A Conversation with an F-35 Maintainer about the Impact of the New F-35 Actuator System on Maintenance
An Interview with Armando Martinez
In an earlier article on the website, we discussed the impact of the design of the F-35 on maintenance.
One system, which was discussed in the article, was the new approach to building and maintaining hydraulic systems. The article discussed the impact of the EHAS or the electrohydrostatic actuation system. According to Bob Fiorentini, who was interviewed for the article, “The EHAS is a revolutionary step in the control of aircraft surfaces. Hydraulic systems for the F35 are not centralized. EHAS allows each unit on the surface to control itself.” Fiorentini added that this “significantly reduces the risk of catastrophic failure. And the EHAS systems reduces the amount of maintenance for the aircraft by eliminating a number of components in the airframe such as hydraulic tubing, hose lines goring through the airframe.”
In this interview, SLD followed up with a key player in shaping the maintenance approach, Armando Martinez. Martinez has many years of experience with the F-16 program before moving over to the F-35 program. When interviewed in late June he was involved with F-35B from the BF-2 through BF-4. He has just been assigned to the test program supporting the F35-C or CF-3, the aircraft that will be tested on the aircraft carrier.
According to his resume, Martinez has “Supervised the interior and exterior completion of Joint Strike Fighter F-35/Block 52 & 60 F-16 Aircraft to include sub-assemblies, avionics, mechanics, and aircraft production sites. Ensure customer, engineering, and FAA specifications and regulations are met on a daily basis.”
In this interview, the focus was on the testing program and on the impact of some of the new build items on the F-35, which affect the maintainability, and performance of the aircraft. A major focus of the interview is on the impact of the EHAS.
SLD: One issue, which was raised in our conversation with the Gunny Sgt. in charge of maintenance on the test aircraft at Pax River, is the cultural change from older aircraft to the F-35. Have you experienced that issue as well on your test flight line here in Fort Worth?
Martinez: Absolutely. I have worked on the BF-2 through BF-4, the STOVL aircraft. I’m telling you right now, it’s not a Harrier at all. You cannot even compare those two aircraft. You can’t compare nomenclature. The only thing you can probably say about the Harrier and the F-35, and I’m talking the STOVL, is that they’re aircraft. The only comparison you can make is they’re aircraft, and that’s it, and people got to draw this line that you cannot compare the Harrier to the F-35 at all. They are maintained completely differently, and because the F-35B is a new aircraft, with new approaches to maintenance, we are shaping new approaches to supporting the aircraft.
And you can ask the question in reverse. Let me take my crew and then try to go maintain a Harrier that we know nothing about. I’ve never worked a Harrier in my life, ever. So if they put me on a Harrier, I would not have a clue what to do with it.
SLD: What are you seeing as you are dealing with the 35 that could be exciting possibilities of maintaining this aircraft?
Martinez: I’ll give you one main exciting development, as a maintainer is that you have self-sustained hydraulic systems. Do you know how difficult it is to change hydraulic lines? Now you’ve got less hydraulics to worry about, a lot less, and most aircraft leak all the time. Ours is going to be a lot easier to maintain.
If you’re comparing the hydraulics on the F-35 to the F-16, there’s a lot of tubing, a lot of hydraulic tubing on the aircraft, which is on the F-16, which is not on the F-35 So when you’re saying a lot of hydraulics… I would say there is roughly a 60% improvement on the F-35 on the hydraulic system, probably even more than that in terms of maintenance associated with hydraulics systems.
SLD: How has the hydraulic system been simplified on the F-35?
Martinez: They greatly simplified the hydraulic systems because everything is self-contained. You’ve got your own hydraulic systems. You got your own actuators.
If you were to compare the F-35 to the F-16, you probably reduced maintenance by 60%. When you have self-sustained systems, and when that system breaks, you just got to change that one component and you’re done, that’s it. Before you had to remove the lines, you got brake lines and now you just got an actuator you pull and you remove and you install a new one.
Credit: Lockheed Martin
SLD: And what is the impact of the improved capability?
Martinez: Let’s say the aircraft was in combat, in an air-to-air fight or whatever, before with older aircraft, you just spray the aircraft and if you shot one of the main hydraulic lines, the pilot is in big trouble. Now they got to actually focus on one actuator, which is not that big and to try to shoot at it. Your target just got way smaller.
SLD: What other impacts coming from having a new hydraulics system?
Martinez: If you’re talking about the old type hydraulics, like in the F-15 and the Harriers, they have many more hydraulic lines, big hydraulic lines, units, all pumping so much pressure all through the aircraft. You’re talking from one end the aircraft to another one and you only had so many systems to pump it in, so you’ve got hydraulic lines going from one side of the aircraft to the other and that takes up space. It takes up weight. It’s very hard to maintain. And just like anything, you got to get a very heavy object in the air, so guess what? You’re going to squeeze all these hydraulics as much as you like because you’re trying to make the aircraft smaller and not as heavy.
So when you start removing all those lines and everything, guess what? Now you got more room for fiber optics, wiring, more capability to the aircraft, and that’s exactly what the JSF is.
***Posted on August 24th, 2010