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Cross Deck Pendant Health Monitoring



OBJECTIVE: Develop a Cross Deck Pendant (CDP) inspection device that provides a "GO / NO-GO" result based on automatic determination of cable health.

DESCRIPTION: Carrier aviation is dependent on the ability to recover aircraft expeditiously and safely aboard ship. The arresting gear system aboard aircraft carriers relies on a steel cable to transfer the energy from the landing aircraft to the arresting gear engines located below the deck. The arresting gear cable consists of two separate cables, the CDP and the purchase cable, connected via a terminal and pin. The CDP is the portion of the cable stretched across the landing area and interfaces with the aircraft tailhook.Automated inspections of the CDP have proven to be problematic to implement due to the challenging operating environment of aircraft carrier flight decks (i.e., steel deck with a stationary steel wire rope). Current inspection procedures take approximately two minutes, requiring sailors to visually inspect, and slide a gloved hand looking for broken wires on the arresting cable, which is currently a 1-7/16” diameter 6x30 (6 strands made up of 30 wires each) right hand lang lay steel wire rope with a polyester core. This method is subjective and relies on the expertise of the maintainer to ascertain the health of the cable. The current replacement criteria is four broken wires in one cable lay.A simple, compact but sophisticated "GO / NO-GO" inspection indicator device available for use by Navy maintenance technicians to help increase the accuracy/reliability of the CDP inspections and cable health is sought. Currently the health of the CDP is classified by the number of broken wires present, with four broken wires requiring the CDP to be removed from operation. Solutions need to meet the performance requirements for environmental ruggedness (MIL-STD-810) and should give a simple binary decision indication on cable health [Ref 2]. The inspection device will need to operate in the following environment: on a steel deck, in all weather conditions, day and night, flight deck electromagnetic interference (EMI) conditions, and greased/kinked cables. Any proposed method that requires cable removal or destroying the cable will not be considered.The ability to predict the cable failure location is desired, as would an estimate of remaining service life. The Navy will consider both in-situ sensors (i.e., part of the cable) and inspection tools (with handheld preferred) that are not part of the cable. However, the inspection must be accomplished while the cable is in operation.

PHASE I: Develop and demonstrate feasibility of a design solution for a handheld steel cable life indicator that can detect a single broken wire without the need for human interpretation in a timeframe that doesn’t significantly exceed the current inspection time and provides a "GO / NO-GO" decision on the health of a CDP. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Build and demonstrate a prototype inspection device, and any interfacing electronics, to inspect the CDP. Final demonstration will be in a test environment representative of the CDP aboard ship.

PHASE III: Finalize a prototype for robustness and shock testing [Ref 2]. Test the prototype at Naval Air Warfare Center Aircraft Division, Lakehurst, New Jersey.Transition to appropriate end users.Wire rope has a wide range of applications in industry, including bridges, elevators, cranes, overhead hoists, ski-lifts, ship moorings and off-shore oil rigs. Broken wire count is a standard method for determining when to replace cables in everything from cranes to winches, so a method of easily identifying broken wires could be beneficial in many non-naval applications.

KEYWORDS: Wire Rope, Cross Deck Pendant, Arresting Gear, Health Monitoring, Nondestructive Inspection, NDI, Steel Rope, Cable Failure


1. “Wire Rope User’s Manual (4th ed., December 2005).” Wire Rope Technical Board. 2. “MIL-STD-810H, DEPARTMENT OF DEFENSE TEST METHOD STANDARD: ENVIRONMENTAL ENGINEERING CONSIDERATIONS AND LABORATORY TESTS (31-JAN-2019).” 3. “U.S. Navy Wire-Rope Handbook, Volume 1 - Design and Engineering of Wire-Rope Systems (Document Number: a955305).”

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