Retractable Runway Edge Sheave for Aircraft Arresting Systems
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Solution Overview
Problem
Existing aircraft arresting systems with runway edge sheaves are not compliant with International Civil Aviation Organization (ICAO) guidelines due to their permanent above-ground installation, creating obstructions and risking damage to cables and runways from aircraft contact.
Innovation Solution
A retractable runway edge sheave system that raises and lowers within a foundation cavity, maintaining cable alignment and tension, and includes optional ramping to protect against aircraft overrun, using mechanisms like hydraulic, pneumatic, or mechanical actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the runway edge sheave is permanently installed above ground, then the cable is accessible to the aircraft tailhook and can be engaged for arrestment, but it creates an airfield obstruction and risks damage from aircraft contact
Solution Approach 1:
The runway edge sheave is made retractable rather than fixed, allowing it to dynamically change position between above-ground (operational) and below-ground (retracted) states. This enables the system to provide cable accessibility when needed while eliminating obstructions during normal operations.
Solution Approach 2:
The sheave operates in periodic cycles, remaining retracted below ground during normal flight operations and rising above ground only during arrestment events when the aircraft engages the cable. This periodic deployment resolves the contradiction by providing accessibility only when required.
2Ease of operation
If the cable is supported above the runway surface, then it is more accessible to the aircraft tailhook and prevents hook skip, but it exposes the cable to continual run-over by aircraft causing damage
Solution Approach 1:
The cable support system transitions from a static above-ground position to a dynamic system that raises the cable only during arrestment events. The sheave remains below ground during normal operations, protecting the cable from run-over damage, and rises only when tailhook engagement is required.
Solution Approach 2:
The cable support function is extracted from a permanent above-ground installation and separated into a retractable mechanism that can be deployed only when needed. This removes the cable from exposure to harmful run-over events while maintaining accessibility for arrestment.
3Stability of the object's composition
If the runway edge sheave is installed permanently above ground with concrete foundation and ramping, then it provides structural stability and protects against rollover, but it creates permanent airfield obstructions
Solution Approach 1:
The sheave assembly is designed to be structurally stable when deployed above ground but can be retracted below ground when not in use. The foundation provides stability during operational deployment while allowing retraction to eliminate obstructions during normal flight operations.
Solution Approach 2:
The sheave assembly is nested within a foundation cavity when retracted, with the sheave housed inside the underground structure. This nesting arrangement provides structural support while keeping the sheave concealed below ground during non-operational periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures ICAO compliance by concealing the sheave below ground when not in use, preventing damage to cables and runways, and ensuring safe aircraft arrestment.
Implementation Method 1
using mechanisms like hydraulic, pneumatic, or mechanical actuation
Implementation Method 2
using mechanisms like hydraulic, pneumatic, or mechanical actuation
Implementation Method 3
The elongated beam is raised and lowered within a foundation cavity, maintaining cable alignment and tension
Data Source
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AI summary
A retractable runway edge sheave for use in an aircraft arresting system. The arresting system functions to extend a cable across a runway for capture by a tailhook of an aircraft. The retractable runway edge sheave is designed to raise and lower the cable. The disclosed system may also feature a ramping system.