Carrier catapults and arresting gear, explained

A carrier launches its fixed-wing aircraft with catapults and recovers them with arresting gear. Nimitz-class carriers use steam catapults and hydraulic arresting gear. The Ford class has new Electromagnetic Aircraft Launch System (EMALS) catapults and electromechanical Advanced Arresting Gear (AAG), according to the fiscal year (FY) 2025 annual report of the Director, Operational Test and Evaluation (DOT&E). That report says the reliability and maintainability of the new systems continue to hurt sortie generation and flight operations. DOT&E calls this the greatest risk to demonstrating the class's operational effectiveness and suitability.

Steam catapults

Naval Air Systems Command (NAVAIR) says on its undated launching systems page that the Navy has used steam to launch carrier aircraft for more than 50 years. The page groups three things under launchers: catapults, catapult control stations, and jet blast deflectors. The control station is the Integrated Catapult Control System (ICCS), called the "bubble," which combines remote stations to provide intercommunication during each launch. Jet blast deflectors are hydraulically controlled panels raised before takeoff to turn hot exhaust away from the deck and waiting aircraft.

The Naval History and Heritage Command aviation chronology dates the initial operational test of the C-11 steam catapult to June 1, 1954, when an S2F-1 Tracker launched from USS Hancock (CVA-19). Tests ran through the month, and the ship recorded 254 launches by Trackers, Banshees, Sky Knights, Cutlasses, Furies, and Skyraiders.

MK-7 arresting gear

NAVAIR's recovery systems page lists the MK-7 Mod 3/4 as the current carrier arresting gear and barricade, able to stop a 50,000-pound aircraft in less than 350 feet. A newer Advanced Recovery Control system replaces the gear's mechanical levers and pulleys with electronic controls. A computer profile for each aircraft and touch screens let the Sailor set each engine to the correct position and watch engine diagnostics.

The Government Accountability Office (GAO) describes the legacy arresting equipment on Nimitz-class carriers as hydraulic in its November 2014 report, GAO-15-22. DOT&E's FY2025 report says the Ford class was first planned with four arresting gear engines and three wires, similar to the flight decks of USS Ronald Reagan (CVN 76) and USS George H.W. Bush (CVN 77).

EMALS and AAG on the Ford class

The same GAO report describes EMALS as using an electrically generated moving magnetic field to propel aircraft, with less physical stress on the aircraft than steam. AAG is an electric motor-based system that rapidly decelerates an aircraft as it lands. DOT&E's FY2025 report says the Ford class's new nuclear plant raises electrical capacity to power both.

The AAG layout changed. The original plan was four engines and three wires. The fourth engine has not been installed, as a cost savings measure. DOT&E's FY2023 report says the Navy committed at a 2016 requirements review board to inform a retrofit decision with operational test results. The FY2025 report says the Navy has allocated FY2026 funding to a fourth-engine alternative, with installation targeted for FY2029, which would restore the ability to rig the barricade if an AAG engine fails.

What GAO and DOT&E reported on reliability

GAO measures reliability as "mean cycles between critical failures," the average number of launches or recoveries before a failure. GAO's table used January 2014 data:

• EMALS: 240 cycles against a requirement of 4,166 with 3 of 4 catapults operating. A second requirement of 1,800 cycles, with all four operating, had no current figure.
• AAG: 20 cycles against a requirement of 16,500.

GAO judged it unlikely that either system would reach the reliability needed for the sortie generation requirement before a demonstration event in 2019, or for years after the ship was ready to deploy.

DOT&E counts mean cycles between operational mission failures (MCBOMF). The FY2021 report gives 272 MCBOMF for EMALS over 8,157 launches through Independent Steaming Event 18, and 41 MCBOMF for AAG over 8,157 recoveries. The FY2023 report cites different developmental test figures: EMALS at 460 MCBOMF in FY2021 and 614 in FY2022, AAG at 115 and 460. It does not explain how they relate to the FY2021 report's numbers.

The FY2025 report adds that the Navy has scored no AAG operational test data since operational testing began in 2022, and that EMALS reliability in the FY2025 workup stayed consistent with FY2023 and FY2024 data. A sustained sortie generation demonstration planned for the third quarter of FY2025 did not happen, because of unplanned launch and recovery equipment maintenance and a constrained schedule. The Navy now plans it for FY2026.

The catapult officer

A September 2014 story from USS George Washington describes 11 yellow-shirted catapult officers, called shooters, responsible for safe and efficient launches. Before a launch, the shooter verifies that pre-flight checks are complete, then gives the signal to launch. Another shooter lists the duties: the catapult is ready, the aircraft is properly configured, everyone is in position, and observers are behind the foul lines. The shooters inspect the catapult and jet blast deflector and enter wind calculations to set the steam needed.

The ship's lead catapult officer says the qualifications take three to six months. The shooters come from naval aviation and also command the five divisions of the ship's air department, which has nearly 750 Sailors.

What to check

• Does a document describe a Nimitz-class carrier (steam and MK-7) or a Ford-class carrier (EMALS and AAG)?
• Which reliability measure and data window does a figure use: GAO's January 2014 data, DOT&E's count through Independent Steaming Event 18, or the FY2021-FY2022 developmental figures?
• Is each figure set against the right requirement: 4,166 cycles for EMALS with 3 of 4 catapults, and 16,500 for AAG?
• Does a description of AAG note that the planned fourth engine was not installed, and that a fourth-engine alternative is targeted for FY2029?
• Has the sustained sortie generation demonstration, moved to FY2026, actually taken place?

Azcuna's ELLMENT, the E-2D Large Language Model Entity, was proposed to NAVAIR PMA-231 under Navy SBIR Phase I topic DON26BZ01-NV010. The prototype, built at private expense on publicly available doctrine, answers with a page-level citation and refuses when the documents do not support an answer. The proposal has been submitted.

Sources

1. 1Launching Systems · Naval Air Systems Command (NAVAIR)
2. 2Recovery Systems · Naval Air Systems Command (NAVAIR)
3. 31954-1959 (Naval Aviation Chronology) · Naval History and Heritage Command
4. 4GAO-15-22, Ford-Class Aircraft Carrier: Congress Should Consider Revising Cost Cap Legislation to Include All Construction Costs · U.S. Government Accountability Office, November 2014
5. 5CVN 78 Gerald R. Ford-Class Nuclear Aircraft Carrier (FY2021 Annual Report) · Director, Operational Test and Evaluation
6. 6CVN 78 Gerald R. Ford-Class Nuclear Aircraft Carrier (FY2023 Annual Report) · Director, Operational Test and Evaluation
7. 7CVN 78 Gerald R. Ford-Class Nuclear Aircraft Carrier (FY2025 Annual Report) · Director, Operational Test and Evaluation
8. 8Face of Defense: Navy 'Shooters' Launch Carrier Jets · USS George Washington, via DVIDS (story dated September 21, 2014)

Where this shows up in our work

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