Landing Gear Safety System Devices

Aircraft landing gear systems are built in accordance with rigorous safety standards to ensure reliability during takeoff, landing, ground operations, and beyond. This is because a malfunction in the system can lead to severe consequences, making it necessary for engineers to integrate various safety devices within aircraft to support safe deployment, retraction, and positioning. In this blog, we will explore four of the primary landing gear safety system devices that are found across aircraft with retractable gear, including the gear safety switch, ground locks, landing gear position indicators, and the nose wheel centering mechanism.

What Are Landing Gear Safety Devices?

While landing gear safety devices can widely vary in design and application, most share the overlapping objectives of:

• Preventing accidental gear retraction while on the ground
• Providing mechanical backups and locks
• Informing pilots of gear status
• Ensuring proper nose wheel alignment for retraction

These devices form an interdependent system focused on upholding safety from the initial runway liftoff to the touchdown at the end of a flight.

Introducing the Main Landing Gear Safety Devices

The Landing Gear Safety Switch

Also known as the “squat switch,” the landing gear safety switch is one of the first lines of defense in safety. This device is typically found on the main gear strut, where it serves to prevent landing gear from retracting while the aircraft is on the ground.

A Breakdown of Operations

Landing gear safety switches are activated by weight-on-wheels pressure, where the compression or extension of a strut will cause the actuation of a switch to control gear positioning. Generally, being on the ground will result in a compressed strut that activates the solenoid lock, while fling allows the solenoid to retract for gear to be raised.

These switches often interface with other systems like thrust reversers or flight computers for operations, as well as may prevent the deployment of other systems like flaps or autopilot features until the aircraft is airborne. Additionally, while the safety switch may be a passive system, it is engineered to offer active prevention against premature retraction.

Ground Locks

Ground locks are physical devices installed on landing gear components to block their movement while the aircraft is parked or undergoing maintenance. There are two main types of ground locks that one may find on the market, these being:

• Pin locks that are inserted through gear assembly holes to secure gear
• Clamp locks that fasten around piston rods of gear actuators

These components are known for being easy to install and verify, their presence offering an added mechanical layer of safety. Additionally, many ground locks offer visual indicators to assist in operations, with bright red streamers and “REMOVE BEFORE FLIGHT” tags being commonplace. As a non-electric backup to other devices, these ground locks offer crews peace of mind.

Landing Gear Position Indicators

Position indicators are crucial tools that communicate real-time gear status to pilots in the cockpit, with a number of options being available for aircraft.

Traditional Light Indicators

• Green lights to indicate gear is down and locked
• Red lights to indicate gear in transit or not locked
• Lights off to indicate that gear is up and locked

Advanced Systems

• LCD screens or multifunction displays may be used to convey positioning.
• Audio alerts may also be used to indicate improper gear configuration.

Position indicators provide a quick visual status check and are essential for pilot decision-making, and it is important that pilots monitor conditions throughout flight.

Nose Wheel Centering Devices

Before nose landing gear can retract, it must be aligned with the longitudinal axis of the aircraft. This is achieved through centering mechanisms like built-in centering cams and roller guide pin systems, both of which offer various functions and benefits.

Built-in Centering Cams

• These cams are designed to engage when gear assemblies are fully extended.
• Upper and lower cams are engineered to align the nose wheel in a straight position.

Roller Guide Pin Systems

• These systems serve to ensure guide pins follow a track that straightens the nose gear during retraction.
• Roller guide pin systems are common on light aircraft.

Procure Landing Gear Safety Device Parts on Purchasing Efficiency

Whether you are interested in indicators, ground locks, roller guide pin systems, or other various solutions for securing landing gear assemblies, look to Purchasing Efficiency and our wide selection of offerings. Here, we proudly offer access to items that have been sourced from leading manufacturers and suppliers from across the globe, all options being ready for purchase today with competitive pricing and a guarantee of timely delivery. With this in mind, begin exploring our options and services, knowing that we are just a call, email, or RFQ form submission away from providing hands-on service and tailored procurement solutions for your comparisons.