Flight Safety Information - November 14, 2023 No. 221 In This Issue : Citing Valve Damage, UND Drops Unleaded Fuel And Returns To 100LL (Updated) : Safety, not speed, should be the priority in launch mishap probes, FAA advisory group says : Plane Hits Car After Overrun : 5 U.S. service members killed in helicopter crash in Mediterranean Sea : PC-24 Loss of Control Incident Under Investigation : Boeing Global Services Disrupted By Cyberattack : Aviation Industry Executives and Government Officials Testify on Airport Safety : FAA Issues Notice on Runway Obstacle Analysis Products for Part 135 Operators : The Crosscheck: ‘Stepped On’ Radio Transmissions : JetBlue SFO Tarmac Collision Forces Passengers Off Plane : Passenger Stuck on Delta Flight in Triple-Digit Heat Describes Chaos: 'People Were Throwing Up, Crying' : Mishap Damaged F-16 Fighting Falcon from Top Gun Command, Navy Confirms : 1 Marine injured in Nevada hard landing of MV-22B Osprey : Conditions That Cause Autorotation Mishaps, Part 1 : CALENDAR OF EVENTS Citing Valve Damage, UND Drops Unleaded Fuel And Returns To 100LL (Updated) By Paul Bertorelli Published: November 8, 2023 Updated: November 9, 2023 After an extensive trial, the University of North Dakota’s flight school has dropped Swift UL94 fuel and resumed use of 100LL. The school said ongoing maintenance monitoring of aircraft using UL94—almost exclusively Lycoming-powered Piper Archers and Seminoles—resulted in measurable exhaust valve recession. The school made the switch back to 100LL on Oct. 27. Partly because students were interested in a less-polluting fuel, the school switched to Swift Fuel’s ASTM-spec UL94 in late June. In four months of flying totaling 46,000 hours, the school found evidence of significant valve recession in some of the Archers. The school’s director of maintenance, Dan Kasowski, told AVweb Wednesday (Nov. 8) that the total number of aircraft impacted isn’t known yet because the data is still being collected. The data is being forwarded to Lycoming for analysis. “The fuel is on-spec, so that’s not a problem. I don’t want to speculate on what it could be. We’re waiting for Lycoming to tell us,” Kasowski said. Valve seat recession was a known problem when unleaded fuels were introduced in the automotive market starting in the 1970s. As explained in this AVweb video, the precise mechanism is debatable, but hardened valve seats and cylinder heads tamped down recession damage. Lycoming addressed this issue in its cylinders during the 1990s and was believed to have valve seats and guides suited for unleaded fuels. Lycoming said it was “proactively evaluating” the data received from UND and would provide appropriate guidance based on its analysis. As of today’s deadline, Swift’s Chris D’Acosta confirmed that Lycoming is looking at materials, pilot operating methods, flight telemetry and additional data to understand the findings at UND. “The comment attributed to equivalent spark plug fouling and replacement vs. 100LL is generally not consistent with our own experience with UL94. This may be an indication of different operating methods at UND than elsewhere,” D’Acosta said. UND’s Jeremy Roesler said when the school made the switch in June, it did so only after setting up a maintenance monitoring program to track potential issues with UL94. “We are overcautious,” he said. “When we started finding these issues, we needed to ask ourselves how bad does it have to get before we switch back to 100LL?” he said. With intense daily flight operations, aircraft down for maintenance were a worry for UND. “We’re big on how it affects our students. It is causing some delays. So it’s not in our best interest to accelerate back to UL94,” he added. To monitor for cylinder wear, the school conducted regular compression checks on its fleet of Archers and also did the so-called “dry tappet” check. This involves removing and cleaning the tappets and reinstalling them with the pushrods in place. The clearance between the rocker arm and the valve stem is then checked. If the valve seat is recessing, this clearance will progressively diminish as the valve recedes farther into the cylinder head. Kasowski said the Lycoming specified minimum clearance is 0.028 inch and some of the cylinders exceeded this limit. If the recession is deep enough, the valve won’t close against the seat and power loss or burned valves can result. Recession was measured only on exhaust valves, not intake valves. In addition to data sent to Lycoming, UND is also sending both cylinders and engines for further analysis. Kasowski said after 46,000 flight hours, the school had about the same replacement rate for spark plugs as on 100LL, nor was spark plug fouling noticeably reduced. Another operator we’ve been monitoring for more than two years is Rabbit Aviation Services in San Carlos, California. The company oversees maintenance and fueling of a pair of flying clubs totaling nearly 10,000 hours of flight per year. Rabbit CEO Dan DeMeo said experience with UL94 has been universally positive with less spark plug fouling and cleaner oil. Rabbit has been offering UL94 for two and a half years. We’ll update the story as more information becomes available. Safety, not speed, should be the priority in launch mishap probes, FAA advisory group says By Elizabeth Howell "I know there's the 'move fast and break things' motto. I'm kind of the 'move fast and fix things' motto." SpaceX's latest Starship prototype is rimmed with frost during a fueling test on Oct. 24, 2023. (Image credit: SpaceX) Safety, not speed, should be the priority when conducting launch mishap investigations, members of a U.S Federal Aviation Administration (FAA) advisory committee say. Amid reports of pressure from companies like SpaceX to add licensing staff to speed up approvals for new launches, FAA committee members instead urged caution Wednesday (Nov. 8) during a livestreamed meeting of the agency's Commercial Space Transportation Advisory Committee (COMSTAC). "We've got to put safety first," Polly Trottenberg, deputy secretary at the U.S. Department of Transportation, emphasized. Paraphrasing Facebook founder Mark Zuckerberg, she said the FAA is often told "to move at exactly the speed of Silicon Valley. I know there's the 'move fast and break things' motto. I'm kind of the 'move fast and fix things' motto." Still, Trottenberg acknowledged there can be a "conservatism" in the public sector, where "failure is swiftly punished" among politicians. She emphasized that safety cannot be compromised. But, she added, "we recognize that we need to find ways to ensure that, if we're not moving at the speed of industry, that we're moving faster where we can." COMSTAC was established in 1984 to report "on critical matters concerning the U.S. commercial space transportation industry" to the FAA administrator, according to the committee's documentation. The membership includes not only senior executives from commercial space transportation, but also representatives from fields such as academia, the satellite industry, local and state government and companies that provide services such as insurance and legal matters. As an advisory group to the FAA, COMSTAC plays no active role in evaluating "mishaps" that arise from failed commercial spaceflight launches. Committee members were also careful during Wednesday's meeting not to discuss ongoing investigations, including that of SpaceX. The company's debut Starship space launch in April saw the spacecraft spin out of control high over coastal Texas. SpaceX deliberately detonated the spacecraft, scattering debris over an environmentally sensitive area. The FAA announced Oct. 31 that it had wrapped up the safety review of Starship, which examined the risks the launch poses to public health and safety. An environmental review with the U.S. Fish and Wildlife Service is still ongoing, however. Meanwhile, Starship has performed several static fires, and SpaceX has emphasized that the system could launch as soon as mid-November if the regulators approve. SpaceX has had mixed feelings about the FAA approval process over the years. For example, SpaceX founder Elon Musk said in 2021 on Twitter — now rebranded after Musk's 2022 takeover as X — that the FAA's space division has "a fundamentally broken regulatory structure," as the rules are based on "a handful of expendable launches per year from a few government facilities." However, on Sept. 8 of this year, in discussing the 2023 relicensing of Starship, Musk posted hat it is "rare" for the FAA "to cause significant delays in launch [as] overwhelmingly, the responsibility is ours." But, on Sept. 5, he noted that Starship was "ready to launch" and is only "awaiting FAA license approval." SpaceX senior officials also told Ars Technica in October, speaking on background, that they want the FAA to double agency licensing staff. SpaceX's Starship explodes minutes after launch after encountering an issue. (Image credit: SpaceX) The FAA leads the investigation of all mishaps that did not, or plausibly could not, result in "a fatality or serious injury to any person;" in cases where such injuries or deaths would be possible, responsibility is led by the U.S. National Transportation Safety Board. Licensing for systems like Starship also can involve multiple government agencies or groups, as the ongoing environmental investigation shows. Committee members acknowledged that there are more space systems than ever and that launch rates are accelerating. While companies would like the FAA to move faster, however, safety must remain the primary consideration, said the agency's Michael O'Donnell at the same meeting. "It's really about applying the regulations reasonably so that you can innovate and you can do things differently," said O'Donnell, the FAA's deputy associate administrator for commercial space transportation. "One thing I've learned is the difference between aviation and space is the tolerance for mishaps. On the space side, it's a very different world." He explained that the aviation industry tends to fly "very similar types of vehicle," while in spaceflight, there's customization: "every single vehicle is unique." The custom builds are part of what makes the licensing process so complex, he emphasized. Blue Origin's New Shepard vehicle suffered an anomaly during an uncrewed launch on Sept. 12, 2022. This screengrab shows New Shepard just before the vehicle's capsule successfully engaged its emergency escape system. (Image credit: Blue Origin) O'Donnell acknowledged, however, that the FAA's flat budget for spaceflight investigation needs to accommodate a burgeoning launch industry "an order of magnitude greater than it was five years ago." (To cite just one example, SpaceX has launched 80 orbital missions already in 2023, quadruple its 2018 rate.) One solution may be for the companies to share safety data along with their "risk acceptance" for certain systems, ranked perhaps between low, medium and high. O'Donnell said this may allow industry and the FAA alike to "then make the determination what the severity is, the likelihood of it (a mishap) happening, and then working from that and trying to build consensus about what the severity is, what the likelihood is, and then work together." Blue Origin's New Shepard vehicle suffered an anomaly during an uncrewed launch on Sept. 12, 2022. This screengrab shows New Shepard just before the vehicle's capsule successfully engaged its emergency escape system. (Image credit: Blue Origin) O'Donnell noted that the FAA and industry would need to agree on what constitutes "safety data," which has been a sticking point. Industry reticence to such sharing has been brought up repeatedly: given each vehicle is so unique, it is difficult to anonymize information, representatives heard at meetings of COMSTAC in October 2018 and again in May 2023. A Rocket Lab Electron rocket launches a Capella Space satellite on Sept. 19, 2023. The rocket suffered an anomaly, resulting in the loss of the satellite. (Image credit: Rocket Lab) While SpaceX has been getting most of the attention from the media concerning mishaps, it's not the only one the agency addressed in 2023. The FAA closed five space mishap investigations this year — such as SpaceX's Starship, and a 2022 incident with an uncrewed Blue Origin New Shepard flight — and still has three that are open, O'Donnell said. One example of an active investigation is that of Rocket Lab, which had a failure on Sept. 19 with its Electron rocket that caused the loss of a commercial Earth observation satellite. An electrical arc within a key power supply system was likely at fault, and the company hopes to fly in late November. (The mishap inquiry continues, but the FAA did tell Rocket Lab its launch license is still active, company representatives recently said.) Plane Hits Car After Overrun By Russ Niles November 12, 2023 There were no injuries when a Lancair IV-P Jetprop overran the runway at Aero Country Airport in McKinney, Texas, on Saturday and collided with a car on a road adjacent to the airport. Jack Schneider, who was at the airport picking up an aircraft to trailer home, got his cellphone recording just in time to capture the crash sequence. According to WFAA News, the pilot told authorities the prop wouldn’t reverse. According to the Aviation Safety Network, the pilot reported a pressurization problem while climbing through 25,000 feet and descended rapidly to make an emergency landing. It went around on the first landing attempt and then overran the runway. The plane is registered to a company in Midland, Texas. 5 U.S. service members killed in helicopter crash in Mediterranean Sea Rebecca Falconer Five American service members were killed in a military helicopter crash during a training exercise in the Mediterranean Sea, U.S. defense officials said Sunday. The big picture: The helicopter "suffered a mishap and crashed" during a "routine air refueling mission" late Friday, per a U.S. European Command statement Sunday that confirmed an investigation into the crash was underway. • All five of those aboard the MH-60 Black Hawk helicopter that crashed off the coast of Cyprus were members of U.S. Army Special Operations forces, U.S. officials told multiple outlets. Zoom out: U.S. aircraft carriers and supporting ships have been deployed to the Mediterranean and thousands of American military personnel have dispatched or prepared for deployment to the Middle East since the Hamas-Israel war began after Hamas attacked Israel on Oct. 7. What they're saying: President Biden in a statement Sunday that noted it was Veterans Day weekend paid tribute to the five service members and others who have "put their lives on the line for our country every day." • Defense Secretary Lloyd Austin also offered condolences in a statement on Sunday. • "While we continue to gather more information about this deadly crash, it is another stark reminder that the brave men and women who defend our great nation put their lives on the line each and every day to keep our country safe," Austin said. PC-24 Loss of Control Incident Under Investigation Aircraft suddenly lost 1,000 in altitude while climbing through 24,000 feet By GORDON GILBERT • Contributor - Accidents and Regulations November 9, 2023 Canada’s Transportation Safety Board has launched an investigation into a November 3 in-flight incident involving a privately operated, Canadian-registered Pilatus PC-24. The TSB said the crew of the light jet declared an emergency after an in-flight “loss of control” incident and landed uneventfully at Kelowna International Airport in British Columbia. According to Flight Safety Foundation’s Aviation Safety Network (ASN), after departing Vancouver, “tracking data show a sudden loss of altitude of nearly 1,000 feet as the twinjet was climbing through FL240.” Registration data for the 2020-model aircraft (S/N 192) show it is registered to Mark Anthony Group, an international drinks company based in Vancouver. Since 2020, ASN has recorded four incidents involving PC-24s. One of the more serious incidents occurred on Dec. 9, 2022, in the UK when a German-registered PC-24 owned by Platoon Aviation and operated by Volkswagen AirService suffered an uncommanded pitch down due to a loss of elevator control, causing the autopilot to disconnect. The aircraft was controllable using pitch trim until the elevator became usable, but there was possible obstruction due to icing, the UK Air Accidents Investigation Branch (AAIB) said. The AAIB’s investigation into the incident is ongoing. Boeing Global Services Disrupted By Cyberattack Michael Bruno November 05, 2023 Days after a Russian-affiliated ransomware group claimed responsibility for a cyber breach, Boeing confirmed a cyberattack was affecting Global Services operations—online, at least. “We are aware of a cyberincident impacting elements of our parts and distribution business,” a Boeing spokesperson told Manufacturing Dive, which like Aviation Week Network is owned by Informa. “This issue does not affect flight safety.” As of Nov. 4, the services.boeing.com website continued to state: “site down due to technical issues.” News reports in late October said ransomware group Lockbit claimed to have sensitive data from the large defense prime and OEM, and it threatened to publish some unless Boeing started cooperating with the hackers by Nov. 2. Citing the U.S. Cybersecurity and Infrastructure Security Agency, Reuters said Lockbit has been responsible for 1,700 cyberattacks in the U.S. over three years. Aviation Industry Executives and Government Officials Testify on Airport Safety Aviation industry leaders testified on improving safety, pilot mental health, and increasing situational-awareness technology following a series of close-call events. Witnesses included National Transportation Safety Board Chair Jennifer Homendy, FAA Air Traffic Organization Chief Operating Officer Tim Arel, National Air Traffic Controller Association President Rich Santa, Air Line Pilots Association President Jason Ambrosi, and former FAA Administrator Randy Babbitt. The Senate Commerce, Science, and Transportation Subcommittee on Aviation Safety, Operations, and Innovation held this hearing. FAA Issues Notice on Runway Obstacle Analysis Products for Part 135 Operators Nov. 6, 2023 The FAA has released new guidance reminding Part 135 operators of the requirements and authorizations necessary to use airport aeronautical data, including airport runway analysis products. In its recent Information for Operators (InFO) 23009, the agency wrote that “routine surveillance” has revealed that some operators lack proper authorization or sufficient knowledge, training and checking on the application of obstacle analysis software, including for one-engine-inoperative departure routing/procedures. The InFO states that Operation Specification (OpSpec) A009 should allow for – and pilot training and procedures, including operator manuals, should address – the safe, daily use of these software products, including how they affect a pilot’s pre-takeoff briefing and flight deck setup. Ben van Niekerk of GrandView Aviation, who co-chairs NBAA’s Part 135 Subcommittee, welcomed the InFO, saying it will serve as an important reminder to operators and crew to align with federal regulations, and will promote the practical application of standards in professional aviators’ daily briefings and activities. “Some pilots do not know how to use airport aeronautical data correctly, which could cause procedural errors and possibly result in a controlled flight into terrain, especially during an engine failure during takeoff, but also during routine operations,” van Niekerk said. “The new InFO is an important proactive step by the FAA to minimize the risk of such avoidable accidents.” Van Niekerk said the aviation community should pursue additional efforts to educate pilots on the proper use of airport aeronautical data. He noted that the FAA recently updated its guidance for inspectors, which also serves as a resource for operators. The updated guidance for inspectors can be found in the FAA’s Dynamic Regulatory System by searching for FAA order 8900.1 Volume 3, Chapter 18, Section 3 (OpSec guidance) and Volume 4, Chapter 3 (approval of performance data). Read InFO 23009. Search the FAA’s Dynamic Regulatory System. The Crosscheck: ‘Stepped On’ Radio Transmissions Roger Cox October 26, 2023 Closest proximity of the Southwest and SkyWest flights at San Diego International Airport. Credit: NTSB There’s a lot of concern about runway incursions at the FAA and in the media right now. The FAA cited six serious incidents that have recently occurred when it issued Safety Alert for Operators (SAFO) 23002 in March. The agency urged everyone to be extra vigilant. Both the FAA and the NTSB picked up the megaphone to emphasize the increased peril using calls to action, a Safety Summit and roundtable discussion. While these efforts are expected from officialdom and well-intended, I suspect that such calls for more care from pilots and controllers miss the mark with their intended audience. Pilots and controllers are already some of the most conscientious professionals in the world. What the folks in the cockpits and the towers would really like to see is some concrete improvements in their tools, their staffing and their work environments. One tool that would help to reduce runway incursions and improve other ATC-pilot communications in general is the anti-blocking circuit in ATC and aircraft radios. The VHF radio frequencies commonly used in air traffic control don’t allow simultaneous transmissions. When a pilot or a controller presses his transmit button at the same time that another pilot or controller is already transmitting, one blocks the other. Sometimes there’s a squeal, sometimes garbling, sometimes one transmission overpowers the other, but generally the outcome is that the transmitted messages don’t get through. Pilots call this “stepping on” another’s radio call. Blocked transmissions have been around since the piston age, but nobody has been able to stop them. Blocked radio transmissions have caused accidents, near-accidents, and runway incursions many times. A blocked transmission was causal in the infamous Tenerife accident between two Boeing 747s in 1977. The latest runway incursion caused by a blocked transmission took place at San Diego International Airport on June 10, 2021. A tower controller left a SkyWest Embraer 170 flight sitting on the departure end of Runway 27 while an inbound Southwest Boeing 737 approached that runway. Realizing the developing conflict, she ordered the SkyWest aircraft to exit the runway and the Southwest 737 to go around. The ATC audio captured the pilot of SWA1648 stating, “Ah,” followed by the tower controller stating, “Southwest sixteen forty-eight go around.” Immediately after the controller unkeyed the transmission, the Southwest pilot stated, “Southwest sixteen forty-eight.” On another recording made by a commercial source, the pilot of the Southwest flight was heard saying, “Ah, is that an airplane on the runway, for Southwest sixteen forty-eight.” The pilot’s question blocked the controller’s go-around command. The Southwest was .84 nm from the end of Runway 27 when the controller and the pilot blocked each other on the frequency. Because the Southwest crew did not hear the go-around order, they continued to the runway and landed. The closest proximity between the two airplanes was 0.18 mi. laterally and 200 ft. vertically. The idea for an anti-blocking circuit in aviation radios has been around for a long time. Testifying before the House Aviation Subcommittee in 2001, retired American Airlines Capt. John Rutty said: “An anti-blocking circuit can prevent a pilot from stepping on an ongoing voice transmission, allowing the other transmission to be completed, uninterrupted. The valid signal in the receiver is sensed and the switch or transfer from receive to transmit is inhibited. The pilot hears an audible beep, which tells him he is not transmitting and, by remaining in the receiver mode, the pilot for sure hears the incoming message, which otherwise would have been blocked.” Rutty went on to suggest starting with just controllers’ radios. An alerting beep on the controller’s radio would let he or she know the information was not being received by at least one aircraft on the same frequency. “This is suggested only for the controllers’ radios as a step that can be done immediately since there would be no rule change required,” Rutty said. Even though an influential congressman and the president of the Air Line Pilots Association were behind the anti-blocking circuit technology, it wasn’t implemented. In considering why such a simple safety tool has been overlooked for so long, I recalled some simple verities I’ve heard about aviation. “There are two kinds of people, ground and air. The ground crowd designs, constructs, dispatches, maintains and otherwise controls and regulates flying. They wield the clout because they control the money and write the rules.” These words were spoken by Len Morgan, a Braniff captain I had the pleasure of flying with in the late 70s. Len went on to explain that people on the ground have their own goals and pressures. Few can grasp the total picture as seen from the air. It’s up to us, he said, to better communicate what we know is wrong with the system. Too many people on the ground seem to have myopia on the topic of anti-blocking circuits. Nobody wants to be the first to make the small investment that could prevent a catastrophic collision. It’s too easy to blame the few pilots and controllers that err and just urge us all to be more vigilant. Instead of “calls to action,” I’d like to see some real action. Get anti-blocking circuits installed in ATC facilities and airplanes, and we won’t have to say “stepped on” again. JetBlue SFO Tarmac Collision Forces Passengers Off Plane Written by George Kelly Published Nov. 07, 2023 • 8:31am Share A JetBlue plane had a collision on the tarmac at San Francisco International Airport (SFO) and forced passengers to deplane, delaying the Monday afternoon service by 10 hours. JetBlue said the airline's Flight 534 to Boston was pushing back from a gate when it was "involved in an incident with a pushback tractor." The tractor is commonly known as a tug. The airline said all customers were deplaned and were offered alternate flight options. There are no reported injuries. "No injuries were reported," the statement said. "Safety is JetBlue’s first priority; we are reviewing this incident, and the aircraft has been taken out of service for inspection." According to flight data, Flight 534 arrived in Boston at 8:10 a.m. Tuesday, 10 hours late. SFO spokesperson Doug Yakel confirmed the incident.] Passenger Stuck on Delta Flight in Triple-Digit Heat Describes Chaos: 'People Were Throwing Up, Crying' Entertainment executive April Love says she and the other passengers were starting to panic after two hours with no air and water: "I felt like I was in the Matrix" By Staff Author Updated on July 31, 2023 04:57PM EDT For one entertainment executive, it was the flight from hell. April Love, an entertainment executive and producer, was trying to return home to Atlanta from Las Vegas on Delta flight 555 on July 17 when she, along with the other passengers, found themselves stuck on the tarmac for three hours with no air-conditioning in triple-digit heat. The event is now being investigated by federal agencies. "It was awful," Love tells PEOPLE of the chaotic ordeal. "After two hours they finally gave us water, but people were passing out, throwing up, babies were screaming. One person had an accident on themselves. It was traumatizing." Love says the flight eventually went back to the gate after several hours, but even then, the passengers had to stay put while other passengers in the deepest distress were tended to. "EMTs had to rush on to tend to people who needed oxygen," Love says, saying that the heat was unbearable, especially since she was in a window seat. The heat index in Las Vegas that day reached a sweltering 114 degrees. "Being pressed against that window, with a full flight, recirculated air, and no water? Oh no. It was completely traumatizing," Love continues. "Completely ridiculous." Passenger Stuck on Delta Flight in Triple-Digit Heat Describes Chaos: 'People Were Throwing Up, Crying' Mishap Damaged F-16 Fighting Falcon from Top Gun Command, Navy Confirms An F-16 Fighting Falcon is recovered after aerial maneuvers at Marine Corps Air Station Miramar, California, on Aug. 2, 2022. (U.S. Air National Guard photo by Master Sgt. Amanda Geiger) 8 Nov 2023 An F-16A Fighting Falcon jet from the command of the Navy's most demanding fighter air combat course, known as Top Gun, was recently damaged in an aviation incident in California, according to the service. The mishap happened at Naval Air Station Lemoore, California, on Sept. 25 during recovery, resulting in damage to the "left tire or main mount," a Navy spokesperson told Military.com. The Naval Safety Center listed it as a Class A mishap, a category of incidents that cause $2.5 million or more in damages, or a destroyed aircraft. 1 Marine injured in Nevada hard landing of MV-22B Osprey By Irene Loewenson Thursday, Nov 2 A Marine was injured after a Marine Corps MV-22B Osprey experienced a hard landing during a training event in Nevada Oct. 24. (Lance Cpl. Andy Martinez/Marine Corps) A Marine was injured after a Marine Corps MV-22B Osprey experienced a hard landing during a training event in Nevada Oct. 24. Four Marines were aboard the tiltrotor aircraft when it landed at approximately 10 p.m. at the Nevada Test and Training Range at Nellis Air Force Base in Las Vegas, Marine spokesman Capt. Johnathon Huizar said in an emailed statement to Marine Corps Times on Oct. 26. One of the crew members went to a nearby hospital and was discharged in good condition, and there were no other injuries, Huizar said. The Marine Corps is still assessing the damage to the aircraft, according to Huizar. But the Naval Safety Command characterized the mishap as Class A. In mishaps where no one died or received a permanent disability, the Class A designation means an aircraft sustained at least $2.5 million in damage. Conditions That Cause Autorotation Mishaps, Part 1 Patrick Veillette, Ph.D. October 31, 2023 An instructor inadvertently moved the throttle lever from idle aft toward the 'off' position, which resulted in a total loss of engine power. The instructor took the controls, conducted a power-off autorotation, and landed the helicopter on the taxiway. It skidded about 180 ft, departed the taxiway onto adjacent grass, and came to rest in a drainage ditch. Credit: FAA How do we provide sufficient training to pilots to make certain they are proficient in the complex emergency procedures in a rotorcraft under a variety of real-world conditions? Even though modern, properly maintained powerplants are reliable, a helicopter pilot must always be prepared to properly execute an autorotation. The U.S. Joint Helicopter Safety Analysis Team (JHSAT) “Compendium Report” (2000, 2001 and 2006) determined that autorotations, both actual emergencies and during training, occurred in 32% of the 523 accidents during that three-year period. An autorotation is a complex perceptual motor skill. Unrecoverable consequences can quickly occur if the pilot’s inputs are incorrect, insufficient, excessive, or poorly timed. The only way to remain proficient is to practice this critical maneuver frequently. Ironically, the safety margins are so thin that sometimes the practice maneuver terminates in an accident. The JHSAT’s report noted that 68 of the 523 accidents, or 13%, occurred during autorotation training. There is no debate within the industry on the importance and necessity of autorotation training. Industry and government working groups have issued numerous advisories to correct some of the common deficiencies. These include recommendations on safety briefings, throttle usage, prudent selection of practice areas, and the necessity to rapidly place the rotor tip-path-plane into a proper orientation for the autorotation. Have these recommendations been effective? Perhaps. The following is a review of autorotation accident data from a recent four-year period to provide a comparison against trends from 15 years ago. A total of 73 helicopter accident investigation final reports involving an autorotation were reviewed in the NTSB’s accident database; they occurred from the 2019 through 2022. Seven accidents resulted in 11 fatal injuries. All other accidents involved non-fatal injuries. Thirty of the 73 occurred during autorotation training. An actual loss of power occurred in eight of the 30 autorotation training accidents. Thirty-eight of the 73 accidents involved turbine-powered helicopters. The rest occurred in piston-powered helicopters. Now let’s dig deeper into the data for important trends. Insufficient Speed-Altitude Combination A Bell UH-1B was conducting heli-logging near Forks, Washington, when the engine failed due to the operator’s exceedance of the engine’s sealing disk life limits. Credit: NTSB Many important helicopter missions are conducted relatively close to the ground and at slow speeds. This is a necessity for the aerial firefighting pilot trying to drop a bucket of water precisely on a smoldering snag, as well as for the pilot hovering mere inches from high-voltage cables as a technician conducts electrical line maintenance. Unfortunately, 22 of the accidents reviewed for this report occurred at an insufficient altitude to adequately establish a steady state autorotation to avoid impact with terrain. This happened to the pilot of a Bell UH-1B who was conducting helilogging operations on March 8, 2019, near Forks, Washington. Shortly after his first external-load lift of the day, company employees heard the pilot call mayday. The helicopter was found inverted in the designated logging area with the cargo line still attached along with a log. The pilot was fatally injured. According to the NTSB accident report, the helicopter operator had not kept accurate documentation of engine cycles. The helicopter’s electronic cycle counter revealed that the sealing disk had exceeded its published life limit of 6,900 cycles. The cycle counter had recorded 12,023 cycles. The NTSB determined the probable cause to be the total loss of engine power due to the failure of the gas generator sealing disk, a result of the operator’s exceedance of the sealing disk’s life limits at too low an altitude for the pilot to accomplish a successful autorotation that resulted in the collision with terrain. There are combinations of initial altitudes and airspeeds from which a safe autorotational landing will be extremely difficult to perform if an engine fails during this precarious phase of flight. The boundaries of these combinations define the height-velocity diagram. The H-V diagram depicts two areas to be avoided: the low-airspeed/high-hover altitude (low flight altitude) region and the high-airspeed/low-altitude region. From these combinations it is almost impossible to demonstrate safe autorotative landings at a vertical touchdown speed within the design limits of the landing gear. Many helicopter missions require extensive periods of time spent precariously close to the margins of the H-V diagram, so from a practical standpoint it isn’t realistic to tell pilots to always avoid flight within the shaded areas on the H-V diagram. In addition, some helicopter missions are conducted in an airborne environment that is hazardous to turbine engine operations. Five prominent parameters in the wildfire airborne environment place abnormal stresses on turbine engines. First, while the “average” air temperature around wildfire incidents tends to be excessively hot, localized plumes of super-heated air rise from the flames. Additionally, radiant heat from the flames elevates air temperatures near the flame front, far above the “ambient” temperatures. Secondly, the air from burning wildland fuel is a complex mixture of gases and aerosols. Thirdly, wildfires also emit large amounts of fine and course particulate matter (PM). Fourth, the air adjacent to the flame front is turbulent. Turbulent air flow through the engine inlet increases the chances of compressor stall and/or engine surges. Fifth, common flight maneuvers necessary for firefighting near the flame front increase the chances of hot gas ingestion into the engine inlet. All five of these conditions exist simultaneously and directly compromise the safety margins of turbine engines. The historical record illustrates razor-thin safety margins in this environment. A Flight Safety Foundation study of helicopter accidents involved in aerial firefighting examined U.S. accident reports from 1974-98 involving helicopters engaged in aerial firefighting. Thirty-four of the 97 accidents were caused by powerplant malfunctions and failures. Thirty-one of the 34 accidents resulted in severe injuries or worse to the occupants due in combination to an engine malfunction near the margins of the H-V envelope as well as the inhospitable terrain underneath the aircraft. Observing operating limits, following a manufacturer’s maintenance schedule, utilizing the manufacturer’s guidelines for normal and all-weather operations, and engine trend monitoring are important elements to maximizing engine reliability, all of which are vital when the consequences of an engine failure don’t allow a safe autorotative landing. In Part 2 of this article, we consider autorotational flares and hard landings. In Part 3 of this article, we consider the Importance Of Realistic Training CALENDAR OF EVENTS • 2024 Women in Aviation International Conference - March 21-23 (Orlando) • 2024 ACSF Safety Symposium – Air Charter Safety Foundation - April 1-3, 2024 • 2024 ISASI - Lisbon, Portugal - September 30 to October 4, 2024 • 2024 NBAA Business Aviation Convention & Exhibition - Oct. 22-24 (Vegas) Curt Lewis