This article is based on technical guidance and safety publications from Airbus and additional industry safety reports.

The Hidden Danger in the Gear: Why Wheel Bearing Maintenance Cannot Be Rushed

Aircraft wheel bearings are among the most stressed components in aviation. Despite supporting loads of up to 500 tons and enduring temperature shifts from sub-zero cruising altitudes to the intense heat of braking, they remain largely hidden from view. According to a technical safety publication by Airbus, the failure of these components is rarely due to design flaws but is almost exclusively the result of improper maintenance.

At AirPro News, we have reviewed the latest guidance from Airbus’s “Safety First” initiative, alongside broader industry data, to understand why these small components continue to pose significant risks to flight safety. The consensus across manufacturers and regulators is clear: strict adherence to maintenance protocols is the only barrier against catastrophic failure.

The Mechanics of Failure

The primary cause of bearing failure, as identified by Airbus and industry data, is maintenance error. Specifically, the issues revolve around incorrect torque application, contamination, and inadequate lubrication. Aircraft use “tapered roller bearings” designed to handle both the weight of the aircraft (radial loads) and side-to-side movement (axial loads). When these bearings are mistreated, the consequences are severe.

The “Double-Torque” Procedure

One of the most critical and frequently misunderstood aspects of wheel installation is the torque procedure. According to Airbus technical guidelines, a specific “double-torque” method is required to ensure the bearings are seated correctly without being overtightened.

The process generally involves three distinct steps:

1. Initial Seating: A high torque is applied while rotating the wheel. This step is crucial to “seat” the rollers and eliminate free play.
2. Back-off: The nut is loosened to relieve stress on the components.
3. Final Torque: A specific, lower torque is applied to set the correct “preload.”

The risk lies in the details. If a technician skips rotating the wheel during the initial torque application, the rollers may not align, leading to a false torque reading. This can result in loose bearings that vibrate and wear prematurely, or tight bearings that overheat and seize.

Real-World Consequences

The failure of a wheel bearing is not merely a maintenance inconvenience; it is a direct threat to the structural integrity of the aircraft. When a bearing seizes, it can generate enough friction to weld components together or shear axles, leading to wheel separation.

Airbus and TSB Canada Data

In one notable case study highlighted by Airbus, an A330 aircraft lost a wheel during takeoff. The investigation revealed that a seized bearing destroyed the axle nut, allowing the wheel to eject from the landing gear. This is not an isolated event. Data from the Transportation Safety Board of Canada (TSB) underscores the prevalence of this issue.

“A study revealed 67 occurrences of nosewheel bearing failures on A319/A320/A321 aircraft worldwide between 1989 and 2004.”

— TSB Canada Data

Cross-Fleet Vulnerabilities

While the Airbus “Safety First” article focuses on their fleet, the physics of bearing failure applies universally. Reports from the UK Air Accidents Investigation Branch (AAIB) detail an incident involving a Boeing 737-800 where a seized bearing generated sufficient heat to compromise the chrome plating and base metal of the axle, causing it to fracture.

Similarly, an investigation into an Embraer EMB-145 (registration G-EMBP) found that moisture contamination due to improper seal installation led to severe overheating and subsequent axle failure. These incidents confirm that regardless of the airframe manufacturer, the root causes, contamination and torque errors, remain consistent.

Industry Best Practices

To mitigate these risks, manufacturers and technical organizations like Timken have established “gold standard” maintenance manuals. The following practices are considered non-negotiable for airworthiness:

• Cleaning is Critical: Technicians must remove all old grease. Old lubricant can hide “spalling” (flaking metal) or heat discoloration (blue or straw-colored metal), which are early signs of fatigue and overheating.
• Pressure Packing: Hand-packing grease is often insufficient. Industry standards recommend using pressure packing tools to ensure grease penetrates behind the cage where the rollers contact the race.
• Grease Compatibility: Mixing clay-based and lithium-based greases can cause the mixture to break down, destroying its lubricating properties. Lithium-based grease is generally preferred for its water-repelling capabilities.
• Wheel Rotation: As emphasized in the torque procedure, the wheel must be rotated while tightening the nut to align the rollers.

AirPro News Analysis

The Human Factor in Maintenance

While the technical steps are well-documented, we believe the persistence of these failures points to a human factors challenge. Wheel bearings are “hidden” components; unlike a tire that shows visible tread wear, a bearing often looks pristine until the moment it fails catastrophically. This lack of visual feedback places an immense burden on the maintenance process itself.

In high-pressure line maintenance environments, the requirement to rotate a wheel while torquing it, a process that relies on “feel” and patience, can be a trap for technicians rushing to clear an aircraft for departure. The data suggests that safety in this domain relies less on new technology and more on a disciplined adherence to the basics: cleaning, inspecting, and respecting the torque procedure.

Regulatory Context

Regulators continue to monitor these risks closely. The FAA has previously issued Airworthiness Directives, such as AD 2012-10-09 for Cessna 560XL aircraft, following reports of brake failure linked to loose bearing components. Furthermore, the FAA Safety Team (FAASTeam) frequently issues alerts reminding operators that “grease is not just grease,” warning that using unapproved substitutes constitutes a violation of FAR Part 43.

Whether operating a General Aviation aircraft or a commercial airliner, the message from the industry is uniform: take care of the wheel bearings, and they will carry the load.

Sources

• Airbus “Safety First”: Take Care of the Wheel Bearings
• Transportation Safety Board of Canada (TSB)
• UK Air Accidents Investigation Branch (AAIB)
• Timken
• Federal Aviation Administration (FAA)

This article summarizes reporting by CBS News and Todd Feurer.

Fatal Small Plane Crash Reported at DuPage Airport

Two individuals were killed Wednesday afternoon when a small twin-engine aircraft crashed shortly after takeoff at DuPage Airport in West Chicago, Illinois. According to reporting by CBS News, local authorities and federal investigators responded to the scene immediately following the incident.

The crash occurred at approximately 1:50 p.m. CST on December 17, 2025. Emergency responders found the aircraft in a snow-covered area near the runway, where both occupants were pronounced dead. As of Thursday morning, the identities of the victims have not been released pending notification of their next of kin.

Incident Details and Immediate Response

The aircraft involved has been identified as a Piper PA-30 Twin Comanche, a light twin-engine monoplane often used for personal touring and flight training. Reporting indicates that the aircraft sustained significant front-end damage upon impact. The flight was in its initial departure phase when the accident occurred.

According to CBS News, the West Chicago Police Department and the Federal Aviation Administration (FAA) were among the first agencies to respond. The airport was temporarily closed to facilitate emergency operations and scene documentation.

In a statement regarding the loss of life, the DuPage Airport Authority expressed their condolences:

“Our thoughts are with the families and loved ones of those who lost their lives in this tragic incident.”

Investigation and Environmental Factors

The National Transportation Safety Board (NTSB) has assumed the lead role in the investigation, with support from the FAA. An NTSB investigator was scheduled to arrive at the crash site on Thursday, December 18, to begin the on-scene examination.

Investigators are expected to focus on three primary categories, the pilot’s history and performance, the mechanical state of the aircraft, and the operating environment. While a preliminary report is typically expected within two to three weeks, a final determination of probable cause may take up to two years.

Weather Conditions

Meteorological data from the time of the crash suggests that weather was likely not a primary adverse factor. Conditions at 1:50 p.m. were reported as:

• Sky: Clear
• Visibility: 10 miles
• Wind: Light from the Southeast at 4 knots
• Temperature: Approximately 39°F (4°C)

Despite the clear skies, the ground remained snow-covered from a previous winter storm, which may complicate the physical recovery of debris.

Background: DuPage Airport and the Piper PA-30

DuPage Airport (KDPA) serves as a critical general aviation hub for the Chicago metropolitan area. It is the third-busiest airport in Illinois, handling approximately 133,000 annual operations. The facility relieves traffic from O’Hare and Midway and is frequently used by corporate jets and flight schools.

The Piper PA-30 Twin Comanche was manufactured between 1963 and 1972. It is known for its fuel efficiency and speed but, like many light twin-engine aircraft, requires specific pilot proficiency to manage engine-out scenarios, particularly during the critical takeoff phase.

AirPro News Analysis

The Critical Nature of Takeoff

While it is too early to speculate on the cause of this specific tragedy, the timing of the crash, shortly after takeoff, highlights one of the most dangerous phases of flight. General aviation accident statistics frequently point to the departure leg as a moment of high workload and low altitude, leaving pilots with limited options in the event of a mechanical failure.

With weather conditions reported as clear and calm, investigators will likely scrutinize the aircraft’s maintenance logs and the engine performance during the climb-out. The “routine” nature of the flight, occurring in excellent visibility, underscores the unpredictable nature of aviation incidents.

Sources

• CBS News

This article summarizes reporting by The Associated Press, The Washington Post, and NTSB public datas.

Senate Passes ROTOR Act to Close Military Flight Tracking Loophole Following D.C. Tragedy

On Wednesday, the U.S. Senate unanimously approved the Rotorcraft Operations Transparency and Oversight Reform (ROTOR) Act, a critical piece of safety legislation designed to prevent mid-air collisions between military and civilian aircraft. The bill’s passage comes nearly a year after a catastrophic crash near Washington, D.C., claimed 67 lives, exposing dangerous gaps in airspace coordination.

According to reporting by The Associated Press and WTOP, the Senate moved quickly to pass the measure (S. 2503) just hours after approving the National Defense Authorization Act (NDAA) for Fiscal Year 2026. The NDAA contained a provision that safety advocates described as a “loophole,” which allowed Military-Aircraft to fly without broadcasting their location during training missions. The ROTOR Act explicitly closes this gap, mandating that military aircraft broadcast their position during training and proficiency flights.

The legislation now heads to the House of Representatives, where sponsors hope for final approval by January 2026.

Correcting the “Dark” Flight Loophole

The legislative maneuvering on Wednesday involved two distinct bills. First, the Senate passed the massive annual defense spending bill (NDAA). According to legislative analysis, Section 373 of the NDAA permitted military aircraft to disable tracking equipment for “sensitive government missions.” Critics and safety officials argued this definition was being interpreted too broadly, effectively allowing routine training flights to operate “in the dark” within crowded civilian airspace.

To address this immediately, Senators Ted Cruz (R-Texas) and Maria Cantwell (D-Wash.) pushed the ROTOR Act through by unanimous consent. As reported by The Washington Post, this “fix-it” bill overrides the NDAA provision regarding training flights.

Key Provisions of the ROTOR Act

• Mandatory Broadcast (ADS-B Out): Military aircraft must use Automatic Dependent Surveillance-Broadcast (ADS-B) technology to transmit their location during training and proficiency flights.
• Situational Awareness (ADS-B In): By 2031, all aircraft, civilian and military, must be equipped with “ADS-B In” technology, allowing pilots to view other aircraft positions directly in the cockpit.
• Safety Review: The FAA is mandated to conduct a comprehensive review of airspace safety around major airports.

This legislation should save lives.

, Senator Ted Cruz (via Senate Commerce Committee statement)

The Catalyst: A Preventable Tragedy

The urgency behind this legislation stems from the horrific mid-air collision on January 29, 2025. According to NTSB investigation reports summarized by the media, American Airlines Flight 5342, a Bombardier CRJ-700 regional jet, collided with a U.S. Army UH-60 Black Hawk Helicopters over the Potomac River near Ronald Reagan Washington National Airport (DCA).

The crash resulted in 67 fatalities: 60 passengers and 4 crew members on the regional jet, and 3 soldiers aboard the helicopter. Investigators determined that the Army helicopter was conducting a training mission with its ADS-B transponder turned off. Consequently, the airliner’s collision avoidance systems could not detect the military aircraft, and air traffic controllers lacked precise visibility of the helicopter’s movements.

NTSB Chair Jennifer Homendy has been a vocal advocate for the reform, stating that the tragedy “could have been avoided” had the helicopter been broadcasting its location. Furthermore, NTSB data revealed a troubling pattern: in the three years leading up to the crash, there were 85 near-misses involving military and civilian aircraft in the D.C. area alone.

Technological Mandates and Industry Pushback

The ROTOR Act pushes the Aviation industry toward full adoption of ADS-B technology. While “ADS-B Out” (transmitting location) is already standard for most commercial aircraft, “ADS-B In” (receiving data from others) is not universally deployed. The CRJ-700 involved in the January crash lacked “In” capability, meaning the pilots relied entirely on Air Traffic Control for separation.

Privacy and Security Concerns

While safety officials celebrate the bill, some stakeholders have raised objections. The Department of Defense (DoD) has historically resisted broad tracking mandates, citing operational security (OPSEC) risks if adversaries can track military movements. The ROTOR Act attempts to balance this by limiting the mandate to training and proficiency flights, rather than combat or sensitive covert operations.

Additionally, the Aircraft Owners and Pilots Association (AOPA) has expressed concerns regarding data privacy. According to reports from Aviation International News, AOPA President Darren Pleasance argued that third parties currently use ADS-B data for non-safety purposes, such as collecting landing fees or tracking private citizens for enforcement actions. The association has lobbied for strict data-use limitations to ensure pilot privacy is not compromised by the new mandates.

AirPro News Analysis

The inclusion of a 2031 mandate for “ADS-B In” represents a significant shift in regulatory philosophy. Historically, the FAA has focused on “ADS-B Out” to aid air traffic controllers. Mandating “In” capability shifts the burden of situational awareness directly into the cockpit. For regional airlines and general aviation operators, this will likely necessitate a substantial retrofit program over the next five years. While the cost will be high, the January 2025 tragedy demonstrated that relying solely on ground-based control is insufficient in mixed-use airspace where military assets operate alongside commercial jets.

Frequently Asked Questions

When will the ROTOR Act become law?

The bill passed the Senate on December 17, 2025. It must now pass the House of Representatives. Sponsors are optimistic it will be signed by the President in January 2026.

Does this apply to all military flights?

No. The bill specifically targets training and proficiency flights. Sensitive government missions may still be exempt from broadcasting their location to preserve operational security.

What is the difference between ADS-B Out and In?

“Out” transmits an aircraft’s GPS data to ground stations and other planes. “In” allows an aircraft to receive that data and display nearby traffic on a screen in the cockpit.

Sources: Associated Press, The Washington Post, NTSB Reports