Fairchild/Dornier C-26 Metroliner: Aircraft Pitot Probe Covers

A pitot tube is a small, slender tube mounted on the exterior of an aircraft and fitted with two holes, each measuring pressure from the incoming airflow. The front hole is placed in the airstream to measure stagnation pressure, while the side hole measures static pressure. Measuring the difference between these two pressures indicates the dynamic pressure, which can then be used to calculate the airspeed of the aircraft.

To ensure accurate airspeed readings and prevent malfunctions, aircraft pitot probes rely on protective covers. These covers act as shields, keeping out debris, dirt, moisture, and even pesky insects like wasps. These foreign objects can easily clog the delicate openings of the probe, leading to inaccurate data and potentially jeopardizing flight safety. Pitot probe covers also offer an extra layer of defense against corrosion and damage caused by rain, snow, and extreme weather conditions.

Sesame Technologies manufactures all their aircraft pitot tube covers with Kevlar®. Some advantages of Kevlar® in pitot covers include:

• Extreme Strength and Durability: Kevlar®'s super-strong fibers provide exceptional resistance to tearing, impact, and abrasion. This makes it ideal for protecting delicate pitot tubes from damage by debris, birds, insects, or accidental bumps during maintenance.
• High Temperature Resistance: Kevlar® can withstand high temperatures (up to 800°F), making it safe to use in the extreme conditions that aircraft may encounter. It won't melt or deform, ensuring protection against the heat of engines or friction during flight.
• Chemical Resistance: Kevlar® doesn't readily break down when exposed to aircraft fluids, cleaning agents, or other chemicals on the tarmac or in the hangar.
• Lightweight: Despite its impressive strength, Kevlar® is quite lightweight, a crucial feature in aviation where every gram counts.
• Flexibility: Kevlar can be woven into a fabric that is soft and pliable, allowing for a snug, secure fit around the pitot tube without the risk of scratching the sensitive equipment.
• Water Repellent: Kevlar® pitot covers are typically water-repellent, reducing the risk of moisture getting trapped inside and potentially causing issues with the pitot-static system.

Ice can build up and block the pitot tube's airspeed sensing ports, preventing air from entering and reaching the pressure sensor. This results in zero airspeed readings, even if the aircraft is moving. Ice accumulation can also alter the aerodynamic shape of the aircraft pitot tube, affecting the airflow and pressure measurements. This can lead to inaccurate airspeed readings, either higher or lower than the actual value. In some pitot tube designs, ice can even penetrate and freeze internal mechanisms, hindering the movement of the pressure sensor diaphragm and causing inaccurate airspeed readings. Repeated ice buildup and thawing cycles can cause stress and damage to the delicate components inside the pitot tube, impacting its long-term accuracy and functionality.

Like any other protective gear, pitot probe covers need regular care to function at their best. Even the most durable materials can break down over time without proper maintenance. Here's how to keep your pitot probe covers in top shape:

• Inspect Frequently: Regularly examine your pitot probe covers for signs of wear and tear. Harsh weather, UV rays, and constant use can lead to dry rot or damage like cracks and holes. If you spot any issues, replace the cover right away to ensure your pitot probes stay fully protected.
• Clean Often: Dirt, debris, and grime can build up on your pitot probe covers, so regular cleaning is essential. Use a mild soap or detergent with lukewarm water and gently scrub the cover. Avoid harsh chemicals or abrasive materials that could damage the fabric. Rinse thoroughly and let the cover air-dry completely before putting it back on.
• Store Securely: Don't just shove your covers in any drawer – they need to maintain their shape. Store covers unfolded, ideally in their original packaging, until they're needed again. Choose a cool, dry place away from extreme temperatures, high humidity, and direct sunlight. Excessive heat, moisture, and sun exposure can cause color fading, making the bright red covers harder to see on your aircraft.

By following these simple tips, you can extend the lifespan of your pitot probe covers and keep your aircraft's sensitive pitot tubes well-protected.