5 Signs Your Passenger Boarding Bridge Needs Maintenance

Executive Summary

Passenger Boarding Bridges (PBBs) are among the most heavily used assets in an airport environment. They operate through thousands of cycles each year, supporting both passenger movement and safe aircraft interface. Yet many of the early warning signs of deterioration remain unnoticed until the system reaches a critical point.

This expanded write-up highlights five major indicators that suggest the need for proactive maintenance intervention. Identifying these signals early allows airport operators to transition from reactive firefighting to structured preventive maintenance, enhancing safety, reducing downtime and optimising the lifecycle cost of these high-value assets.

1. Unusual Movement, Abnormal Noise or Alignment Shifts

A well-functioning PBB has predictable behaviour, smooth movement, consistent alignment and quiet operation. Any deviation from this predictable pattern warrants immediate inspection.

Common symptoms include:

• Jerky motion during extension or retraction
• Cabin drifting or shifting after docking
• Audible grinding, popping, whining or “binding” sounds
• Noticeable delay in movement commands
• Sudden stops or hesitations in the drive mechanism

These irregularities often result from:

• Worn drive bearings or fatigued bushings
• Misaligned guidance rails
• Worn tyres/wheels or incorrect tyre pressure
• Faulty encoders or limit switches
• Contamination or degradation of hydraulic fluid

Operational risk: Even minor misalignment can cause aircraft door-frame damage, which may lead to costly claims and operational delays. Abnormal motion is almost always a precursor to larger failures, making early intervention critical.

2. Corrosion, Structural Degradation or Component Fatigue

As exposed steel structures, PBBs endure some of the toughest environmental conditions on the airside.

Key degradation indicators:

• Rust streaks, pitting or corrosion on support beams and walkways
• Fatigue cracks around welds, joints and lifting columns
• Dents or deformation in telescopic tubes
• Loose bolts and distorted structural fittings
• Degraded or peeling protective coatings

Environmental elements, such as high humidity, temperature extremes, de-icing chemicals, jet blast and coastal salt exposure, cause progressive deterioration.

Why this matters:

Structural fatigue affects the bridge’s stability and telescoping accuracy. What starts as minor corrosion can escalate into structural warping, misalignment and ultimately unsafe docking conditions. Refurbishment or reinforcement is far more cost-efficient when planned early rather than executed after a structural failure.

3. Faults in Safety or Control Systems

Modern PBBs are technology-intensive, incorporating advanced safety, sensor and automation systems to ensure safe, efficient operation.

Warning signs include:

• Proximity sensors failing to detect aircraft door position
• Floor not maintaining level (auto-levelling malfunction)
• Frequent error codes or system lockouts on operator consoles
• Slow response between operator command and bridge movement
• Auto docking overshooting or undershooting target positions
• Emergency stop being activated unintentionally

Failures often arise from:

• Sensor misalignment
• Loose wiring or corroded connectors
• PLC logic errors or outdated firmware
• Faulty servo drives or motor controllers

Operational impact:

A malfunctioning control system can quickly escalate into a safety incident, passenger injury, aircraft fuselage damage or a complete gate shutdown. Proactive diagnostics and periodic calibration are essential for ensuring safety integrity.

4. Increasing Downtime, Frequent Repairs or Repeated Operational Interruptions

Maintenance logs serve as the most objective indicator of asset health.

Key patterns to watch for:

• More frequent unscheduled repairs
• Repeated hydraulic leaks from the lifting column
• Frequent wheel/tyre changes
• Recurring control-system or PLC faults
• Increase in operator complaints
• Prolonged recovery time for minor faults

A rising trend in repair frequency usually indicates underlying problems such as component fatigue, ageing systems or inadequate preventive maintenance.

Strategic questions for asset managers:

• Has the preventive maintenance programme matured with asset age?
• Are inspections being carried out with sufficient depth and frequency?
• Are repeated issues being root-caused or simply patched?
• Is there a case to upgrade parts, improve OEM relationships or standardise spares?

“Fixing only what breaks” may work temporarily, but for high-criticality equipment like PBBs, it dramatically increases lifecycle cost and risk exposure.

5. Environmental or Operational Mismatch: Usage Beyond Design Capacity

Many PBBs remain in service for 15–25 years. However, airport operations evolve, aircraft types, turnaround times and environmental conditions shift over time.

Signs of mismatch include:

• Gate repurposed for larger aircraft without recalibrating the PBB
• Increased duty cycles due to high-traffic schedules
• Added loads from GPU, PCA or additional utility routing
• Exposure to more extreme temperatures or coastal conditions
• Mechanical strain from tighter turnaround windows

Even if the PBB continues operating normally, these “silent” stressors accelerate wear.

Why this matters:

Operating beyond design limits shortens structural and mechanical life and increases the rate of failure across motors, sensors, telescopic sections and lifting mechanisms. Early recalibration or equipment strengthening helps sustain operational reliability.

Conclusion

Understanding and acting on these five indicators, movement irregularities, structural degradation, safety-system faults, increased downtime and operational mismatch, gives engineering teams a powerful advantage. Proactive maintenance preserves safety, enhances asset reliability, reduces aircraft damage risk and ensures uninterrupted gate operations.

“Passenger boarding bridges rarely fail without warning, the challenge is recognising the signals before they disrupt operations. When vibrations, slower docking cycles or inconsistent alignment go unnoticed, risk quickly shifts from inconvenience to operational and safety exposure. At GEMS, we view PBB maintenance not as a repair task but as a critical reliability intervention that protects turnaround time, passenger experience and airline trust.”

— Roy Sebastian, CEO GEMS

GEMS provides comprehensive airport engineering and management services including asset maintenance, predictive analytics, innovation deployment, GSE optimisation and operational oversight.

For specialised support:

📧 Rohitkumar.Singh@gmrgroup.in

📞 +91 97171 99753