October 18, 2023 - No. 043 In This Issue : FAA To Mandate CFM Leap Vibration Issue Fix : EASA is addressing potential Airbus A330/A340 landing gear collapses : Pratt & Whitney-Powered A320neo roundings Jump As Inspections Begin : The history and importance of the rudder in aircraft : Boeing Expands Scope of Inspections for 737-MAX Flaw : Is your ESA (electronically steered antenna ) overweight baggage? : An Engineering Masterpiece: F4U CORSAIR : Skydiving aircraft TPE331 engine failure due to component life-limit unintentionally exceeded : GE Aerospace T901 Engines Accepted by U.S. Army in Support of Improved Turbine Engine Program October 13, 2023 : Pratt & Whitney Canada Achieves 200th Engine Type Certification the PW127XT-L Regional Turboprop : In An Emergency, Trust But Verify, Part 1 The NTSB responds to the accident site, in Part 2 of this article. FAA To Mandate CFM Leap Vibration Issue Fix Sean Broderick October 10, 2023 The FAA plans to mandate a recently introduced fix for CFM International Leap 1A non-synchronous vibration (NSV) problems that has led to several in-service incidents. In a draft airworthiness directive (AD) set for publication Oct. 11, the FAA proposes requiring operators to monitor NSV levels and replace the No. 3 bearing “spring finger housing” to prevent premature wear, the FAA said. Certain conditions would trigger a requirement to replace stage 2 high-pressure turbine nozzle assembly honeycomb and stator stationary seals. The directive would give operators of affected Airbus A320neo-family aircraft 125 cycles to calculate NSV data and repeat the process every 125 cycles. If certain CFM-specified thresholds are exceeded, the bearing must be changed. In addition, it would mandate swapping the bearing out before the engine reaches 9,900 cycles. CFM issued recommended instructions in a June 2023 service bulletin. Aviation Week reported in June that the fix was in the works. The FAA’s directive is based on the bulletin. “This AD was prompted by a report of multiple aborted takeoffs and air turn-backs caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration,” the FAA said. “Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV.” The fix is one of several changes CFM is rolling out on the Leap family to address nagging issues. The most significant is a reverse bleed system that CFM expects to solve a long-running fuel nozzle coking issue. It also plans to introduce a new Leap 1-series turbine blade in 2024 that will increase engine durability, particularly when operating in hot, dusty environments. The new blade will be incorporated into production engines and available for retrofits. EASA is addressing potential Airbus A330/A340 landing gear collapses BY RYTIS BERESNEVICIUS 2023-08-30 The European Union Aviation Safety Agency (EASA) has acted upon being notified of irregularities in quality of manufacturing of the Airbus A330 and A340 main landing gear (MLG), which could result in the collapse of the MLG. EASA has noted that “occurrences have been reported of quality non-conformity on MLG axles where the high velocity oxygen-fuel coating on the bearing journal runout areas had excessive coating compared to the drawing limits,” according to its latest airworthiness directive (AD). The excessive coating “could lead to spalling of the protective coating, which could expose the base material and allow corrosion to develop”. Subsequently, the condition, if not corrected, “could lead to an MLG axle failure, possibly resulting in MLG collapse, with consequent damage to the aeroplane and injury to occupants”. The AD affects all Airbus A330ceo and A330neo, as well as A340-300 aircraft of all Manufacturer Serial Numbers (MSN). Airlines operating either the A330 or A340-300s will have to inspect MLGs with Part Number (P/N) 55-2117042-00, with EASA providing a list of 59 aircraft with the affected part installed on them on the date of manufacture. The inspections will need to be conducted within 24 months of the part’s entry into service date. Thereafter, operators will be required to inspect the affected part at intervals of no more than 24 months. If discrepancies are found during any such inspections, airlines are urged to contact SAFRAN Landing Systems before the aircraft’s next flight to receive instructions on how to amend the condition. SAFRAN should then provide the compliance time to fix the parts. If the manufacturer does not, EASA urges airlines to ensure that they do so before the next flight of the A330/A340-300. If airlines have an aircraft whose Manufacturer Serial Number (MSN) matches the list of MSNs provided by EASA, they will have to replace the affected part within 150 months of the part’s entry into service. The European regulator has noted that replacing the whole MLG with an MLG with a serviceable part – that is, one not affected by the AD – complies with the requirements of the directive. Requesting a grace period Two Airbus A330 operators, Delta Air Lines and Cathay Pacific, have commented on the directive. In total, Delta Air Lines provided three comments to EASA. In one, the carrier asked to include the permanent repair of the MLG as a means of complying with the directive, with the airline mentioning a repair procedure defined by Airbus’ Component Maintenance Manual (CMM) 32-13-25. EASA disagreed, saying that the current CMM does not have the repair procedure as yet. However, when Airbus does include the procedure in the manual, the regulator will amend the directive accordingly. Furthermore, Delta Air Lines requested that the compliance time would also include “24 months after the AD effective date, whichever is later” in addition to the part’s entry into service date benchmark. The United States (US)-based airline said that, if EASA would not grant a grace period, it would have to ground three aircraft on the AD’s effective date. “Existing data does not support a general extension of the compliance time as proposed,” the European safety agency replied. Meanwhile, Cathay Pacific has noted that not all Airbus A330 and/or A340 MLGs can support the affected parts, which should exempt certain aircraft from the directive. “The AD should be exact as to which aircraft and landing gear are affected by this quality issue specified in the AD,” the Hong Kong International Airport (HKG)-based airline continued. EASA disagreed, saying that the affected MLGs “can be installed on aeroplanes having specific mod installed in production, or service bulletin [SB] in service”. “Consequently, the AD has to be applicable to all MSN of those [aircraft] models on which an enhanced MLG is eligible for installation (either mod or SB),” EASA concluded. The European regulator published the AD on August 30, 2023, with the effective date being September 13, 2023. Pratt & Whitney-Powered A320neo Groundings Jump As Inspections Begin Sean Broderick Daniel Williams October 16, 2023 Groundings of Pratt & Whitney-powered Airbus A320neos are climbing fast as operators remove engines for accelerated inspections recommended by the manufacturer and mandated by regulators. The percentage of the PW1100G-powered Airbus fleet on the ground stood at 19% at the end of September, or 267 aircraft out of 1,378 in the global fleet, an Aviation Week analysis shows. The figure is a 6% jump compared to August 31’s figure of 175 aircraft out of 1,358, the data show. Mandates issued by the FAA and European Union Aviation Safety Agency (EASA) gave affected operators until late September to remove the first batch of engines flagged for inspections. The initial batch consisted of about 140 engines, Pratt said when it unveiled its fleet management plan to address potential cracks in certain high-pressure turbine disks and high-pressure compressor integrally bladed rotors (IBR). Aviation Week’s analysis looks at ground days on an airframe-by-airframe basis. Anything that did not fly for at least 15 days is considered grounded. Not all of the idled aircraft are parked for the disk and IBR checks. Many have been parked for months awaiting repairs related to long-running durability problems on the PW1000 fleet, which powers some A320neo-family variants and all A220s and Embraer E2s. Some may be down for routine maintenance or operator-related reasons, such as capacity management. September’s sharp rise in A320neo inactivity is almost surely linked to the new inspections, however. Pratt has said the number of grounded A320neos is expected to approach 650 in the first half of 2024 as more deadlines approach and operators pull affected engines. Pratt calculates that about 1,200 of the 3,000 engines that have the suspect parts will need inspections by mid-2024. More than half of the initial checks are unscheduled, driven by revised inspection intervals required to ensure contaminated powder metal incorporated into the disks and IBRs do not lead to cracks. The surge in unscheduled checks combined with hundreds of already planned overhauls and related need for parts means turnaround times (TATs) will grow to perhaps 300 days. MTU, a PW1000 development partner and maintenance provider, said that capacity issues and parts shortages mean the so-called “hospital visits” to address durability issues have TATs of about 150 days—more than double a routine narrowbody engine overhaul. The disk and IBR checks will be integrated into heavier workscopes that are closer to full overhauls to help keep the engines in service for as long as possible once they are back in the field. The latest fleet management plan and the September deadline affects only A320neo engines. Inspection plans for the PW1500s on A220 and PW1900s on E2s are still being determined. Pratt executives have said they expect far less disruption in those fleets compared to the A320neos. Aviation Week figures showed 15% of the 292-aircraft A220 fleet and 11% of the 94-aircraft E2 fleet was on the ground on Sept. 30. The majority of these are likely linked to engines in shops to address long-running durability issues. The history and importance of the rudder in aircraft BY ROSITA MICKEVICIUTE 2023-10-14 Note: Interesting photos in the original document. The world of aviation is a marvel of human innovation and engineering. While many components of an aircraft contribute to its safe and efficient flight, one essential element that’s often overlooked is the rudder. Here we’ll delve into the historical evolution of the rudder in aviation, its crucial role in aircraft control and its importance in maintaining safety during flight. We will also explore some of the worst aircraft accidents where rudder-related issues have proved critical, highlighting the lessons learned and safety improvements made as a result. What is a rudder and why is it important? Within the context of flight, a rudder is a movable control surface located on the vertical stabilizer at the rear of the aircraft. Its primary function is to control yaw, the side-to-side movement of the aircraft. Yaw control is essential for maintaining stability during flight, especially in adverse weather conditions or during maneuvers. Therefore, the rudder plays a pivotal role in aircraft maneuverability. By deflecting the rudder, pilots can initiate and control turns, counteract adverse yaw during banking and maintain a straight flight path during crosswinds. When landing in adverse crosswind conditions, pilots can employ a technique known as a sideslip, or simply ‘a slip’. This technique involves using the rudder and ailerons in opposite directions to align the aircraft’s fuselage with the runway. Additionally, a forward slip can be utilized, swiftly decreasing an aircraft’s altitude by generating increased drag. In most aircraft, the rudder is operated by using the flight deck rudder pedals, which are mechanically connected to the rudder. It is also connected to hydraulic systems, especially in larger and more complex aircraft. Hydraulic systems assist in moving the rudder and other control surfaces by providing the power necessary to operate them. History In the early days of flight, rudders bore little resemblance to their modern counterparts. Aviation pioneers like the Wright brothers and Glenn Curtiss made significant contributions to the development of rudder technology. For early gliders, making a banked turn occasionally resulted in the aircraft losing control and spinning uncontrollably. To address this issue, the Wright brothers introduced a fixed tail to their 1902 glider, which was subsequently modified into a movable rudder later in the same year. These rudimentary rudders were limited in their effectiveness, though. As aviation progressed, engineers and designers experimented with various rudder configurations and control mechanisms. The introduction of ailerons and elevators alongside the rudder improved overall control: the ailerons control the roll of the aircraft, while the elevator manages the aircraft’s nose position and wing angle of attack. Key milestones, such as the development of the NACA (National Advisory Committee for Aeronautics) airfoil and the incorporation of wind tunnel testing, also greatly enhanced rudder design. Worst aircraft accidents involving the rudder Tragically, certain aviation accidents serve as stark reminders of the significance of the rudder and the consequences of its malfunction or mishandling. Several accidents in history have been linked to rudder-related issues, often with devastating outcomes. One notable incident is the crash of Japan Airlines Flight 123 in 1985, resulting from improper repairs to the aircraft’s tail fin, ultimately causing a catastrophic rudder failure. After this accident, several critical recommendations were adopted to enhance aviation safety. These included stricter adherence to manufacturer-recommended repair guidelines, more rigorous structural inspections, increased training and awareness, improved regulatory oversight, better record-keeping and enhanced communication within the industry. Another instance occurred in 1994 involving USAir Flight 427, when a rudder malfunction led to a plane crash. According to the National Transportation Safety Board (NTSB) investigation, the rudder unexpectedly deflected to the left without any input from the flight crew, ultimately resulting in the crash. The NTSB’s findings determined that the accident’s primary cause was a jam in the aircraft’s power control unit (PCU), which forced the rudder to move in a manner it hadn’t been commanded to, leading to a loss of control. In response to the accident, several crucial safety measures were implemented. These included redesigning the rudder control system to prevent jamming, revising maintenance procedures, enhancing pilot training for handling emergencies, updating aviation regulations and introducing regular inspections of rudder control systems. To sum up In conclusion, the rudder is a fundamental component of aircraft design that has evolved significantly. Over the years, this has involved countless innovations and refinements, resulting in the sophisticated rudders we see used on modern aircraft today. The rudder’s importance in aviation cannot be overstated. It is the key to controlling yaw and maintaining stability during flight, especially in challenging conditions. As evidenced by past accidents, any mishandling or malfunction of the rudder can have catastrophic consequences. As such, it is crucial for both aircraft manufacturers and operators to prioritize the proper design, maintenance and training associated with the rudder to ensure that modern flight is safe and efficient. Boeing Expands Scope of Inspections for 737-MAX Flaw by Rich Thomaselli Last updated: 6:00 PM ET, Sun October 15, 2023 Boeing said last week that it will expand the scope of its investigation into a production defect on the 737-MAX 8 airplane. Apparently, more inspections are needed. They are trying to correct a production flaw in which some holes were improperly drilled. The 737-MAX is arguably the most popular plane in the world. The airplane manufacturer first made the revelation in August. "We continue to take the time necessary to ensure each airplane meets our standards and regulatory requirements prior to ticketing and delivery," Boeing said in a statement. Boeing has an earnings call scheduled for October 25 and declined to comment further. Boeing has notified its airline customers as well as the Federal Aviation Administration about the problem and the increase in inspections. Is your ESA overweight baggage? By ThinKom PR Posted October 14, 2023 In Blog, In the News, ThinAir Common sense suggests that a lower profile atop the fuselage is key to minimizing the drag impact of antenna installations. So it is counterintuitive that a slightly taller radome is much more efficient than a flat-top electronically steered antenna (ESA). But the numbers do not lie. ThinKom contracted with David Lednicer of Aeromechanical Solutions in Redmond, WA to perform computational fluid dynamic (CFD) analysis of the Ka1717 antenna on the ERJ-175 and the CRJ700, two leading aircraft types in the regional jet market. Similar analysis was performed using publicly available data of representative ESA antenna systems promoted in the market today. The results show that the streamlined shape of ThinKom’s Ka1717 radome reduces drag by 75-90%, removing as much as 400 pounds of increased cruise weight penalty as compared to ESA designs. That adds up to millions of dollars in extra fuel expense and tens of thousands of tons of excess carbon dioxide (CO2) emissions over the life of the aircraft, even for a modest size fleet. The value of smooth airflow across the curved Ka1717 radome is readily apparent when comparing the three antenna types The dramatic drag increase from flat-top ESAs comes from their sharp edges and flat surfaces. Rather than facilitating efficient aerodynamic flow across the radome, these features – while lowering the profile – increase turbulence and create shock waves. Without a smooth transition from the turbulent boundary layer of air flow back to the fuselage, an air cavity is created. This flow separation delivers a retardation force on the surface and trailing edge of the installation, increasing drag on the airframe. Shock waves radiate off the sharp leading edge of flat-top designs, delivering a 5-10x increase in drag compared to the Ka1717 radome Moreover, the problem does not disappear with the much smaller installation of a LEO-only ESA. Indeed, the Ka1717 shows a 90% reduction in drag penalty on the CRJ700 compared to both the LEO-GEO ESA and the smaller LEO-only ESA installations. The drag penalty of flat-top ESAs is even more pronounced on the CRJ700, with the Ka1717 delivering up to 90% lower cruise weight penalty Flat-top ESA radomes serve a critical cooling function for their system. Many ESAs, particularly larger LEO-GEO ESAs, consume significant power as they transmit and receive data (a different – and also notable – challenge for them). This power converts to heat, which is convectively transferred directly from the flat surface to the airstream. Adopting a curved radome over the ESA would resolve the poor drag performance, but would also trap that heat inside the radome, further complicating the already inherent thermal challenges. Drag is, of course, just one component to consider when selecting inflight connectivity hardware. But when it comes to the radome, choosing a flat-top surface can be a real drag. More information on how the Ka1717 compares to ESAs is available here. An Engineering Masterpiece: F4U CORSAIR It’s fair to say the rate of aircraft development through the 1940’s was substantial. From biplanes to jet fighters in less than a decade! In this issue we’re going to take a look at another of the types that pushed the boundaries of aeronautics, the mighty Vought F4U Corsair! GA Buyer Europe Jamie Chalkley 11th October 2023 Note: See photos in the original article. In the opening months of 1938, the U.S. Navy Bureau of Aeronautics made a request for a fighter aircraft (destined for carrier operations) that could achieve the highest cruise speed that design and engineering could provide, and – at the other end of the speed envelope – a low enough stalling speed to allow for carrier operations (actually specified as needing to be less than 70 miles per hour), and achieve a range of over 1,000 miles. A company by the name of ‘Vought’ was selected for the job and got the contract. They did an outstanding job producing an aircraft that in later years would go up against (and hold it’s own) such aircraft as the MiG-15! Started by Chance ‘Vought’ was established in 1917 by Chance M. Vought (a former chief engineer of the Wright Company) and a gentleman by the name of Birdseye Lewis. Following multiple changes of ownership and transition through the time that followed it actually ended up being part of Northrop Grumman some 80 years later! Like most manufacturers of aircraft in the dawn of aviation, Vought made history with his developments in aeronautics. In 1922 his aircraft, the ‘Vought VE-7 trainer’ made the first takeoff from the deck of America’s first aircraft carrier, the USS Langley. And it was his knowledge of carrier deck landings that would be needed as they designed their prototype XF4U-1 Corsair. For a fighter (or any aircraft for that matter) to land safely on an aircraft carrier (and for it to remain in sufficient condition to make another flight after!) the landing gear needed to be very strong. So, a short, stout leg was on the drawing board from early on. But to give the aircraft sufficient power they needed a big engine. And I mean a BIG engine; the Pratt-Whitney R-1830 Wasp (which through development became the R-2800 Double Wasp). However, it wasn’t the bulk size of the engine that was the issue. It was the 13 ft propeller (13ft 4 inches to be exact)! To achieve prop clearance, it needed to be sufficiently high enough off the ground but also needed those short legs I mentioned. Being an aircraft designer wasn’t easy! But solve the issue they did, and the solution became one of the most distinctive features of the aircraft; the inverted gull-wing. This ‘bent wing’ design allowed the huge prop to clear the deck and provided adequate space to accommodate a nice short (relative) landing gear. Another feature of the gull wing was its ability to fold for storage. Space on an aircraft carrier was (and still is) very limited. So, making use of the aircraft hydraulic system, each wing could be folded up vertically allowing more aircraft to be parked on deck. But the engineers and design team didn’t stop there, to seek out speeds at the higher end of the envelope, they designed the wheels to swivel 90 degrees so they could retract and fit flush inside the wing. The tailwheel and arrestor hook also retracted flush into the airframe. And to keep the aircraft surfaces as aerodynamically clean as possible, they used large section panels that were attached to the frame using spot welding, this eliminated the use of rivets common to so many other types and helped produce a beautiful clean surface. Indeed, the aircraft had nothing non-essential protruding into the airflow. And this all counted in the performance department; during testing dive speeds approaching 550 mph were achieved making it one of the fastest prop driven aircraft in the sky! Power of the Wasp The beast of an engine finally selected was the Pratt-Whitney R-2800 ‘Double Wasp’ radial engine, this whopping great powerplant had a two-stage supercharger and in the year of 1940 was the most powerful aircraft engine in the world! It’s 18 cylinders, each produced over 100 hp each! In fact, there were so many cylinders they couldn’t fit them wrapped once around the engine, they had to wrap them round twice (hence the ‘Double’ Wasp). The 46 litre air-cooled radial engine could produce 2,760 hp at its war emergency power rating (a five minute limit for extended power…). And as already noted above, the only way to convert that kind of horsepower into sufficient thrust was with a huge Hamilton Standard Hydromatic propeller. This boasted a double-acting governor and used oil pressure on both sides of the propeller piston allowing for a greater blade angle range. And with its 3 enormous blades spinning, it measured 13 feet 4 inches across the prop diameter. Jet combat performance The first flight of the prototype XF4U-1 was made on 29 May 1940, and only a few months after a later example clocked a cruise speed of 405 miles per hour becoming the first production aircraft to exceed 400 mph. The US Navy seemed quite pleased with the results and during the summer of 1941 they placed an order for just under 600 aircraft. Over the next 11 years that figure grew to reach a production number of over 12,500 aircraft! And with all good models, testing and development continued, indeed Charles Lindbergh flew the aircraft as a civilian technical advisor and advancements in design were found, as was an upward trend of the air speed indicator; the aircraft proceeded to reliably clock a top speed of 446 mph! aka Jet Speed! But, at that kind of speed, some issues were evident; the fabric covered control surfaces began to deform, increasing drag which progressively slowed the aircraft down by a few miles per hour. That was fixed however by replacing the fabric surfaces with metal surfaces (duralumin) which alleviated the problem. It was on these examples that during full-power dive tests from 45,000 ft, those speeds of up to 550 mph were reached (45,000 ft... that's higher than the service ceiling of a Boeing 747!). Carrier landings were initially a challenge in the Corsair, that very long nose (14 ft in front of the pilot) caused difficulty seeing the touchdown point and in keeping signalling marshaller in sight, and the aircraft stall characteristics in the landing configuration were most unforgiving. During testing with the British, test pilots evaluated this and adopted a new approach (literally), which significantly improved matters for carrier landings; instead of the normal circuit pattern of downwind, crosswind, final approach, the pilot was recommended, once established downwind, to make a slow continuous curved approach, whilst this delayed the aircraft being lined up with the runway deck until almost landing on it, it did allow the pilot to keep the signals marshaller in view (not to mention the back of the ship!) The Corsair is undoubtedly a stunning looking aircraft, but it was so much more from a design and engineering point of view. It was a masterpiece! Fast, powerful, and versatile, and if you’re lucky enough to see one up close you can’t help but stand and stare in wonder and its size and presence. A truly impressive aircraft. Vought F4U Corsair Wingspan: 12.5 m Length: 9.99 m Height: 4.58 m MGW: 6,350 kg Powerplant: 2,325 hp VNE: 446 mph (IAS) Cruise speed: 215 mph (IAS) Service ceiling: 41,500 ft More info: www.TASCVintage.com Skydiving aircraft TPE331 engine failure due to component life-limit unintentionally exceeded Note: See technical photos in the original article. A turboprop-powered DHC-2 Beaver sustained an engine failure soon after parachutists had exited the aircraft above a drop zone at Moruya Airport on the New South Wales south coast, an ATSB report details. The aircraft was conducting skydiving drops overhead Moruya on 4 April 2022 when, on the second flight of the day, and soon after the parachutists had exited, the pilot heard a loud bang and briefly experienced vibrations. Believing the aircraft had experienced an engine failure, the pilot pulled the fuel emergency shut-off lever, feathered the propeller, assessed the position of the parachutists, and conducted a forced landing at Moruya Airport. “A post-flight examination of the aircraft identified holes in the cowling above the engine compartment, perforation of the external wall of the engine combustion chamber, holes through the exhaust assembly, and significant damage to the turbine section,” said ATSB Director Transport Safety Kerri Hughes. “A low-cycle fatigue crack had initiated in the 3rd-stage turbine wheel of the Honeywell International TPE331 engine and grown to failure.” The ATSB investigation established that errors by a previous maintainer of the aircraft when determining the engine operating cycles and engine component total equivalent cycles meant that the 3rd-stage turbine wheel remained in-service beyond the component life-limit. “This incident highlights the critical importance of accurate records of equivalent cycles accrued by an engine and engine components,” said Ms Hughes. “Cycles should be diligently recorded, calculated, and checked to ensure the equivalent cycles accrued by a component is known with confidence. “This means that components can be replaced prior to the published in-service life-limit being reached.” Read the report: Engine failure involving de Havilland Canada DHC-2 Beaver, VH-AAX, overhead Moruya Airport, New South Wales, on 4 April 2022 Skydiving aircraft TPE331 engine failure due to component life-limit unintentionally exceeded GE Aerospace T901 Engines Accepted by U.S. Army in Support of Improved Turbine Engine Program October 13, 2023 LYNN, Mass. – GE Aerospace announced today the acceptance of the first two T901-GE-900 flight test engines to the U.S. Army which will support the Future Attack Reconnaissance Aircraft (FARA) Competitive Prototype program. The next-generation rotorcraft engines – which will power the U.S. Army’s UH-60 Black Hawk, AH-64 Apache and FARA – were officially accepted by the Defense Contract Management Agency at GE’s Lynn, MA facility. “We are thrilled to announce the acceptance of the revolutionary T901 by the U.S. Army,” says Amy Gowder, president and CEO, Defense & Systems at GE Aerospace. “The performance, power, and reliability of the T901 – combined with GE’s decades of experience powering Army rotorcraft – will ensure our warfighters have a significant advantage on the battlefield.” The T901 engine was built on GE’s unparalleled experience powering the Black Hawk and Apache for the past four decades with its combat-proven T700 engine, a run that has resulted in more than 100 million flight hours. The T901 was developed in response to a need from the U.S. Army for increased power. The new engine provides 50 percent more power and reduced life cycle costs with fewer parts and a simpler design. The engine’s fuel efficiency will improve the enduring fleet’s range, loiter time and fuel consumption, all while reducing maintenance and sustainment costs. The T901 design draws from an impressive stack of commercial technologies, including 3D-modeling, the use of ceramic matrix composites (CMCs), and 3D-printed (additive) parts. The use of CMCs and additive manufacturing enables the engine to produce more power with less weight. Another notable design feature of the T901 is the engine’s modular design, an aspect that was carried over from the legendary T700. The modular design is one key to the T901’s low cost, growth, reliability, maintainability, and reduced life-cycle costs. Through the application of this proven technology, the T901 can easily integrate with the Army’s existing helicopters while exceeding performance requirements. Beyond the advanced design and hardware, the T901 features the latest diagnostic and prognostic tools with a modular architecture that enables the service with the flexibility to improve readiness at the lowest life cycle costs. Pratt & Whitney Canada Achieves 200th Engine Type Certification - the PW127XT-L Regional Turboprop PR Newswire - Wed Oct 11, 4:30AM CDT Partnership Content INNSBRUCK, Austria, Oct. 11, 2023 /PRNewswire/ -- Pratt & Whitney Canada, an RTX (NYSE:RTX) business, announced today that Transport Canada Civil Aviation has type certified the PW127XT-L regional turboprop engine. This marks another significant milestone for the company as its 200th type certification since the introduction of the original and now ubiquitous PT6 engine in 1963. In An Emergency, Trust But Verify, Part 1 Roger Cox September 25, 2023 Transair Boeing 737-275C freighter Credit: NTSB It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so. (Attributed to Mark Twain) A Boeing 737-275C freighter was departing Daniel K. Inouye International Airport (HNL) at 0134 Hawaii-Aleutian standard time on July 2, 2021, when the crew heard a “pop” passing through 400 ft. The two pilots knew something was wrong almost immediately. The airplane yawed to the right, and the first officer (FO), who was the pilot flying, initially thought the right engine had failed. Four minutes after the initial failure, he changed his mind. He spoke with a tone of certainty when he said it was the left engine that failed, and the captain took his word for it. What the FO thought just wasn’t so. The left engine was running fine but was reduced to idle thrust. During the next 12 minutes before the airplane splashed down in the Pacific, neither pilot made any attempt to advance the left throttle, even after it became apparent the freighter would continue to descend into the water. Why did the pilots just tune out the left engine? What happened during that four minutes after the right engine failed to change their minds? NTSB investigators sought to find out. The accident airplane was one of five aging Boeing 737-200s operated by Rhoades Aviation, a Part 121 all-cargo airline based in Honolulu. The company had a business name—Transair—painted on the fuselage. Of the company’s 230 employees, 24 were pilots. The two pilots involved in the accident reported for duty at midnight on July 1, about 15 minutes early. They performed their preflight duties and the FO obtained the ATC clearance. They were cleared to the Kahului Airport on Maui with an initial heading of 155 deg. and an initial altitude of 5,000 ft. All seven pallet positions were loaded with cargo and the 737 had 14,000 lb. of fuel aboard. The crew commenced a taxi to Runway 8R at 0123. At 0132, Honolulu Tower cleared them for takeoff. The FO was the pilot flying. As they rolled down the runway, the captain called “vee one,” then “rotate,” then “vee two,” then “positive rate.” At 0133:46 the FO called “gear up.” Up to this point, the crew had performed their crew coordination perfectly, exactly by the book. They used the right verbiage for the change of controls and made all the right callouts. Six seconds later, that coordination would be severely challenged. The cockpit voice recorder (CVR) recorded the sound of a “thud” and a low frequency vibration tone. The FO said “oh!” and the captain said “lost (an) engine, you got it?” The FO continued to control the airplane and the captain said, “yep...you lost number.” The FO replied, “number two…yep.” The captain agreed. They were channeling each other’s thoughts. They both thought the right engine had failed. During the FO’s takeoff brief, he had described the plan for an engine out emergency after V1 “if we lose the engine at vee one we'll climb straight out to five hundred feet, one point three DME, whichever comes first, we’ll start a right turn to two twenty up to eight hundred, we'll level off, we’ll accelerate, we’ll clean up, we’ll coordinate ATC, run the checklists as appropriate.” Out of 500 ft., the captain called out “five hundred eight hundred,” prompted the turn to 220 deg., and raised the flaps. Then he tried, at first unsuccessfully, to get the attention of the tower. Twice he told the tower he had an emergency and was turning to a 220 heading, and twice the tower gave him a routine clearance without acknowledging the emergency. The captain spent almost a minute and a half trying to get the tower’s attention. While the captain was focused on the radio, the FO tried to level the airplane at 2,000 ft. but allowed the airplane to accelerate to 252 kts. To correct, he pulled both thrust levers back together “in unison.” The flight data recorder (FDR) showed that he continued to retard the left engine, but not the right. That thrust reduction began to take place at 0135:18, about one minute before the captain was able to return his attention to the engine instruments. By the time the captain looked at the EPR (engine pressure ratio) gages, the left engine was at idle, 1.05 EPR, and the right engine was at 1.12 EPR. Finally, the tower said, “Rhoades express eight ten you are cleared visual approach runway four right, you can turn in toward the airport.” It was 0136. The captain did not turn back. Instead, he decided to take control of the airplane and have the FO “set things up.” Shortly thereafter, he was interrupted again, this time by company dispatch: “eight ten uhh dispatch uhh...let me know what’s going on.” • The captain ignored the radio call and said to the FO, “read the gauges and see which one...who one...which...who has the EGT (exhaust gas temperature)?” • The left engine EPR was lower than the right. • The FO replied, “yep so it looks like the number one.” • “Number one is gone?” the captain asked. • “It’s gone yep. So, we have number two.” • The captain confirmed, “so we have number two, okay.” From this point on, the crew’s confusion became ever greater. The captain called for the “engine failure shutdown checklist” but didn’t specify which engine should be shut down. He took control of the radios but confused the controller by saying he could turn toward the airport but wasn’t ready to land. The controller issued a 250 deg. heading. It was 0138:53 and they were still headed away from the airport. The captain pushed the right thrust lever up to 1.22 EPR, and the FO pointed out the right engine was running hot. “We’re red line here,” he said, and “we should pull the right [thrust lever] back a little bit.” He did not run the checklist. The airplane was sinking and slowing. The captain had lost sight of the airport and asked the controller for vectors back to the airport. “We might lose the other engine too,” he said. As the airplane descended through 1,050 ft., the airspeed was 157 kts. and the stick shaker sounded briefly. Sounding bewildered, the captain said, “what’s this?” followed by “we can’t keep going down.” The right engine EGT was “beyond max.” An electric voice sounded, “five hundred.” The captain began a rather long radio transmission, asking for fire trucks to be ready and the Coast Guard to be notified. The FO pleaded with him, “just fly the airplane!” The captain continued to talk with the tower as the airplane descended, even asking for a heading to another airport—Kalaeloa (JRF). That airport was off to his left 3 mi., but he was well below 300 ft. by this time. The EGPWS (enhanced ground proximity warning system) began sounding, “terrain, terrain,” and “pull up, pull up.” The CVR recorded the sounds of impact at 0145:17. Pilots Recovered From Sinking 737 Credit: NTSB The wreckage of the Transair 737 came to rest on the ocean floor. The airplane struck the water hard and came to a quick stop. The FO’s seatback failed and he struck the top of his head on an object. Both he and the captain opened their side windows and escaped as ocean water flowed into the cockpit. The FO clung to the nose section, then spotted a large wooden pallet afloat and moved to it. The captain swam along the left side of the airplane, finally grabbing the tail section. Ocean waves knocked him off the tail several times. A Coast Guard rescue helicopter shined a spotlight on the FO, who pointed to the captain. The helicopter flew to the tail section, and a rescue swimmer descended and secured the captain. After they were hoisted up to the helicopter, the swimmer re-entered the water to assist the FO. He helped the rescue vessel pick the FO out of the water. The NTSB responds to the accident site, in Part 2 of this article. Curt Lewis