FORT WORTH, Texas—Lockheed Martin [LMT] is exceeding the Defense Department’s specification for F-35 low observable maintenance thanks to lessons learned, innovation and designing low observable as a system, according to a company official.
Lockheed Martin spokesman Mark Johnson said recently that the low observable maintenance standard for F-35 is to have less than, or equal to, 0.32 maintenance manhours per flight hour for low observable repair at fleet maturity of 200,000 hours. Johnson said the company is at less than, or equal to, 0.28 maintenance manhours per flight hour at 42,000 hours for the current fleet. Lockheed Martin F-35 Business Development Manager Kevin McCormick told Defense Daily during an October tour of the production factory here that the company’s current status ahead of DoD’s low observable maintenance standard puts the company further along than it was on F-22, B-2 and F-117.
Low observable is more than just a coating on the F-35 that helps it go undetected by enemy radar, or at least reduce detection. McCormick said Thursday via a spokesman low observable is the shape the aircraft, alignment of details of the external mold line and various materials, their integration together, flight tactics and a sustainment structure to maintain high availability. Other aspects of low observable include internal fuel tanks, fixed array radar, full line-of-sight blockage, reduced signature nozzles and large capacity internal fuel tanks.
McCormick said Tuesday that the F-35 was designed for “end-of-life” stealth, meaning if low observable defects are routinely repaired over the life of the airplane, it will remain fully low observable mission capable until it is retired without completely stripping and recoating the stealth materials. He said if the company were required to do so, it would take it approximately one month to completely strip the aircraft and re-coat it with stealth materials using the company’s robotic spray application system like it has in production facility’s aircraft final finish facility. McCormick said since Lockheed Martin does not currently have a program requirement to strip and re-coat the F-35, it has no experience with this.
This stringent “end-of-life” stealth design, McCormick said, mandated an affordable, holistic, “cradle-to-grave” approach incorporating supportable low observable design features, durable materials, simple repairs, effective training and a robust signature tracking and optimized maintenance planning capability.
McCormick said the F-35’s low observable material suite is significantly simplified, benefiting from aggressive applications of lessons learned from other stealth aircraft. A traditionally-delicate low observable feature is now the most durable, he said, because it is manufactured into the aircraft’s skin. McCormick said all the low observable materials were also designed and extensively qualified for the Navy’s harsh at-sea environment. These qualities, he said, result in the unprecedented durability of the low observable system. The F-35C carrier variant is the Navy’s variant.
Lockheed Martin, McCormick said, established the Supportable Low Observable Repair Development Center (SLORDC) in mid-2004 to define and mature effective tools and processes to maintain the stealth system, even before the first jet flew. He said these include simple hand tools unique to F-35 as well as judicious reuse of legacy tools for the operational units to perform their maintenance.
McCormick said the processes are the step-by-step techniques that maintainers use to repair damage to the surface, or to restore the low observable where, in a few cases, the low observable must be removed to access certain systems internal to the aircraft. He said customer maintenance personnel, low observable experienced or not, participated in the validation and qualification of these processes.
McCormick said a six-person team with employees from both Lockheed Martin and F-35 subcontractor Northrop Grumman [NOC] comprise the SLORDC. He declined to say if the center works on other platforms.
Another reason F-35 low observable maintenance is so small, McCormick said, is the Low Observable Health Assessment System (LOHAS), which he called a user-friendly system for the registration of damages and repairs that accurately calculates the signature status and maintenance requirements for the jet. This, he said, optimizes maintenance resources and minimizing “recreational maintenance.”
DoD’s F-35 Joint Program Office (JPO) did not respond to multiple requests for comment. The F-35 is developed by Lockheed Martin with subcontractors BAE Systems, Northrop Grumman and Pratt & Whitney of United Technologies Corp. [UTX]