Aircraft Cowl Latch Assembly External Serviceability
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Solution Overview
Problem
Existing latch assemblies for aircraft cowls are difficult and time-consuming to inspect, replace, and service due to their installation from the backside and requirement for removing insulation and mechanical fasteners, necessitating access to the interior of the cowl.
Innovation Solution
A latch assembly design that allows for installation and removal from the exterior of the cowl without accessing the interior, featuring a latch pin seated in angularly offset slots and a keeper mechanism to secure the cowl in a closed position, enabling the latch to be removed as a modular unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the latch assembly is installed from the backside of the cowl and mechanically fastened with bolts and/or rivets, then the latch assembly is securely fastened to the cowl, but the latch assembly becomes difficult and time-consuming to inspect, replace and service
Solution Approach 1:
The latch assembly is divided into separable components: the latch body mounted on the exterior of the cowl, and the latch pin that can be independently removed. This segmentation allows the latch to be serviced without removing it from the cowl structure, resolving the contradiction between secure fastening and ease of repair.
Solution Approach 2:
The latch pin is extracted as a removable component from the traditional bolted connection system. By replacing permanent mechanical fasteners with an extractable pin mechanism, the latch can be quickly removed and serviced from the exterior without requiring access to the interior of the cowl or removal of insulation.
2Object-affected harmful factors
If the latch assembly is covered with insulation material and other components of the nacelle, then the latch assembly is protected and integrated into the nacelle structure, but access to the latch assembly requires removal of insulation and other components
Solution Approach 1:
Instead of mounting the latch from the interior backside of the cowl, the latch body is inverted and mounted on the exterior surface. This inversion allows the latch to function while being accessible from the outside, eliminating the need to remove insulation and other components for access while maintaining environmental protection.
Solution Approach 2:
The latch body serves as an intermediary element mounted on the exterior, mediating between the cowl structure and the locking function. This intermediary positioning allows the latch to be protected by the nacelle structure while remaining externally accessible without requiring removal of insulation or other components.
3Ease of operation
If the latch pin is subjected to cyclic loading during operation, then the latch functions properly during opening and closing cycles, but the latch pin may fail due to fatigue over time
Solution Approach 1:
The latch pin is designed with a finite life expectation and is intended to be replaced periodically as a preventive measure before fatigue failure occurs. This preliminary replacement strategy ensures continuous reliability while allowing the pin to undergo cyclic loading during normal operation.
Solution Approach 2:
The latch pin is designed as a consumable, relatively inexpensive component that is replaced periodically rather than maintained indefinitely. This approach accepts the pin as a short-lived element subject to fatigue, but the low cost and ease of replacement maintain overall system reliability.
Data Source
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AI summary
An assembly (20) is provided for an aircraft. This aircraft assembly (20) includes a cowl (22A) and a latch assembly (26). The cowl (22A) is configured to move between an open position and a closed position. The latch assembly (26) includes a latch (36) and a housing (42). The latch (36) is pivotally mounted to the housing (42). The housing (42) is connected to the cowl (22A). The latch assembly (26) is configured such that the latch (36) is removable from the housing (42) while the housing (42) is connected to the cowl (22A) and the cowl (22A) is in the closed position.