By Geoff Fein
While concerns that recent findings from a F-18 assessment program show a number of Hornets might not reach the goal of 10,000 flight hours, thus increasing the Navy’s strike fighter gap, the actual impact won’t be known until further studies are completed later this year, a Navy official said.
To stave off an expected strike fighter gap of 69 aircraft in 2017, the Navy began to upgrade its legacy Boeing [BA] F-18 A through D model Hornets. The effort was divided into the Service Life Assessment Program phases 1 and 2 and a Phase 1 Service Life Extension Program (SLEP).
SLAP phase 1 began in December 2001 and ended in October 2005. The study looked to extend the number of catapult take-offs, trap landings and field landings, as well as stretch the Hornet’s flight hours from 6,000 to 8,000, Capt. Mark Darrah, F/A-18E/F and EA-18G program manager, told Defense Daily yesterday.
“What we had to do to do that wasn’t as extensive as we initially thought,” he said. “So we were able to do some inspections and give ourselves some interim flight clearance out to 8,000 [flight hours].”
Naval Air Systems Command (NAVAIR) officials knew at that point there were things they needed to determine as they got to the 8,000-hour limit, Darrah said.
“As we did the modeling, we determined that many areas that we suspected wouldn’t make 8,000 didn’t,” he added.
“That validated some of the information we had from Phase 1. And we were also able to determine that obviously if we were not able to make it to 8,000 we were not going to make it to 10,000. That would mean we would have to do a little more work than we probably expected we would have to do, to get to 10,000,” Darrah said.
Now, Darrah and his staff are trying to determine in detail those areas that won’t make it to 8,000-flight hours and what will need to be done to get them to that goal.
“Is it inspections which we expect many of them will be? As we go through this process we are going to update the current inspections we already have from the Phase 1 effort. We are probably going to have to augment or enhance some of those,” he said. “Some of those areas we already inspected we may have to repair.”
This is a new area for the F-18 program office, Darrah said.
“We are really going to have to look at. Is it better for us to replace a part instead of repair a part which is a big difference? That’s where we are with the SLAP phase 2 results,” he said. “As we plan the SLEP part of that, which is the phase we are in now, planning for the SLEP from the results we got, we are going to have to decide things like– can we just continue to inspect in a periodic way or will we have to repair an area, or does it make more sense because of time or money to just replace [a part]?”
That is the effort that is currently underway, Darrah said.
“Over the next several months, through the early November time frame, we will get a better understanding which will also mean we will have a better understanding of the cost if we decide to either inspect, repair or replace,” he added.
Darrah said it is safe to assume this will add cost and time to modifying the Hornets.
Now, with more detailed information, inspections will not only look at a specific area, but areas adjacent to an inspection site, Darrah noted.
“We have also discovered there are some areas that have more difficult access. There are parts we identified that don’t make 8,000 that are not as accessible as areas we are currently inspecting,” he said.
That will require those aircraft to go into depot-level maintenance, Darrah added.
At the organizational level, maintenance inspections are handled by sailors, because all that is required is for them to remove a panel to take a look. But having to undertake a more extensive examination requires the aircraft to go into the depot, because workers there can take the plane apart and access areas that the organizational level folks can’t, Darrah explained.
“What we are finding now is that there were some areas that the sailors were looking at that have adjacent structure that now may have to be looked at by the depot,” he said. “So all we are doing now is realigning those inspections with the depot work. That’s going to add more time in the depot. That’s cost because you are spending more time in the depot.”
The Navy has the funding to increase the number of cats, traps, landings, and get out to 8,000 flight hours, under the Phase 1 effort, Darrah said.
“We now know we have some areas that don’t make 8,000 that we are going to have to do additional inspections and repairs and so on. That’s not funded,” he said.
Darrah said they will request additional funding to continue the effort to take the Hornet out to 10,000 flight hours. But just how much money he thinks the Navy will need is an unknown. “We have no idea.”
Engineering work currently underway will provide those cost estimates, he added.
“If we just have to inspect, that’s going to be significantly less of a bill than if we have to do a major repair of a piece of a structure,” Darrah said. “And that’s what we are doing right now, determining whether we have to inspect, repair or replace.”
The issues that surfaced as a result of the initial SLAP were not altogether surprising, Darrah said.
After all, the Hornet was designed for 6,000 flight hours, he noted. “We are trying to extend it to 10,000. That’s a 66 percent increase in its service life.”
There are 159 locations on the Hornet that require analysis. According to documents provided to lawmakers, 57 percent of those areas, or “hotspots,” didn’t make it to 8,000 hours.
“The analysis we have [received] identified several of those key areas that don’t make 8,000 and we kind of expected that might be the case,” Darrah said.
Engineers are working to determine if all of those areas are the same for all the Hornet configurations, he added. “It’s very complex.”
The Navy has 636 legacy Hornets, 50 percent of which are beyond the original 6,000-flight hour service life, according to the Navy. Adding in the international partners which are flying legacy Hornets, and that number jumps to more than a thousand aircraft in operation worldwide.
The average age of the Hornet fleet is approximately 18 years, and the Navy has planned to keep the Hornet in service until 2023, the Navy said.