Friday, February 7, 2014

EMALS and AAG Status

The new Ford class carrier will be introducing several new technologies, among them the Electromagnetic Aircraft Launching System (EMALS) and Advanced Arresting Gear (AAG).  The Navy insists that the EMALS and AAG systems will work as advertised and points to extensive land based testing as proof.  What the Navy isn’t pointing out is the failure rates.  Fortunately, DOT&E has provided that data (1).

EMALS is the replacement for the old steam powered catapults.  The system will use electric motors rather than steam to launch aircraft.  As DOT&E reports,

“At the Lakehurst, New Jersey, test site, over 1,967 launches have been conducted and 201 chargeable failures have occurred. Based on available data, the program estimates that EMALS has approximately 240 Mean Cycles Between Critical Failure in the shipboard configuration, where a cycle represents the launch of one aircraft. Based on expected reliability growth, the failure rate is presently five times higher than should be expected.”

Thus, the system looks perfectly capable of launching aircraft but the reliability is highly suspect at the moment.  I’m also not quite sure about the numbers.  If 201 failures have occurred in 1967 launches, that’s a failure every 10 launches – not great odds for the pilot!!!  I’m not sure how the 240 cycles between critical failure is calculated unless some of the 201 failures weren’t considered critical?  Regardless, that’s a severe reliability issue.

Similarly, the AAG replaces the older style arresting system.  Again, the report states,

“At the Lakehurst, New Jersey test site, 71 arrestments were conducted earlier this year and 9 chargeable failures occurred. The Program Office estimates that AAG has approximately 20 Mean Cycles Between Operational Mission Failure in the shipboard configuration, where a cycle represents the recovery of one aircraft. Based on expected reliability growth, the failure rate is presently 248 times higher than should be expected.”

As with the EMALS, the system appears functionally capable but highly unreliable.

The problems are not unusual for new technology and are fixable given enough time.  This, however, demonstrates the problem with concurrent research and production, as we’ve pointed out many times.  The Ford’s delivery, already way behind schedule, will slip still further, barring an unlikely miracle.

There would have been absolutely no penalty or problem with building one more conventional Nimitz carrier while the new technologies were undergoing development.  The carrier construction schedule could have been maintained, a new functional carrier could have joined the fleet, and a great deal of concurrency construction penalty costs avoided.  The Ford will have to sit idle for months or years after delivery while the bugs are worked out, anyway.  Frankly, it’s hard to believe that Navy leadership could be this irresponsible.

(1) Director, Operational Test and Evaluation, Annual Report, 2013


  1. An EMALS launch system is supposed to dramatically expand the operational lifespan of carrier aircraft launched from it. So, in the long term, there would be some pretty significant drawbacks.

    1. Jrggrop, that's a commonly cited benefit of EMALS but I've never seen any data supporting that or any definitive statement to that effect from a Navy source. I suspect that claim has been made up by supporters. Do you know of a source that supports that claim?

      Note that I'm not disputing the claim. It may well be true. I'm just trying to find an authoritative source to support the claim. Thanks!

    2. 'supposed to" You are spouting MARKETING propoganda.

      The fact is that it puts more stress on airplanes.

    3. "The fact is that it puts more stress on airplanes."

      Do you have any evidence to support that claim? If not, I no more believe that than the opposite claim, also unsupported.

      This blog is based on facts and data. Offer some or don't make the claim.

  2. Build a little test a lot. We got out of that and we get the last decade+ of Navy R&D.

    1. Also: "You get what you inspect, not what you expect."


  3. I noted that the DoT&E talk about "expected" failure rates, but did not compare them against current steam catapults failure rates. Last I heard those were not so great either. What is the current launch failure rate for operational carriers.

    Also what type of failure where they counting? Were they talking about simple mechanical break downs that prevent attempting a launch. Or were they talking about they type of failure that results in a lost of an aircraft? The type of failure is important to know when evaluating these numbers.

    Also the electrical breaking on the AAG is not exactly new technology. But I expect they are trying to recapture the energy form the landing, which would be a mistake as those system often fail in the civilian world.

    As for the time required for the Ford to reach the fleet, I am sure that the people in charge of building her knew all about the delays inherent with and technological development program. Those delays are part of the cost of creating new things. The problem is that outside forces (Ie OSD) limited them to one ship[ to do the testing on. Both CVN 78 and CVN79n should have been used to handle the testing of these new system, thereby reducing the ships failure due to a single system malfunction.

  4. "Land-based tests of the system in New Jersey have demonstrated a reliability rate of only 240 launches without a failure, when it should be above 1,250 launches without failure at this stage of the Gerald Ford’s development.

    Meanwhile, a companion system, known as the advanced arresting gear, which is designed to safely snare landing aircraft with cables stretched across the deck, is similarly unreliable, according to the report. In the tests, the system of cables has averaged 20 successful landings without failure. That is far less than the 4,950 successful landings it should be achieving without failure. The ultimate goal is for the system to work 16,500 times without failure."

    Can't find the numbers for conventional catapult/arresting gear but it looks like the new system is no where near reliable enough. It would be nice to see the comparisons between old and new but my guess is USN doesn't want to release that the way, easy to say we need to know the specific failures,blah,blah,blah when you're not the one seating on a ejection seat in the middle of the ocean at night ready to be catapulted. No matter how you slice it, 1 failure in 10 launches SUCKS!

  5. So its good that they are not mothballing the GW, it has working catapults and arrestor gear.

    “”””Pentagon Drops Plan to Mothball USS George Washington Aircraft Carrier””


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