Amid Criticism, US Navy Confident in New Arresting Gear System for Next Carrier
Christopher P. Cavas
WASHINGTON — A host of new technologies and systems will begin to enter service when the new aircraft carrier Gerald R. Ford (CVN 78) is delivered in the first half of 2016, and for over a decade it’s been a good question whether all the new whiz-bang technology will be ready in time.
While the US Navy and its suppliers remain under scrutiny to make it all happen, they’re also increasingly confident the key new technologies — including the dual-band radar (DBR), electromagnetic aircraft launch system (EMALS) and advanced arresting gear (AAG) — will be delivered.
The latter two technologies represent a major shift for carrier operations, allowing aircraft to be launched and recovered without bulky and manpower-intensive steam catapults and hydraulic wires.
But, program officials have acknowledged, testing and development of the systems will continue past the ship’s planned March 2016 delivery date. Initial operational test and evaluation work isn’t to start until the second half of 2017, with integration testing continuing to the end of that year. The ship’s initial deployment is scheduled to take place in 2019.
Worries over concurrent design, testing, development and construction have been a feature of the CVN 78 program since its inception in the 2000s, when the George W. Bush administration’s emphasis on transformation forced the Navy to bring forward several technologies still in development. Years after the first contracts were issued for the ship, those worries persist, despite reassurances
“Concerns over system integration within platform space, weight and power reservations have been resolved,” program officials told the Government Accountability Office (GAO) in a report released in March. “Land-based testing for EMALS and DBR has progressed enough that program officials do not anticipate significant redesign. Further, the AAG test schedule remains on track to support ship delivery and sea trials.”
But in a November report on the carrier program, GAO continued to sound a worried tone.
“The shipboard test program is further at risk because additional design changes and modifications to the shipboard AAG units remain likely,” GAO wrote. “This is because the Navy will now be conducting land-based testing of AAG even as shipboard testing is under way.”
GAO also cited delays in AAG development, which have added four and a half years to the arresting gear program, with testing continuing to the end of 2016.
Yet Navy officials are more confident than ever that the new radar and launch systems will be ready. Less has been said about the AAG, which uses a new electric motor-based system and energy-absorbing water twisters to bring supersonic jet aircraft to a halt within a distance of about 340 feet. As of now, the arresting gear seems to have more outstanding issues than the DBR or EMALS.
“AAG has had, over the past four years, several developmental tests … that have delayed our test program,” Capt. Stephen Tedford, program manager for the Navy’s Aircraft Launch, Recovery and Equipment Office, said in a December interview.
But, he said, the GAO’s claim of four and a half years of AAG delays is not accurate.
“We have had delays on the advanced arresting gear, that is a true statement,” Tedford said. “We are continuing to work through those delays, and I believe we are still in support of ship delivery in 2016.”
A serious problem with the water twisters, discovered early in 2012, was a key factor in the delays, he explained. Internal plates that take the force of the water weren’t strong enough, and finding a solution took time.
“In the arresting gear case, we have had certain specific issues with respect to the water twisters that put us out of test for quite a while,” Tedford said. “I can’t run the system until that specific issue is solved, until we had replacement water twisters, and we could actually get back into full envelope testing, and not just the low end. Until I actually start testing at the upper end where the energy is highest, when I am stressing the system the most, and when I am likely to find my next issue. But I can’t get back in to test, I can’t find the next issue.”
Water twister technology isn’t new, Tedford explained, and manufacturer General Atomics describes the system as simple and proven. But existing systems are fixed in their capacity to absorb energy.
“Ours are variable,” Tedford said. “You have an actual moving plate inside the water twister that adjusts how much resistance to the water is generated. Generally, there was an underestimation of the forces involved inside the water twister. You are talking about a three-dimensional flow field, it is very difficult to predict, and it was underestimated.”
The solution, he said, was to use thicker plates. “We beefed up the entire design of the water twister. The footprint, the outer diameter and the size and the shape are all still the same. It is the internal components that we have made stronger.”
AAG tests have yet to involve real aircraft. Rather, dead loads simulating the weight of planes have been used to test the system at a jet car track installed at Joint Base McGuire-Dix-Lakehurst, New Jersey. “To date, that site has executed 537 dead loads, so the system does work,” Tedford said.
A full-scale AAG is being built into a runway at Lakehurst — the same runway where an EMALS has been installed and running tests since 2011. Aircraft recoveries will begin in late 2015, Tedford said.
GAO also repeated longstanding criticisms that the Navy is performing tests while delivering components to the ship, meaning expensive changes are made when problems are found. The situation was envisioned and accepted long ago, but there is little question changes are easier to make before parts are installed — and for both the EMALS and AAG, 94 percent of the hardware has been delivered to the Ford.
“Yes, we have been concurrent, with respect to design and production, for several years now, and that has continued,” Tedford acknowledged. “Where we have been able to get designs changed into the production hardware prior to delivery to the ship, we have done so. For those that are outstanding, we have a field change work package program that brings those changes to the ship.”
Where to make changes is decided on a case-by-case basis.
“As we have discovery of design changes in a development test program, we make a determination on each and every one if that redesign is required on the ship, and when it is required on the ship,” Tedford said. “Every one is categorized as it relates to the ship construction and test schedule, as well as her post-delivery, post shakedown availability schedule. It really depends on the critical nature of the design change.”
GAO also raised concerns about reliability of both the EMALS and AAG systems. But certifying system reliability, Tedford pointed out, can be difficult to prove before a system is installed.
“Reliability comes from a significant number of cycles on any system, it is statistics-based,” Tedford said. “So you have to have hundreds of thousands of cycles in order to achieve system reliability. And the way that reliability growth is established is, it’s not just from the system installed at Lakehurst, it’s in combination with the ship and the second ship of class, and the third ship of class over time. So it was never in our program, as a requirement or anything else, in order to meet threshold reliability for either system when the ship delivered, simply because it is not possible to get there statistically.”
The single EMALS catapult at Lakehurst, he pointed out, “is as close as we can get to the ship-based system on land, but it is not a four-catapult, identical system to what they have on CVN 78. Plus, realize that the testing that we do has been just that — it has been developmental testing. We are trying to find faults in the system. We are trying to find where it fails. That is the point. We are not intentionally doing reliability testing, which would be part of the envelope — repetitive, the same test point over and over and over again — to build reliability. That actually is in the next phase of the test program that kicks off later this year.”
Tedford admits challenges remain, but he declared confidence.
“Both of these systems work,” he said. “EMALS is on a great trajectory right now, and advanced arresting gear is on a similar vector.
“We are very excited,” he added.Back to Top