October 16, 2024 - No. 42 In This Issue : Air Force maintainers will learn more about mishaps but can’t share it : Air Force maintenance mishaps are rising. Can a worksheet fix it? : Contractor crushed by T-38 jet suffered broken ribs, spinal fractures : MRO Memo: Delta Rewarded For TechOps Investment : Spate of Runway Safety Incidents Sparks Avionics Innovation : British Airways cancels some long-haul flights amid engine woes : New Five-blade Propeller for King Air 200 Series Earns INAC Venezuela Approval : FAA's oversight not enough to address Boeing manufacturing, production issues, report finds : New Technologies Drive APU Performance Improvements : LATAM’s B777s fly with shark skin foils Air Force maintainers will learn more about mishaps but can’t share it By Stephen Losey Oct 14, 2024, 07:02 AM The Air Force is expanding its maintainer training and briefings on mishaps and will require those airmen to sign non-disclosure agreements for the first time as part of the expanded effort. (Senior Airman Mark Sulaica/U.S. Air Force) The Air Force is trying to halt an increase in maintenance-related aircraft mishaps by putting new safety training and briefings in place for maintainers that the service says will now require those airmen to sign non-disclosure agreements, or NDAs, in the process. An NDA is a legal contract that prevents the sharing of such information. This is the first time all aircraft maintainers have received such mishap training, which contain more details on mishaps that the Air Force considers privileged information, necessitating the NDAs, according to Air Force officials. Privileged information includes the factors and causes that led to a mishap, findings of an accident investigation and recommendations, Air Force spokeswoman Ann Stefanek said in an email. The annual safety trainings and recurring briefings began in August, she said, after Air Force Chief of Safety Brig. Gen. Sean Choquette pushed for the change. It applies to all aircraft maintenance personnel that conduct hands-on maintenance of Air Force aircraft, including those in the Air Force Reserve and Air National Guard. Air crews for years have had similar training and NDA requirements, Stefanek said, which has reduced mishaps and saved lives. The beefed-up training and briefings will allow the Air Force to confidentially share the details on these accidents and quickly teach maintainers what lessons have been learned, Stefanek said. Without the confidentiality provided by NDAs, Stefanek said, “we don’t quickly get to the root cause of a mishap, and mishap prevention is critical to mission readiness and our national security.” But some critics worry that the NDAs could stifle the Air Force publicly acknowledging its mishaps. The new NDAs first surfaced publicly on the unofficial Air Force amn/nco/snco Facebook page, which on Sept. 30 posted a screenshot of an Air Combat Command email instructing maintainers to sign an NDA by Oct. 11. That email said the spike in maintenance-related mishaps over the last two years has cost the Air Force more than $79 million. Retired airman Steven Mayne, who runs the Air Force amn/nco/snco Facebook page and often posts news and submitted photographs of Air Force aviation mishaps shortly after they occur, fears the NDA requirement will lead to less public reporting of such accidents. “Perhaps the Air Force wants to achieve a chilling effect [on public release] with NDAs, and is tired of accidents getting out with Congress, media and the public demanding answers,” Mayne said in an email. The Air Force’s most serious aviation mishaps hit a five-year high in 2023, an Air Force Times analysis found earlier this year. That corresponded with a spike in maintenance-related accidents that have increasingly injured airmen on the job. Top Air Force officials have said pinning down the causes of the maintenance mishap increase has proven difficult. Stefanek said no maintainers will be required to sign NDAs. But if maintainers do not sign the agreements, she said, they would not be allowed to access any privileged safety information “and would not be as fully equipped to help prevent mishaps and injuries.” Before maintainers are asked to sign NDAs, Stefanek said, they are first trained on what privileged safety information is, and what their requirements are to protect it. NDAs are already required for some other airmen to receive access to sensitive information, she said. “This requirement is an effort to bring aviation maintainers into the same trusted fold [as aircrew] to prevent mishaps,” Stefanek said. “Without the ability to share what happened on a mishap, prevention doesn’t happen.” Because aircraft maintainers have never regularly received this training, Stefanek said, this has created a “gap in our hazard and mishap mitigation effort.” In the past, such training has occurred at only the local level, making it hard to put the lessons learned in place across the entire Air Force. Misplaced flashlight in F-35 engine results in $4 million in damage By Sarah Sicard Friday, Jan 19, 2024 An F-35A Lightning II, like the one seen here, was severely damaged when a misplaced flashlight was sucked into the aircraft’s inlet engine. (Master Sgt. Ryan Campbell/Air National Guard) A foreign object left inside an F-35 engine at Luke Air Force Base, Arizona, in early 2023 caused nearly $4 million in damages, a recent Air Force accident investigation report revealed. The item — a handheld flashlight — was sucked into the engine’s air intake during a maintenance ground run on the night of March 15, Air & Space Forces Magazine first reported. The aircraft belonged to the 56th Fighter Wing. During an idling procedure, a team of three maintainers started the engine without issue before going through typical checks, including idling for five minutes to monitor for fuel leaks. It wasn’t until the airmen turned off the engine that anything seemed amiss. During the shutdown, one maintainer noted “abnormal noises.” None of the airmen were injured. One of the maintainers carried out a tool inventory check after installing a “metering plug into an engine fuel line,” the investigation noted. The process took place before another maintainer used the flashlight to carry out a “Before Operations Servicing” inspection, the report said. Investigators determined that the maintainers’ lack of adherence to standard cautionary items highlighted in the Joint Technical Data checklist before the run contributed to their leaving the flashlight behind. Investigators also found that “complacency” related to the F-35′s Autonomic Logistics Information System, or ALIS, is partly to blame. “The substantial number of checklists and difficulty in accessing the correct ones causes complacency when users reference the required maintenance procedures,” the report noted. Ultimately, the mishap damaged the aircraft’s second stage rotor, third stage rotor, fifth stage rotor, sixth stage rotor, fuel nozzle, bypass duct, high pressure compressor, high pressure turbine and fan inlet variable vane, the report found. In total, the estimated cost of damages associated with the accident came in at $3,933,106. The report concluded that the inspecting maintainer “failed to clear the inlet of foreign objects after completing the required inspections for an engine run after they exited the aircraft inlet.” “Failure to complete checklist tasks resulted in a flashlight being left inside the inlet,” the report said. Contractor crushed by T-38 jet suffered broken ribs, spinal fractures By Courtney Mabeus-Brown Monday, Apr 1, 2024 A T-38 Talon taxis on a runway at Holloman Air Force Base, New Mexico, March 7, 2024. (Senior Airman Nicholas Paczkowski/Air Force) A civilian maintainer was hospitalized for nearly a week with multiple broken bones and other injuries after the nose of a T-38A Talon training jet collapsed on him at Holloman Air Force Base, New Mexico, in February 2023, according to an Air Force investigation. The unnamed contractor was lubricating the Talon’s landing gear as part of routine maintenance on the jet, assigned to the 509th Bomb Wing at Whiteman Air Force Base, Missouri, when he removed a safety pin that caused the nose gear to retract as he worked on the plane, the service concluded in an investigation report published March 28. The Talon’s nose crushed the man for several minutes, breaking several ribs and leaving him with spinal fractures. It took seven people to lift the aircraft off of him; he was airlifted to a hospital in Texas. Aircraft damages cost more than $116,000 to repair, the report said. The Talon’s forward nose landing gear door, an antenna, forward fuselage and pitot boom, which calculates speed, were damaged in the accident, which was classified as a “Class B” mishap. Class B incidents cause between $600,000 and $2.5 million in damages, permanent partial disability or inpatient hospitalization of three or more personnel, or a combination of those factors. The maintainer worked for Texas-based M1 Support Services, a contractor that maintains T-38s for the 49th Maintenance Group at Holloman. He was qualified to work on fighter jets, and had several years of experience working on helicopters with the Alaska Air National Guard. However, the accident report noted that the contractor’s tendency to deviate from required maintenance guidance and procedures “substantially contributed” to the mishap. His errors included removing the safety pin, which locks the landing gear in place, while the aircraft was not suspended by jacks; applying grease to the aircraft by putting it on his hand, instead of using a lube gun; and pulling on components with “noticeable force” when the Talon began to fall, according to the report. He also failed to review aircraft maintenance forms and perform a safety check before beginning his work that day, investigators said. In addition, the Air Force found that the maintainer had signed off on paperwork for a pre-flight check on a different aircraft earlier in the day, writing that the work was done at 6 p.m. He had already been taken to a hospital by 4 p.m. that day. Investigators also noted that M1 Support Services had slipped in regularly turning around flight-ready aircraft, based on the company’s own records, but said the contractor’s operational tempo wasn’t a factor in last year’s mishap. No personnel appeared to be lacking in training or maintenance qualifications. Investigators also found that though the mishap aircraft’s nose wheel and tire assembly were replaced earlier in the month because of a wobble, that didn’t contribute to the accident. M1 Support Services declined to comment. The Air Force operates a fleet of more than 500 supersonic T-38s, which are used to train American and foreign fighter and bomber pilots. The service is planning to eventually replace the six-decade old Talons with the T-7 Red Hawk. The jet weighs more than 6,600 pounds, according to the Smithsonian Institution’s National Air and Space Museum. Its maximum takeoff weight can reach about 12,000 pounds when loaded with fuel and additional equipment. The Air Force logged three Class A and B mishaps in the T-38, as well as 21 accidents during ground operations across all aircraft, in fiscal year 2023, according to safety data the service provided to Air Force Times. T-38s have recorded at least one Class A mishap each year since FY18 as well. Those accidents accrue more than $2.5 million in damages, destroy an aircraft, or cause a fatality or permanent disability. MRO Memo: Delta Rewarded For TechOps Investment Alex Derber October 14, 2024 Credit: Delta Air Lines Delta Air Lines’ investment in its MRO operations are paying dividends, with the airline reporting that maintenance-related cancelations were down 75% year over year for the first nine months of 2024. “We made an incremental investment in maintenance that we talked about, the $350 million, that's having the impact that we wanted,” noted chief financial officer Dan Janki on a recent earnings call. Earlier this year, Janki said improvements to Delta TechOps would serve it well as it started again to target more third-party business after a period focusing much more on its own fleet. “I'm very excited as to what you talk about a 5-10 year timeline on that … Our ability to capture that business [third-party MRO work] is going to be even stronger than we were thinking pre-pandemic given what we've all been through,” he said in April. On the more recent earnings call, meanwhile, Delta chief executive Ed Bastian highlighted the potential for artificial intelligence (AI) and other technologies to drive efficiencies across the business. “We have great opportunities with the technology foundation that we've built. We are in the very early stages of understanding the potential of AI for our business, and there's no question that there are some really interesting applications to drive better predictive modeling and opportunities, whether that's on the revenue front or on the efficiency and the cost front,” he said. Those comments followed Delta TechOps last week publicizing FAA acceptance for it to add drone inspections into the aircraft maintenance manual for its entire mainline fleet. The small drones can photograph a narrowbody aircraft in less than 90 min., and a widebody in under two hr., compared to manual inspections which can average around 16 hr. Delta received the acceptance in February, integrated drone inspections into the AMM in June and then started with visual inspections following lightning strikes. Spate of Runway Safety Incidents Sparks Avionics Innovation Surf-A warns of runway incursions by aircraft, as well as excursions, and wrong-surface events In June, Honeywell demonstrated the Surf-A system in a series of flights between Seattle and Yakima, Washington, using its Boeing 757 testbed. © Honeywell Aerospace By Hanneke Weitering • Science & Technology Editor July 26, 2024 After a spate of incidents involving near-misses at airports in the U.S. in the last year, the National Transportation Safety Board (NTSB) has once again called on the FAA to develop a system that alerts flight crews to the risk of a runway incursion. On June 20, the agency issued investigative reports on two high-profile incidents involving runway incursions at Austin Bergstrom International Airport in Texas and John F. Kennedy International Airport in New York. In those reports, the agency reiterated its recommendation that the FAA collaborate with aircraft and avionics manufacturers to devise an onboard safety alert system. The same week the NTSB issued those reports, Honeywell Aerospace coincidentally began a three-week-long flight demonstration tour to show a system under development that does exactly what the NTSB requested. Called Surf-A, Honeywell’s runway surface alert system provides a “third set of eyes” for pilots, Thea Feyereisen, a senior technical fellow at Honeywell Aerospace, told reporters during a flight demonstration at Boeing Field in Seattle. Honeywell Aerospace has been flight-testing the Surf-A software on a modified Boeing 757 test aircraft, which the team flew around the U.S. and Europe in June to demonstrate the technology to airline officials and other stakeholders. If all goes according to plan, Surf-A could gain FAA certification and availability for retrofit in the next 12 to 18 months. Surf-A issues aural alerts and optional text warnings on the navigation display to warn pilots of potential runway incursions, excursions, or other wrong-surface events, such as taking off or landing on a taxiway. The software uses GPS and ADS-B data in the runway engagement zone to monitor traffic and provides an aural alert to the pilot when its algorithms determine that the airplane is on a trajectory that could result in a collision in the next 30 seconds. Increasingly Close Calls This year has already seen a staggering number of runway incursions. In the first quarter of 2024, the FAA counted 451 runway incursion events, up from 367 during that quarter of 2023. According to the FAA’s runway safety statistics, about 1,700 runway incursions get reported in the U.S. every year. Roughly two-thirds of them resulted from pilot deviations while air traffic control issues and wayward ground vehicles account for the rest. The most recent collision on U.S. soil happened in October 2023 at William P. Hobby Airport (KHOU) in Houston, where a Raytheon Hawker 850 attempted to take off and clipped the tail of a Cessna Mustang that approached an intersecting runway to land. Officials reported no injuries, but both jets sustained heavy damage. An NTSB investigation found that the crew of the Hawker business jet did not follow ATC instructions to line up and wait. While collisions remain rare, close calls in similar situations have become increasingly common. In many cases, those close calls are merely seconds away from a potentially catastrophic accident. By giving pilots earlier notice of a potential collision, Surf-A could save a lot of lives, according to Feyereisen. On January 2, five people died in a crash at Tokyo Haneda Airport when an Airbus A350 operated by Japan Airlines landed on the same runway where a Japan Coast Guard de Havilland Dash 8 waited to take off. Investigators determined that the Coast Guard aircraft entered the runway without clearance from ATC 40 seconds before the collision. Had the A350 been equipped with Surf-A, the crew would have heard a “traffic on runway” warning in time to execute a go-around. Although the control towers at Haneda Airport were equipped with a runway collision detection system, ATC failed to notice that the Dash 8 had entered the runway, according to Feyereisen. “There was a flashing red light on the top of the monitor, and nobody was looking at that display,” she said. “Just like on the flight deck, it’s an integration challenge.” In a subsequent close call in April at JFK, a Swiss Air Airbus A330 received ATC clearance to take off while ATC cleared four other jetliners to cross the same runway. The A330 crew rejected their takeoff clearance when they saw other aircraft crossing the runway. That incident followed another close call at JFK in January 2023, when distracted pilots in an American Airlines 777-200 missed a turn while taxiing and crossed a runway without ATC clearance, putting them in the path of a Delta Air Lines 737-900ER on its takeoff roll. Airport surveillance detection equipment (ASDE-X) alerted the control tower of a potential collision, and controllers promptly canceled the 737’s takeoff clearance. If the aircraft had been equipped with Surf-A, the pilots would have received the Honeywell alert 14 seconds before they received the alert from air traffic control, Feyereisen said. During the April 17 incursion, the ASDE-X system at JFK did not issue an alert to ATC because the Swiss Air A330 “never reached the thresholds of both acceleration and velocity that would indicate to the system that the jetliner was in a ‘departure state,’” the NTSB determined. Surf-A would have audibly alerted the pilot of the A330 of traffic on the runway once the takeoff roll reached an acceleration of 4 knots per second. The Surf-A system also provides optional situational awareness messages that appear in green on the display but do not issue aural alerts. So, even before commencing the takeoff roll, the A330 crew would have gotten notified about the incursion. While ASDE-X has proven its worth on multiple occasions, the system has flaws—most notably its susceptibility to human error among air traffic controllers, Feyereisen explained. “They have to hear the alert. They have to cognitively process the alert. They have to then spit out the right instructions,” she said. “ASDE-X adds additional potential for human error and it adds additional delay.” Furthermore, ASDE-X's high cost has limited installation at only 35 of the busiest airports in the U.S. since its inception in 2003. The Evolution of Runway Surface Alerts Surf-A builds upon Honeywell’s already-certified runway awareness and advisory system and SmartRunway/SmartLanding software, which use the aircraft’s GPS location combined with geographical data to provide onboard alerts when a pilot runs a risk of a runway overrun or wrong-surface landing. SmartRunway and SmartLanding can also alert pilots when takeoff flaps are not set, an approach is unstable, or if a runway is too short, for example. The SmartRunway/SmartLanding technology available today enhances the pilot’s awareness of their own aircraft and ground features, and Surf-A aids the technology by incorporating real-time runway traffic from ADS-B equipment. The next evolution of the Honeywell technology—Surf-IA (Situational Awareness on the Airport Surface with Indications and Alerts)—adds more sophisticated visual indicators to the flight displays. Honeywell has been testing the system since 2018 in collaboration with Airbus and Dassault. Whereas developers intended Surf-IA for forward fit on new aircraft, the more basic Surf-A system can serve as a retrofit that is affordable and simple to install, Feyereisen explained. “It's our desire to get this not just as a forward-fit option but retrofit, and to get this capability to all levels of capable aircraft,” she said. British Airways cancels some long-haul flights amid engine woes Cancellations are affecting passengers on Boeing 787 aircraft Published: October 11, 2024 21:19 Bloomberg Rolls-Royce says issues are hurting airlines across industry. Image Credit: Bloomberg British Airways has been forced to cancel some long-haul flights as the UK carrier suffers from issues afflicting its Boeing Co. 787 aircraft that are having knock-on effects on other parts of its fleet. Customers whose flights were canceled were notified by the IAG SA-owned carrier that it had to temporarily ground some 787 aircraft amid unspecified engine issues, according to a email notification seen by Bloomberg. British Airways did not respond to requests for comment. The carrier said it's been using Boeing 777 planes that it has on standby to avoid cancellations, but the heavier use of those older jets means they require routine maintenance and sufficient downtime. The airline's existing fleet of 787 aircraft are powered by Rolls-Royce Holdings Plc's Trent 1000 engines. The UK manufacturer said it continues to "work with British Airways and all of our customers to minimize the impact of the limited availability of spares due to the current supply chain constraints," according to a statement. Rolls-Royce said the issue goes beyond British Airways, highlighting how a persistent shortage of components continues to affect the aviation industry. British Airways recently switched over to General Electric to power its new set of 787 aircraft, dealing a blow to Rolls-Royce, which has seen its share on that model dwindle. The Trent 1000 was previously plagued by technical issues, causing disruption for carriers using that model. Rolls-Royce has since sought to improve the reliability of the powerplant, alongside other engines such as the Trent XWB used on the Airbus SE A350 model. British Airways is in the middle of a fleet upgrade cycle, though like many airlines around the world the company has been hit by delivery delays. The 777X, the next-generation of the popular 777 aircraft, for example, is already about five years behind schedule, forcing carriers to to use their existing aircraft for longer or outright cancel some routes. New Five-blade Propeller for King Air 200 Series Earns INAC Venezuela Approval By Kim Blonigen October 8, 2024 Value Added The National Institute of Civil Aeronautics (INAC) Venezuela has accepted the Federal Aviation Administration’s supplemental type certification (STC SA03209NY) for the installation of the Quiet Fan Jet composite propeller MTV-27-1-E-C-F-R(P)/CFR225-55f on the Beechcraft King Air 200 series powered by P&WC PT6A-41, -42, -52, -61 propeller turbines. This installation is already certified by EASA, FAA Transport Canada, ANAC Brazil and DGAC Mexico. According to manufacturer MT-Propeller, the benefits of the installation include: • General performance improvement (5% takeoff & climb, 3 kts cruise with 1,800 rpm). • Approximately 25 pounds less weight than the original 4-blade propellers with aluminum blades. • No propeller speed restrictions on ground while operating in low idle. • Unbeatable esthetic ramp appeal. • All models comply with the strict German noise regulations for unrestricted airport operations in Germany and other European countries. Additionally, the MT-Propeller for the King Air 200 series has more ground clearance for less blade tip erosion and FODs due to its smaller diameter. The natural composite blades provide significant inside and outside noise reduction, have no life limitation and are repairable in case of an FOD, according to MT-Propeller, which adds, “They also provide best vibration damping characteristics for almost vibration free propeller operation and have bonded on nickel alloy leading edges for superior erosion protection of the blades.” MT-Propeller holds more than 220 STCs worldwide and is the OEM supplier for more than 90% of the European aircraft industry as well as 30% of the U.S. aircraft industry. The company has more than 30,000 propeller systems with more than 100,000 blades in service and offers a factory-certified network of 62 service centers. Find more at mt-propeller.com. New Five-blade Propeller for King Air 200 Series Earns INAC Venezuela Approval FAA's oversight not enough to address Boeing manufacturing, production issues, report finds The report found that the FAA's audits are not comprehensive enough to catch manufacturing or production errors. The FAA gave the company 90 days to produce a turnaround plan after one of its jetliners suffered a blowout of a side panel in the cabin during a flight in January. Author: Helen Smith Published: 1:24 PM PDT October 11, 2024 Updated: 1:24 PM PDT October 11, 2024 SEATTLE — A report into the Federal Aviation Administration's (FAA) oversight of Boeing found several "weaknesses" in the agency's process which have resulted in a failure to address consistent manufacturing and production problems at the company. The FAA has been under scrutiny since the January 2024 door plug blowout aboard a 737 Max 9 jet. A Boeing plane which had been delivered to Alaska Airlines two months prior lost a panel while at 16,000 feet. The National Transportation Safety Board's preliminary investigation revealed that bolts that were supposed to be securing the door plug to the jet were left off the fuselage at the company's Renton factory following maintenance work in October 2023. The FAA is charged with ensuring that Boeing and other aircraft manufacturers comply with federal safety requirements in production and manufacturing. However, the company has "experienced multiple manufacturing issues" with the 737 and 787 aircraft production lines since 2018. A report by the U.S. Department of Transportation's Office of Inspector General (OIG) found that the FAA isn't able to fully identify and resolve issues with Boeing's production process due to "weaknesses" in its oversight. The report cited that although the FAA is completing more than the required number of audits, the agency is not being comprehensive enough to identify "discrepancies and noncompliances" on the production line. According to the OIG, Boeing keeps data that the FAA could use to more specifically tailor its audits, but the agency does not utilize it. The report found that the FAA is also not performing audits outside of first-shift work on Monday through Friday, leaving processes that take place when fewer workers are on the line unreviewed. The report found that the FAA is also unable to assure that Boeing's suppliers are producing parts that comply with approved designs. The company has pointed fingers at its suppliers when answering for several manufacturing issues on the 737 and 787 aircraft. Boeing relies on thousands of suppliers for aircraft parts. The FAA is similarly charged with being unable to track or resolve repetitive issues in Boeing's manufacturing process or adequately address allegations that employees are subject to "undue pressure" to complete jets despite reported concerns or inadequate inspection time. Fifteen of 34 allegations of undue pressure at Boeing factories have been unresolved for more than a year. Two of those cases have been unresolved for more than two years. The OIG submitted this report and 16 recommendations to the FAA in August. The FAA concurred with all 16 recommendations and proposed actions to remedy the issues identified in the report along with completion dates. The OIG said it considers all 16 recommendations resolved pending completion of the planned actions. New Technologies Drive APU Performance Improvements Paul Seidenman October 07, 2024 A technician services a Honeywell HGT1700 APU component at Lufthansa Technik. Credit: Lufthansa Technik Encased in the tail cone of commercial, business, and military aircraft, auxiliary power units enable cabin environmental control system operation without relying on ground power sources. They are also essential for the safety of flight operations such as extended twin-engine operations approvals, main engine restarts and emergency back-up of flight control systems. To enable those functions with greater reliability, auxiliary power unit (APU) technology is being continuously advanced. One recent example is Honeywell Aerospace Technologies’ High Efficiency Mode (HEM) APU upgrade. “The High Efficiency Mode upgrade is the first software-enabled reliability and fuel efficiency upgrade,” says Roy Boyd, Honeywell’s senior director of offering management for APUs. Boyd says the upgrade enables a 2% fuel savings, CO2 savings of 22 metric tons and 1,500 hr. of time on wing reliability per year. The upgrade entails the purchase of a software key that is uploaded to the aircraft for 131-9A APUs, series 25 and above, and 131-9B APUs, series 49 and above. For the prior series 131-9As and 131-9Bs, the APU can be modified at the next major repair shop visit to enable improved fuel savings and time on wing. The modification of the pre-series 25 (9A) or pre-series 49 (9B) will require installation of the new compressor diffuser along with the software key, which is directly loaded into the data memory module through its software loader. The HEM upgrade was first certified in November 2020 on Airbus A319, A320 and A321 aircraft with the 131-9A APU. In April 2023, Boeing certified HEM on 737-600s, -800s and -900s, and 737 MAXs with the 131-9B APU. “Since the release of HEM, Honeywell has modified 1,334 APUs, resulting in fuel savings of [approximately 1.8 million] gallons and 17,341 metric tons of CO2,” says Boyd. He adds that along with the retrofit, HEM technology is now included in new production APUs for the Boeing 737 MAX, and the Airbus A319, A320 and A321. Honeywell says its High Efficiency Mode APU upgrade provides 2% fuel savings and saves 22 metric tons of CO2 annually. Credit: Honeywell Aerospace Technologies In a further development, Boyd reports that Honeywell planned to release a load compressor seal upgrade via service bulletin for the 131-9A APU on the A320 family in September. The load compressor, he explains, provides all the pressurized air for the aircraft’s air cycle machines, enabling air conditioning in the main cabin, and additional pneumatic air for secondary systems such as main engine start. “This upgraded seal design and system will eliminate oil leakage across the compressor seal, further reducing odor in the cabin (OIC) events,” he says. “OIC events are most prevalent on the 131-9A application to the A320 family, which is why the load compressor seal upgrade will be specific to that APU.” Boyd says Honeywell is also in the final development stages of the 331-500B2 APU for the new Boeing 777X. The 331-500B2 incorporates new updates qualifying it to the latest fire resistance and fireproof certification in the industry. He says additional technology focuses on improved software that enables improved cycling cool-down and de-oiling functions, and an improved starter and ignition system. APU TRENDS APU on-wing trend monitoring has taken off over the past couple of years, according to Roger Willis, APU program director at StandardAero’s Maryville, Tennessee facility. “This allows for better troubleshooting and reduced downtime on the aircraft, along with a reduction in the carrying cost associated with spare APU line replacement units (LRU) and spare APUs to cover failures or removals,” says Willis, noting that LRUs and life-limited components (LLC) drive the majority of APU removals. “With trend monitoring, there is better planning of scheduled and unscheduled removals regarding LLCs. For LRUs, new service bulletins to increase on-wing time have been developed.” StandardAero says APU on-wing monitoring has taken off over the past few years. Credit: StandardAero Willis says APU trend monitoring has shown an 8-10% improvement in on-wing reliability over the past 3 years, depending on the model. He says this is also largely due to new repair development utilizing material improvements, plus service bulletin modifications to the APU and/or its LRUs. “Service bulletins are issued regularly, driving improvements on current APU units, but there is also an increasing number of items—such as the outer ducts—on APUs that are made of lighter material such as carbon fiber, which help to reduce weight,” says Willis. Asked about any trends toward smaller APUs, Willis says that he has not seen a noticeable change in size among new-generation APU designs. “New-generation APUs and upgrades to existing APUs tend to be focused on reductions in fuel consumption and emissions,” he says. Chap Berrier, vice president of global sales at APU MRO specialist Tag Aero, reports that different metals and OEM-proprietary coatings are now being applied to the APU hot section. “In addition to the hot section, the new metals and coatings upgrades are being applied to turbine wheels and the compressor, among other life-limited parts,” he says. Berrier also attributes greater on-wing longevity to the anti-erosion properties of those coatings and metals, due to their resistance to the extreme temperatures of hot gas. “Aircraft technology is getting better at monitoring the health of the APUs, of which one of the key indicators is exhaust gas temperature,” he says. “That is a good indicator as to how well the APU is performing.” NEW TECHNOLOGY OPPORTUNITIES Ole Gosau, head of APU services at Lufthansa Technik, says that in recent years, APU OEMs have put more emphasis on continuous product improvements rather than on disruptive solutions, such as novel architectures or new technological or engineering approaches. “Generally, the industry is sticking to the proven radial gas turbine architectures, stabilizing the reliability and extending the on-wing times,” he says. “Moreover, the implementation of service bulletins and the eradication of known weaknesses have been among the priorities.” As a result, Gosau says APU innovations have been taking place at a smaller scale, concentrating on parts coatings technology, the rotor system and more advanced materials. Tag Aero says different metals and OEM-proprietary coatings are now being applied to the APU hot section. Credit: Tag Aero “We are seeing an increased percentage of titanium parts for the impellers and three stages of turbine blades for the larger APUs as examples,” he says. “Newer APU types have, on the one hand, made noteworthy progress over legacy types, for instance, when it comes to improving the time-on wing or reducing the occurrence of oil smell events. On the other hand, the achieved benefits were usually accompanied by a significant increase in material prices.” When asked if APU OEMs might introduce any radically new technology, Gosau says he does not foresee a near-term replacement of the current generation APU systems architectures. “Things might change with new aircraft propulsion architectures, which, in my opinion, are still at least a decade and a half away,” he says. “One—but not the only one—could be hydrogen. In the meantime, as a stop-gap solution, APUs can be fueled with the same sustainable aviation fuels as the main turbofan engines.” APU power derived from a hydrogen fuel cell is not out of the question. Emissions, noise, fuel and maintenance reduction would be its advantages, explains Jenny Kavanagh, chief strategy officer at Cranfield Aerospace Solutions in the UK. “Conventionally powered APUs have been reported to contribute 20% of all aircraft on ground emissions and up to 10% of all aircraft emissions at airports. Hydrogen fuel cells only emit water, providing a completely clean solution,” says Kavanagh. “Although hydrogen is more expensive (at least for now) than kerosene, you need a lot less of it due to the higher efficiency of fuel cells versus gas turbines, as well as the higher energy density of hydrogen. “In addition, hydrogen fuel cells have a much higher period between overhauls, meaning the reliability is higher and maintenance costs are reduced,” says Kavanaugh. She adds that hydrogen fuel cells are relatively silent, citing APUs as one of the largest contributors to ramp and gate noise at airports. Kavanaugh says Cranfield has identified specific challenges related to the installation of a hydrogen APU in a conventionally powered aircraft. “Current fuel cell technology takes up a lot of space and therefore any hydrogen fuel cell system used as an APU would need to be packaged in a way that would allow it to fit into the aircraft APU bay in the tail,” she says. “[Cranfield] has already solved this challenge. Weight will also be a challenge, but our initial assessments show this is manageable.” LATAM’s B777s fly with shark skin foils The South American airline decided to equip 5 of its B777 aircraft with AeroSHARK foils. This results in annual savings of up to 2,000 metric tons of jet fuel and 6,000 metric tons of greenhouse gas emissions. LATAM is the first Latin American carrier to adopt this innovative, cost and CO2 saving technology. The retrofit decision now taken by the LATAM management, was preceded by a one-and-a-half-year-long trial phase with a Boeing 777 that had been fitted with shark skin foils. Extracted data proved that kerosene consumption was reduced by around one percent thanks to the low air resistance of the aircraft’s outer skin. LATAM is the first airline based in the Americas to install the drag reducing AeroSHARK foil on its B777 aircraft – courtesy: Lufthansa Technik CO2 savings correspond to 28 flights One percentage point doesn’t sound like much at first, but every step towards reducing CO2 emissions in aviation is a sensible and climate-friendly measure, mostly enabled by technological progress. Yet it should be coupled with political decisions like the introduction of a single sky scheme in Europe, and the optimization of flight routes, preventing fuel-consuming zigzag flight paths. This has long been demanded by IATA, TIACA and most airlines. Based on the trial phase of LATAM’s B777, the savings in greenhouse gases correspond to around 28 flights from Sao Paulo to Miami, 6,566 km apart by aerial distance. AeroSHARK technology was developed jointly by Lufthansa Technik and the chemical company, BASF. The first user was Lufthansa Cargo, whose B777 freighter fleet is successively being covered with the foil during maintenance intervals. The AeroSHARK decision makes LATAM a pioneer in America Prior to Lufthansa Cargo and LATAM, Taiwanese carrier, EVA Air Cargo decided to equip its entire fleet of nine B777F with the drag-reducing AeroSHARK surface technology. The Asian airline’s first modified B777F has been operating since April. It was followed by Japanese carrier ANA, whose first B777F was covered with the film at the beginning of September. Further freighters and passenger aircraft in the company’s fleet are to follow, ANA states in a release. Hence, LATAM is the third airline to opt for the innovative AeroSHARK technology for its Triple Seven passenger aircraft. It had already phased out its B777 freighters years ago in favor of B767Fs. “Our fleet modernization strategy is a cornerstone of our commitment to sustainability and our vision to reach net zero by 2050. We remain focused on innovation and the adoption of cutting-edge technologies, ensuring that our fleet evolves in line with our environmental goals,” said Sebastián Acuto, Director of Fleet and Projects at LATAM Airlines Group. The foil project is about to expand Robin Johansson, Lufthansa Technik Senior Sales Director, Latin America and the Caribbean, said, “LATAM’s decision confirms once again: AeroSHARK works. This further encourages us to use our engineering skills and innovative strength to contribute to aviation with lower CO₂ emissions. We look forward to collaborating with more customers globally and applying our fuel-saving sharkskin technology to even more aircraft,” Mr. Johansson concluded. In DEC22, Lufthansa Technik obtained the Supplemental Type Certificate (STC) from the European Union Aviation Safety Agency (EASA), for the application of AeroSHARK on Boeing 777 aircraft. The company is working on applying the foil to larger areas of the B777-300ER and B777F, and extending the project further by including other aircraft models. Curt Lewis