Female soldiers carry out a ruck march in 2011 at Fort Bragg, N.C., during the Cultural Support Assessment and Selection program, which identified women to serve alongside elite U.S. soldiers with U.S. Army Special Operations Command in cultural support teams in war zones. (Photo by Staff Sgt. Russell Klika/ U.S. Army)

Kara Hultgreen and Carey Lohrenz were about to make history. As naval officers and aviators in 1994, they were part of the first class of female fighter pilots in the history of the Navy, and preparing to fly the legendary F-14 Tomcat in combat from an aircraft carrier deploying to the Persian Gulf.

Within months, however, virtually everything went wrong. Hultgreen, a lieutenant who used the call signs “Hulk and “Revlon,” died off the coast of San Diego as her jet crashed Oct. 25, 1994, during training on a final approach to land on the USS Abraham Lincoln. Investigators attributed the incident to engine trouble and pilot error.

Lohrenz, a lieutenant who used the call sign “Vixen,” exhibited below-average performance in the following months as the Abraham Lincoln crossed the Pacific, according to personnel records leaked to the media at the time and a subsequent inspector general investigation. Her commanding officer eventually disqualified her from flying in 1995 while at sea.

Their struggles are a dark spot in naval history. The investigation, prompted by a complaint from Lohrenz’s family, found that female fighter pilots received accelerated training to send them to carrier squadrons before they may have been ready. They also faced open hostility from some males pilots and a crush of media attention that, in Lohrenz’s case, adversely affected her ability to fly, the investigation found. In addition, female pilots on the Abraham Lincoln also were ordered to undergo numerous pregnancy tests, infuriating some of them.

The case, outlined in an inspector general report released in 1997, underscores the challenges the Pentagon faces now as it prepares to open all ground combat jobs by April 1 following a landmark this month by Defense Secretary Ashton B. Carter. Many cultural issues have been raised in ground units that could complicate the integration effort, according to documents newly released by the Pentagon last weekend.

About 110,000 more jobs across the services will be opened with the move — 10 percent of the active-duty force. The jobs are primarily in the Army and Marine Corps, with some Special Operations jobs in the other forces — Navy SEAL and Air Force pararescueman, for example. The services must submit implementation plans for how they will do carry out integration by January, with the work to begin no later than April.

A U.S. Army Special Forces soldier fires an M240 machine gun April 22, 2015, at a firing range in Camp Shelby, Miss. (Photo by Staff Sgt. Osvaldo Equite/ Army)

Many men in ground combat jobs remain deeply skeptical that combat effectiveness will remain the military’s top priority as the integration occurs, according to the documents, which were releasesd just days after Carter’s announcement.

study completed for U.S. Special Operations Command this year by the Rand National Defense Research Institute found that opposition to opening all jobs to women is “deep-seated and intensely felt” among all types of Special Operations forces, mostly due to the belief that it will compromise combat effectiveness.

One unidentified Navy SEAL officer, when asked if women should be allowed to earn Naval Special Warfare Command’s coveted “SEAL Trident” decoration, offered an apparently sarcastic alternative.

“No,” he said, according to the Rand report. “They could get a mermaid with two guns crossed.”

Overall, 85 percent of those polled were opposed to letting women into their jobs, and 71 percent opposed letting women in their unit. The interviews were carried out in summer 2014.

Another document in the trove released by the Pentagon details the effort this year at the Army’s Ranger School, where women were allowed to attend for the first time as the Army examined how to better integrate them in combat. Nineteen women started the class beginning in April, with three ultimately completing all requirements and graduating.

[After historic graduation, Army removes all restrictions on women attending Ranger School]

The Ranger School’s assessment said that that while the female students generally felt they were treated fairly, some Ranger instructors — all men, and frequently combat veterans — said they were frustrated when it seemed like the Army did not trust them to act professionally in evaluating women. They also did not like the presence of female soldiers who were brought in by the Army as “observer/advisers” to assist in the effort.

Instructors, the assessment said, “also reported that repetitive senior leader visits did not set positive conditions. Additionally, [they] felt pressure from outside infantry peers to maintain standards and ‘hold the line’ with respect to female students. Evidence suggests that the perception of ubiquitous attention potentially led many [instructors] to overly adhere to grading rules and regulations to avoid scrutiny.”

Maj. Lisa Jaster — who eventually became one of the first three women to graduate the Army’s Ranger School — carries another soldier on her back at Fort Benning, Ga., on April 26. (Photo by Spec. Dacotah Lane/ U.S. Army)

A spokesman for the Army, Brig. Gen. Malcolm Frost, said the service does not want to address specifics in the newly released studies until each of the services develop recommendations for how to integrate women. Senior Army leaders, including Chief of Staff Gen. Mark A. Milley, said in a memo released last week that military readiness is the service’s top priority, and integrating women into all jobs can improve it if done correctly.

The Marine Corps, meanwhile, has demonstrated the most institutional opposition to allowing women into all combat jobs. Its former commandant, Gen. Joseph F. Dunford — since promoted to become chairman of the Joint Chiefs of Staff — was the only service chief to advise against integrating all jobs in his recommendation to Carter. The new commandant, Gen. Robert B. Neller, said in a short video released Dec. 5 that the service would immediately begin planning for integration while maintaining its standards and maximizing the skills of all Marines.

“We have a decision,” Neller said. “It’s time to move out.”

[Navy secretary criticizes controversial Marine Corps gender integration study]

Marine Sgt. Maj. Justin LeHew, an Iraq War veteran who earned awards for valor and was previously critical of opening all jobs to women, said “folks can stop bitching about the decision that was made and focus now on making it work — that’s what Marines do.”

It has been disheartening, LeHew said, to see negative comments directed at women who serve since Carter’s decision was announced.

“When it comes right down to it,” LeHew said, “I would much rather fight with a female warrior than a male coward any day of the week.”

The sergeant major said he believes the Marine Corps will now focus on making sure women who gravitate toward jobs in combat get the best and most challenging training possible to increase their ability to survive and fight on the battlefield.

“Combat effectiveness means her place in the line needs to be as solid as any other place in the line, and I am going to do everything in my power on my watch to make her the fastest, strongest, most agile, most resilient and most lethal female warrior that the world has ever seen in these newly opened combat arms fields,” LeHew said. “To do anything less is un-Marine like and quite frankly, un-American.”

Marine Cpl. Jacklyn Dean, a female mortarman, secures an 81mm medium-weight mortar at Twentynine Palms, Calif., during a gender integration evaluation the Marine Corps ran this year.  (U.S. Marine Corps photo by Cpl. Paul S. Martinez/Released)

Marine Maj. Katelyn van Dam, a Cobra attack helicopter pilot in the Reserve who deployed to Afghanistan in 2011 and campaigned for the opening of all jobs to women through an effort known as No Exceptions, said she would have been “over the moon” if she had been able to become part of a ground combat unit when she joined the Marine Corps in 2006. But she added that work will need to be done to change the culture.

“I don’t dismiss concerns, because there is change and change can be scary,” she said. “What I do dismiss is when people are so overwhelmed by their concerns that they think that they can’t be overcome. That’s silly to me. They’re not looking for a solution. They’re just stuck being concerned.”

That was the case for some service members in the 1990s, too — but the pressure on Hultgreen and Lohrenz also went unaddressed by too many people in their unit, according to the inspector general investigation. Lohrenz, who came from a family of military officers, joined Carrier Air Wing 11 in San Diego after finishing in the top 10 percent of her class in flight school, but struggled to adjust to life in an operational squadron amid intense media interest and concerns about her ability to her job from some colleagues, investigators found.

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“Those who did not correctly associate aspects of LT Lohrenz’s conduct, behavior and and performance with symptoms of stress failed to take effective action to address her problems because she assured them that she could cope without any assistance,” the IG report said. “They did not give sufficient consideration to the real possibility that a new pilot, trying to prove herself, would likely be hesitant to admit that she could not deal with, or compartmentalize, her stress.”

Lohrenz was allowed to fly again in 1997, although never again from aircraft carriers. She left the Navy in 1999, and now works as a motivational speaker. She declined several requests for an interview, but referred The Post to a 2013 piece she wrote for Time magazine in which she argued that strong leadership will be needed to effectively integrate ground combat units with women.

“Being one of the first women to fly a combat fighter aircraft, I quickly learned to recognize the difference between effective, fearless leadership and poor leadership,” she wrote. “Strong leaders do not permit witch hunts, react emotionally to problems that surface in the media, or ‘slow-roll’ policy implementation.”

The former commanding officer of the carrier wing, retired Navy Capt. Dennie Gillespie, said in a phone interview that it was difficult integrating Hultgreen and Lohrenz in his unit because they were not ready to fly off aircraft carriers. He added that he was not perfect in how he handled integration, but does not regret grounding Lohrenz.

Gillespie said his unit was under “tremendous pressure” to integrate women, regardless of their qualifications, something he fears will happen to ground combat units now too.

“I fear that the politics of Washington will put people in harm’s way,” he said. “If the team is weakened, the whole operation is weakened. And I’m not saying that a woman will weaken the team. But, they better be damned sure that the people they put out there do the job in uncompromising fashion.”

Hultgreen’s mother, Sally Spears, said that her daughter, who died at 29, would be gratified to see women have the chance to keep compete for jobs that have always been closed. But she predicted that it will be difficult “to change a lot of people’s minds, particularly men who have served for a long time.” The problems that might occur, she said, could be very similar to what happened in 1994 and 1995.

“I don’t understand why people would be opposed to giving someone who is physically and mentally qualified a chance to compete for a job,” Spears said. “That’s all these women are asking for. They’re asking for the chance to compete.”

Julie Tate contributed to this report.