In aviation, safety isn’t just about avoiding disasters, it's about preventing them altogether. One often-overlooked component that plays a critical role in both safety and performance is the aircraft engine mount. 

This unsung hero connects the engine to the airframe, handles intense vibrations, and helps maintain precise engine alignment during flight. When engine mounts begin to fail, the consequences can be both costly and dangerous.

Spotting early signs of failure not only protects your aircraft but also avoids unnecessary downtime and expensive repairs. In this blog, we’ll explore what aircraft engine mounts do, the symptoms of failure, why they deteriorate, and how professional aviation welding technicians can make a difference.

Common Signs Of Aircraft Engine Mount Failure

Failure doesn’t always happen suddenly. It usually starts small, with subtle hints that something isn’t quite right. Below are the most common symptoms of deteriorating or damaged engine mounts.

Unusual Engine Vibrations In The Cockpit

If you start feeling increased or irregular vibrations in the cockpit or through the fuselage, this could indicate that the mounts are no longer isolating engine movement as they should. Damaged mounts lose their ability to cushion the engine’s movement, causing vibrations to transfer directly to the airframe.

Pilots often report feeling a hum or shudder that wasn’t there before. While vibration can result from various sources, deteriorating engine mounts are one of the primary culprits, and ignoring them can lead to stress fractures elsewhere in the airframe.

Audible Clunks, Rattles, Or Bangs During Flight

Odd noises during engine startup, shutdown, or throttle changes often indicate mechanical looseness. These sounds may occur when the engine shifts slightly within its mounting due to cracked or broken mounts. 

If you hear metal-on-metal noise or anything that resembles rattling from the engine bay, it's worth investigating further.

A stable engine should operate with minimal movement relative to its mount. Any movement that allows banging or rattling usually means the engine is no longer fully supported.

Visible Cracks, Corrosion, Or Deformation

Routine inspections should always include a visual check of the engine mount structure. Look for hairline cracks, flaking paint, rust formation, or any signs of metal fatigue. Even minor surface flaws can be early indicators of a weakening structure. Cracked welds, especially at high-stress junction points, are also a red flag. 

This is particularly important for older aircraft or those used frequently in high-vibration environments, such as training planes or aerobatic models. Transport Canada’s Standard 625 Appendix B specifically highlights the importance of inspecting engine mounts for cracks, looseness, and corrosion as part of scheduled maintenance protocols.

Engine Misalignment Or Tilting

Engine alignment within the cowling should remain precise. If the engine appears slightly tilted, slanted, or otherwise misaligned, this is a serious warning sign. Misalignment stresses the propeller shaft, fuel lines, and control linkages, leading to broader system failures.

Proper alignment is essential not only for performance but also for safety, as it helps prevent uneven wear and imbalances in the flight system.

Fluid Leaks Near The Mounting Points

Oil stains, coolant drips, or hydraulic leaks around the engine mounting areas might not seem related to the mounts, but they often are. A worn mount can cause abnormal movement of the engine, which stresses fluid lines and seals, leading to leaks.

Leaking fluids may signal compromised seals, often brought on by misalignment or vibration that the engine mount is supposed to prevent.

Why Engine Mounts Deteriorate Over Time

Understanding what causes aircraft engine mounts to break down can help operators and technicians take preventive action. Several factors contribute to mount deterioration, working together over time.

Operational Fatigue And Repetitive Stress

Engine mounts endure a massive amount of mechanical stress from takeoff thrust, vibration, and in-flight turbulence. Over time, this stress leads to fatigue. Even the most robust materials like steel or titanium alloys can crack or deform after thousands of flight hours.

Aircraft that fly regularly in rough air or operate under high-power conditions, such as crop dusters, flight schools, or floatplanes are especially susceptible.

Corrosive Environmental Exposure

Exposure to salt, moisture, chemicals, and fluctuating temperatures accelerates the corrosion of metal components. Aircraft based near coastal regions or in humid climates face higher risks. Rust and oxidation slowly degrade the integrity of the engine mount, weakening the structure over time.

Regular application of anti-corrosion coatings and controlled hangar storage can help delay this damage.

Improper Installation Or Previous Damage

Engine mounts must be installed to exact specifications. If fasteners are over- or under-torqued, or if the structure is forced into place, stress fractures can develop early on. Additionally, mounts that have undergone previous repairs without following certified procedures are more likely to fail prematurely.

How Maintenance Technicians Detect Engine Mount Issues

While some symptoms are visible or audible, others require professional inspection using advanced techniques.

Visual And Physical Inspection

Technicians will typically begin with a visual inspection, looking for cracks, corrosion, and wear. They may use borescopes to look in tight spaces and check the flexibility and tightness of each mounting point.

Non-Destructive Testing (NDT)

Dye penetrant inspection and magnetic particle testing are commonly used to identify subsurface cracks. These methods allow maintenance teams to identify invisible stress points before they develop into structural failures.

Vibration Analysis And Engine Alignment Checks

More advanced facilities use vibration analysis to check whether the engine is transmitting irregular forces through the airframe. Laser alignment tools may also be used to confirm that the engine is sitting within manufacturer's tolerances.

Best Practices To Prolong Engine Mount Life

Being proactive with care and inspection can extend the lifespan of your engine mounts and prevent avoidable repairs.

• Follow the Scheduled Maintenance Intervals outlined by the aircraft manufacturer or governing aviation authority (like Transport Canada or the FAA).
  
  
• Protect Against Corrosion by applying approved sealants and keeping the engine bay dry and clean.
  
  
• Avoid Overloading the engine mount with unauthorized engine modifications or aggressive flying behaviour.
  
  
• Always Use Certified Repair Shops for inspections, welding, or replacements.
  

About Us

Acorn Welding is a leading provider of aviation welding and manufacturing solutions, specializing in the repair and overhaul of aircraft engine mounts, exhaust systems, and related components. With a commitment to quality and safety, our team of certified technicians ensures that every product meets stringent industry standards. For more information or to schedule a consultation, contact us today.