Proper landing gear maintenance is critical to aircraft safety—especially when it comes to main landing gear (MLG) oleo struts and shock pads.
For aircraft like the Ercoupe, Forney, and Alon series, landing gear design plays a direct role in ground handling, takeoff performance, and landing stability. Maintaining the correct geometry isn’t just recommended—it’s essential.
In this guide, we’ll break down how oleo struts and shock pads function, why tail height matters, and how to properly maintain your aircraft’s landing gear system.
Why Oleo Strut & Shock Pad Maintenance Matters
Aircraft in this category are uniquely designed to maintain a slightly negative wing angle of attack while on the ground.
This design allows the aircraft to:
- Remain stable during ground operations
- Prevent unintended liftoff before rotation
- Avoid “ballooning” after landing
However, this performance depends entirely on maintaining proper tail height.
If landing gear components wear or degrade, the aircraft geometry changes, compromising safety and performance.
Understanding Aircraft Tail Height & Geometry
For proper operation, these aircraft are designed to sit at approximately:
- 75 inches of tail height
- Slight negative angle of attack on the ground
If this height decreases:
- Angle of attack becomes more positive
- Takeoff characteristics change
- Landing behavior becomes less predictable
Even small changes in landing gear condition can significantly impact flight safety.
Nose Landing Gear (NLG): Key Considerations
The nose landing gear system includes:
- A taxi spring (supports static height)
- An oil-filled oleo strut (absorbs landing forces)
Important notes:
- The taxi spring determines fixed nose height
- Oleo strut provides shock absorption only
- Adjustments require proper spring selection, not just servicing
Modifications (like dual nose forks) may require different spring configurations to maintain proper geometry.
Main Landing Gear (MLG): Shock Pads & Performance
Unlike the nose gear, the main landing gear relies entirely on rubber shock pads (taxi stack).
These pads:
- Support the aircraft’s weight at rest
- Maintain correct tail height
- Absorb ground loads during taxi
The Problem with Aging Shock Pads
Over time, rubber shock pads:
- Compress and lose elasticity
- Reduce overall landing gear height
- Lower tail height
This gradual change often goes unnoticed—but has major performance implications.
Signs Your Shock Pads Need Attention
Watch for these common indicators:
- Reduced tail height
- Aircraft sitting “low” on the ramp
- Changes in takeoff rotation feel
- Less stable ground handling
- Increased bounce or stiffness during taxi
If your aircraft no longer sits at the correct height, your shock pads may be worn out.
Oleo Strut Maintenance: What to Check
While MLG height is controlled by shock pads, oleo struts still play a key role in impact absorption.
Inspect Your Oleo Strut For:
- Proper fluid levels
- Smooth compression and rebound
- No leaks or visible damage
- Consistent damping during landing loads
A poorly maintained oleo strut can lead to harsh landings and increased structural stress.
Why Proper Landing Gear Height Is Critical
Maintaining correct landing gear height ensures:
- Safe Takeoff Performance
Prevents premature liftoff and unstable rotation
- Controlled Landings
Reduces bounce and improves rollout stability
- Structural Protection
Absorbs loads properly to protect the airframe
- Consistent Handling
Maintains predictable ground and flight behavior
Best Practices for Aircraft Landing Gear Maintenance
To keep your aircraft performing safely:
- Regularly inspect shock pads for compression and aging
- Verify tail height meets manufacturer specifications
- Check oleo strut condition and fluid levels
- Monitor changes in handling or ride quality
- Replace worn components proactively—not reactively
Don’t wait for a problem, landing gear degradation happens gradually.
When to Replace Shock Pads or Service Oleo Struts
You should take action if:
- Tail height falls below recommended specs
- Shock pads show visible compression or aging
- Oleo strut performance becomes inconsistent
- Aircraft handling changes noticeably
In many cases, replacing shock pads restores the aircraft’s original geometry and performance.
Final Thoughts: Don’t Overlook Landing Gear Geometry
Your aircraft’s landing gear isn’t just about absorbing impact, it directly affects how your aircraft flies and handles on the ground.
A small loss in height can lead to:
- Altered aerodynamics
- Reduced safety margins
- Unpredictable performance
Taking the time to maintain your MLG shock pads and oleo strut system ensures your aircraft performs exactly as designed.
Need Help with Aircraft Landing Gear Maintenance?
Alpha Aviation provides expert support and components for:
- Oleo strut maintenance
- Shock pad replacement
- Landing gear inspections
- Aircraft-specific maintenance solutions
Contact Alpha Aviation today to ensure your aircraft’s landing gear is operating safely and correctly.
