Samwise Aeronautical Mechanics
NTSB FOIA Analysis Confirms Fuel Switches Cut Before China Eastern Flight 5735 Crashed
Flight data released through a Freedom of Information Act request shows that both fuel control switches on China Eastern Airlines Flight MU5735 were moved to the cutoff position approximately 23 seconds before the Boeing 737-800's flight data recorder stopped operating. The March 2022 crash in Guangzhou Province killed all 132 aboard. The NTSB analysis — released to a Chinese citizen in late April and subsequently published publicly — found no mechanical fault that would explain the switch positions. The aircraft's cockpit voice recorder remains under Chinese authority and has not been made public. China's CAAC has not issued a final accident report.
Sources: Aviation Week
Port Authority Expands Vehicle Transponder Program After Fatal LaGuardia Runway Collision
The Port Authority of New York and New Jersey announced plans to expand its vehicle transponder program in the wake of the March 22 collision at LaGuardia Airport that killed both pilots of an Air Canada Jazz CRJ-900 after it struck an unequipped aircraft rescue and firefighting vehicle on landing. The NTSB's preliminary investigation found that the airport's ASDE-X surface surveillance system could not uniquely identify the seven responding emergency vehicles, detecting them only as unidentified radar targets. The FAA separately committed $16.5 million to equip approximately 1,900 of its own vehicles at 44 airports with Vehicle Movement Area Transmitters.
Sources: Aviation Week
FAA Issues Airworthiness Directive for ATR-42 Flap Asymmetry Detection Mechanism
The FAA published AD 2026-09-13 on May 14, requiring special detailed inspections of flap asymmetry detection mechanisms on all ATR-42-200, -300, and -320 airplanes. The directive was prompted by a maintenance report discovering that a flap asymmetry detector and interconnection shaft had worn splines and were not mechanically engaged. If undetected, the condition could cause loss of flap asymmetry monitoring — a critical safety function that alerts crews to asymmetrical flap extension or retraction. The AD, effective June 18, 2026, applies to 17 U.S.-registered airplanes. Estimated compliance cost is 2 work-hours per aircraft at $170 each. The directive mirrors EASA AD 2025-0087.
Sources: Federal Register
NASA X-59 Expands Flight Envelope Testing Toward First Supersonic Milestone
NASA's X-59 quiet supersonic research aircraft completed its first wheels-up flights in April and has now reached a test tempo of two flights per day from Edwards AFB in California. The Lockheed Martin Skunk Works aircraft has accumulated approximately 19.6 flight hours across 16 flights, with the current phase evaluating flying qualities, structural loads, and flutter performance across the speed envelope. The program is building toward its first Mach 1 flight, a milestone that will verify the aircraft's low-boom design before community overflight testing begins. The X-59 is the central element of NASA's Quesst mission to assess whether supersonic overland commercial flight can be restored.
Sources: NASA.gov
Analysis: Boeing's 777 Program Represents the Peak of Airframe Engineering Discipline
Leeham News argues the Boeing 777 program — launched October 1990, first flown June 1994, and certified April 1995 — marks the peak of what it calls Boeing's pre-production change incorporation discipline. The analysis credits two decades of accumulated airframe engineering experience and Boeing's first fully digital design process, which allowed structural changes to be incorporated before tooling commitment. The article contends the 1997 McDonnell Douglas merger shifted Boeing's internal culture away from engineering excellence. The 777-9, the newest variant in the family, is identified as the latest expression of the structural design legacy the original programme established.
Sources: Leeham News
FAA Proposes AD for Airbus Helicopters With Inverted Main Gear Box Engine Flange
The FAA issued a Notice of Proposed Rulemaking on May 15 targeting certain Airbus Helicopters AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, EC130B4, and EC130T2 models after discovering that the engine flange on the main gear box engine coupling may have been installed in an inverted position during final assembly. The defect affects helicopters manufactured before May 15, 2023. An inverted flange could result in loss of power transmission to the main rotor, leading to loss of control. The proposed AD would require inspecting the main gear box engine coupling for correct installation and applicable corrective actions. Comments are due June 29, 2026.
Sources: Federal Register
Bjorn's Corner Launches New Series on Airliner Structural Engineering and Materials
Leeham News began a new weekly technical series on airliner structural engineering, opening with an overview of how airframes must carry flight and ground loads across service lives exceeding 30,000 cycles. Author Bjorn Fehrm explains that the discipline is inseparable from materials science: advances in high-strength aluminum alloys in the mid-20th century, followed by titanium and carbon fiber reinforced polymer composites, drove successive revolutions in airframe design and construction. The series follows Fehrm's completed work on Blended Wing Body airliners and will address structural challenges facing designers of next-generation narrowbody aircraft, including composite fuselage integration and fatigue characterization methodologies.
Sources: Leeham News