Fan Cowl Latch Push Pin Visual Indicator
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Solution Overview
Problem
Existing latches for fan cowl panels in turbofan propulsion systems are often overlooked during pre-flight inspections, leading to potential separation of the panels during flight if not properly secured, as their location can be obscured and manual engagement is not guaranteed before engine operation.
Innovation Solution
A latching mechanism featuring a push pin that extends when the handle is opened, creating a visible separation between the fan cowl panels and the nacelle structure when unlatched, ensuring that maintenance personnel can easily identify an unlatched state and preventing accidental separation during flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional latches are used for fan cowl panels, then the latching function is achieved, but the location is obscured and difficult to detect during inspection
Solution Approach 1:
The latch mechanism incorporates a visible indicator that changes position or appearance based on the latched/unlatched state. The indicator provides a clear visual signal to maintenance personnel about the status of the latch, making it easily detectable during pre-flight inspections without requiring close examination of the latch mechanism itself.
Solution Approach 2:
The patent introduces an indicator mechanism that acts as an intermediary between the actual latch and the inspector. This indicator translates the internal latch state into an externally visible signal, allowing remote detection of the latch status without direct observation of the obscured latch location.
2Ease of operation
If manual engagement of latches is required, then the latching function is achieved, but accidental unlatching or improper engagement may occur
Solution Approach 1:
The latch mechanism is designed with self-latching capability where the act of closing the panel automatically engages the latch through a cam or lever action. The visible indicator simultaneously provides feedback that the latch is engaged, eliminating the need for separate manual engagement steps and reducing the risk of improper operation.
Solution Approach 2:
The mechanism includes features that prevent accidental unlatching during normal operations. The latch design incorporates positive engagement elements and requires deliberate action to release, preventing unintended opening while maintaining ease of intentional operation.
3Difficulty of detecting and measuring
If the push pin extends when the latch opens, then visible separation is created for detection, but additional mechanical complexity is introduced
Solution Approach 1:
The push pin indicator is integrated into the existing latch mechanism structure rather than being a separate system. The push pin is mechanically linked to the latch operation, so that unlatching automatically extends the push pin to create visible separation. This merging approach provides detection functionality without adding significant complexity.
Data Source
AI summary
A nacelle may include fan cowl panels which may be opened to provide access to the fan case. A latching mechanism may latch a left fan cowl panel to a right fan cowl panel. As a handle is opened to unlatch the latching mechanism, the movement of the handle may cause a push pin to create a separation between the left fan cowl panel and the right fan cowl panel. The separation may create a visual indication that the fan cowl panels are not latched together, which may prevent an aircraft from inadvertently taking off with unlatched fan cowl panels. The push pin when extended may prevent closure of the fan cowl panels.