A Complete Guide to Maintaining Aircraft Winglets

At first glance, although winglets may appear to be simple extensions of an aircraft’s fixed wingtips, they serve the specific purpose of reducing vortices that would otherwise generate drag and diminish aerodynamic efficiency. By managing these wingtip vortices more effectively, winglets contribute to measurable fuel savings, improved climb performance, and better handling. Like any functional part of an aircraft, they rely on consistent, properly executed maintenance to perform as intended. For your reference, this blog will first cover the common winglet types found on modern aircraft, then discuss maintenance intervals and procedures technicians should generally follow to preserve their airworthiness.

The Diverse Winglet Types

Winglets across airframes vary in their geometry and structural complexity, with the usual overarching types including:

• Classic Vertical Winglets: Classic vertical winglets, sometimes referred to as canted winglets, are one of the earliest configurations. Recognizable by their sharply angled upward extension from the wingtip, these designs typically meet the wing at a defined, non-blended joint that can concentrate aerodynamic loads at the wing–winglet interface.
• Blended Winglets: Blended winglets are an evolution of classic winglets, developed to improve aerodynamic efficiency by replacing abrupt angular junctions with a smooth, continuous curvature between the wing and the upward-swept extension. This update significantly reduces interference drag at the base and distributes structural loads more evenly, but any minor deformation can disrupt the precise airflow these designs are intended to deliver.
• Multi-Element Winglets: Incorporating both an upward-sweeping component and a downward-angled ventral strake that resembles a swept blade, multi-element winglets modify vortex behavior more aggressively. This design relies on more intricately attached aerodynamic surfaces than other winglet types.

Essential Winglet Maintenance Practices

Effective winglet care is dependent on visual assessments and structural examinations in accordance with the aircraft manufacturer’s maintenance manual (AMM) and structural repair manual (SRM). Any winglet maintenance program must establish a consistent inspection and repair schedule that lines up appropriately with flight cycles, operational environments, and materials used for the winglet.

Routine Visual Inspections

During daily walk-arounds or preflight checks, technicians have to verify the overall condition of winglets or wingtip devices. These inspections focus on issues that can be assessed externally without reliance on specialized equipment, such as:

• Surface Conditions: Inspect outer surfaces for visible cracks, dents, abrasions, or signs of impact. Because lightning protection systems are incorporated into the winglet structure, technicians need to look out for apparent lightning-strike marks or burn patterns. Meanwhile, composite winglets should be checked for indications of delamination like uneven or soft areas and bubbling. 
• Attachment Hardware: Check that all externally visible fasteners and fairing attachments are present and appear secure. While verifying torque values is not part of a walk-around, technicians should note any signs of loose, missing, or damaged hardware, as well as misalignment or visible gaps at the wing–winglet interface.
• Drainage Openings: Sometimes, OEMs incorporate drainage paths to prevent moisture accumulation within enclosed winglet cavities. If they are present, look for any blocked openings that could lead to internal corrosion, water retention, or freeze-related damage if left unaddressed.

Scheduled Structural Maintenance

At specified intervals, typically aligned with A-checks or C-checks, more detailed procedures are required. These structural maintenance tasks can include:

• Non-Destructive Testing (NDT): NDT techniques like ultrasonic inspection and eddy-current testing are used to detect internal cracking, delamination, or other subsurface defects in both composite and metallic winglet structures.
• Fastener Torque Verification: Like we noted, winglets need correctly installed fasteners to maintain structural alignment and load transfer, so they must be re-torqued or replaced as necessary to fall within limits specified in the AMM.
• Corrosion Prevention and Treatment: Metallic and hybrid winglet designs, as well as any metallic fittings used, must be treated for corrosion or degradation. This can include cleaning, corrosion removal, application of protective coatings, repainting, or even full replacements. 
• Fairing Alignment Checks: For winglets that incorporate multiple aerodynamic elements, all fairings and secondary surfaces have to be appropriately aligned and secured to avoid any lapses in aerodynamic performance and wear caused by excessive vibration or movement.

Maintenance Tips for Typical Causes of Wear

In combination with regular inspections and maintenance, operators should be aware of some common causes of damage to be as proactive as possible in repairs. These include:

• Environmental Exposure: UV radiation, saltwater environments, and precipitation can weaken composite layers or accelerate corrosion. As such, aircraft that are often in coastal or humid environments should undergo more frequent winglet checks.
• Operational Stress: High-cycle aircraft experience repetitive bending and torsional loads on winglets, which increases the risk of fatigue cracks.
• Foreign Object Damage: Hail, birds, or debris can strike the winglet and cause surface damage or internal issues. If operators know that winglets have been hit in any way, an inspection has to occur immediately.
• Improper Repairs: Inadequate bonding, incorrect fastener replacement, or non-approved surface treatments can all compromise structural strength, requiring great care on part of technicians to avoid making existing problems worse.

Secure Replacement Winglet Parts from Find NSN

As we have covered, even minor surface imperfections or loose hardware on winglets can escalate into more serious issues if left unaddressed. Following regular maintenance intervals and strictly using approved materials are integral aspects of keeping winglets flight-ready. If you find yourself requiring replacement winglet fasteners, composite sections, or other such parts that meet your aircraft’s specifications, we have you covered on Find NSN.

With an extensive catalog of products from vetted manufacturers, you can be sure that any item from us will comply with all certification and traceability standards. You also never have to compromise any of your requirements with us, as we at ASAP Semiconductor always aim to offer competitive pricing and delivery times for every part ordered on Find NSN. Taking all of this into account, get in touch with a team member today to see how we can best serve your procurement needs.