Clarification: This story has been updated to note legal actions discussed in the story were not addressed during a media briefing. The lawsuit referenced was included in the story for context. The Army is unable to comment on pending litigation. 

NASHVILLE, Tenn. — The U.S. Army is having to keep some legacy trainer helicopters in its fleet at the initial entry rotary-wing training schoolhouse and it is generating extra costs, according to the commander of the U.S. Army's Aviation Center of Excellence.

"When you look at having to maintain a TH-67 and OH-58 Kiowa Warrior training helicopters to offset the limited number of [LUH-72A Lakota helicopters] we have, that becomes slightly costly because it’s a legacy fleet with some limitation on the number of spare parts it has," Maj. Gen. William Gayler told reporters Thursday at the Army Aviation Association of America’s annual summit.

"We have to maintain a bit of logistics base to support that aircraft," he said, adding that the original plan was to have a pure fleet of LUH-72As to avoid having to carry multiple kinds of spare parts, among other complications.

As part of the Army’s larger Aviation Restructure Initiative that divested Kiowa Warriors and replaced them with AH-64 Apache helicopters teamed with Shadow unmanned aircraft systems, the service also decided to divest its TH-67 single-engine trainers and replace them with dual-engine Lakotas already in the Army inventory.

Several companies like Bell Helicopter and AgustaWestland were hoping at the time to sell military training helicopters to several services, including the Army.

In part, the Army is having to keep the TH-67 trainer aircraft in the fleet due to a years-long lawsuit. The Army is unable to comment on pending lawsuits and Gayler did not address the lawsuit during the briefing with reporters.

AgustaWestland sued the U.S. Army in September 2014, filing a premature complaint over a standard sources-sought notice the Army issued. The service was seeking those capable of building Lakota helicopters in preparation to buy more of the aircraft for the training fleet. The Army needed just 16 more aircraft to complete the training fleet.

The case dragged out in court until August 2016, when the court rendered its opinion issuing injunctive relief for AgustaWestland, meaning the Army could not move forward with its planned helicopter purchase.

The Army has appealed the U.S. Court of Federal Claims' ruling to stop the service’s procurement of the 16 Lakotas, arguing that the court overstepped its authority, misinterpreted government procurement terms and requirements, and improperly supplemented the record with outside information irrelevant to making a decision.

The court has yet to make a decision on the Army’s appeal to reverse the lower court’s decision.

For now, Gayler said, Fort Rucker is continuing to train pilots on both the TH-67 and Lakota. The school determines which pilots train on which aircraft based on timing — when aircraft are available as pilots enter the course.

The classes are kept separate, he added, meaning an entire class either trains on the TH-67 or Lakota.

When the Army made the decision to use the Lakota for its training aircraft, it generated quite a bit of backlash from believers in a single-engine training platform. The fear was that it would be too complicated to begin training on a dual-engine aircraft with a glass cockpit, and that the Lakota would be exponentially more expensive to operate.

But according to Gayler: "What we have noticed thus far is that the Lakota is a tremendous platform to instruct our primary flight training, our initial entry rotary-wing training. It is much easier for a student and young aviator to kind of progress through the primary tasks because the airframe is not as difficult to learn to fly as the legacy aircraft is."

The aircraft also makes it easy to transition into other helicopters because all of the other aircraft in the Army’s fleet are dual-engine, so there’s no need to teach the transition between a single-engine aircraft and a multi-engine one, Gayler explained.

"Everyone that I’ve asked has commented on the speed at which a young aviator learns tasks because they are not necessarily wrestling the aircraft to kind of keep it in one spot," he said. "It’s very stable."

The Army has yet to see the true cost of the airframe for the training mission, but "right now it seems to be relatively low," Gayler said. "But overtime, these aircraft are going to probably fly significantly more than our aircraft fleets do. It’s just the nature of our business."