planes and more. In addition to performance, CarlisleIT’s vibration and shock testing also helps OEMs evaluate conformance to product’s specification requirements, determines resonate frequencies and behavior during sudden deceleration.
“Product testing is a very important part of the manufacturing process, and we have a team of experts who will make sure that every product is 100% ready to go to market,” said Rob Degrave, product line manager, Aerostructures for CarlisleIT. “As a leading supplier of interconnect technologies and services, our goal is to provide as many high-quality services to OEMs as possible to ensure that they continue to achieve their goals and foster innovation that propels the industry forward.”
In spite of a laudable safety record, recent airframe and engine incidents have together raised concern about whether we might be taking the vast improvements in safety over the last two decades for granted. Certainly, the series of high profile engine failures have caught the attention of many. What’s going on and what can be done to address these mishaps?
About the time the CFM 56 engine experienced its uncontained engine failure on Southwest 1380, killing a passenger in the direct line of fire of the rocketing engine parts, the industry was already in the thick of a series of engine failures.
These incidents culminated in twin incidents on February 20. United Flight 328, a 26-year-old 777 powered by Pratt & Whitney 4000 engines experienced an engine failure during taking off from Denver, cascading engine parts across the landscape. The same day, a PW4000 powered 747-400 cargoliner, operated by Longtail Aviation, experienced a mid-air explosion and fire on a PW4000 engine, similarly raining parts over its flight path.
These two incidents and several both before and after Southwest 1380 raise concerns about maintenance and even design and manufacturing and whether our laudable safety record on crashes is in jeopardy.
The Big Picture
We know most things went right during these events. Like those before them, the United crew, who oddly remain unnamed despite the wide-spread coverage, were able to safely land the aircraft. In its March 5 incident update, NTSB reported the spar valve, which stops fuel flow to the engine worked. But examination of the engine accessories showed multiple broken fuel, oil, and hydraulic lines and the gearbox was fractured, all feeding the dramatic fire caught in passenger images.
“It must be pointed out the aircraft landed safely,” The Giles Group’s Carol Giles, shown below, told Aerospace Tech Review. “The good news is the reliability and piloting skills that come into play, mitigates what could have been a huge catastrophe.”
At a time when the industry has delivered unprecedented safety, one is right to ask what might be going on. While crashes have occurred overseas and remain achingly few and far between, we do have numerous airframe and engine incidents that, together, raise concern and begs the question whether we are taking the vast improvements in safety over the last two decades for granted.
Certainly, the series of engine failures have caught the attention of Congress.
“Two senior U.S. lawmakers said the FAA has failed to turn over a report to Congress on airline engine safety required under a 2018 law,” reported Assurance Ltd. “Without the report it was impossible for anyone ‘to know whether the best practices and recommendations to improve airline engine safety could have helped to prevent the engine mishaps that have taken place since the October 2019 safety review.’ Recommendations to improve airline engine safety have been languishing for well over a year. Even more concerning is the potential missed opportunity to address similar airline engine safety issues before they occurred again.”
Adam Pilarski, Avitas senior vice president, shown right, thinks the problem is more systemic than just isolated incidents affecting airframes and engines.
“It’s not just the 737 Max,” he told Aerospace Tech Review. “Every manufacturer has problems. Every single one and I think they tried to do too much too soon because of demand. We tried to go too fast into large production. The manufacturers, unfortunately, didn’t get their stuff together before producing record numbers of engines or aircraft. Their only approach was to ask how they can squeeze out another few cents through minor tweaks not how to produce the vast numbers of engines needed. We saw similar problems with the OEMs both Boeing and Airbus.”
Pilarski noted engine issues are not unique to Pratt having affected CFM, GE and Rolls Royce.
“The problem is,” Pilarski added, “manufacturing is not sexy. Manufacturers only wanted to push out more products rather than focus on the boring stuff.
“This has been happening for years and is not new,” he continued. “They were looking at market demand rather than thinking of how to produce thousands of units. I think they didn’t focus on how you actually put it together – the boring things. They didn’t make the right effort.”
He also questions whether manufacturer emphasis on aftermarket service came at the expense of production capabilities. He has previously noted manufacturers don’t make money on engines but make it up in aftermarket service programs.
“I don’t know if the current issues are systemic from design all the way through to manufacturing,” Giles added. “It’s hard to think that every manufacturer would have a systemic issue. But it’s good to question whether or not we are going too fast.”
Pilarski sees these problems as a test for the new leadership.
“We don’t know how the new leaders at these companies will address these issues,” he said, noting Pratt is now under Raytheon after its merger with UTC. “John Slattery, who I respect and admire as much as I did David Joyce, is now heading up GE. He’s a brilliant marketing guy but his strength is not in the boring development and delivery of engines. But using baseball language, he has a good bench.”
He also sees how Covid could benefit the industry. “To some degree the disaster we have now with Covid gives manufacturers breathing room since no one is pushing for new aircraft immediately,” he pointed out. “Now is a good time to do the boring stuff, figure out what went wrong with design and actually delivering one unit after another in the thousands.”
Giles also agrees Covid is an opportunity to examine what is happening with new engines and the engine/airframe combination.
“We should be asking ourselves these questions,” she concluded, noting United 328 prompted internal company discussions whether it was about bad maintenance or, perhaps, a design issue.
“You don’t know until you do the investigation,” she told Aerospace Tech Review. “I’m not sure what the root cause is of the engine events, but they are major.”
Perhaps the point is that whether the company is run by marketing, bean counters or engineers, it can still go astray as the industry has already seen.
While the 737 Max may be the latest poster child, there have been serious issues with aircraft design and production with every new aircraft and, in the past 20 years, few have been delivered on time owing in part to development and production problems.
Even after delivery some, like the 787, have been grounded because of battery fires. Similarly, Pratt’s Geared TurboFan, powering the A320new, A220 and Embraer E190 has struggled through the engine problems. The question is whether what we are seeing is normal teething or a systemic problem.
Of course, there is Air Force and 787 quality issues and now the electrical system problems on 106 737 MAXs built in 2019 that is now complicating the MAX’s return to service.
Problems with Rolls Royce’s Trent 1000 prompted a redesign of the turbine blades and replacement owing to premature wear, disrupting global 787 operations. In mid 2020, EASA issued an airworthiness directive prompted by another issue, unrelated to the Trent’s previous problems. It called for one-time, ultra-high sensitivity fluorescent penetrant inspection of seal fins and replacement of parts if cracks are identified. It prompted the company to revise its inspection regime on the low-pressure turbine and focused on the disc seal fins. Rubbing wear between discs and interstage static seals could prompt cracks in the front seal fins and lead to disc cracks in the low-pressure turbine discs.
Problems have also occurred on GEnx-powered 787s after an inflight failure in 2016. The GEnx-1B-PIP2 engine suffered substantial damage when ice on the fan blades broke loose, causing the FAA to order engines replaced or repaired because it feared failure of both engines in flight.
The list goes on.
New SMS Requirements
All this is happening against a backdrop of international requirements for manufacturers to implement the Safety Management Systems (SMS) that have been widely adopted throughout the industry and is considered a significant contributor to improving safety.
SMS is a decision-making system based on proactively identifying, assessing and controlling hazards and safety risks before they result in accidents and incidents, and analyzing performance data for continuous improvement, according to the Aerospace Industries Association, involved in developing voluntary SMS standards.
Work within the industry has been ongoing since the first decade of the century culminating in the adoption of ICAO Annex 19 requiring SMS development for design and production approval holders. The FAA embraced this effort, reporting in 2018 on its Manufacturers SMS (MSMS) Pilot Project and the Part 21/SMS Aviation Rulemaking Committee (ARC), as part of an effort to develop a rulemaking package. The Notice of Proposed Rule Making (NPRM) was tabled in 2018.
Simultaneously, however, the manufacturing industry developed a standard for voluntary SMS programs known as National Aerospace Standard (NAS 9927) or Safety Management Systems and Practices for Design and Manufacturing. NAS 9927 was approved by the FAA, which encouraged industry to implement the voluntary program.
The publication of the international industry standard developed by the world’s leading aerospace designers, manufacturers and maintenance organizations, promises improved safety performance and enhanced safety culture.
Implementing a Safety Management System for Design, Manufacturing and Maintenance Providers is available free.
The team that spent two years developing the standard and included the AeroSpace and Defense Association of Europe (ASD), Aerospace Industries Association of America (AIA), Aerospace Industries Association of Brazil (AIAB), the Aerospace Industries Association of Canada (AIAC) and the General Aviation Manufacturers Association (GAMA). It enables the global aviation industry to implement a SMS consistent with the International Civil Aviation Organization’s (ICAO) Annex 19. The organizations continue their work to ensure future revisions are effective.
“Development of an internationally-recognized SMS Standard that is consistent with Annex 19 means that we now have a tool to implement key safety measures in a consistent manner up and down our industry, which ultimately results in a more accountable safety system,” said David Silver, AIA’s vice president for civil aviation at the time.
“SMS for manufacturing is coming down the pike very fast,” Giles indicated. “MROs have implemented SMS because regulators around the world are requiring it.”
Finding Root Causes
But SMS is a pro-active solution while other programs dig to find the root cause of problems and, according to Pilarksi, that may be what is needed.
In the late 1990s, the FAA developed a safety system requiring airlines to identify problems and follow them back to the root cause which could be as simple as the wrong tools or inadequate training. This system then requires corrections ensure the issue does not arise again. It is like a safety investigation designed to prevent the crash, not determine what went wrong and why after the fact.
There seem to be four trends colliding. The first, as Pilarski noted, the rush to meet demand. Second, are industry efforts to reduce maintenance costs by increasing time between overhauls and inspections.
Pilarski has noted in the past that it is harder to predict component lifecycles and repair costs with new designs and materials.
The question is whether the intervals between those maintenance events are really what they should be.
The infamous issues with the Rolls Royce Trent engine powering the 787 prompted the company to reduce the time between servicing as did the two United and one JAL incidents.
After a previous engine failure caused by a fractured fan blade on a United Honolulu-bound flight in 2018, United’s inspections for the 777 were set at 6500 cycles but United 328 had flown only 3000 cycles. Pratt then reduced it to 1000 cycles before the FAA mandated immediate inspections which grounded the aircraft.
After the Honolulu incident the National Transportation Safety Board cited insufficient training for Thermal Acoustic Image (TAI) inspections developed by Pratt & Whitney. It said maintenance technicians misdiagnosed a problem with the blade. In response Pratt created a more formal inspection training curriculum after which the FAA issued an AD requiring stepped up inspections.
Assurance Ltd. Director Andy Evans explained TAI causes movement between each side contacting any inclusion in the metal, creating heat by friction which is then detected by a thermal sensor.
Evans said TAI is rare in the MRO industry which relies more heavily on conventional ultrasonics which, like sonar develops an acoustic reflection for internal defect detection.
“It’s a current MRO issue,” Evans told Aerospace Tech Review. “The concern from the 2018 NTSB investigation is there were shockingly big flaws in the PW process in the early days.
Hopefully, inspections have been much more tightly controlled in recent years, but the JAL event suggests the FAA airworthiness directive compliance times may have been too generous.”
Evans found it surprising that the NTSB investigation on the 2018 incident yielded no recommendations. “It again — like Sioux City did a generation earlier — highlights the critical nature of NDI in engine overhaul shops, the importance of properly specifying the technique, ensuring competent inspectors, considering the human factors and ensuring the process is quality assured.”
Last July, Assurance published an analysis of NDI process failures in United’s Honolulu incident shortly after NTSB published is report identifying a low-cycle fatigue fracture. The engine had been overhauled by Pratt’s Overhaul and Repair facility in 2015. Blades received a fluorescent penetrant inspection as well as TAI, developed by Pratt in 2005 to inspect interior surfaces of the hollow core fan blade, according to the NTSB.
Interestingly, the 2015 and earlier 2010 TAI inspections revealed a thermal indication in the same location as the low-cycle fracture. This was attributed to flaking paint which affected about 25% of blades, said the board.
The report further noted that Pratt identified TAI as a new and emerging technology meaning it didn’t have to develop a formal initial and recurrent training program, certify TAI inspectors or have Level 3 inspector on staff in conformance with normal NDI practice. Despite the time between development of TAI and the 2018 engine failure, the inspection process was still categorized as new and emerging despite being used on over 9000 blades.
While the manufacturer had developed formal training on TAI the two inspectors working on the engine were not permitted to attend in favor of clearing out a backlog of blades in the shop.
“So,” said the Assurance report, “clearing the backlog appears to have been more important than formal training on the inspection. It also noted the backlog resulted in overtime begging questions about personnel fatigue. One inspector complained the procedures were ‘written for the lab rather than the shops and had lots of gaps.’”
The board also noted environmental problems in the inspection room that was bathed in sunlight that could throw off the TAI scanners. The Assurance report also questioned the frequency of FAA visits to the inspection facility.
After post-incident inspection revealed the thermal indications at the location of the fatigue crack, Pratt initiated an “over-inspection of all digital images of the TAI’s accomplished on the PW4000 112-inch fan blades according to the NTSB findings. That prompted the AD requiring an initial and recurring TAI inspections of the hollow core blades.
Another issue focuses on nacelles that are supposed to contain engine failures but clearly do not and may have fallen victim to the tweaks Pilarski spoke about.
Manufacturers and FAA have been struggling with this issue for years. They are trying to develop more robust designs beyond protecting against fan blade break up and expanding to protect against disintegration of disks such as happened to an Engine Alliance powered Airbus 380 over Greenland in 2017.
Boeing is also working on solutions for when fan blades fly forward, according to FAA, which said the work relates to the 737 and will result in mandating a design change.
Evan expects a modification to make the nose cowling attachment more robust to emerge as an AD. He also noted the aircraft in service are dwindling with the retirement announcement of JAL’s 777 fleet recently. Even so, United expects to return its 777s to the fleet “in the near future,” according to statements on its earnings call.
The numerous engine incidents also begs questions about the generosity of ETOPs operations. However, it is early days yet to suggest changes will come especially with 40 years of ETOPS operational experience in the industry.
Given the issues running through both engines and airframes, it may well be time to pause and take stock to ensure advancements made in the last two decades in materials and design are not somehow becoming counterproductive to safety.
MTI Instruments announced their newest product addition, the PBS-4100+ Portable Vibration and Balancing System, “PBS Gen 4.”
“We are excited to announce our new PBS Gen 4 as it is fully portable, lightweight and rugged, and more importantly, it is the most powerful system in its class on the market,” said MTI Instruments’ president, Moshe Binyamin. “Additionally, this compact form factor system is designed to be used on the go with extended frequency range. We also expanded the capability set to include numerous innovative capabilities.”
The PBS Gen 4 is designed for commercial aviation mobile applications, featuring a new high-visibility case and up to four hours of continuous use on a single battery charge.
Included in the new system is a third tachometer input, supporting three-spool engines and geared-reduction fans giving the technician more information than ever before. The frequency range has been extended to 25 kHz, to support turboshaft and APU testing which streamlines vibration survey and balancing processes. With engine backup and restoration capabilities, users can be sure engine parameters are configured correctly every time. While the unit reflects the latest in balancing system technology, it remains easy to use with limited training required, especially for technicians familiar with previous iterations of MTI’s PBS systems.
The PBS Gen 4 integrates features that ensure the system is easier to use than any PBS before it.
“The new cable check is a fantastic addition which, once it hits the market, I believe will quickly become the new standard in the future,” said Hamish Haridas, field service representative, Vital Link Europe Ltd. “The quick switch is also a great addition which will alleviate having to remind the operators that conducting vibration survey is in another ‘screen’, making balancing seamless.”
The new software has enhanced protection against online threats, with continuing updates provided, ensuring seamless workflow and limited downtime due to cybersecurity issues.
“The true differentiator is all of the technology and software packed into a simple easy to use interface,” said Ken Ameika, global director of Sales at MTI Instruments. “Today and tomorrow, when engine vibration levels need to be negated, the WinPBS balancing wizard will get the job done quickly and easily. It even supports both trial weight and stored influence coefficient balancing methods. There is no other system on the market that can do what the PBS-4100+ does as efficiently and easily.”
With vibration diagnostics that can help identify vibration sources and onboard spectral analysis finding potential problems before they occur, the system helps identify concerns before they become safety risks in-flight situations. With unique tachometer signal conditioning circuitry, speed signals from all engine types, as well as tachometer generators, add a higher level of diagnostics, available only to users of the PBS-4100+ system.